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Nebraska and South Dakota

Cooperative Extension Service / South Dakota State University and University of Nebraska / U.S. Department of Agriculture

Nebraska Cooperative Extension EC 95-273-CESS 38

SWINENUTRITION GUIDE

Table of ContentsIntroduction .................................................................................................................................................................................. 1

Nutrient Sources .......................................................................................................................................................................... 1Energy .................................................................................................................................................................................... 1Protein and amino acids ...................................................................................................................................................... 4Minerals ................................................................................................................................................................................. 7Vitamins ................................................................................................................................................................................. 9

Bioavailability............................................................................................................................................................................... 9

Nutrient Interactions ................................................................................................................................................................... 10

Ingredient Quality ....................................................................................................................................................................... 12

Feed Additives ............................................................................................................................................................................. 14

Feed Processing ............................................................................................................................................................................ 18

Water .............................................................................................................................................................................................. 19

Feed Intake.................................................................................................................................................................................... 20

Health ............................................................................................................................................................................................ 22

Nutrient Recommendations ....................................................................................................................................................... 22

Practical Applications and Outcomes ....................................................................................................................................... 27Breeding Herd Management............................................................................................................................................... 28Growing Pig Management .................................................................................................................................................. 31Example Diets ....................................................................................................................................................................... 32

Tools for Quantifying Performance ........................................................................................................................................... 34

Methods of Supplying Nutrients ............................................................................................................................................... 37

Conversion Factors, Abbreviations and Symbols ................................................................................................................... 40

Index .............................................................................................................................................................................................. 41

Additional Information Sources ................................................................................................................................................ 42Issued July 2000

5,000 copies

Duane E. Reese, Extension Swine Specialist, University of NebraskaRobert C. Thaler, Extension Swine Specialist, South Dakota State University

Michael C. Brumm, Extension Swine Specialist, University of NebraskaAustin J. Lewis, Professor, Swine Nutrition, University of Nebraska

Phillip S. Miller, Associate Professor, Swine Nutrition, University of NebraskaGeorge W. Libal, Professor Emeritus, Swine Nutrition, South Dakota State University

We appreciate the contributions of the following people for their assistance in preparing this publication.

Industry AdvisorsDonnie R. Campbell, Roche Vitamins Inc.

Richard P. Chapple, Purina Mills, Inc.W. F. Nickelson, Livestock Nutrition & Management Services

Wayne L. Stockland, Consolidated Nutrition, L. C.Bob Woerman, Land O’Lakes/Harvest States Feed

Additional ReviewerC. Ross Hamilton, Darling International

The University of Nebraska and South Dakota State University are solely responsible for the content of this publication.No endorsement of these firms is intended, nor a discredit to any one omitted from the list.

This publication is available at: <http://ianrwww.unl.edu/pubs/swine/ec273.htm>.

Figure 1. Factors that were considered when developing nutrient recommendations.

SafetyMargin

NutrientInteractions

Genotype&

Productivity

FeedIntake Water Feed

ProcessingAlternativeFeedstuffs

NutrientBioavailability

Economics Health

Industry advisors representingvarious facets of the pork industrywere recruited to review and chal-lenge the concepts incorporated inthis publication. Also, in situationswhere “gray areas” existed, theseindustry representatives madespecific proposals or recommenda-tions. Therefore, our ultimate goalwas to use the knowledge ofrespected swine nutritionists whorepresent a cross section of the feedindustry to improve the applicationof this publication. In preparingthis publication, a priority has beento discuss some of the controversialand experimental swine nutritionissues currently being explored.The discussion of these issues hasbeen focused to emphasize resultspresented in the scientific litera-ture.

Introduction

This publication is a revision ofthe previous swine nutrition publi-cation prepared by the Universityof Nebraska and South DakotaState University. The focus of thepublication continues to be onnutrient recommendations forswine. Specific factors (nutritional,environmental and managerial)that affect nutrient recommenda-tions (Figure 1) have been consid-ered and discussed. We believe thatthe identification and descriptionof the factors in Figure 1 providethe framework for the nutrientrecommendations presented inTables 11 to 16.

Nutrient Sources

An essential part of a soundfeeding strategy is to make gooddecisions on which ingredients touse in the diet. Ingredients providenutrients that pigs require for nor-mal performance. Pigs do notrequire specific ingredients in theirdiet, but instead require energy andnutrients such as amino acids,minerals and vitamins. There arenumerous ingredients available touse in pig feed. Information in thissection is intended to help peoplemake good decisions on sources ofnutrients.

Energy

Pigs need energy for mainte-nance, growth, reproduction and

FeedAdditives

GovermentRegulations

ManureManagement

FeedIngredient

Quality

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Table 1. Relative feeding values and maximum usage rates of energy sources. A * denotes no nutritional limitations in a balanced dieta

Maximum recommended percent of complete dietsb

Ingredient (as-fed) Feeding value relative to corn, %c Starter Grow-finish Gestation Lactation

Alfalfa meal, dehy 70 to 80 0 10 25 0

Alfalfa hay, early bloom 65 to 75 0 10 60 0

Bakery waste, dehy 110 to 120 * * * *

Barley (48 lb/bu) 90 to 100 25 *d * *e

Beet pulp 80 to 90 0 10 50 10

Corn distillers grains w/solubles, dehy 110 to 120 5 15 40 10

Corn gluten feed 95 to 105 5 10 * 10

Corn, high lysine 100 to 110 * * * *

Corn, high oil 100 to 110 * * * *

Corn, hominy feed 95 to 105 0 60 60 60

Corn, yellow (> 40 lb/bu) 100 * * * *

Fats/oils (stabilized) 190 to 200 5 5 5 5

Millet, proso 85 to 95 40 * * 40

Milo, grain sorghum (> 48 lb/bu) 95 to 97 * * * 40

Molasses (77% DM) 55 to 65 5 5 5 5

Oats (38 lb/bu) 85 to 95 15 30 * 10

Oats, high lysine 85 to 95 30 60 * 10

Oat groats 110 to 120 * * * *

Ryef 85 to 95 0 25 20 10

Triticalef,g 95 to 105 20 40 40 40

Wheat bran 80 to 90 0 10 30 10

Wheat, hard (> 55 lb/bu)h 100 to 110 30 * * 40

Wheat middlings 110 to 120 5 25 * 10

aAssumes diets are balanced for essential amino acids, minerals and vitamins.bHigher levels may be fed although performance may decrease. Economic considerations should influence actual inclusion rates.cCorn = 100%. Values apply when ingredients are fed at no more than the maximum recommended % of complete diet. A range is presented tocompensate for quality variation.dFor maximum performance, limit barley to 2/3 of the grain for 45 to 130 lb pigs. No limitation for pigs > 130 lb.eIncreased fiber in barley will reduce the ME/lb of feed. Thus, less should be used when feed intake is low.fErgot free.gLow trypsin inhibitor varieties. Feed value tends to be highly variable.hCoarsely ground. See the Feed Processing section for details.

lactation. The bulk of the pig’senergy requirement is met bycarbohydrates and fats. Fats andoils are dense sources of energy,containing about 2.25 times morecalories than carbohydrates. Theenergy content of feedstuffs andenergy requirements of pigs arecommonly expressed as metaboliz-able energy (ME). The ME contentof a feedstuff is determined by sub-

tracting energy lost in the feces,urine and gasses from the grossenergy in the feedstuff.

Although many cereal grains canprovide economical sources of energyfor pigs in the Midwest, corn is usedextensively in Nebraska and SouthDakota. However, economic condi-tions can change, making otherenergy sources attractive for inclusionin pig diets.

How does one know whetheranother energy source is moreeconomical?

Focus on the relative feedingvalue of energy sources shown inTable 1 rather than on achieving acertain feed efficiency or growthrate when evaluating alternative en-ergy sources. Substituting milo forcorn, for example, likely will reducefeed efficiency, but may reduce the

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cost of gain also. The feeding valueswere calculated using the ME, di-gestible lysine and available phos-phorus content of feedstuffs. Corn,soybean meal (44% CP) anddicalcium phosphate were used asreference feedstuffs. Corn is as-sumed to have a feeding value of100%. Grain sorghum (milo), for ex-ample, has a feeding value about95% that of corn. Thus, milo can re-place corn in the diet when theprice of milo is less than 95% of theprice of the same weight of corn.For example, if corn costs $.04/lb,milo would become more economi-cal to feed when it is less than$.038/lb ($.04/lb x .95 = $.038/lb).The feeding value of milo is slightlyless than that of corn because it hasless ME and digestible lysine.

The relative feeding valuesapply when ingredients are in-cluded in diets in quantities nogreater than those shown in Table1. When ingredients are included indiets at lower levels than indicatedin Table 1, the feeding value mayincrease slightly. Average daily gainand reproductive performance willnot normally be reduced by replac-ing corn with any of the energysources at the levels shown in Table1. A range in feeding value is pre-sented to account for variation iningredient quality and individualproducer goals. Also, be sure toconsider factors such as storagecosts and ingredient quality andavailability.

Is carcass backfat affected byusing alternate energy sources?

Backfat thickness may decreaseby up to .1 inches when oats, bar-ley, or other lower energy ingredi-ents replace all the corn in the dietif fat is not added to make the dietsisocaloric. Details on how addedfat affects backfat are presented inthe Practical Applications and Out-comes section of this publication.The fatty acid profile of backfat ismade slightly more unsaturatedwhen high-oil corn, full-fat soy-beans and vegetable oils are

included in the diet of finishingpigs. There has been no evidencethat this has contributed to “softpork” or a loss of carcass value.However, feeding more than 10%whole sunflower seeds to finishingpigs will result in “soft pork.”Adjustments for possible changesin carcass merit have not beenmade in the feeding values shownin Table 1.

How should alternate energysources be included in the diet?

Two methods are acceptable.Check Table 1 to see if there is asuggested limitation on the quan-tity of the ingredient to include inthe diet. The first method is toreformulate the diet on a total ordigestible lysine basis. Formulatingon a digestible lysine basis is moreprecise. The advantage of formulat-ing on a lysine basis is that theadditional lysine in wheat and bar-ley, for example, can be takenadvantage of. This means lesssupplemental protein is needed inthe diet. Check the tryptophan,threonine and methionine levels ofthe diet during formulation toensure they are adequate. The sec-ond method is to substitute thealternate energy source for corn ona pound-for-pound basis in thediet. This procedure is acceptablefor all energy sources in Table 1,except fat and molasses. Theseenergy sources contribute no pro-tein or amino acids to the diet, sothe diet must be reformulated. Donot formulate diets on a proteinbasis because the diet may be defi-cient in lysine, resulting in reducedpig performance.

What sources of fat areavailable?

Common sources of animaland vegetable fat and their MEvalues are listed in Table 29. Alsoavailable are blended combinationsof animal fat, vegetable oil andrefined or rerendered restaurantgrease.

Animal fat and soybean oil arethe most common fat sources usedin swine diets. Animal fats in theMidwest generally include tallow,choice white grease and yellowgrease. These are solid at roomtemperature and must be heated toabout 140 to 150oF before they canbe blended into the diet. In con-trast, vegetable oils are liquid atroom temperature and can beadded to the diet without heating.Also, in general, oils are preferredover animal fat in diets for pigsweighing less than 15 lb.

Fats are available in a variety offorms including fats contained incomplete diets, commercial supple-ments, dried fat products, whole soy-beans and high-oil corn, in additionto fats obtained directly from refin-ers and renderers. Probably the easi-est method of incorporating fat indiets made on the farm is to use full-fat soybeans or high-oil corn. Dietsthat contain full-fat soybeans as thesole supplemental protein source pro-vide 3 to 4% extra fat. High-oil corn-soybean meal diets also contain 3 to4% additional fat. Fat that is addedto a swine diet should be stabilizedwith an antioxidant or preservative(e.g. BHT, BHA, or ethoxyquin) toavoid rancidity.

Are some energy sources bettersuited for pigs in the summerthan winter?

Yes. Fat will improve pig per-formance more when provided inthe summer than in the winter. Lessheat is produced by pigs when theydigest fat compared with starch orfiber. This allows pigs fed dietswith added fat to continue to con-sume large amounts of energy dur-ing hot weather when feed intake isnormally reduced. Thus, fat is gen-erally more cost effective when fedin the summer than in the winter.In contrast, when low-energy, high-fiber feedstuffs such as alfalfa, bar-ley and oats are digested by pigs,heat production is increased. Thisextra heat can be used to help main-tain body temperature during the

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winter. Energy sources with a highfiber content are therefore more costeffective for pigs fed during winterthan summer.

Does low protein corn have alower feeding value than normalcorn?

Not likely. Results from severalstudies indicate that the relation-ship between the crude proteincontent and lysine content of cornis poor. Thus, corn containing 7 to7.5% CP may have the sameamount of lysine as 8.5% CP corn.The lack of a good correlation be-tween corn crude protein andlysine content indicates that oneshould not automatically increasethe amount of protein supplementor crystalline lysine in the dietwhen using low protein corn.Moreover, in a 1994 study of cornproduced in the Midwest, 77% ofthe samples contained between .23and .28% lysine. If the lysine con-tent of corn in a finisher diet for-mulated to contain .65% lysineranges from .23 to .28%, the lysineconcentration in the complete dietranges from only .63 to .67%.

Protein and AminoAcids

Pigs of all ages and stages ofthe life cycle require amino acids toenable them to grow and repro-duce. Amino acids are the struc-tural units of protein. Duringdigestion, proteins are brokendown into amino acids and pep-tides. The amino acids and pep-tides are absorbed into the bodyand are used to build new proteins,such as muscle. Thus, pigs requireamino acids, not protein. Diets thatare “balanced” with respect toamino acids contain a desirablelevel and ratio of the 10 essentialamino acids required by pigs formaintenance, growth, reproductionand lactation. Those 10 essentialamino acids for swine are arginine,histidine, isoleucine, leucine, lysine,

methionine, phenylalanine, threo-nine, tryptophan and valine. Theproteins of corn and other cerealgrains are deficient in certain essen-tial amino acids. Protein supple-ments are used to correct the aminoacid deficiencies in grains. Forexample, the correct combinationof grain and soybean meal providesa good balance of amino acids.

Soybean meal is often the mosteconomical source of amino acidsfor pigs in Nebraska and SouthDakota. However, economic condi-tions can change, making alterna-tive amino acid sources attractivefor use in pig feed.

How does one determinewhether another source of aminoacids is more economical?

Use the relative feeding valueof amino acid sources shown inTable 2 when considering alterna-tive amino acid sources. Thesefeeding values were calculatedusing the ME, digestible lysine andavailable phosphorus content offeedstuffs. Corn, soybean meal (44%CP) and dicalcium phosphate wereused as reference feedstuffs. Soy-bean meal (44% CP) is assumed tohave a feeding value of 100%. Goodquality meat and bone meal, for ex-ample, has a feeding value of 110%of that of soybean meal. Thus, meatand bone meal can replace soybeanmeal in the diet when the price ofmeat and bone meal is less thanabout 110% of the price of the sameweight of soybean meal. For ex-ample, if the meat and bone mealprice is less than about $220/ton, itis a better buy than 44% CP soy-bean meal that costs $200/ton($200/ton x 1.10 = $220/ton).

The relative feeding values ap-ply when ingredients are includedin diets in quantities no greaterthan those shown in Table 2. Aver-age daily gain and reproductiveperformance will not normally bereduced by replacing soybean mealwith any of the amino acid sourcesat the levels shown in Table 2. Arange in feeding value is presented

to account for variation in ingredi-ent quality and individual producergoals. Most amino acid sources arebyproducts and subject to somevariation in quality, because of theprocessing methods used. Also, besure to consider factors such as stor-age costs, handling characteristicsand availability.

Are there differences inuniformity of product amongprotein sources?

Animal protein products varyin composition and quality morethan plant protein sources. Meatand bone meal and meat meal arebyproducts of the meat packing in-dustry, and their composition de-pends on the animals slaughtered.Methods of processing also influ-ence the quality of animal proteins.The rendering process (270 to280oF) is sufficient to kill salmonellaand other bacteria present in theraw material, but through im-proper handling, the renderedproduct can be recontaminanted.Buying animal proteins from a reli-able supplier will reduce the impactof this quality variation on pig per-formance.

Many plant proteins are moreuniform because they are madefrom a single source. Also, methodsof processing plant proteins havebecome standardized, and thesame kind of product can be pro-duced year round. However, im-proper processing can occur in theproduction of soybean meal andother plant proteins. Also, calciumcarbonate (limestone) can be addedto plant protein products (up to.5%) to prevent them from becom-ing lumpy and to maintain goodflow characteristics. The additionalcalcium is no problem as long asone knows how much is in the pro-tein source.

Salmonella contamination tradi-tionally has been associated with ani-mal protein products. However,recent evidence indicates that grainsand plant protein products can alsobe contaminated with salmonella.

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Table 2. Relative feeding values and maximum usage rates of protein and amino acid sources. A * denotes no nutritional limitation in abalanced dieta

Feeding value relative Maximum recommended percent of complete dietsb

to 44% CPIngredient (as-fed) soybean meal, %c Starter Grow-finish Gestation Lactation Comments

Blood meal, spray-dried 220 to 230 3 6 5 5 low in isoleucine

Canola meal 70 to 80 0 15 15 15 antinutritional factors

Corn distillers grains w/solubles, dehy 45 to 55 5 15 40 10 poor amino acid balance

Corn gluten feed 40 to 50 5 10 90 10 high in fiber

Fish meal, menhaden 160 to 170 20 6 6 6 “fishy” taste in pork

Meat and bone meal 105 to 115 * * * * high mineral;low tryptophan content

Meat meal 130 to 140 * * * * high mineral content

Plasma proteins, spray-dried 205 to 215 * * * *

Skim milk, dried 105 to 115 * * * * low fat solublevitamin content

Soy protein concentrate 135 to 145 * * * *

Soybean meal, 46.5% CP, dehulled 105 to 110 * * * *

Soybean meal, 44% CP 100 * * * *

Soybeans, full-fat, cooked 85 to 95 * * * *

Sunflower meal, 36% CPd 55 to 65 0 * * * low in lysine

Whey, dried 55 to 65 30 15 5 5 high in lactose

aAssumes diets are balanced for essential amino acids, minerals and vitamins.bHigher levels may be fed although performance may decrease. Economic considerations should influence actual inclusion rates.c44% CP soybean meal = 100%. Values apply when ingredients are fed at no more than maximum recommended % of complete diet. A range ispresented to compensate for quality variation.dLower protein sunflower meal sources are available. Due to variability in nutrient content, these are not recommended for use in swine diets.

What is meant by digestibleamino acids?

Only a certain proportion ofeach of the amino acids in afeedstuff is digested and absorbedby pigs. Digestibility values for ma-jor amino acids in many feedstuffsare shown in Table 3. To calculatethe digestible amino acid content ofa feedstuff, multiply the total quan-tity of the amino acid in thefeedstuff by its digestibility valuein Table 3. For example, the digest-ible lysine content of 44% CP soy-bean meal containing 2.83% lysineis 2.41% (2.83 x .85). Differences indigestibility can be ignored whenformulating diets that consistprimarily of corn or milo and soy-bean meal (with no byproductingredients). Thus, these diets canbe formulated on a total amino acidbasis. When nontraditional orbyproduct ingredients are used in

feed, it is best to formulate the dieton a digestible amino acid basis.Otherwise, pigs may not performas expected. Digestible lysine rec-ommendations are given in Tables11, 12, 13, 14, and 15.

What is meant by ideal proteinor amino acid balance?

The concept of an ideal proteinor ideal amino acid balance is toprovide a perfect pattern of essen-tial and nonessential amino acids inthe diet without any excesses ordeficiencies. This pattern is sup-posed to reflect the exact aminoacid requirements of the pig formaintenance and growth. There-fore, an ideal protein providesexactly 100% of the recommendedlevel of each amino acid. Althoughstandard diets are usually formu-lated to meet the pig’s requirementfor lysine (the most limiting amino

acid), excesses of many other aminoacids exist. Two practical methodscan provide a more ideal balance ofamino acids in pig feed: Use a com-bination of supplemental proteinsources or formulate the diet withcrystalline amino acids.

Questions often are askedabout whether the excess aminoacids hurt pig performance andwhether reduction or elimination ofthe excesses would improve pigperformance. There is little evi-dence to indicate that the perfor-mance of pigs fed diets containing amore ideal balance of amino acids isbetter or worse than that of pigs fedpractical corn-or milo-soybeanmeal-based diets. However, ifexcess amino acids are reduced,nitrogen excreted through the urineand feces will be reduced, meaningthat less nitrogen is in the manure.This will reduce the amount of land

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Table 3. Apparent digestibility (%) of amino acidsa at the terminal ileumb, c

Ingredient Lys Trp Thr Met Cys

Grains

Barley 68 70 66 80 76

Corn 66 64 69 86 78

Milo 62 75 68 81 79

Oat groats 79 80 76 85 80

Oats 70 72 59 79 69

Rye 64 67 59 76 74

Triticale 76 74 69 85 83

Wheat 73 81 72 85 84

Wheat bran 69 65 60 76 70

Wheat middlings 75 77 69 82 82

Protein Sources

Alfalfa meal, 17% CP 50 39 51 64 20

Blood meal, spray-dried 91 88 86 85 81

Canola meal 74 73 69 82 79

Corn gluten feed, 23% CP 51 47 57 79 53

Dried distillers grains with solubles 47 50 55 72 57

Dried skim milk 91 90 85 92 81

Dried whey 82 78 79 84 86

Feather meal 54 63 74 65 71

Fish meal, Menhaden 89 79 85 88 73

Meat and bone meal 74 60 70 79 55

Meat meal 83 73 79 85 55

Plasma proteins, spray-dried 87 92 82 64 —

Soybean meal, 48.5% CP 85 81 78 86 79

Soybean meal, 44.0% CP 85 80 78 86 77

Soybeans, extruded 81 75 77 78 76

Sunflower meal, 42% CP 74 76 71 87 74

aAmino acid abbreviations: Lys = lysine, Trp = tryptophan, Thr = threonine, Met = methion-ine, and Cys = cystine.bMost common ingredients are in bold-italic.cFrom NRC. 1998. Nutrient Requirements of Swine. 10th Edn. National Academy Press,Washington, DC.

required to properly manage thenitrogen in the manure. Unlessthere is a strong incentive to reducenitrogen in the manure, choosesources of amino acids that will pro-duce the lowest cost gain.

How should alternate aminoacid sources be included in thediet?

Check Table 2 to see if there is asuggested limitation on the quan-tity of the ingredient to include inthe diet. Then reformulate the diet

on a total or digestible lysine basisand check that the tryptophan,threonine and methionine levels areadequate. Formulating on a digest-ible lysine basis is the most precise.Do not formulate diets on a proteinbasis because the diet could bedeficient in lysine and (or) otheramino acids, resulting in reducedpig performance.

When is it economical to usecrystalline amino acids in swinediets and how can they be used?

It depends on the price of thecrystalline amino acids and theprices of grain and supplemen-tal protein sources. The use ofL-lysine•HCl as a source of crystal-line lysine is often economicallysound. Crystalline methionine iscommercially available and inex-pensive. Crystalline tryptophanand threonine can be purchased infeed-grade forms, but currentlythey are rather expensive. Crystal-line lysine and tryptophan togetherin the same source is now commer-cially available. Other sources com-bining these crystalline amino acidsas well as others may be developedin the future.

Three pounds of L-lysine•HCl(containing 78% pure lysine) plus97 lb of corn contribute the sameamount of digestible lysine as 100lb of 44% CP soybean meal. IfL-lysine•HCl is used, one mustmonitor dietary tryptophan, threo-nine and methionine levels andmaintain sufficient intact protein(e.g., soybean meal) in the diet tomeet the requirements for theseamino acids. Greater reductions ofintact protein may be possiblewhen using products containingboth crystalline lysine andtryptophan. As when addingL-lysine•HCl, monitor dietarythreonine and methionine levelswhen using these products. Thelevel of crystalline amino acidssupplemented will depend on thefeeds used in the formulation andis usually dependent on the secondlimiting amino acid. That aminoacid changes depending on theingredients used. In most swinediets lysine is first limiting andeither tryptophan or threonine issecond limiting. However, startingpig diets containing large amountsof plasma proteins and blood mealneed to be supplemented withcrystalline methionine.

Use caution when consideringcrystalline amino acids as substi-tutes for intact protein in gestationor lactation diets. Gestating sowsare usually fed once per day, and re-

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search in limit-fed pigs indicatesthat crystalline amino acids areused less efficiently than they arewhen pigs consume feed severaltimes per day. There is evidencethat in some circumstances lacta-tion diets can be co-limiting inlysine and another amino acid(s).In these circumstances, replace-ment of intact protein with lysinealone could lead to a deficiency ofother amino acids. An amino aciddeficiency causes reduced litterweight gain and sow lactation feedintake.

A factor not traditionally con-sidered when evaluating the use ofcrystalline amino acids in swinediets is nitrogen content of themanure. As stated previously,reducing excess amino acids willresult in a decrease in the nitrogencontent of the manure. When incor-porated properly, the use of crystal-line amino acids will accomplishthat without affecting growth per-formance. This means the producerneeds fewer acres to spread themanure on and potentially lessodor.

To ensure proper distribution inthe complete feed, amino acidsmust be combined with a carrier toachieve a minimum volume beforethey are added to the mixer (seeFeed Processing section).

Can soybean meal serve as thesole source of supplementalprotein in the diet?

Yes, but only for pigs heavierthan about 25 lb. Younger, lighterpigs have a reduced ability to usethe complex proteins found in soy-bean meal. In addition, startingpigs may develop an allergic reac-tion to certain proteins in soybeanmeal, causing difficulty in digestingand utilizing feed. It is desirable toinclude less allergenic, highlydigestible amino acid sources indiets for starting pigs; for example,spray-dried plasma proteins andblood meal, menhaden fish meal,dried whey, and(or) soy proteinconcentrate, although soybean meal

would be a less expensive source ofamino acids.

Minerals

Minerals serve many importantfunctions in pig nutrition. Theserange from structural functions inbone to a wide variety of chemicalreactions essential for maintenance,growth, reproduction and lactation.Pigs require at least 13 minerals. Ofthese calcium, chloride, copper,iodine, iron, manganese, phospho-rus, selenium, sodium and zincshould routinely be added to thediet. Practical corn-or milo-soybeanmeal based diets contain sufficientlevels of magnesium, potassiumand sulfur.

What are the major sources ofminerals for swine?

Major sources of the mineralscommonly added to swine diets arelisted in Table 4. In addition, therelative bioavailability of mineralsfrom several sources are listed inthe table to ensure precise diet for-mulation. Base decisions on whichsource of trace mineral to use pri-marily on price per unit of availableelement. The use of selenium in ani-mal feeds is regulated by the FDA.

What is meant by availablephosphorus?

Like amino acids, a certain pro-portion of the phosphorus in afeedstuff cannot be used by pigs.Most of the phosphorus in cornand other feed grains, soybeanmeal, oilseed meals and otherbyproducts of seed origin occurs asthe organic complex phytate. Phos-phorus in this form is poorly avail-able to pigs because they lack theenzyme phytase, which releases thephosphorus. Research indicatesthere are large differences in phos-phorus availability among feed-stuffs. In the most precise type ofdiet formulation, adjustments aremade for these differences. That is,diets are formulated on an availablerather than total phosphorus basis.

When diets contain primarily cornor milo and soybean meal it is ap-propriate to formulate them on atotal phosphorus basis. However,when nontraditional or byproductingredients are used in pig feed,formulate the diets on an availablephosphorus basis. See Tables 11, 12,13, 14 and 15 for available and totalphosphorus recommendations forcomplete feeds. Table 29 containsthe available phosphorus content ofseveral ingredients.

Supplementing swine dietswith phytase has been effective inimproving the availability of phos-phorus in corn and soybean meal.This means less inorganic phos-phorus (e.g., from dicalciumphosphate) is needed in the diet,resulting in less phosphorus in themanure. While most manure man-agement plans are based on nitro-gen, there is increasing interest inbasing them on phosphorus. This isin an effort to decrease phosphorusbuildup in the soil, and to reducethe potential for phosphorus run-off into lakes and rivers. However,land requirements for a phospho-rus-based swine manure manage-ment plan are at least twice thatrequired for a nitrogen-based plan.Therefore, depending on the cost ofmanure application and whetherthe manure management plan isbased on nitrogen or phosphorus,the use of phytase in swine dietsmay be economical.

The development of low phy-tate phosphorus varieties of corn isanother method producers can useto reduce phosphorus excretionand use of inorganic phosphorus.Preliminary data indicate that theuse of these varieties can reducephosphorus excretion and the useof inorganic phosphorus and mayimprove the digestibility of othernutrients. However, factors such asyield drag, cost of raising the crop,etc, must be considered whendeciding whether to use lowphytate phosphorus corn.

What are chelated or

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Table 4. Mineral sources and bioavailabilitiesa,b

Content ofMineral element,element Source Formula % RB, %b Comments

Calcium Calcium carbonate CaCO3 38.5 90 to 100 LimestoneOyster shell

Curacao phosphate 35.1 Unkd

Defluorinated rock phosphate 32 90 to 100 < 1 part F to 100 parts PDicalcium phosphate CaHPO4•2H2O and

CaHPO4 20 to 24 90 to 100 Grey granules

Monocalcium phosphate CaH4(PO4)2•H2O 17 90 to 100Soft rock phosphate 16 70 Colloidal phosphateSteamed bone meal 29.8 Unk

Copper Cupric acetate Cu(C2H3O2)2 100Cupric carbonate CuCO3•Cu(OH)2 50 to 55 60 to 100 Dark-green crystalsCupric chloride, tribasic Cu2(OH)3Cl 58 100 Green crystalsCupric oxide CuO 75 0 to 10 Black powder or granules;

not recommended as acopper supplement

Cupric sulfate CuSO4•5H2O 25.2 100 Blue or ultramarine crystals

Iodine Ethylenediaminedihydroiodiode (EDDI) NH2CH2CH2NH2•2HI 79.5 100 White

Calcium iodate Ca(IO3)2 64.0 100 Stable source

Potassium iodide KI 68.8 100 Used in iodized salt (.01%)

Iron Ferric chloride FeCl3•6H2O 20.7 40 to 100Ferric oxide Fe2O3 69.9 0 Red - used as a coloring

pigment; not recommendedas an iron supplement

Ferrous carbonate FeCO3 38 15 to 80 BeigeFerrous fumarate FeC4H2O4 32.5 95 Reddish-brownFerrous oxide FeO 77.8 Unk Black powderFerrous sulfate (1 H2O) FeSO4•H2O 30 100 Green to brown crystalsFerrous sulfate (7 H2O) FeSO4•7H2O 20 100 Greenish crystals

Manganese Manganous dioxide MnO2 63.1 35 to 95 Black powderManganous carbonate MnCO3 46.4 30 to 100 Rose-colored crystalsManganous chloride MnCl2•4H2O 27.5 100 Rose-colored crystalsManganous oxide MnO 60 70 Green to brown powderManganous sulfate MnSO4•H2O 29.5 100 White to cream powder

Phosphorus Curacao phosphate 14.2 40 to 60Defluorinated rock phosphate 18 85 to 95 < 1 part F to 100 parts PDicalcium phosphate CaHPO4•2H2O

and CaHPO4 18.5 95 to 100 Grey granulesMonocalcium phosphate CaH4(PO4)2•H2O 21.1 100Monosodium phosphate NaH2PO4•H2O 24.9 100 Large white crystalsSoft rock phosphate 9.1 30 to 50Steamed bone meal 12.5 80 to 90

Selenium Sodium selenate Na2SeO4•10H2O 21.4 100 White crystalsSodium selenite Na2SeO3 45 100 White to light pink crystals

Zinc Zinc carbonate ZnCO3 56 100 White crystalsZinc oxide ZnO 72 50 to 80 Grayish powderZinc sulfate (1 H2O) ZnSO4•H2O 35.5 100 White crystalsZinc sulfate (7 H2O) ZnSO4•7H2O 22.3 100

aMost common sources are in bold-italic.bFrom NRC. 1998. Nutrient Requirements of Swine. 10th Edn. National Academy Press, Washington, DC.cRB = relative bioavailability. Values are expressed relative to the bioavailability in the most common source.dUnk = unknown.

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proteinated trace minerals?Trace minerals generally are

added to swine diets as inorganicsalts, such as copper sulfate, ironsulfate, zinc oxide, etc. Chelatedforms of some trace minerals havebecome available. Trace mineralsare bound to a compound such as aprotein or individual amino acid toform a chelate (e.g. zinc-methionineand iron-lysine). The chelate isdesigned to enhance the absorptionof the trace mineral from the smallintestine. Research in pigs, how-ever, has demonstrated that thebioavailability of the minerals inchelated forms is not alwaysgreater and is sometimes lowerthan the bioavailability of elementsin inorganic salts. Usually theinorganic forms of trace mineralsare most economical.

How important are dietaryelectrolytes?

Electrolytes (minerals) are essen-tial to maintaining water balance inpigs. Electrolyte balance is particu-larly important for starting pigs,because they are more susceptible todiarrhea, which can cause severedehydration. The major elementsinvolved in electrolyte balance aresodium, chloride, potassium, magne-sium and calcium, but sodium, chlo-ride and potassium predominate. Wedo not recommend including electro-lytes in swine diets at levels exceed-ing those shown in Tables 11, 12, 13,14, 15 and 16 even in times of stress,such as those associated with wean-ing and feeder pig sales and trans-fers.

Vitamins

Vitamins are organic com-pounds that are required in verysmall amounts for maintenance,growth, reproduction and lactation.Some vitamins (thiamin, vitaminB6, and vitamin C) probably do notneed to be included in the dietbecause they are synthesized fromother compounds in the body or by

microorganisms in the digestivetract, or grain-soybean meal dietscontain sufficient amounts to meetthe pig’s requirement. Vitamins areclassified as either fat soluble (vita-mins A, D, E and K) or watersoluble. The water soluble vitaminsroutinely added to all swine dietsinclude niacin, pantothenic acid,riboflavin and vitamin B12. In addi-tion, biotin, choline and folic acidroutinely are added to diets forbreeding swine.

Vitamin potency in feed andmanufactured products willdecrease with exposure to light,high humidity, heat, rancid fat andoxygen. Vitamins can be destroyedwhen in contact with minerals overa prolonged period of time. Forbest results, store basemixes andtrace mineral-vitamin premixes in acool, dry, dark place and use themwithin 30 days of purchase.Premixes containing only vitaminscan be stored longer.

What are the major sources ofvitamins for pigs?

Major sources of supplementalvitamins for pigs are listed in Table5. Although vitamins are present ingrains and protein supplements, itis usually better to rely on vitaminssupplied by sources in Table 5. Thereason is that vitamins in grainsand protein sources may be lostduring storage, drying and pro-cessing or may be unavailable tothe pig. An exception is made forcholine, folic acid and biotin. Webelieve that the amounts of thesevitamins that are present in grainsand protein sources are sufficientfor normal growth, but they shouldbe supplemented in diets for breed-ing swine. All the vitamin recom-mendations in this publication areadded levels.

Is there a difference betweensynthetic and natural forms ofvitamin E?

Yes. The most common form ofsynthetic vitamin E used is dl-α-tocopheryl acetate. It is very stable

during storage and/or in mixedfeed. The natural form of vitamin E(d-α-tocopherol) sometimes isused. It is less stable and exhibits adecline in activity over time. How-ever, it has a higher relative biologi-cal activity than dl-α-tocopherylacetate (Table 5). In one study, start-ing pigs performed the samewhether dl-α-tocopheryl acetate ord-α-tocopherol in an encapsulatedmatrix was included in the feed.However, d-α-tocopherol was moreeffectively absorbed than dl-α-tocopheryl acetate. Make decisionson which source of vitamin E to useprimarily on price per unit of avail-able vitamin and on how long thevitamin supplement or feed will bestored.

Bioavailability

Nutrients present in feedstuffsare not fully available to pigs. Gen-erally, only a portion of each nutri-ent can be used. This is becausefeedstuffs are not completelydigested and because nutrientsoccasionally occur in forms thatpigs are not able to use. The portionthat is absorbed in a form suitablefor use is said to be bioavailable.The amount that is bioavailabledepends primarily on the feedingredient itself. For example, theiron in ferrous sulfate is much morebioavailable than the iron in ferricoxide. However, there are otherfactors that also can influence bio-availability. These include thephysiological and nutritional statusof the animal (e.g., if an animal isdeficient in a nutrient, bioavail-ability is often increased) and inter-actions among nutrients (e.g., highcalcium levels reduce zincbioavailability).

Precise diet formulation recog-nizes differences in nutrient bio-availability among feedstuffs and is,therefore, based on the bioavailablecontent rather than the total contentof nutrients. Of course, nutrient

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Table 5. Vitamin sources and bioavailabilitiesa

Vitamin 1 IU equals Sources RB, %b Comments

Vitamin A .3 mg retinol or .344 µµµµµg vitamin A Vitamin A acetate Unkc use coated form oracetate or 1 USP unit (all-trans retinyl acetate) cross-linked stabilized

beadlet form.55 µg vitamin A palmitate Vitamin A palmitate Unk used primarily in food.36 µg vitamin A propionate Vitamin A propionate Unk used primarily in

injectibles

Vitamin D .025 µg cholecalciferol or 1 USP Vitamin D3 (cholecalciferol) Unk coated form moreunit or 1 ICU stable

Vitamin E 1 mg DL-α-tocopheryl acetate dl-α-tocopheryl acetate (all rac) 100.735 mg d-α-tocopheryl acetate d-α-tocopheryl acetate (RRR) 136.909 mg dl-α-tocopherol dl-α-tocopherol (all rac) 110 very unstable.671 mg d-α-tocopherol d-α-tocopherol (RRR) 149 very unstable

Vitamin K 1 Ansbacher unit = 20 Dam units Menadione sodium bisulfite (MSB) 100 coated form more= .0008 mg menadione stable

Menadione sodium bisulfite complex (MSBC) 100 legal for poultry onlyMenadione dimethylpyrimidinolbisulfite (MPB) 100

Riboflavin No IU-use µg or mg Crystalline riboflavin 100 spray-dried

Niacin No IU-use µg or mg Niacinamide 100 fine crystalline powderNicotinic acid 100 fine crystalline powder

Pantothenic acid No IU-use µµµµµg or mg d-calcium pantothenate 100 spray-drieddl-calcium pantothenate 50dl-calcium pantothenate - calciumchloride complex 50

Vitamin B12 1 µg cyanocobalamin or 1 USP unit Cyanocobalamin Unk crystalline powderor 11,000 LLD (L. lactis Dorner) units dilution

Choline No IU-use µg or mg Choline chloride Unk hygroscopic

Biotin No IU-use µg or mg d-biotin Unk spray-dried

Folic acid No IU-use µg or mg Folic acid Unk spray-dried

aMost common sources are in bold-italic.bRB=relative bioavailability. Values are expressed relative to the bioavailability in the most common source.cUnk = unknown.

recommendations should also bestated in terms of bioavailablerequirements, but for many nutri-ents there is an inadequate amountof data about requirements inbioavailable terms to permit this. Inpractice, nutrients that have thelargest effect on diet cost (e.g.,amino acids and phosphorus) usu-ally are formulated on a bioavail-able basis.

To enable readers to formulatediets on a bioavailable basis and toevaluate more critically ingredientsfor possible inclusion in swine diets,tables of amino acid, mineral andvitamin bioavailabilities are pro-vided (Tables 3, 4, and 5). The val-ues for amino acid bioavailability

are based on apparent digestibilitiesat the terminal ileum of growingpigs. Although apparentdigestibilities can differ somewhatfrom true bioavailabilities for somefeedstuffs, these digestibilities arewidely accepted as similar to bio-availabilities for most commonfeedstuffs used in the USA.Crystalline amino acids (i.e.,L-lysine•HCl, L-tryptophan,L-threonine, and DL-methionine)are assumed to be 100% bioavail-able. Most of the values for miner-als and vitamins are based ongrowth assays using slope-ratioprocedures and are relative bio-availabilities (i.e., they are relativeto a standard source that is assigned

a value of 100%). The bioavailablephosphorus content of feedstuffs iscontained in Table 29.

NutrientInteractions

The absolute requirement forone nutrient can be influenced bythe amounts of other nutrients inthe diet. There will always be anexcess concentration of some nutri-ents when using common ingredi-ents. In some cases, excesses of onenutrient may cause an undesirableinteraction with another nutrient.Interactions can include mineral

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with mineral, mineral with vitamin,vitamin with amino acid, andamino acid with amino acid.Although there are many nutrientinteractions, only a few are of prac-tical importance when formulatingswine diets with common ingredi-ents. However, others may be im-portant when using nontraditionalingredients. Some of the more fre-quent nutrient interactions that cancause problems are discussed in thissection.

Calcium and Phosphorus

Calcium is the most deficientmineral in diets formulated withcereal grains and oilseed meals.Phosphorus is also deficient inplant materials. Furthermore, muchof the phosphorus in plants occursas the organic complex phytatewhich renders it mostly unavail-able to the pig. Thus, it is necessaryto supplement diets with both cal-cium and phosphorus for satisfac-tory performance. Although thelevel of each nutrient is important,the ratio of calcium to phosphorusmay be more important in certainsituations. The calcium:phosphorusratio in grain and oilseed meal-based diets should normally bebetween 1:1 to 1.5:1, althoughwider ratios may be acceptableunder certain circumstances. How-ever, caution is necessary becausehigh levels of calcium interferewith phosphorus absorption. Atmarginal levels of phosphorus, theratio must be close to 1:1. As longas both calcium and phosphoruslevels meet or exceed recom-mended levels, a ratio less than 1:1is not detrimental, but usuallyresults in more costly diets. Atexcess levels of phosphorus (imply-ing considerable inorganic phos-phorus is included) the calcium tophosphorus ratio may exceed 1.5:1.The total calcium to available phos-phorus ratio in the diet needs to beclose to 2:1.

Calcium and Zinc

The absorption of zinc isaffected by the level of calcium inthe diet. High levels of calciumincluded in diets with high levelsof phytate cause zinc to be boundin a complex that renders both zincand phosphorus unavailable to thepig. When formulation of dietsresults in high levels of calcium,zinc must be increased. The levelsof zinc suggested in this publica-tion assume reasonable levels ofcalcium.

Copper, Iron and Zinc

These three minerals areinvolved in interactions; however,the effects of increasing levels ofone or more of these minerals in thediet are not consistent.

Excess iron and zinc reducecopper availability. Extremely highlevels of zinc can lead to a copperdeficiency, which is characterizedby anemia. Because of metabolicinteractions, zinc sources withrelatively low bioavailability (e.g.,zinc oxide) might be superior tosources with high availability (e.g.,zinc sulfate) when including zinc athigh levels for nonnutritionalpurposes.

High levels of copper (e.g., 250ppm) are used as a growth pro-motant, and these levels are nottoxic unless diets are deficient iniron and zinc (and high in calcium).When 500 ppm of copper has beenfed there has been mixed success inlowering stored levels of copper byincreasing zinc levels in the diet.

Vitamin E and Selenium

The interaction between vita-min E and selenium is related tothe protection of tissues against thedetrimental effects of peroxides.Vitamin E helps protect againstperoxide damage by scavengingfree radicals before they can attackcellular membranes and cause oxi-dative damage. Selenium is a com-

ponent of glutathione peroxidase,an enzyme involved in the destruc-tion of peroxides. Although vita-min E and selenium may not besubstituted for one another, theinteraction between the two nutri-ents results from the sparing effectof one on the need for the other. Inaddition, vitamin E plays an anti-oxidant role in feed. Trace minerals,such as copper, zinc, and ironincrease oxidation and thusincrease the destruction of vitaminE in stored feed. Other naturalantioxidants, such as vitamin A,are also attacked and can sparevitamin E in this role. Factors thataffect the amount of vitamin E andselenium to supplement are thelevel and type of dietary fat,presence of antioxidants in the feed,level of trace mineral inclusion andlength and conditions of feedstorage.

Amino Acids

Absolute requirements forindividual amino acids can bedetermined assuming that allamino acids are provided in suffi-cient quantities without excesses(i.e., ideal protein ratios). However,when least-cost or best-cost dietsare formulated, excesses of someamino acids are inevitable. The firstlimiting amino acid in these formu-lations (the amino acid for whichthe target level is last to be met asthe amino acid source is increasedin the diet) is usually lysine, butcan be tryptophan, methionine,threonine, isoleucine or valine atcertain growth phases and withcertain combinations of ingredi-ents. The requirements for theessential amino acids methionineand phenylalanine depend on thelevel of the nonessential aminoacids, cystine and tyrosine, respec-tively. Methionine can be convertedto cystine, and up to 50% of therequirement for total sulfur aminoacids (methionine + cystine) can beprovided by cystine. The same situ-ation exists for phenylalanine and

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Table 6. Normal test or bushel weightof grains

Grain lb/bushel

Barley 48

Corn 56

Milo 56

Oats 38b

Wheat 60

a1 bushel (U.S.) = 32 quarts.bAlthough 32 lb test weight is the stan-dard, oat producers are paid on a 38 lb/bushel basis.

tyrosine (up to 50% of the require-ment for total aromatic amino acids[phenylalanine and tyrosine] can beprovided by tyrosine). However,neither cystine nor tyrosine can beconverted to the essential aminoacids methionine and phenylala-nine.

• Amino Acid ImbalanceThis occurs when an essential

amino acid other than the one thatis first limiting is supplied inexcess. It may occur as a result ofadding a crystalline amino acid ora protein source high in that aminoacid. The result is that the firstlimiting amino acid, which issupplied at a level that should besufficient, now becomes deficient.Feed intake is reduced, and, as aresult, there is a proportionalreduction in pig gain. To correct thesituation, the level of the excessiveamino acid must be decreased orthe level of the first-limiting aminoacid must be increased.

• Amino Acid ToxicityThis condition resembles an

amino acid imbalance in that anamino acid other than the firstlimiting amino acid is supplied inexcess quantity. However, an aminoacid toxicity can not be corrected byadding higher levels of the first lim-iting amino acid. Toxicitiesinvariably are caused by excessadditions of crystalline amino acidsand are corrected by reducing oreliminating the amino acid addi-tions. While methionine and tryp-tophan are two amino acids thatcan cause toxicities, lysine andthreonine rarely cause toxicityproblems. Lower feed intake andpig gains can be expected as aresult of amino acid toxicities.

• Amino Acid AntagonismThis condition results from the

excess of one amino acid that has anegative effect on a structurallysimilar amino acid. Because struc-turally similar amino acids com-pete for the same absorption and

transport sites in the small intestine,high levels of one amino acid maycreate a metabolic deficiency of theother amino acid, even when thatsecond amino acid is supplied atthe required level in the diet. Lysineand arginine and leucine and iso-leucine are examples of structurallysimilar amino acids that competefor absorption sites. An antagonismresults in lower feed intake, lowerpig gains and poorer feed efficiency.Antagonisms rarely are a problemin pigs fed grain and oilseed mealdiets.

The negative effect on feed effi-ciency can range from 0 to 15%,depending on how much the testweight is lowered and which grainis fed. Fat can be added to dietscontaining low test weight grains tooffset a possible reduction in pigperformance.

In general, it is best to use lowtest weight grains in finishing andgestation diets (if they are free ofmycotoxins) because older pigs uselower energy feedstuffs better thanyounger pigs. The feeding levelduring gestation may have to beincreased to compensate for thelower energy value of the light testweight grain. Also, include low testweight grains in the diet by weight,not volume. Therefore, scales onmixing equipment are necessary tomake diets properly.

• Low Test Weight CornCorn weighing between 40 to

56 lb/bushel has the same feedingvalue for growing-finishing swinewhen compared on an equal mois-ture basis. When test weight dropsbelow about 40 lb/bushel, growthrate and feed efficiency maydecrease by 5 to 10%.

• Low Test Weight MiloLate planting, a cool growing

season, or an early frost can lead tolow test weight milo. It should beused only in growing, finishing andgestation diets. According to arecent study, there was no differ-ence in gain or feed efficiency forgrowing-finishing pigs fed either 45

IngredientQuality

Quality of the ingredients usedin swine diets can have a largeeffect on performance. Test weightof grains, nutrient variability ofbyproducts and presence ofmycotoxins all affect the feedingvalue of ingredients. However,when properly formulated, dietscontaining byproducts andweather-stressed grains can pro-vide an economic alternative forswine producers.

What is the relationshipbetween the test weight of grainand feeding value?

Most previous research indi-cates low test weight grains containmore protein and fiber and lessstarch and ME than normal grains,implying that low test weightgrains have a lower feeding valuethan normal grains (Table 6). How-ever, more recent research on cornsuggests there is a poor relation-ship between test weight and nutri-tional value. There is generalagreement that pig growth rate sel-dom is affected by grain test weightas long as the test weight is notreduced by more than about 25%.However, if low test weight grainhas less ME, pigs will compensateby increasing feed consumption,resulting in a poorer feed efficiency.

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or 55 lb/bushel milo. However,feeding 35 lb/bushel milo resultedin 13% and 6% poorer feed efficien-cies in the growing and finishingphases, respectively. For miloweighing less than 45lb/bushel, uselocal prices to determine what pricethe milo has to be to offset the ex-pected poorer feed efficiency.

• Low Test Weight WheatResearch indicates finishing

pigs fed 45 to 51 lb/bushel wheatwere 7.3% less efficient than thosefed 59 lb bushel wheat. Whendetermining the economics of feed-ing low test weight wheat, assumeit to have a feeding value of about90% of normal wheat.

• Low Test Weight BarleyIn growing-finishing pigs,

expect about a 5% increase in theamount of feed required per poundof gain for every 2.5 lb reduction inbarley test weight from 49 to 44lb/bushel, with an additional 7%poorer feed efficiency for 39lb/bushel barley. If the barley isscab-infested, it should be fed onlyto growing-finishing pigs andlimited to 10% or less of the diet.

• Low Test Weight OatsResearch indicates that low test

weight oats can be fed effectively tofinishing swine. Pigs fed diets con-taining 33% oats (32 lb/bushel oats)gained the same as pigs fed corn di-ets but required 5.1% more feed.Therefore, depending on economics,light test weight oats can be used infinishing diets.

Can I use high-moisture cornand frost-damaged soybeans inswine diets?

High-moisture corn (>18%moisture) will have the same feed-ing value as dry corn (12% mois-ture) on a dry-matter basis. Sincehigh-moisture corn contains ahigher percentage of moisture, alarger percentage of high-moisturecorn must be added to a ton of feedto achieve the same nutrient levels

achieved with “normal” corn. Also,it must be kept in mind that ensiledor organic acid-treated corn can notbe sold at the elevator. It can onlybe used for livestock feed, so onlymake what can be fed in a year.

Extruded green soybeans havethe same feeding value as extrudedmature soybeans. Because of anti-growth factors (e.g., trypsin inhibi-tors), mature and immature rawsoybeans must be heat-treated toinactivate these compounds beforefeeding them to swine. The onlyexception is gestating sows, whichcan use raw soybeans as the solesource of supplemental protein.Factors to consider in determiningwhether to feed or sell your soy-beans (mature or immature) andbuy soybean meal are extrusioncosts, shrink (8 to 10%), lower pro-tein content of extruded soybeans,an improvement in feed efficiencydue to fat addition, and truckingand storage costs.

Can I market my moldy grainthrough hogs?

Under certain adverse condi-tions, grains may become moldy. Itis not the molds themselves, butrather the mycotoxins the moldsproduce that cause the negativeeffects. The main mycotoxins asso-ciated with grains are aflatoxin,zearalenone, vomitoxin (DON),fumonisins and ergot. Aflatoxinsare found primarily in warmer cli-mates, whereas zearalenone andDON occur in cool, wet conditions.Aflatoxins suppress the immunesystem, cause a reduction in perfor-mance, and at high concentrations(1,000 ppb) death. Zearalenone willcause reproductive problems, infer-tility, high preweaning death lossand possibly abortions. Thoughzearalenone’s effects on growingand finishing pigs are minimal, itwill cause prepubertal gilts toexhibit red, swollen vulvas andcould affect future breeding.Vomitoxin causes feed refusal withlittle effect on the reproductiveherd. However, feed refusal associ-

ated with DON will result in adecrease in daily gain. Fumonisinscan cause respiratory problems inpigs. Ergot occurs mainly in rye,wheat, barley, and triticale, andresults in lactation failure and poorgrowth. Recommendations are tokeep all mycotoxin-contaminatedgrains out of breeding herd andstarting diets, and not to exceed thefollowing rates in other diets:

Aflatoxin 200 ppb in grow-ing-finishing diets

Zearalenone 1 ppm in growingdiets and 3 ppm infinishing diets

Vomitoxin 1 ppm in growing-(DON) finishing dietsFumonisins 5 ppmErgot 10% contaminated

grain in growing-finishing diets

There are products availablethat will lessen the impact of afla-toxin (pellet binders, clays, etc.),but there are no products that canbe added to swine diets to reducethe detrimental effects ofzearalenone, DON, fumonisins andergot. Drying the grain and addingmold inhibitors will decrease anyfurther mold growth, but they haveno effect on the mycotoxins alreadypresent.

Should I analyze the feedstuffsI am using?

Byproducts from the foodindustry such as soybean meal, sun-flower meal, dried bakery products,etc. can be excellent feedstuffs forswine. However, since they arebyproducts, they are more variablein nutrient content than grains. Toensure proper diet formulation, anutrient analysis should be con-ducted on all byproducts used inswine diets. Depending on the qual-ity of soybeans used and theamount of hulls added back, theprotein content of 44% CP soybeanmeal can range from 37 to 45%.Therefore, it is essential to knowwhat kind of product you are

13

working with before using in thediet. Submit a representativesample to an accredited laboratoryand have it analyzed for the mainnutrient(s) being provided by thebyproduct. Consider a mycotoxinscreen on grain when drought orwet growing conditions persist,storage problems are suspected, orcertain abnormalities are observedin animals.

What are proper samplingtechniques?

When sampling either indi-vidual feedstuffs or processed com-plete feeds for laboratory analysis,it is essential to get a representativesample. If using a grain trier/probeto obtain samples from a mixer orbagged feed, take at least ten 1/2pound samples/ton of feed fromdifferent locations and combinethem into one composite sample foranalysis. If sampling from an un-loading auger, take at least ten 1/2pound samples/ton during the en-tire unloading process, except forthe initial and final outputs. Mix thesamples, split them in half and sendhalf of the composite sample in foranalysis. Store the properly datedand labeled remainder in a freezerfor reference. Use the same tech-niques when taking a grain sampleto test for mycotoxins except makesure the sample is sent to the lab ina either a paper or cloth sack. Usingplastic bags or metal cans maycause mold growth to occur in tran-sit. For details on interpretation oflaboratory results, see the Univer-sity of Nebraska NebGuide G88-892(Mixing Quality Pig Feed).

Category IIDrugs that require withdrawal

at the lowest continuous use levelfor at least one species for which itis approved or is regulated on a “noresidue” or “zero tolerance” basisbecause of carcinogenic concerns.

There are three types of medicatedfeeds that can incorporate drugsfrom categories I or II:

Type A Medicated ArticleThis product is classified as a

drug by the FDA and must be clas-sified as a “Medicated Type A Arti-cle” on the label. The manufacturerof a Type A article must hold aneffective new animal drug applica-tion (FD-356) and comply with thecurrent medicated premix and goodmanufacturing practice regulations.

Type B ProductThis product is classified as a

medicated feed. The manufacturerof a Type B product from a Type Aarticle containing a Category IIdrug requires a medicated feedapplication (FDA - 1900).

Type C ProductType C products are intended to

be used as a complete feed. Themanufacture of a Type C productcontaining a Category II drugmanufactured from a Type A articlerequires a medicated feed applica-tion (FDA - 1900).

What is a nutraceutical?Unfortunately, no legal defini-

tion for “nutraceutical” exists. It isgenerally assumed that a nutra-ceutical is compound between anutrient and pharmaceutical.Although these compounds/ingredients have a defined nutri-tional role, pharmacological doses(many fold greater than concentra-tions needed to elicit a nutritionalresponse) elicit separate effects onpig health or growth. Examples ofingredients considered as nutra-ceuticals are: zinc oxide, copper sul-fate, carnitine, organic chromium,and conjugated linoleic acid.

Feed Additives

Feed additives are compoundsthat may elicit a response indepen-dent of contributions to the pig’senergy, amino acid, mineral, and(or)vitamin requirements. Typically,these feed additives are added topig diets in small amounts. In

addition, certain nutrients, such ascopper and zinc, have been addedat pharmacological concentrations(i.e., at high levels the nutrient actsas a drug-see section onnutraceuticals).

How are feed additivesregulated?

The distribution of all animalfeeds entering interstate commerceis regulated by the FDA (Food andDrug Administration). In addition,the FDA monitors the amounts ofdrugs or feed additives used in themanufacturing of medicated feeds.Specific state laws and regulationsmay also exist regarding the distri-bution of feeds and the productionof medicated feeds. Besides consult-ing state and federal regulations,there are two publications that maybe helpful:

The Feed Additive Compendium,updated monthly

The Miller Publishing Company12400 Whitewater Drive, Suite 160Minnetonka, MN 55343http:/www.feedstuffs.com

Official Publication of the Associationof American Feed Control Officials(AAFCO)Sharon Senesac, AAFCO AssistantTreasurerP.O. Box 478Oxford, IN 47971http:/www.aafco.org/

How does the FDA describedrug categories used in medicatedfeeds?

The program that describes theclassification of drugs used in medi-cated animal feeds is commonlyknown as “Second Generation.”This regulatory scheme dividesdrugs into two major categories:

Category IDrugs that require no with-

drawal at the lowest approved con-tinuous use level for all species.

14

Because nutraceuticals are labeledas dietary supplements, they areregulated under the Federal Food,Drug, and Cosmetic Act (FFDCA).

Compounds not receivingGRAS (Generally Recognized asSafe) status, (i.e., ingredients that donot have a previous history of usein animal feeds) are of concern.Specifically, ingredients that makeclaims regarding the treatment, pre-vention, cure, or mitigation of a dis-ease; or affect the structure/function of the body not related toits nutritional role are considered adrug under FFDCA regulations.Although the FDA has placed lowersignificance on regulating nutra-ceutical ingredients without drugclaims, the FDA’s condonation ofthese ingredients is not indicated.

How do feed additives affectpig performance?

There are many feed additivesthat have been documented to affectpig performance. Unfortunately,there is not enough space availablein this section to cover all these feedadditives in detail. The recom-mended levels for several feedadditives are not provided because ofeither variable usage in the industryor pending status with the FDA. Inall cases, if feed additives are to beused, manufacturer and federalguidelines should be followed.

Presented in Table 7 is a briefdescription of the performance cri-teria, percent improvement, and uselevels for several feed additives. Formost of these feed additives,responses have been identifiedwithin a range to indicate the vari-ability reported in the literature.

The response to antibiotics var-ies considerably due to age of thepig, disease level, type and level ofantibiotic, season of year, and otherenvironmental factors. Younger pigsshow a greater response than olderpigs to antibiotics in the feed (Table7). In most cases, these responseswere recorded in “clean” environ-ments (i.e., the overall health statusof the pigs and housing conditions

were good to excellent). In a “dirty”environment, the response to antibi-otics may be greater than shown inTable 7. Antibiotics do not substi-tute for good management, espe-cially a thorough cleaning offacilities. It may be more economi-cal to correct the underlying prob-lem affecting pig performance thanto use antibiotics in the feed.

Some compounds are includedin swine diets to avoid feed spoil-age and promote feed intake (Table8). Although improvements in per-formance are not cited for the feedadditives listed in Table 8, circum-stances exist where their inclusionin swine diets may increase feedintake and hence gain.

How do I choose a feedadditive?

The information in Tables 7 and8 is presented to allow one to esti-mate the economic benefit of usingsome feed additives. When animprovement in feed efficiency isshown, use that to estimate the eco-nomic benefit of using the additive.For example, assume feed/gain isimproved by an average of 2%when an antibiotic is added to fin-isher feed. If feed without an antibi-otic costs $100/ton, you can affordto pay about $102/ton (100 × 1.02)for the medicated feed assuming nobenefit from improved daily gain. Ifa faster growth rate is consideredimportant, factor that in also. Whenconsidering a feed additive, givehigh priority to feed additives thatshow consistent results fromresearch trials. Also, consult thefeed label to learn what the additiveis approved for and withdrawaltime. Feed additives increase thecost of the diet, thus it is importantto reevaluate their use periodically.

How much antibiotic can beadded to feed and can antibioticsbe mixed together?

Consult the feed label or theFeed Additive Compendium for detailson the approved level(s) in com-plete feed and which antibiotics can

be fed in combination. If it is notlegal to feed certain antibioticstogether, consider feeding them inrotation. Moreover, rotating anti-biotics may be useful if there is evi-dence that the effectiveness of thecurrent antibiotic is decreasing. Therotation may be annual or whenpigs are switched to different diets.

What are the withdrawalperiods for feed additives?

Certain feed additives must bewithdrawn from the feed beforeslaughter to ensure residue-free car-casses. Consult the feed label forwithdrawal time for the specificfeed additive that is being fed.

Should antibiotics be fed to thebreeding herd?

Herds that have experiencedproblems with conception rates andnumbers of pigs born and weanedhave often been helped by the addi-tion of therapeutic levels of antibi-otics to sow diets. Antibiotics areeffective if fed for two weeks beforeand after breeding and(or) from oneweek before farrowing to weaning.Results from a regional researchstudy (850 litters) showed animprovement in litter size (.5 pigs/litter) and a slight reduction (nega-tive response) in feed intake duringlactation with the addition of chlo-rtetracycline (200 g/ton) from oneweek before to 15 days after breed-ing. In the same study, chlortetracy-cline addition from day 110 ofgestation to weaning improved theoverall conception rate nearly 6%.In instances where reproductiveproblems prevail in a herd, a spe-cific diagnosis should be made inconsultation with a veterinarian orswine specialist prior to routineinclusion of antibiotics in breedingherd diets. Check the withdrawaltime to avoid carcass residues incull sows.

How do probiotics andantibiotics differ?

Probiotics play a different rolethan antibiotics in the digestive

15

Table 7. Performance criteria, percent improvement, and use levels of some common feed additives

Performance Growth Improvement, %Compound criterion stage (average response) Use level

Antibiotics Daily gain Starting 4.2 to 136 (15) Variablea

(for growth Growing-finishing 0 to 8.9 (3.6)promotion) Feed/gain Starting 1.7 to 42.7 (6.5)

Growing-finishing -1.8 to 3.8 (2.4)

Probiotics Daily gain Starting -9 to 11 Variablea

Growing-finishing -9 to 5Feed/gain Starting -2 to 21

Growing-finish -4 to 5

Copper sulfate Daily gain Starting (24) 125 to 250 ppmFeed/gain (9.7)

Zinc oxide Daily gain Starting 0 to 25 2,500 to 3,000 ppmc

Feed/gain 0 to 8

Yucca plant extract Daily gain Growing-finishing -1 to 8 57 g/tonFeed/gain 0 to 5

Mycotoxin binders

HSCAd Daily gain Growing-finishing 63 to 87e .5%Clays Daily gain 71 to 89e .5%

Acidifiersf Daily gain Starting 0 to 13 3%Feed/gain 0 to 14

Phytase Daily gain Growing-finishing 0 to 17g 136 to 225 units/lb ofcompete feed

Feed/gain 0 to 7g (300 to 500 units/kg ofcomplete feed)

Carnitine Fat accretion Starting and 0 to - 40%growing-finishing

Daily gain Starting and 0 to 17% VariableFeed intake growing-finishing 0 to 17%Feed/gain 0 to 17%

Litter size Gestation 0 to 12% 50 ppmBirth weight 0 to 12%

Chromiumh Lean gain Growing-finishing 0 to 6% Variable

Litter size Gestation 0 to 10% 200 ppb

Conjugated linoleic acid Lean gain Growing-finishing 0 to 5% .3%i

Feed/gain 0 to 30%Belly firmness 16 to 50%

Ractopamine hydrochloride Daily gain Finishing 7 to 10% 4.5 to 18 g/tonFeed/gain 8 to 13%

Carcass lean % 2 to 6%

aUse level will depend on the specific antibiotic.bUse level will depend on the specific probiotic.cToxicity problems may develop if these levels are provided past about 28 days postweaning.dHydrated sodium calcium aluminosilicate.eRecovery of lost growth rate when feed is contaminated with aflatoxin.fFumaric acid.gResponse will vary depending on the total level of available phosphorus in the diet.hOrganic chromium.iEstimated from the contribution of conjugated linoleic acid from natural ingredients. Not supplied as purified conjugated linoleic acid.

16

Table 8. Function of several feed additives included in swine diets to maintain palatabil-ity and(or) feed quality

Compound Function

Antioxidantsa Prohibit fatty acid oxidation and formation of peroxide freeradicals. Protect feed sources against the destruction of somevitamins (vitamin A and E). Routine use is recommended.

Mold inhibitorsb Increase number of days to mold growth in feed by 5 to 10days. The greatest benefits are observed where grains being fedare higher than normal in moisture (> 13% moisture).

Flavors May improve palatability of feed, especially when byproductingredients are used. Routine use of flavors is notrecommended.

ae.g., ethoxyquin, butylated hydroxy tolulene (BHT) and butylated hydroxy anisole (BHA).be.g., propionic acid and sorbic acid.

tract. It has been theorized thatprobiotics increase the populationof desirable microorganisms insteadof killing or inhibiting undesirableorganisms. The most commonmicroorganisms included in pro-biotic products are Lactobacillusspecies, which are normal inhabit-ants of the digestive tract of healthyanimals. These bacteria may helpremove waste products and inhibitthe growth of certain undesirablebacteria. The response to probioticsin pig feed appears to be greater forstarting compared to growing-finishing pigs (Table 7). When posi-tive responses have been observedwith probiotics it has usually beenat weaning.

What is carnitine and its effectas a feed additive?

Carnitine is a naturally occur-ring nutrient and until now waswidely thought to be synthesized insufficient quantities by the pig tomeet its requirement. It is involvedin the transport of fatty acids intocertain parts of the cell so they canbe used to produce energy. Car-nitine has received limited attentionin the growing-finishing phase ofproduction. Although improve-ments in feed efficiency and lean-ness have been observed, recentreports have only documented theresponse in early-weaned pigs(until 35 days postweaning).

There have been interestingfindings from experiments examin-ing the role of carnitine in gestationdiets. Studies indicate that inclusionof 50 ppm carnitine in gestationdiets can improve litter size and(or)pig birth weight. It appears that theimprovements in litter size andbirth weight may be related to theduration of carnitine supplementa-tion. Nonetheless, the response ofboth litter size and birth weighthave ranged from 0 to 12%.

What effect does chromiumhave as a feed additive?

Chromium (Cr), specificallyorganic Cr (Cr 3+) has been identi-fied as having a role in swine feed-ing programs. It should be kept inmind that although pigs do have aCr requirement and Cr is found inpig tissues, forms of elemental Cr,e.g., Cr 6+ can be toxic. Thus, the rolethat organic Cr fulfills may be inaddition to its classical nutrient role- see previous section on nutraceuticals.

Organic Cr (namely, Cr-tripicolinate) has been shown toimprove growing-finishing growthperformance, and carcass leanness.The results have been variable andsome researchers have failed todetect improvements in carcasscharacteristics or growth perfor-mance criteria.

Recently, favorable responses insow reproductive performance have

been observed with the addition oforganic Cr to sow gestation and lac-tation diets. Supplementation of 200ppb of Cr from Cr-tripicolinateimproved sow fertility, number ofpigs born and weaned, and reducedsow death loss. Females need to befed the Cr for about six monthsbefore an improvement in repro-ductive performance can beexpected.

What is conjugated linoleic acidand its effect as a feed additive?

Conjugated linoleic acid (CLA)is a mixture of polyunsaturatedfatty acids. CLA is found primarilyin products derived from rumi-nants. It is produced by the mico-flora in the rumen and can bepurchased commercially. The mostconsistent and dramatic effect ofincluding CLA in the diet ofgrowing-finishing pigs has been onbelly firmness, and to a lesserdegree on feed efficiency and car-cass lean percentage (see Table 7).

What is ractopamine hydro-chloride and its effect as a feedadditive?

Ractopamine hydrochloride is asynthetic beta-adrenergic agonist.Ractopamine has a chemical struc-ture similar to dopamine, norepi-nephrine, and epinephrine, whichare naturally occurring substancesin animals. These substances,including ractopamine, affect bodymetabolism via adrenergic recep-tors on specific tissues. Ractopa-mine is approved for increased rateof weight gain, improved feed effi-ciency, and increased carcass lean-ness in finishing swine fed acomplete ration containing at least16% crude protein from 150 to 240lb. A feed mill or veterinary feeddirective are not required for use ofractopamine. Because ractopaminelowers feed intake 2 to 4% andincreases carcass muscle deposition,logic dictates that the dietary aminoacid requirement on a percentagebasis and possibly on an absolute(total) basis is increased.

17

Table 9. Hammermill and roller mill recommendations to achieve a 700-micron averageparticle size

Hammermill Roller mill

Grain Screen size, inches Corrugations/inch

Barley 1/8 10 to 12

Corn 3/16 8 to 10

Oats 1/8 10 to 12

Milo 1/8 12 to 14

Wheat a 10 to 12

aTo avoid palatability problems, wheat should be coarsely ground or rolled to achieve the proper particle size. See text for details.

Feed Processing

Processing feed is an importantstep between the nutritionist andthe pig. No matter how preciselydiets are formulated, pig perfor-mance will suffer if the diets arenot processed and mixed properly.Critical components of feed prepa-ration include particle size reduc-tion and mixing efficiency.

What average particle size doyou recommend for swine diets?

We recommend an average par-ticle size of 650 to 750 microns forall grains except wheat. Finelyground wheat creates palatabilityproblems, thus the optimum par-ticle size for wheat is 850 to 1250microns for pigs < 130 lb and 1400to 1800 microns for sows and pigs> 130 lb. Avoid feeding wholekernels of wheat. Process feed sothe standard deviation (a measureof particle size variation) is 2 to 2.5.

Reducing ingredient particlesize has several advantages. First, itcreates more surface area availablefor digestion resulting in improvedfeed efficiency. Second, it improvesmixing and handling characteris-tics. The more uniform the feed-stuffs are in terms of particle size,the easier they are mixed. A smallparticle size reduces the amount ofsegregation of feedstuffs that mayoccur in bulk bins, augers, andfeeders. However, there are severalcosts associated with smaller par-ticle size. The smaller the particlesize the greater the energy and timerequirements of processing. Also,there may be increases in dustiness,feed bridging and gastric ulcers.

How do hammermills androller mills compare?

Particle size usually is reducedby grinding or rolling the grain.Grinding with a hammermill is themost common method. Hammer-mills have a greater capacity/unitof horsepower, can more easily

should be turned or replaced whenit becomes dull or develops largeholes.

Both types of mills can achievethe desired particle size. Producersneed to evaluate such factors asnumber and types of grain used,time availability, managementcapabilities, initial investment, andoperating costs when determiningthe best system for their individualoperations.

What are the key factorsinvolved in making high qualityfeed?

Once the grain has been pro-cessed to the correct particle size, itmust be properly mixed with theother ingredients to achieve the de-sired diet. Key points in obtaining agood mix are:

• Weighing the ingredientsWithout weigh scales, the

chances of getting the correct num-ber of pounds of each ingredient inthe mixer is reduced. Adding toolittle or too much grain will sub-stantially concentrate or dilute theamounts of other ingredients in thediet. Volumetric systems can besatisfactory but they must be recali-brated frequently. However,because of differences in bulkdensity of different grains andbatches of soybean meal, basemixesand premixes, weigh scales areessential in ensuring proper dietpreparation.

process different grains and canmore easily be adjusted or repaired.However, hammermills requiremore energy and produce more“fines,” and consequentially moredust, than roller mills.

Roller mills use 25 to 30% lessenergy than hammermills to pro-duce a 700-micron particle, butrequire more management. Also,because the rolls must be read-justed to accommodate differentfeedstuffs, roller mills are difficultto use when processing several dif-ferent grains. There are three essen-tial criteria for producing a 700 to800-micron particle with a rollermill: (1) a differential drive withone roll moving 50 to 75% fasterthan the other roll to produce ashearing action instead of a crush-ing action, (2) the correct numberof corrugations/inch to slice thegrain and (3) a spiral of 1 to 2" perevery 12" of roll length to increaseshearing action and decrease fines.Recommendations for corruga-tions/inch for roller mills andscreen sizes for hammermills areshown in Table 9.

To ensure a consistent particlesize, both hammermills and rollermills need periodic maintenance.Magnets should be placed inappropriate locations to preventmetal objects from reaching the rollsor screen. Hammers need to beturned or replaced when worn, androlls need to be regrooved whenworn or damaged. Because thescreen also helps “cut” the grain, it

18

• Mixing timesRun vertical screw mixers at

the proper speed for at least 15minutes after the last ingredient isadded. Horizontal and drum mix-ers should run for 5 to 10 minutesafter the addition of the last ingre-dient. Older, worn mixers need tobe run longer.

• Sequencing and premixingAdd at least half of the grain or

all of the supplemental protein be-fore adding any other ingredients.Also, if an ingredient is added atless than 2% of the total batch (< 40lb in a ton batch) in a vertical screwmixer or less than 1% in a horizon-tal mixer, it needs to be premixed toa larger volume to ensure propermixing.

What about other methods ofprocessing?

Alternate methods of process-ing feedstuffs and feed includeextrusion, roasting, pelleting, steamflaking, expanding and microniz-ing. Extrusion and roasting aremost commonly used in the heattreatment of soybeans to inactivateantinutritional factors found in rawsoybeans. Extrusion involves theuse of heat, pressure, and possiblysteam on ingredients or feeds.Roasting is a simpler process, butthere is a greater potential for over-and under-heating. Expanding issimilar to extrusion, and the resultshave been mixed at best with swinediets, especially when economicsare considered. Steam flaking andmicronizing are processing meth-ods that usually do not increaseperformance enough to justify thecost of processing.

Pelleting swine diets is becomingmore popular. This is especially truein starter pig diets because pelletingprevents bridging in feeders whenusing diets high in milk products.Pelleting corn or milo-based diets forgrowing and finishing pigs results ina 5 to 8% improvement in feed effi-ciency and increases daily gain by 3to 6%. Pelleting barley or oat-based

diets improves feed efficiency by 7 to10% and daily gain by 3 to 6%. Theimprovement in feed efficiency is dueto a decrease in feed wastage andimproved nutrient use. However, thedecision to pellet diets other than inthe starting phase should to be basedon economics. In general, the moreexpensive the diet the more economi-cal it is to offer as a pellet.

When determining the economicbenefit of any form of processing, thefollowing formula can be used:

New diet cost - old diet cost x 100Old diet cost

< or = % improvement in feedefficiency needed to offsetadded diet cost

For example, assume pelleting willincrease the diet cost from $110/tonto $125/ton. Therefore, a 13.6%improvement in feed efficiency isneeded to cover the pelleting cost.Any improvement in feed effi-ciency above that will be profit.

$125 - $110 x 100 = 13.6%$110 improvement

in feedefficiency

Water

Water is one of the most impor-tant components of a feeding pro-gram for swine. Vital to all bodyfunctions, water accounts for asmuch as 80% of body weight inpigs at birth and declines to about50% in market swine.

How much water does a pigconsume?

Refer to Table 10 for estimatedwater needs of various classes ofswine. In general, a pig will con-sume 1/4 to 1/3 gallon of water forevery pound of dry feed. The waterrequirements are variable, with theneed for water increasing when apig has diarrhea or experiences

warm or hot environmental condi-tions. Diets high in salt or proteinor other ingredients whosebyproducts of digestion andmetabolism are excreted via thekidney also increase water needs.

Lactating sows must haveunlimited access to water if theyare to produce milk adequately.Suckling pigs older than 10 to 14days of age need water in additionto that in milk for optimum perfor-mance.

With typical nipple drinkingdevices, the rate of delivery (cups/minute) has little effect on per-formance as long as a minimaldelivery rate is achieved with thedevice. Pigs generally make up forreduced delivery rates by spendingmore time at the drinking device.Suggested minimum delivery ratesfor nipple drinking devices are:

starting pigs — 1 to 1.5 cups/minute

growing-finishing pigs — 2 to3 cups/minute

sows and boars — 3 to 4cups/minute

For all classes of swine that arehoused in pens, we recommendthat at least one nipple drinkerdevice be provided for every 15pigs in the social group, with aminimum of 2 devices per group.We recommend one nipple drinkerdevice for every 10 pigs in thenursery.

Recent research suggests that ifwater waste is a concern, the use ofwet/dry feeders or bowl drinkersmay result in which the nippledrinker is incorporated in the feed

Table 10. Water consumption by pigs

Waterconsumption,

Class gallon/pig/day

Gestating sow 2 to 3

Lactating sow 4 to 5

Starting pig (13 to 45 lb) .5 to 1

Growing pig (45 to 130 lb) 1

Finishing pig (130 to 250 lb) 1.5 to 2

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bowl of the feeder as the sole sourceof water may result in up to a 40%reduction in slurry volume. Newerdesigns of drinking devices mayalso reduce water wastage whencompared to traditional nippledrinking devices. Consideration ofthe need for wasted water forproper functioning of manure trans-fer and storage devices is a consid-eration in drinker device selection.

What about water quality?Water that meets standards for

human consumption is ideal. Mostproblems with water quality arerelated to bacterial contamination,either in the well or water deliverysystem. A laboratory result equal toor less than 1 coliform per 100 mL isconsidered acceptable for all classesof swine. Levels higher than 5 bac-teria forming colonies per 100 mLare cause for immediate concernand remedial action.

Water containing elevatedlevels of sulfates (so called stinkywater) will cause a slight to moder-ate diarrhea with a characteristicblack color in the feces. Water con-taining up to 3,000 ppm sulfate or5,000 ppm total dissolved solids(TDS) can be consumed safely byswine after a period of adaptation.

Many laboratories report elec-trical conductivity as an estimatorof TDS. Although the constant inthe formula varies somewhatdepending on the sulfate content ofthe water in question, a generalestimate of TDS is:

TDS = K/.75

where: TDS = Total DissolvedSolids in ppmK = electricalconductivity inmicroomhmos.75 = constant

Water containing up to 100 ppmNO3-N (nitrate-nitrogen) or 440ppm NO3 (nitrate) is consideredsafe for all classes of swine. Recent

research results suggest that watercontaining up to 450 ppm NO3-N or1,980 ppm NO3 will not cause ad-verse reactions in growing-finishingpigs.

Water normally contains miner-als that are added to swine diets(e.g. calcium or sodium). However,minerals from a water sourceshould not substitute for quantitiesrecommended in the feed.

Do you recommend using watersweeteners or water acidifiers?

No. Water sweeteners andacidifiers have been ineffective inroutinely enhancing water intakeand improving the performance ofstarting pigs.

Feed Intake

Feed intake is used synony-mously with feed disappearancefrom feeders or storage bins. Feeddisappearance includes feed that iseaten and feed that is wasted orspilled and probably overestimatesactual feed consumed. Certain pro-cessing methods (e.g., pelleting),feeder design and managementpractices reduce feed disappear-ance because feed wastage is re-duced, but they may have littleeffect on feed intake. Other prac-tices, such as liquid or paste feed-ing, may produce a real increase infeed consumption.

Why is feed intake important?Growing pigs and lactating

sows generally are given free or adlibitum access to feed, whereasboars and non-lactating gilts orsows are limit-fed. It is assumedthat when swine are not limit-fed,they will consume feed in quanti-ties sufficient for maximum pro-duction. A number of factors mayalter feed consumption, resulting ingreater or lesser amounts of feedconsumed than expected. As feedconsumption varies, so does the

daily supply of nutrients. Nutrientintake can be standardized by ad-justing nutrient levels in a diet in-versely with changes in feed intake.However, altering nutrient densityis not advisable when energy is thelimiting factor.

What factors affect feedintake?

Pigs consume feed in meals. Aspigs advance from weaning toslaughter weight, meal frequencydecreases from about 12 to fivemeals per day. Factors that alterdaily feed consumption do so byeither reducing or prolonging theduration of individual meals asopposed to affecting meal fre-quency.

• Energy densityThe amount of energy con-

sumed depends on the amount offeed eaten and the amount ofenergy per pound of feed. Pigstypically eat until their energyrequirements are satisfied. Addingfat to a diet reduces feed intakebecause energy density increases.Fibrous feeds (e.g., barley, alfalfaand oats) dilute energy density andincrease bulk when added to a diet.As dietary fiber increases, feedintake increases until gastrointesti-nal capacity is reached, causingintake to reach a plateau. Thisplateau may occur before energyneeds are satisfied. Energy dilutionis of particular concern for pigsweighing less than 80 lb and formost lactating sows. This isbecause energy intake tends to belimiting for maximum performancein these classes of swine, evenwhen they are fed low-fiber diets.

• TemperatureConsistent exposure to envi-

ronmental temperatures above orbelow the pig’s thermoneutral zoneaffects feed consumption. As envi-ronmental temperature increasesfrom comfortable to moderatelystressful, feed consumptiondeclines proportionally. However,

20

amounts when given free access tofeed. However, it is not possible tomake general statements about dif-ferences in feed intake amonggenetic lines. For example, somehigh lean gain genotypes werethought to have reduced feedintake. This might seem logicalbecause carcass leanness isincreased by restricting feed intake.However, there is evidence thatpigs with high lean growth poten-tial and those with medium or lowlean growth eat similar amounts offeed. Therefore, feed intake pat-terns of genetic lines should bedetermined from previous recordsand daily consumption should notbe used to classify pigs accordingto lean growth type.

• WeaningSeverely restricted consumption

at weaning is a common occurrenceand the principal cause ofpostweaning lag. This problem hasbeen addressed in our nutrient rec-ommendations (Table 11), and fur-ther adjustments in nutrient densityare not needed. The starter 1 (ortransition) diet should containhighly palatable and digestibleingredients (see example diets inTable 19) to encourage pigs to begineating as quickly as possible.

• Amino acidsPigs fed diets that are not cor-

rectly balanced for amino acidsmay exhibit reduced feed intake.The severity varies depending onthe levels and characteristics of theamino acids involved. Formulationerrors that allow some alternativefeed ingredients or crystallineamino acids to be used incorrectlycause these problems. Such errorscan be avoided by using our lysine,tryptophan, threonine and me-thionine recommendations whenformulating diets.

• Gestation feedingSows that are overfed during

gestation exhibit reduced feed con-sumption during lactation. The

excess energy consumed duringgestation is stored as fat and usedduring lactation, resulting ingreater lactation weight loss. Sowsfed our recommended amountsduring gestation (adjusted for envi-ronment as necessary) gain lessweight during gestation and loseless weight during lactation. Theyobtain the additional energyneeded during lactation by eatingmore feed. The total amount offeed eaten for the combined gesta-tion and lactation periods may besimilar whether sows are overfedor fed correctly during gestation.However, sows that are too fat atfarrowing may cause managementdifficulties and are more likely tocrush their pigs.

• Feed acceptabilityPigs may reduce consumption

or refuse to eat when the diet con-tains unpalatable or objectionableingredients. This may be noticedfirst among limit-fed swine,because they eat well definedmeals. The effects on pigs givenfree access to feed are less obviousand may not be noticed until per-formance losses occur. Certainodors, textures, flavors and tastes(especially bitter) may contribute toreduced feed intake. Some ingredi-ents may reduce palatability whenlarge quantities are used in the diet.Small quantities of mold and(or)mycotoxin contaminated feeds maydramatically reduce feed intake. Toavoid these problems, do not usepoor quality ingredients in swinediets.

Stale feed may be consideredunacceptable to swine that are hesi-tant to eat because of stress. Lactat-ing sows, newly weaned pigs andpigs recovering from disease can beencouraged to eat by providingfresh feed several times per day.Spilled or wasted feed left on theground or floor of a pig pen formore than 30 minutes probably willnot be eaten.

extreme heat stress drasticallyreduces feed consumption. Suscep-tibility to heat stress increases asbody weight increases. Conversely,feed consumption increases asenvironmental temperature isreduced within a moderate range.Finishing pigs in a cold environ-ment eat more because their main-tenance energy requirement isincreased to maintain body tem-perature. Growth rate may not beaffected, but poorer feed efficiencyresults. However, severely cold-stressed pigs may not growbecause they can not consume suf-ficient amounts of energy abovetheir maintenance requirement. Theeffects of cold weather are less det-rimental as body weight increases.Limit-fed swine are an exceptionbecause they can not voluntarilyadjust energy intake. The managermust make these adjustments andincrease feeding level according toseverity of the cold stress.

• GenderA summary of eight studies

below shows that feed consumptionis affected by gender. Although dif-ferences in feed intake between bar-rows and gilts may occur at lighterweights, they probably are not ofpractical importance until pigsweigh about 80 lb or more. After 80lb, barrows will consume more feedthan gilts. It appears boars consumeless feed than gilts during thegrower phase, but they have similarfeed intakes in the finisher phase.

Relative effect of sex on feed intake (boar = 100)

Phase Boar Barrow Gilt

Grower (45 to 130 lb) 100 108 105Finisher (130 to 250 lb) 100 114 101

• GeneticsGenetics play an important role

in determining feed intake levels inswine. Genetic lines selected prima-rily for improved feed efficiency orfor leanness may also be indirectlyselected for low feed consumption.Thus, pigs from different geneticlines may consume different

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• Other factorsCrowding, limited feeder space

and disease often reduce feed con-sumption. These problems shouldbe identified and treated by makingthe appropriate changes in manage-ment or facilities, rather than bymaking diet changes. Further, alter-ing nutrient density will not over-come performance reductionsresulting from crowding. Feederdesign and management affect feedconsumption somewhat, but play agreater role in managing feed wast-age. Assuming adequate feedaccess is provided, feeder designusually is of less importance thanadjustments to reduce or minimizefeed wastage. One exception maybe sows during lactation, if thefeeder design limits a sow’s accessto feed.

Health

When pigs are exposed to anti-gens (substances foreign to the body),there may be fewer nutrients avail-able for normal growth. Managementprocedures such as segregated earlyweaning (SEW) or medicated earlyweaning (MEW) are being employedto reduce or eliminate the pig’s expo-sure to antigens. Presumably becauseof an improved health status, SEW orMEW pigs consume more feed, growfaster and require less feed per unitof gain from weaning to slaughterweight than do pigs weaned afterabout 21 days of age and kept in thevicinity of older pigs.

Information on the relationshipbetween pig health and nutrientrequirements is being generated.Preliminary research indicates thatamino acid requirements(expressed as amount/day) areincreased in high-health pigs,because of their greater capacity forlean growth. Starting pigs derivedfrom SEW or MEW programsshould not require diets containinghigher concentrations of nutrientsthan those listed in Table 11. Their

NutrientRecommendations

We believe the nutrient recom-mendations in Tables 11, 12, 13, 14,15 and 16 will result in a “best-cost” feeding strategy for most pro-ducers the majority of the time.However, certain conditions (i.e.,specific genetic populations, eco-nomic, nutrient availability, nutri-ent profile and nutrientinteractions) may require signifi-cant deviations from the recom-mendations presented. Also, thecurrent debate surrounding theenvironmental consequences ofnitrogen and phosphorus excretionwas considered in the developmentof amino acid and phosphorusrecommendations.

Although crude protein valuesstill appear on feed labels and insome feeding recommendations,we did not list dietary proteinrecommendations because pigs donot require protein in their diet.Instead they require amino acids,which are found in protein. Therecommended levels for the mostcritical amino acids are given inTables 11, 12, 13, 14 and 15. Lysine isthe first limiting amino acid ingrain-soybean meal-based diets. Inthese diets, there is a strong rela-tionship between the protein and

greater nutrient demand should bemet by a higher feed consumption.The lean gain classifications forgrowing-finishing pigs in this pub-lication are a function of both thepig’s genetics and the environment.Health status is one of the environ-mental constraints on lean gain.Therefore, based on the availableevidence, we believe categorizinggrowing-finishing pigs as high,medium or low lean gain and feed-ing them as described in this publi-cation accounts for the impact ofhealth status on amino acidrequirements.

the lysine level of the diet. Forexample, a corn or milo soybeanmeal-based diet containing .95%lysine will contain about 18% pro-tein. A diet with .80% lysine willcontain about 16% protein and adiet with .65% lysine has about 14%protein.

The recommendations for tryp-tophan, threonine, methionine andmethionine+cystine were derivedfrom an optimum pattern or ratioamong amino acids that we estab-lished (Table 17). We assumed thatthe pattern of amino acids requiredchanges throughout the growthstages, except for tryptophan andmethionine. Lysine is needed in amuch larger proportion for the syn-thesis of new tissue than for main-tenance. Thus, for example, therecommended amount of threoninein the diet as a percent of lysineincreases from 64% in the startingphase to 68% in the finishing phase.

The ranges presented for tracemineral and vitamin additions offerfeed manufacturers greater flexibil-ity, which often results in cost sav-ings in preparing custom productsfrom our nutrient recommenda-tions. The minimum values gen-erally represent the quantityrecommended by the NationalResearch Council (1998). The uppervalues do not represent the maxi-mum safe or tolerance levels, butinstead a reference point abovewhich further additions will notlikely improve performance. We donot necessarily recommend supply-ing minimum or maximum levelson a routine basis. An example ofappropriate trace mineral and vita-min additions to pig feed is shownin Table 16.

The recommendations reflectdifferences in nutrient require-ments for pigs according to theirstage of production, sex, leangrowth rate and milk production.We assumed the same feed intakefor pigs with different lean growthrates, an assumption that is not al-ways true. We also assumed pigsare housed under thermoneutral

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Table 11. Nutrient recommendations for growing swine (as-fed basis)a, b

Type of diet Starter 1 Starter 2 Starter 3 Grower 1 Grower 2 Finisher 1 Finisher 2/transitionc

Body wt, lb 8 to 13 13 to 25 25 to 45 45 to 80 80 to 130 130 to 190 190 to 250Expected feed intake, lb/dayd .55 1.2 2.0 3.3 4.6 5.8 6.9

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -% of Diet - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total 1.55 1.35 1.20 1.00 .85 .70 .55Lysine, digestible 1.29 1.12 .99 .82 .68 .55 .41Tryptophan .28 .24 .22 .18 .15 .13 .10Threonine .99 .86 .77 .66 .56 .48 .37Methionine .40 .35 .31 .26 .22 .18 .14Methionine+cystine .88 .77 .68 .57 .49 .41 .32Calcium .90 .85 .75 .70 .60 .55 .50Phosphorus, total .77 .67 .62 .58 .51 .47 .43Phosphorus, available .56 .44 .34 .29 .22 .19 .16

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Calculated Daily Intake, g - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total 3.9 7.4 10.9 15.0 17.8 18.4 17.2Lysine, digestible 3.2 6.1 9.0 12.2 14.2 14.5 13.0Tryptophan .7 1.3 2.0 2.7 3.2 3.3 3.1Threonine 2.5 4.7 7.0 9.9 11.7 12.5 11.7Methionine 1.0 1.9 2.8 3.9 4.6 4.8 4.5Methionine+cystine 2.2 4.2 6.2 8.6 10.1 10.7 10.0Calcium 2.3 4.6 6.8 10.5 12.5 14.5 15.7Phosphorus, total 1.9 3.7 5.6 8.7 10.7 12.4 13.5Phosphorus, available 1.4 2.4 3.1 4.3 4.6 5.0 5.0

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Additions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Minerals

Salt, %e 0 to .4 0 to .4 .25 to .4 .25 to .4 .25 to .4 .25 to .4 .25 to .4Copper, ppm 6 to 15 6 to 15 5 to 15 4 to 15 4 to 15 3 to 15 3 to 15Iodine, ppm .15 to .5 .15 to .5 .15 to .5 .15 to .5 .15 to .5 .15 to .5 .15 to .5Iron, ppm 100 to 150 90 to 150 80 to 150 70 to 150 60 to 150 50 to 150 40 to 150Manganese, ppm 4 to 30 3 to 30 3 to 30 3 to 30 2 to 30 2 to 30 2 to 30Selenium, ppmf .3 .3 .3 .3 .3 .3 .3Zinc, ppm 100 to 150 90 to 150 80 to 150 70 to 150 60 to 150 50 to 150 50 to 150

Vitamins

Vitamin A, IU/lb 1000 to 4000 900 to 4000 800 to 4000 700 to 4000 650 to 4000 600 to 4000 600 to 4000Vitamin D3, IU/lb 100 to 400 90 to 400 80 to 400 70 to 400 70 to 400 70 to 400 70 to 400Vitamin E, IU/lb 7.5 to 30 6 to 30 5 to 30 5 to 20 5 to 20 5 to 20 5 to 20Vitamin K, mg/lbg 1 to 3 1 to 3 1 to 3 1 to 3 1 to 3 1 to 3 1 to 3Riboflavin, mg/lb 2 to 10 2 to 10 2 to 10 2 to 10 1 to 10 1 to 10 1 to 10Niacin, mg/lb 10 to 50 7 to 50 6 to 50 5 to 50 4 to 50 4 to 50 3 to 50Pantothenic acid, mg/lb 6 to 25 5 to 25 4 to 25 4 to 25 4 to 25 4 to 25 3 to 25Choline, mg/lbh 0 to 100 0 to 100 0 to 100 0 to 100 0 to 100 0 to 100 0 to 100Biotin, mg/lb 0 0 0 0 0 0 0Vitamin B12, mg/lb .01 to .02 .01 to .02 .01 to .02 .005 to .02 .003 to .02 .003 to .02 .002 to .02Folic acid, mg/lb 0 0 0 0 0 0 0

aAssumes a mixture of medium lean gain barrows and gilts (.55 to .70 lb of fat-free lean/day from 45 to 250 lb). All diets are full-fed underthermoneutral conditions.bDigestible and available nutrient levels are calculations based on a corn-soybean meal diet.cProvide a total of 4 lb/pig (at least 3 lb after weaning) to pigs > 13 lb at weaning, but < 28 days of age.dAverage dietary ME density is 1.5 Mcal/lb.eAdjust salt additions according to quantity of dried whey and plasma proteins included in the diet. Dietary sodium levels > 3000 ppm are notlikely to improve performance.fMaximum legal addition is .3 ppm.gMenadione activity.hSoybean meal is an excellent source of choline. Starting diets containing less than 100 lb soybean meal/ton should contain about 50 mg/lb ofadded choline.

23

Table 12. Recommended dietary levels (%) of amino acids for HIGH, MEDIUM, and LOW lean gain swine (as-fed basis)a, b, c

Type of diet Grower 1 Grower 2 Finisher 1 Finisher 2Body wt, lb 45 to 80 80 to 130 130 to 190 190 to 250

Sexd B G B G B G B GExpected feed intake, lb/daye 3.3 3.3 4.7 4.5 6.2 5.5 7.2 6.6

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - High Lean Gainf - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total 1.10 1.10 .97 1.01 .77 .87 .62 .68Lysine, digestible .90 .90 .78 .82 .61 .70 .49 .54Tryptophan .20 .20 .17 .18 .14 .16 .11 .12Threonine .73 .73 .64 .67 .52 .59 .42 .46Methionine .29 .29 .25 .26 .20 .23 .16 .18Methionine+cystine .63 .63 .55 .58 .45 .50 .36 .39

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Medium Lean Gaing- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total 1.00 1.00 .83 .87 .65 .74 .53 .57Lysine, digestible .82 .82 .67 .70 .52 .59 .41 .44Tryptophan .18 .18 .15 .16 .12 .13 .09 .10Threonine .66 .66 .55 .58 .44 .50 .36 .39Methionine .26 .26 .22 .23 .17 .19 .14 .15Methionine+cystine .57 .57 .48 .50 .38 .43 .31 .33

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Low Lean Gainh - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total .80 .80 .69 .72 .55 .62 .45 .49Lysine, digestible .64 .64 .54 .57 .42 .48 .33 .37Tryptophan .14 .14 .12 .13 .10 .11 .08 .09Threonine .53 .53 .45 .47 .37 .42 .31 .34Methionine .21 .21 .18 .19 .14 .16 .12 .13Methionine+cystine .46 .46 .39 .41 .32 .36 .26 .29

aAll diets are full fed under thermoneutral conditions.bDigestible nutrient levels are calculations based on a corn-soybean meal diet.cSufficient data are not available to indicate that requirements for other nutrients are different from those in Table 11 for animals of theseweights.dB=barrows and G=gilts.eAverage dietary ME density is 1.5 Mcal/lb.f> .70 lb of fat-free lean/day from 45 to 250 lb.g.55 to .70 lb of fat-free lean/day from 45 to 250 lb.h< .55 lb of fat-free lean/day from 45 to 250 lb.

conditions, which is also not alwaystrue.

When is it appropriate to alterdietary nutrient density accordingto feed intake?

• Starting and growing pigsThe daily amino acid and min-

eral recommendations for startingand growing pigs (8 to 130 lb) weredesigned for pigs consuming thequantities of feed indicated at thetop of Tables 11, 12, 13, and 15.When these pigs consume less feedthan indicated, we do not recom-mend increasing amino acid andmineral concentrations in anattempt to maintain our calculateddaily nutrient intakes. In otherwords, do not attempt to formulatediets for starting and growing pigs

for a specific intake of nutrients.The relationship between lean

gain and energy intake is linear forpigs within this weight range.Changes in energy intake directlyaffect lean gain, which may alteramino acid requirements. If energyis limiting because feed consump-tion is lower than expected, leangain also will be lower. In this case,providing more amino acids byincreasing the percentages in thediet probably will not improve pigperformance. An exception mightbe when fat is added to the dietand feed intake is reduced becauseless feed is required to meet thepig’s energy requirement. There-fore, increasing the percentages ofamino acids and minerals to main-tain a constant nutrient:calorie ratiois recommended. However, newly

weaned pigs (< 28 days of age) donot respond to changes in energydensity of the diet. Nutrient levelsshould not be adjusted in thesediets until pigs have been weanedfor about two weeks.

Higher than expected con-sumption during the starting andgrowing phases is not a problemand our recommended percentagesof amino acids and minerals shouldbe maintained. This will result indaily nutrient intakes that exceedour calculated levels. Energy intakewill also be greater than expected,so the additional amino acids andminerals will be needed to supportincreased lean gain.

• Finishing pigsAt times, it may be advisable to

increase the percentages of amino

24

Table 13. Calculated daily intake (g) of amino acids for HIGH, MEDIUM, and LOW lean gain swine (as-fed basis)a, b, c

Type of diet Grower 1 Grower 2 Finisher 1 Finisher 2Body wt, lb 45 to 80 80 to 130 130 to 190 190 to 250

Sexd B G B G B G B GExpected feed intake, lb/daye 3.3 3.3 4.7 4.5 6.2 5.5 7.2 6.6

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - High Lean Gainf - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total 16.5 16.5 20.8 20.7 21.7 21.7 20.4 20.4Lysine, digestible 13.5 13.5 16.7 16.7 17.2 17.2 15.9 15.9Tryptophan 3.0 3.0 3.7 3.7 3.9 3.9 3.7 3.7Threonine 10.9 10.9 13.7 13.7 14.8 14.8 13.9 13.9Methionine 4.3 4.3 5.4 5.4 5.6 5.6 5.3 5.3Methionine+cystine 9.4 9.4 11.8 11.8 12.6 12.6 11.8 11.8

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Medium Lean Gaing - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Low Lean Gainh - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


aAll diets are full fed under thermoneutral conditions.bDigestible nutrient levels are calculations based on a corn-soybean meal diet.cSufficient data are not available to indicate that requirements for other nutrients are different from those in Table 11 for animals of these weights.dB=barrows and G=gilts.eAverage dietary ME density is 1.5 Mcal/lb.f> .70 lb of fat-free lean/day from 45 to 250 lb.g.55 to .70 lb of fat-free lean/day from 45 to 250 lb.h< .55 lb of fat-free lean/day from 45 to 250 lb.

acids and minerals in the diet of fin-ishing pigs (> 130 lb) consuming lessfeed than indicated in Tables 11, 12,13 and 15. In other words, it may beappropriate to formulate finishingdiets to a specific intake of nutrients.Compared with younger pigs, energyintake and lean gain are not as closelyrelated during this stage. Moderatereductions in energy intake are lesslikely to affect lean growth rate.Therefore, if actual feed intake iswithin 90% of listed levels, our cal-culated daily amino acid and mineralrecommendations should be main-tained by increasing the density ofthese nutrients in the diet.

For example, assume 190 to 250lb finishing pigs were fed a dietcontaining .55% lysine and theirfeed intake was 6.4 lb or 2905 g/day. Therefore, the pigs’ daily

lysine intake was 16.0 g/day (2905x .055) which is below that recom-mended in Table 11. The pigs’lysine intake was reduced becausethey were consuming about 7% lessfeed than expected (Table 11).Because the reduction in feed intakeis within 10% of the expectedamount shown in Table 11, the dietcan be reformulated so the pigs con-sume the recommended amount oflysine (17.2g/day).

17.2 g lysine/day = .00592905 g feed/day

.0059 x100 = .59% lysine

Similarly, nutrient densityshould be increased to maintain aconstant nutrient:calorie ratio whenfat is added to the diet. However,the percentages of amino acids and

minerals in the diet should not beadjusted when severe reductions infeed consumption (> 10%) occur.Examples of when not to increasenutrient density include (1) heatstress resulting from continuedexposure to temperatures in excessof 90oF and (2) crowding.

During the finishing stages,increases in feed intake may occurduring periods when additionalenergy is needed for maintenance(such as during cold weather).Additional amino acids and miner-als are not needed. Thus, we rec-ommend that producers reduce thepercentages of amino acids andminerals in the diet to maintain ourcalculated daily intakes of thesenutrients. This recommendationonly applies when temperaturesremain cold for a prolonged

25

Table 14. Nutrient recommendations for adult breeding swine (as-fed basis)a, b

Type of diet Developing gilt Gestation Lactation Breeding BoarBody wt, lb 230 lb to flushing21-day litter weight < 120 lb > 120 lb

Expected feed intake, lb/dayc 6.0d 4.0d 10.5 12.0 12.0 14.0 5.5d

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - % of Diet - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total .70 .55 .90 .85 1.05 1.00 .70Lysine, digestible .54 .42 .73 .69 .87 .82 .54Tryptophan .13 .10 .16 .15 .19 .18 .13Threonine .48 .45 .58 .55 .67 .64 .57Methionine .18 .14 .23 .21 .26 .25 .18Methionine+cystine .41 .37 .43 .41 .51 .48 .47Calcium .75 .90 .90 .90 .90 .90 .75Phosphorus. total .65 .75 .75 .75 .75 .75 .65Phosphorus, available .40 .49 .49 .49 .49 .49 .40

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - Calculated Daily Intake, g - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total 19.1 10.0 43.0 46.5 57.4 63.5 17.5Lysine, digestible 14.7 7.7 34.8 37.6 47.1 52.1 13.4Tryptophan 3.4 1.9 7.7 8.4 10.3 11.4 3.3Threonine 13.0 8.1 27.5 29.8 36.7 40.6 14.2Methionine 5.0 2.6 10.8 11.6 14.4 15.9 4.6Methionine+cystine 11.1 6.7 20.6 22.3 27.6 30.5 11.7Calcium 20.4 16.3 42.9 49.0 49.0 57.2 18.7Phosphorus, total 17.7 13.5 35.6 41.0 41.0 47.5 16.2Phosphorus, available 11.0 8.9 23.5 26.5 26.5 31.0 10.0

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Additions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Minerals

Salt, % .4 to .6 .4 to .6 .4 to .6 .4 to .6 .4 to .6 .4 to .6 .4 to .6Copper, ppm 5 to 15 5 to 15 5 to 15 5 to 15 5 to 15 5 to 15 5 to 15Iodine, ppm .15 to .5 .15 to .5 .15 to .5 .15 to .5 .15 to .5 .15 to .5 .15 to .5Iron, ppm 80 to 150 80 to 150 80 to 150 80 to 150 80 to 150 80 to 150 80 to 150Manganese, ppm 20 to 40 20 to 40 20 to 40 20 to 40 20 to 40 20 to 40 20 to 40Selenium, ppme .3 .3 .3 .3 .3 .3 .3Zinc, ppm 80 to 150 80 to 150 80 to 150 80 to 150 80 to 150 80 to 150 80 to 150

Vitamins

Vitamin A, IU/lb 2000 to 5000 2000 to 5000 2000 to 5000 2000 to 5000 2000 to 5000 2000 to 5000 2000 to 5000Vitamin D3, IU/lb 90 to 500 90 to 500 90 to 500 90 to 500 90 to 500 90 to 500 90 to 500Vitamin E, IU/lb 20 to 40 20 to 40 20 to 40 20 to 40 20 to 40 20 to 40 20 to 40Vitamin K, mg/lbf 1 to 3 1 to 3 1 to 3 1 to 3 1 to 3 1 to 3 1 to 3Riboflavin, mg/lb 2 to 10 2 to 10 2 to 10 2 to 10 2 to 10 2 to 10 2 to 10Niacin, mg/lb 5 to 50 5 to 50 5 to 50 5 to 50 5 to 50 5 to 50 5 to 50Pantothenic acid, mg/lb 6 to 25 6 to 25 6 to 25 6 to 25 6 to 25 6 to 25 6 to 25Choline, mg/lb 250 to 500 250 to 500 250 to 500 250 to 500 250 to 500 250 to 500 0 to 500Biotin, mg/lb 0 to .2 0 to .2 0 to .2 0 to .2 0 to .2 0 to .2 0 to .2Vitamin B12, mg/lb .007 to .02 .007 to .02 .007 to .02 .007 to .02 .007 to .02 .007 to .02 .007 to .02Folic acid, mg/lb .6 to 1.8 .6 to 1.8 .6 to 1.8 .6 to 1.8 .6 to 1.8 .6 to 1.8 .6 to 1.8

aAll diets are full fed (except developing gilt, gestation and breeding boar diets) under thermoneutral conditions.bDietary and available nutrient levels are calculations based on a corn-soybean meal diet.cAverage dietary ME density is 1.5 Mcal/lb.dAdjust to achieve a desired body condition or weight gain.eMaximum legal addition is .3 ppm.fMenadione activity.

26

Table 15. Nutrient recommendations for developing breeding swine (as-fed basis)a, b, c

Type of diet Terminal-line developing boar Maternal-line developing gilt

Body wt, lb 45 to 80 80 to 130 130 to 190 190 to 230 45 to 80 80 to 130 130 to 190 190 to 230

Expected feed intake, lb/dayd 3.1 4.3 5.5 6.5 3.3 4.5 5.5 6.5

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - % of Diet - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total 1.25 1.10 .90 .70 1.10 .95 .80 .65Lysine, digestible 1.03 .90 .72 .56 .91 .77 .64 .51Tryptophan .23 .20 .16 .13 .20 .17 .14 .12Threonine .83 .72 .61 .48 .73 .63 .54 .44Methionine .33 .29 .23 .18 .29 .25 .21 .17Methionine+cystine .71 .62 .52 .41 .63 .54 .46 .38Calcium .90 .85 .80 .75 .85 .80 .75 .70Phosphorus, total .80 .75 .70 .65 .75 .70 .65 .60Phosphorus, available .51 .47 .44 .40 .47 .43 .39 .35

- - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - Calculated Daily Intake, g - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Lysine, total 17.6 21.4 22.4 20.8 16.5 19.4 20.0 19.1Lysine, digestible 14.4 17.5 18.1 16.4 13.6 15.8 16.0 15.0Tryptophan 3.2 3.9 4.0 3.7 3.0 3.5 3.6 3.4Threonine 11.6 14.1 15.2 14.1 10.9 12.8 13.6 13.0Methionine 4.6 5.6 5.8 5.4 4.3 5.0 5.2 5.0Methionine+cystine 10.0 12.2 13.0 12.1 9.4 11.1 11.6 11.1Calcium 12.7 16.6 20.0 22.1 12.7 16.3 18.7 20.7Phosphorus, total 11.3 14.6 17.5 19.2 11.2 14.3 16.2 17.7Phosphorus, available 7.2 9.2 11.0 11.8 7.0 8.8 9.7 10.3aAll diets are full-fed under thermoneutral conditions.bDigestible and available nutrient levels are calculations based on a corn-soybean meal diet.cSufficient data are not available to indicate that requirements for other nutrients are different from those in Table 11 for animals of these weights.dAverage dietary ME density is 1.5 Mcal/lb.

period. Temperatures should bemonitored where the pig is (sameheight and location). Rememberthat air movement, bedding,humidity and group size affect howpigs perceive temperature.

Including fibrous ingredientsin the diet will increase feedconsumption. Nutrient density canbe reduced in these diets to main-tain a constant nutrient:calorie ratio.As temperatures fall below thelower critical temperature, con-sumption of fibrous diets may notincrease to the same extent as forlow-fiber diets. This is because (1)feed intake has already increased inresponse to the reduced energy den-sity and (2) consumption of bulkydiets is limited by gastrointestinalcapacity. Therefore, reductions innutrient density other than for ener-gy density are not recommended.

• Adult breeding swineBreeding boars or gestating

sows and gilts fed amounts differ-

PracticalApplications and

Outcomes

The recommendations and con-cepts presented in this publicationare intended to help pork producersapply appropriate nutrition-basedtechnologies. These technologies aredesigned so that nutrition does notlimit production potential and prof-itability in most situations. How-ever, pigs must be capable ofresponding to improved nutrition.Weaknesses in the operation such ascrowding, poor sanitation, inad-equate ventilation, chronic disease,and lack of proper temperaturecontrol will limit the response tonutrition. Optimum nutrition cannot substitute for good manage-ment practices but must be used tocomplement good management.

ent from those recommended inTable 14 should receive our calcu-lated daily nutrient intakes. Thus,the percentages of amino acids andminerals should be increased forlower feeding levels and decreasedfor higher feeding levels. This isparticularly important for boarsbecause inadequate amino acidintake can depress libido. If dietsdesigned for higher feeding levelsare formulated on a total phospho-rus basis, check to see if the dailyavailable phosphorus recommen-dation in Table 14 is met. It is pos-sible to meet our total phosphorusrecommendation but not the avail-able phosphorus recommendationwith diets containing largeamounts of corn or milo. Lactationdiets should not be adjusted whensows consume more feed thanlisted in Table 14. Adding fat to lac-tation diets will reduce feed intakeslightly. The nutrient:calorie ratioshould be held constant in lactationdiets containing fat by increasing

the percentages of amino acids andminerals.

27

Table 16. Example dietary additions of salt, trace minerals and vitamins from concentrates,base mixes, or premixesa, b

Type of diet Starter Grower Finisher Breeding

Body wt, lb 8 to 45 45 to 130 130 to 250

- - - - - - - - - - - - - - - - - - - - - - - - - - Additions - - - - - - - - - - - - - - - - - - - - - - - - - -

Minerals

Salt, % .3c .3 .3 .5

Copper, ppm 10 8 6 10

Iodine, ppm .25 .2 .15 .25

Iron, ppm 125 100 75 125

Manganese, ppm 15 12 9 30

Selenium, ppmd .3 .3 .3 .3

Zinc, ppm 125 100 75 125

Vitamins

Vitamin A, IU/lb 2500 2000 1500 3000

Vitamin D3, IU/lb 250 200 150 300

Vitamin E, IU/lb 14 11 8.5 30

Vitamin K, mg/lbe 2 1.6 1.2 2

Riboflavin, mg/lb 5 4 3 5

Niacin, mg/lb 15 12 9 15

Pantothenic acid, mg/lb 10 8 6 10

Choline, mg/lb 0f 0 0 250

Biotin, mg/lb 0 0 0 .1

Vitamin B12, mg/lb .015 .012 .009 .01

Folic acid, mg/lb 0 0 0 .75

aIf selenium is not included in the trace mineral premix, one trace mineral premix will supplythese additions. The amount of trace mineral premix added/ton of feed will vary.bTwo vitamin premixes (one for starter to finisher and one for breeding swine) will supplythese additions. The amount of vitamin premix added/ton of feed will vary.cAdjust salt additions in the starter diet according to the quantity of dried whey and plasmaproteins included in the diet. Dietary sodium levels > 3000 ppm are not likely to improve pigperformance.dMaximum legal addition is .3 ppm.eMenadione activity.fSoybean meal is an excellent source of choline. Starting diets containing less than 100 lb soy-bean meal/ton should contain 50 mg/lb of added choline.

Table 17. Amino acid ratios for pigs in relation to lysine (lysine =100)

Type of diet Starter Grower Finisher Gestation Lactation

Body wt, lb 8 to 45 45 to 130 130 to 250

Lysine 100 100 100 100 100

Tryptophan 18 18 18 19 18

Threonine 64 66 68 81 64

Methionine 26 26 26 26 25

Methionine + Cystine 57 57 58 67 48

Breeding HerdManagement

A “limit-feeding” program is rec-ommended for developing gilts afterthey reach about 230 lb and for ges-tating females and breeding boars.However, a “limit-feeding” programshould limit only energy and not theintake of other nutrients, such asamino acids, minerals and vitamins.Energy intake is limited to keep ani-mals from becoming too fat. Exces-sive feeding of breeding animalsleads to increased feed cost andinterferes with reproduction andlongevity. Sows that are overfedimmediately after breeding andthroughout gestation often sufferhigh embryonic mortality, and thusproduce smaller litters than sows fedproper amounts. Sows that havebecome too fat tend to have more far-rowing difficulties, crush more pigsand eat poorly during lactation. Thisis especially true during the summerwhen sows are subject to heat stress.

The dietary nutrient recommen-dations for developing gilts, gestat-ing females and breeding boarsshown in Table 14 assume that theyare fed 6, 4 and 5.5 lb of feed daily,respectively. When daily feed intakeis adjusted, it is important that theconcentrations of amino acids, min-erals, and vitamins in the diet beadjusted accordingly. Aim to pro-vide a constant daily intake ofamino acids, minerals, and vitaminsregardless of feed intake.

How much feed shouldgestating sows and developinggilts receive?

During mild weather (spring/fall) about 6 to 6.5 Mcal of ME peranimal per day (4 to 4.5 lb of a cornor milo-soybean diet) will keep 350--to 400-lb gestating sows in “good”condition. However, energy intakewill need to be decreased or increaseddepending on the condition andweight of the sow and environmentalconditions. See Table 18 for approxi-mate energy and feed needs of ges-

28

Table 18. Approximate daily energy and feed needs of gestating sows and 1- to 2-year-oldbreeding boarsa

Sows Boars

Body wt, lb Mcal ME/day lb feed/dayb Mcal ME/day lb feed/dayb

300 5.4 3.7 5.9 4.0

400 6.5 4.4 6.9 4.7

500 7.4 5.0 7.9 5.3

aAnimals housed on dry floors in crates in an environmentally controlled facility with mini-mal drafts and ambient temperature 65oF.bCorn-soybean meal diet containing 1.5 Mcal ME/lb

tating sows according to their bodyweight. Sows (350 to 400 lb) housedoutside during the winter shouldreceive about 7.5 to 9.0 Mcal of ME/day (5 to 6 lb of a corn or milo-soybean meal diet). Developing giltsshould be restricted to about 90% ofad libitum feed intake or about 6 lb/day from about 230 lb until 2 weeksbefore mating.

How can limit-feeding of sowsbe accomplished?

The success of limit-feedingsows and gilts depends on control-ling the intake of each animal. Caremust be taken to see that eachreceives her share. Individual sowfeeding stalls are effective devicesfor controlling boss sows. Intervalfeeding is another practical methodfor limiting the feed intake of sowsduring pregnancy. With intervalfeeding sows are allowed to con-sume two or three days worth offeed in one day and then wait twoor three days before being pro-vided access to feed again. Adjust-ments in daily intake are made byaltering either the time on thefeeder (2 to 12 hours) or time offthe feeder (2 or 3 days). For exam-ple, two hours out of 72 is an ade-quate feeding time if enough feederspace is provided so all sows caneat at one time. With time on thefeeders restricted, one feeder holeper sow is essential. More totalfeed is required during gestationwhen sows are interval-fed,because feed efficiency is reduced.For gilts every-third-day feeding isnot recommended, because theygain less weight and farrow smallerpigs than gilts fed once daily. Giltsare not as able as sows to consumelarge quantities of feed in short timeintervals.

What about flushing?Litter size in limit-fed gilts can

be increased by increasing theirfeed intake or allowing ad libitumaccess to feed beginning 11 to 14days before mating. This is called“flushing.” Higher energy intake

during this time will maximize thenumber of eggs released by the ova-ries. Reduce feed intake to about 4to 4.5 lb/day when mating occurs.Overfeeding during early gestationmay increase embryonic mortalityand reduce litter size.

Should feed intake beincreased during late gestation?

The majority of fetal develop-ment occurs during the last 2 to 3weeks of gestation. Research indi-cates that giving sows 2 to 3 lbmore feed per day during the last 2to 3 weeks of gestation can slightlyimprove the number of pigsweaned per litter. Do not give extrafeed to fat sows during late gesta-tion, or they probably will havepoor feed intakes during lactation.

How should lactating sows befed?

Sows should be full-fed duringlactation to obtain maximum milkproduction, minimize weight lossand improve rebreeding perfor-mance. Many sows perform bestwhen they are allowed to consume allthe feed they can beginning the daythey farrow. Severe feed restrictionafter farrowing predisposes sows toconstipation and delayed return toestrus. It is easier for some people,however, to detect lactational prob-lems in sows if they are offered lim-ited amounts of feed during the first3 days after farrowing. If limit-feeding is practiced, provide at least3 lb of feed the day of farrowing andincrease the offering 3 lb/day there-

after. By day four postfarrowing, thesow should be given ad libitum (freechoice) access to feed. Record theamount of feed added to the sow’sfeeder daily, especially if more thanone person is feeding the sows.

How about feeding afterweaning?

After weaning, feeding ratewill depend on how adequately thefemale was fed during lactationand her body condition. Generally,4 to 4.5 lb/day of a corn or milo-soybean meal diet is adequate. Pro-vide 5 or more pounds of feed/dayto thin sows. Do not withhold feedfrom sows after weaning, becauseit reduces subsequent litter size.

How should developing andbreeding boars be fed?

Guidelines for feeding develop-ing boars are shown in Table 15.When the boars weigh about 230 lbthey should begin to receiverestricted quantities of feed toavoid excessive weight gain. Offerthe boars about 5 to 5.5 lb of a cornor milo-soybean meal diet/day(about 7.5 Mcal of ME/day). Thediet should contain nutrient levelssimilar to those for developing giltsshown in Table 14. When boars arebetween about 1 year and 2 yearsof age, we suggest they be fed togain about .4 to .55 lb/day (145 to200 lb/year). To accomplish thisand maintain fertility, feed breed-ing boars a different diet than theone used for gestating females. Thegoal is to restrict energy intake to

29

slow growth rate, but to maintainhigh amino acid, vitamin and min-eral intakes to preserve fertility andlibido. Weigh boars periodically todetermine the appropriate feedingrate for specific conditions. Table 18gives approximate energy and feed-ing rates to allow boars to gainabout .4 to .55 lb/day. Boars > 2years of age should be fed to gainat a slower rate, because they arenearing their mature body size. Aswith sows, the daily feeding ratemust be changed to reflect differ-ences due to housing temperatureand body condition of the boar.

What role does fiber ornonstarch polysaccharides have insow diets?

Plant-based feed ingredientscontain fiber or nonstarch polysac-charides (NSP) which cannot bedigested by pigs. Instead NSP arefermented by microorganisms inthe large intestine. The most abun-dant NSP in plants include cellu-lose, hemicelluloses and pectins.Gestating sows are excellent candi-dates to receive high NSP-contain-ing diets. Limit-fed gestating sowsobtain more energy from fibrousfeedstuffs than growing pigs doand they have a higher fermenta-tion capacity in the hindgut. Inaddition, sows can consume moreof a concentrate diet than necessaryto meet their energy requirementduring gestation. This excess feedintake capacity can be exploited byincluding low-energy, bulky feedsin the diets of gestating sows.

Litter size weaned may beimproved by about .5 pigs/litterwhen NSP is added to the sow dietduring gestation. In addition, NSPin the sow diet may improve sowlongevity in the herd. To maximizethe chance of an improvement insow reproductive performance fromincreased NSP intake, it seems sowsshould consume 350 to 400 g/d ofneutral detergent fiber (NDF) dur-ing gestation. Diets containing 45%wheat midds, 20% soybean hulls,25% alfalfa meal, 30% sugar beet

pulp, or 40% oats provide sowsabout 350 g/d of NDF. There is nostrong evidence that increasing theNSP level in the lactation diet im-proves sow reproductive perfor-mance. Fibrous ingredients in thelactation diet may help control con-stipation, however (see the nextquestion). Bulky diets containing ahigh level of NSP results in a sowthat is more “satisfied” after con-suming a meal than one fed typicalcorn or milo-soybean meal-baseddiets. The same situation has beenobserved with breeding boars. Con-sider that the costs associated withmanure handling may increase dueto the larger volume of solids pro-duced when high NSP diets are fed.

Can sow constipation becontrolled by feeding a specificfeed ingredient?

Maybe. Results with laxativesare variable. Most of the publishedresearch indicates that laxatives donot improve sow reproductive per-formance. Often sows are consti-pated because they are not givenenough feed during the first fewdays after farrowing. If sows areconstipated, try offering them morefeed after farrowing before addinga laxative to the diet. Also, checkthat the sows have an ample sup-ply of water.

Fibrous feedstuffs or certainchemicals may serve as laxatives.Fibrous feedstuffs such as beetpulp, alfalfa, oats, pysillium, soy-bean hulls and wheat bran have ahigh water binding capacity andcan act as a laxative. Chemical laxa-tives include potassium chloride (15lb/ton), Epsom salts (30 lb/ton),and Glauber salts (60 lb/ton). Theseinclusion rates are recommendedwhen sows are fed 4 to 4.5 lb offeed/day. The level can be cut inhalf when sows are full-fed. Naturallaxative feedstuffs are preferred be-cause mineral salts may alter waterbalance in the body and irritate thedigestive system. Limit the amountof beet pulp, alfalfa, oats and wheatbran in the diet according to guide-

lines in Table 1 to avoid reducingthe energy density of the diet toomuch.

How does fat affect breedingherd performance?

Feeding fat to sows during lategestation may improve pigpreweaning survival rate by 2 to3%. The greatest response todietary fat is achieved in herds inwhich pig preweaning survival rateis less than 80%. For best results,sows should consume at least 2.5 lbof added fat before farrowing to im-prove pig survival rate. Feeding alactation diet with 3% added fat atthe rate of 6 lb/day for 14 days be-fore farrowing would be sufficient.

Sow feed intake usuallydecreases when fat is added to thelactation diet; however, energyintake may be increased slightly,especially during hot weather. Agreater increase in energy intake islikely during hot weather whensows are drip-cooled. Much of thisadditional energy consumed bysows fed fat-supplemented diets ismade available to the litter via themilk. Consequently, added fat mayincrease litter gain but does little toreduce sow weight loss duringlactation.

How can developing orreplacement gilts be fed to reducethe number of “downer sows”?

The dietary calcium and phos-phorus levels we recommend forgrowing-finishing pigs shown inTable 11 support excellent rates ofgain and feed efficiency, but are notsufficient to build the skeletal struc-ture and mineral reserves neededby developing gilts to reduce“downer sow” problems. Thedietary phosphorus level necessaryto achieve maximum growth andfeed efficiency is at least .1% lessthan that needed to achieve maxi-mum bone mineralization. Thus, werecommend that developing giltsfrom 45 to 230 lb be fed diets con-taining the levels of calcium andphosphorus shown in Table 15.

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Dietary calcium and phosphorusrecommendations for gilts afterthey are placed on a limit-feedingprogram at about 230 lb are shownin Table 14.

Will higher dietary levels ofcalcium, phosphorus, and othernutrients improve feet and legsoundness?

Probably not, although propernutrition is clearly important inmaintaining feet and leg sound-ness. Many research studies haveinvestigated the influence of nutri-tion on feet and leg soundness. Aslong as the diets contained nutrientdensities similar to the recommen-dations in this publication, no rela-tionship between nutrition and feetand leg soundness was found. Inother words, if pigs are fed accord-ing to the guidelines in this publica-tion, any feet and leg soundnessproblems encountered likely arecaused by genetic or environmentalfactors other than nutrition.

Growing PigManagement

Pigs undergo many physiologi-cal changes between weaning andmarket weight. The digestive sys-tem converts from one best suitedto using milk to one suitable for thebreakdown and absorption ofcomplex carbohydrates and pro-teins found in grain and soybeanmeal. Daily feed intake normallyincreases steadily between weaningand market weight. Lean growthrate reaches a plateau when thepigs weigh about 130 lb anddeclines thereafter. These changesare the basis for the feeding recom-mendations listed for growing-finishing pigs in this nutritionguide.

Pigs should have ad libitumaccess to feeds reformulated tocontain different ingredients andnutrient densities as they grow. Thisis commonly called “phase feed-ing.” Phase feeding is essential to

optimizing pig performance andcontrolling feed costs in a swineenterprise by limiting the time thatnutrients are over- or underfed. Inaddition, phase feeding reduces theamount of nitrogen and phosphoruspigs excrete. Starting pigs weighingless than about 25 lb should be feddiets containing several specialtyingredients. Thereafter, switch themto grain-soybean meal-based dietscontaining few, if any, specialty in-gredients. Reduce the nutrient den-sity of the diet as pigs approachmarket weight.

How does fat affect growingpig performance?

In growing-finishing pigs, fatconsistently improves feed effi-ciency. On average, feed efficiencyis improved by 2% for each 1%increment of added fat. Feedefficiency and daily gain areimproved more by feeding fat topigs during the summer than thewinter. For example, daily gain maybe increased by 1% for each 1% ad-dition of fat in the summer, whereaslittle, if any, improvement in gain isexpected in the winter. Carcass fatcontent is not greatly altered unlessadded fat levels exceed 5% of thediet and the amino acid:calorie ratioin the diet is not maintained con-stant. Energy intake is a major fac-tor limiting lean growth rate in pigsweighing less than about 130 lb. Fatadditions to grain-soybean mealdiets may increase energy intake,especially in hot weather, and im-prove lean growth rate in youngpigs. On the other hand, added fatis less valuable in finishing pigs, be-cause energy intake from grain-soy-bean meal diets is often sufficient tomaximize lean growth rate. Fatoften is added to starting pig dietsto aid in the manufacture ofpelleted, milk product-based diets.Also, research indicates that aslittle as 2.5% added fat (50 lb/ton)reduces dust in confinement build-ings by about 25%. Similar effectsare observed in feed mills. Reduceddust levels have improved health

implications for both pigs andpeople.

What happens when dietscontain too much protein?

Feeding excessive amounts ofprotein and amino acids usuallywastes money, results in increasednitrogen excretion, and reducesgrowth rate and feed efficiency. Agreater amount of nitrogen in themanure has the potential for con-taminating the environment,including increasing the level ofammonia in the atmosphere. Pigsalso will consume more water andthey may exhibit a mild diarrhea.

Should high levels of zinc beadded to starting pig diets?

Nutritionists typically add 100to 150 ppm of zinc to starting pigdiets to meet requirements forgrowth. Recently there has beeninterest in feeding nursery pigsdiets containing 2,000 to 3,000 ppmof zinc to combat postweaningstress and diarrhea. Also, zinc ionscause the organism responsible forswine dysentery (S. hyodysenteriae)to produce less toxin. Researchresults indicate the response tohigh levels of zinc in the diet ishighly variable; in some studies nochange in growth rate or feed effi-ciency has been observed, but inothers the response has been large(Table 7). Also, feces are madefirmer by high levels of zinc in thefeed. However, questions remainabout how zinc-containing manuremay affect anaerobic lagoons andthe soil. Over 99% of the zinc fed topigs is excreted in the manure.These factors suggest that the deci-sion to use high levels of zinc shouldbe made on a case-by-case basis.Careful monitoring of pig perfor-mance when high levels of zinc areadded is recommended. It is impor-tant that the extra zinc be suppliedby zinc oxide; otherwise toxicityproblems may develop. Add 2,500 to3,000 ppm (7.0 to 8.3 lb of zinc oxide/ton of complete feed assuming thezinc oxide contains 72% zinc) to feed

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for a maximum of 28 days postwean-ing, because zinc at these levels maybe toxic. Maintain about 10 ppm ofcopper in any diet containing 2,000to 3,000 ppm of zinc, because there isno additional growth response fromhigher dietary copper fortification.

What about separate sexfeeding?

Penning barrows separatelyfrom gilts and feeding them differ-ent diets allows producers to gainbetter precision in feeding pigs. Thefeed intake of gilts and barrowsbegins to differ significantly whenthey weigh about 80 lb. From 80 lbuntil market weight, gilts consumeabout 8% less feed than barrowsdo, but they deposit lean tissue atleast as fast as barrows. Thus, giltsneed diets with a greater concentra-tion of amino acids than barrowsdo; otherwise they will experienceslower growth and poorer effi-ciency of gain, and produce car-casses with lower lean content thantheir potential. The decision toseparate barrows from gilts andfeed them different diets should bebased on the producer’s produc-tion and marketing goals. A mar-keting system that rewards carcassleanness (value-based) usually isnecessary to maximize returnsfrom separate sex feeding. We haveprovided separate amino acid rec-ommendations for barrows andgilts in this publication.

What nutritional technologiesare available to reduce carcassbackfat or improve leanness?

The most effective way toreduce backfat or improve leannessis through genetic improvement.Nutritional strategies that maximizelean growth and minimize excessenergy intake over that required formaximum lean growth will producethe leanest carcasses. See Table 7 fora list of feed additives that areeffective in reducing carcass backfator improving leanness. Other tech-nologies are described below.

• Limit-feedingThe principle behind limit-

feeding is to reduce the amount ofexcess energy pigs have availablefor fat synthesis. Research showsthat restricting feed intake of finish-ing pigs (> 125 lb) to 80 or 85% ofad libitum causes an 11 to 17%(about .15 inches) reduction in 10th-rib backfat. However, the number ofdays to market increases by abouttwo weeks. Limit-feeding can bedone by restricting the time pigshave access to self feeders or floorfeeding several times each day. Wedo not recommend limit-feeding to80 or 85% of ad libitum intake, be-cause currently the increased pro-duction costs (which includeincreased management to monitorand adjust feed delivery devices)generally are not offset by a highercarcass premium.

• Dietary amino acid levelIn general, as dietary amino

acid density increases, carcassbackfat decreases. However, a largeincrease in the lysine level of fin-isher diets causes a relatively smallreduction in backfat. In a recentlarge study, a 47% increase indietary lysine level (from .59 to.87%) for medium lean gain finish-ing barrows reduced their backfatby 6% or .08 inches. No additionalreduction in backfat was observedwhen the diet contained more than.73% lysine. In gilts, carcass backfatwas reduced by 11% or .11 incheswhen dietary lysine level wasincreased from .59 to .87% duringthe finishing phase.

• BetaineA byproduct of sugar beet pro-

cessing, betaine currently is beingevaluated in finishing pig diets. Insome cases backfat has beenreduced by 8 to 14% when dietscontaining 1,250 ppm of betainewere fed for 35 to 40 days beforeslaughter. On the other hand, somestudies have shown no response tobetaine supplementation. Webelieve the response to betaine in

corn or milo-soybean meal diets isnot consistent enough to warrantroutine use. Thus, evaluate the useof betaine on a case-by-case basis.

Example Diets

Example diets for all classes ofswine are presented in Tables 19,21, 22, 24 and 25. Ingredient analy-sis values in Table 29 were used toformulate the diets. Diets contain-ing added fat were formulated tocontain the same lysine:calorie ratioas diets without added fat. Fatreduces feed intake and unless theamino acid density is increased pigperformance may be compromiseddue to a shortage of amino acidsrelative to calories. In general, thesediets promote best-cost gain.Because ingredient price and avail-ability are not constant, considerusing alternate feedstuffs to opti-mize cost of gain. Refer to Tables 1and 2 for guidelines when usingalternate energy and proteinsources.

Diets for 8 to 45 lb pigs

For reasons explained in theMethods of Supplying Nutrients sec-tion we recommend that most pro-ducers purchase complete pelleteddiets for starting pigs weighing lessthan about 25 lb. We present exam-ple starting diets to show many ofthe typical ingredients used in start-ing diets today. It is necessary to useat least three different diets forstarting pigs up to 45 lb to achievegood performance at low cost.

The starter 1/transition diet(Table 19) is a multipurpose diet.That is, it can be introduced to pigsbefore weaning as creep feed, fedto starting pigs from 8 to 13 lb bodyweight, or provided to pigs heavierthan 13 lb at weaning. Creep feed-ing is recommended beginning atabout 10 days of age for pigsweaned at 3 to 4 weeks of age andlater. There is general agreementthat a positive correlation existsbetween weight at weaning and

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by providing small amounts of feedin a shallow pan or on the floor sev-eral times each day. Be sure the pigshave access to fresh water.

Producers who wean pigs atabout 2 weeks old (8 lb bodyweight) should feed the starter 1diet until the pigs weigh about 13lb. In addition, any pig that weighsmore than 13 lb at weaning, but isless than 28 days of age, should beprovided about 3 lb of the starter 1diet before it is given the starter 2diet. Body weight is not a goodindicator of a weaned pig’s abilityto digest diets containing largeamounts of the complex carbohy-drates and proteins found in grainand soybean meal. Providinglimited amounts of a highly digest-ible, nutrient dense diet after wean-ing helps pigs make the transitionto dry feed.

Table 20 shows suggested totalintakes of each starter diet accord-ing to pig weaning age. Manyproducers control nursery feedcosts by planning to feed a prede-termined quantity of each diet.When the designated amount of afirst diet is consumed, pigs areswitched to the next, less expensive,diet in the sequence. It is importantto monitor the weight of a few pigschosen at random about every twoweeks to determine if the pigs aregrowing as expected. Checkinggrowth rate helps ensure pigs areswitched to the next diet in thesequence at the proper time.

Diets for 45 to 250 lb pigs

Diets for growing-finishing pigsare shown in Tables 21 and 22. Table23 presents examples of how feedduring the growing-finishing phasemay be distributed depending onthe pigs’ growth rate. Many produc-ers switch diets according to esti-mated pig weight. An alternativemethod would be to provide a pre-determined amount of each diet.When that amount is consumed,switch pigs to the next diet in thesequence. This eliminates guessing

Table 19. Example diets for 8 to 45 lb growing pigs

Starter 1/transitiona Starter 2 Starter 3

Ingredient (8 to 13 lb) (13 to 25 lb)b (25 to 45 lb)b

1 1 2 1 2

Corn 605 891 882 1209 1044Soybean meal, 44% CP 189 620 615 712 720Soy protein concentrate 60Dried whey, edible 550 300 300 100Plasma proteins, spray-dried 120Oat groats 250Fish meal, select menhaden 100 80Blood meal, spray-dried 50Fat (stabilized) 60 60 60 60L-Lysine•HCl 3 1 1 1 1DL-methionine 2 2 1Dicalcium phosphate

(22% Ca, 18.5% P) 11 25 13 24 22Limestone 13 18 15 19 18Salt 2 4 4 6 6Vitamin mixc 5 5 5 5 5Trace mineral mixc 3 3 3 3 3Copper sulfate 1 1 1 1Zinc oxide (72% Zn) 7Antibiotic 20 20 20 20 20

Total 2000 2000 2000 2000 2000

Calculated analysis:Lysine, % 1.55 1.35 1.35 1.20 1.24Lysine:calorie, g/Mcal ME 4.6 4.0 4.0 3.7 3.7Protein, % 21.6 21.4 21.6 20.7 20.8Calcium, % .90 .85 .85 .75 .75Phosphorus, % .77 .67 .67 .62 .62

aProvide a total of 4 lb/pig (at least 3 lb after weaning) to pigs > 13 lb at weaning, but < 28 daysof age.bGround whole oats can replace up to 300 lb of corn/ton if edema disease is a problem. Milo cansubstitute for corn.cSee Table 16 for nutrient levels. Amount added/ton of feed will depend on the carrier.

Table 20. Suggested distribution of starting feed according to pig weaning agea

Weaning age, days

Diet (body wt, lb) 14 21 28

-------------------------------lb/pig-------------------------------

Starter 1/transition (8 to 13) 6 3 3

Starter 2 (13 to 25) 15 15 12

Starter 3 (25 to 45) 45 45 45

Total 66 63 60aSee Table 19 for ingredient composition.

subsequent performance. Pigs thatare heavier at weaning usuallymaintain their weight advantage tomarket weight. Therefore, creepfeeding should be considered if itwill result in a heavier pig at wean-ing. For pigs weaned at less than 3

weeks of age, the value of creepfeed is questionable, because theyoften consume very little feed. Thequality of the creep diet and how itis managed has a significant impacton whether creep feeding succeeds.Encourage creep feed consumption

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Table 23. Examples of growing-finishing feed usage according to pig growth ratea

Average daily gain (lb/day) from 45 to 250 lbDiet (body wt, lb) 1.6 1.8 2.0

-------------------------lb of feed/pig---------------------Grower 1 (45 to 80) 90 80 75Grower 2 (80 to 130) 160 140 125Finisher 1 (130 to 190) 205 180 165Finisher 2 (190 to 250) 240 210 190

Total 695 610 555aCorn or milo-soybean meal diets fed to barrows and gilts under thermoneutral conditionswith minimal feed wastage.

Table 21. Example diets for 45 to 130 lb growing pigsa

Grower 1 Grower 2(45 to 80 lb) (80 to 130 lb)

Ingredient 1 2 3 4 5

Corn or milo 1367 1419 1272 1489 1319Soybean meal, 44% CP 580 525 615 464L-Lysine•HCl 2Fat (stablized) 60Soybeans, full-fat, cooked 635Dicalcium phosphate

(22% Ca, 18.5% P) 22 23 22 17 15Limestone 18 18 18 17 18Salt 6 6 6 6 6Vitamin mixb 4 4 4 4 4Trace mineral mixb 3 3 3 3 3

Total 2000 2000 2000 2000 2000Calculated analysis:

Lysine, % 1.00 1.00 1.04 .85 .88Lysine:calorie, g:Mcal ME 3.1 3.1 3.1 2.6 2.6Protein, % 18.4 17.5 18.8 16.4 16.7Calcium, % .70 .70 .70 .60 .60Phosphorus, % .58 .58 .58 .51 .51

aAssumes a mixture of medium lean gain barrows and gilts. All diets are full-fed underthermoneutral conditions.bSee Table 16 for nutrient levels. Amount added/ton of feed will depend on the carrier.

the weight of pigs to decide whento switch diets and the possibility offeeding higher nutrient dense dietstoo long. It is important to monitorthe weight of a few pigs chosen atrandom every three to four weeksto determine if the pigs are growingas expected. Checking growth ratehelps ensure pigs are switched tothe next diet in the sequence at theproper time. Phase feeding is mostconvenient when facilities are oper-ated on an all-in/all-out basis. Pro-ducers who have not fed pigs in thismanner and who do not know thefeed intake patterns of their pigscan use the information in Table 23as a reference. Average daily gaindata for growing-finishing pigs isneeded to use Table 23.

Diets for the breeding herd

Suggested gilt developing, ges-tation, breeding boar, and lactationdiets are shown in Tables 24 and 25.The gestation diets shown aredesigned to be fed so that sowsreceive 5.9 Mcal of ME/day. If adifferent amount of energy intake isrequired, reformulate the diets asdescribed earlier. Feed used for thebreeding herd will be about 2,200lb/animal/year in well managed,confinement gestation units. Thatincreases to about 2,500 lb/animal/year in outdoor accommodations.

Tools forQuantifyingPerformance

We have provided nutrient rec-ommendations based on fat-freelean growth rate, 21-day litterweight and feed intake in this pub-lication. These factors influence thequantity of nutrients pigs require.By monitoring pig performance, itis possible to formulate diets tospecific production situations and

Table 22. Example diets for 130 to 250 lb finishing pigsa

Finisher 1 Finisher 2(130 to 190 lb) (190 to 250 lb)

Ingredient 1 2 3 1 2 3

Corn or milo 1613 1665 1548 1731 1646Barley 1888Soybean meal, 44% CP 345 290 370 230 75L-Lysine•HCl 2Fat (stabilized) 40Soybeans, full-fat, cooked 315Dicalcium phosphate

(22% Ca, 18.5% P) 14 16 14 12 8 11Limestone 17 16 17 16 18 17Salt 6 6 6 6 6 6Vitamin mixb 3 3 3 3 3 3Trace mineral mixb 2 2 2 2 2 2

Total 2000 2000 2000 2000 2000 2000Calculated analysis:

Lysine, % .70 .70 .72 .55 .49 .56Lysine:calorie,

g:Mcal ME 2.1 2.1 2.1 1.7 1.7 1.7Protein, % 14.3 13.4 14.6 12.2 12.3 12.4Calcium, % .55 .55 .55 .50 .50 .50Phosphorus, % .47 .47 .47 .43 .43 .43

aAssumes a mixture of medium lean gain barrows and gilts. All diets are full-fed underthermoneutral conditions.bSee Table 16 for nutrient levels. Amount added/ton of feed will depend on the carrier.

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Table 24. Example diets for gestating sows, breeding boars, and developing gilts (230 lbto breeding)

Breedingboar and

developingGestation gilt

Ingredient 1 2 3 4 5 1

Corn or milo 1678 1588 1233 1400 1577Barley 1836Oats 500Alfalfa hay, 16% CP 400Soybean meal, 44% CP 235 184 131 90 350Soybeans, full-fata 324Dicalcium phosphate

(22% Ca, 18.5% P) 47 48 44 43 32 34Limestone 17 17 16 3 19 16Salt 10 10 10 10 10 10Vitamin mixb 10 10 10 10 10 10Trace mineral mixb 3 3 3 3 3 3

Total 2000 2000 2000 2000 2000 2000Daily intake:

Feed, lb 4.0 3.9 4.2 4.4 4.6 6.0c

ME, Mcal 5.9 5.9 5.9 5.9 5.9 8.9Lysine, g 10.0 10.1 10.0 10.0 10.4 19.0Protein, g 220 218 229 237 259 387Calcium, g 16.3 16.3 16.2 16.4 16.3 20.4Phosphorus, g 13.6 13.5 13.5 13.6 13.6 17.7

Calculated analysis:Lysine, % .55 .57 .52 .50 .50 .70Lysine:calorie,

g:Mcal ME 1.7 1.7 1.7 1.7 1.7 2.2Protein, % 12.1 12.3 12.0 11.9 12.4 14.2Calcium, % .90 .92 .85 .82 .78 .75Phosphorus, % .75 .76 .71 .68 .65 .65

aRaw or cooked.bSee Table 16 for nutrient levels. Amount added/ton will depend on the carrier.cProvide breeding boars 5.5 lb/day to meet daily nutrient recommendations in Table 14.

reduce the consequences of under-feeding or overfeeding nutrients.This section will describe tools touse in quantifying pig performance.The procedures involve feedinghigh nutrient dense diets to asample of pigs to evaluate their per-formance when dietary nutrientdensity is not likely a limiting fac-tor. Once the performance potentialof the pigs is known, diets can beformulated.

How do I estimate fat-free leangrowth rate?

There are several methods tomeasure lean growth in swine. First,you can determine the quantity oflean in the pig initially and in thecarcass at slaughter and the numberof days on test. Use the followingformula to estimate rate of fat-freelean gain:

lb lean/day on test = final lb lean - initiallb lean

days on test

Final pounds of lean in the car-cass can be obtained by using thelot average for fat-free lean index(FFLI) and hot carcass weight. Thisinformation is provided on packerkill sheets in the Nebraska andSouth Dakota area. The FFLI is thepercentage of edible, lean meat in acarcass, factoring out intramuscularfat (i.e., marbling). Because the FFLIadjusts lean content to represent nointramuscular fat, it will normallybe 5 to 7% less than customary per-cent lean values. Daily lean gain us-ing the FFLI results in lean gainwith 0% fat, therefore the valueswill be lower than lean gain ex-pressed on a 5% fat basis. Use thefollowing formula to estimatepounds of lean in the carcass:

lb of lean = (FFLI/100) x HCWT

where FFLI = fat-free lean index

HCWT = hot carcass weight, lb

To estimate pounds of fat-freelean in a 40 to 50 lb pig use the fol-lowing equation:

Table 25. Example diets for lactating sows

Lactation

Ingredient 1 2 3 4

Corn 1407 1322 1233 1294Soybean meal, 44% CP 510 535 625Fat (stabilized) 60Soybeans, full-fata 685Dicalcium phosphate

(22% Ca, 18.5% P) 43 42 41 39Limestone 17 18 18 19Salt 10 10 10 10Vitamin mixb 10 10 10 10Trace mineral mixb 3 3 3 3

Total 2000 2000 2000 2000Calculated analysis:

Lysine, % .90 .93 .92 1.05Lysine:calorie, g:Mcal ME 2.8 2.8 2.8 3.3Protein, % 17.1 17.3 17.2 19.1Calcium, % .90 .90 .90 .90Phosphorus, % .75 .75 .75 .75

aCooked. Raw soybeans have resulted in decreased pig weaning weights and increased sowweight loss during lactation compared with soybean meal.bSee Table 16 for nutrient levels. Amount added/ton of feed will depend on the carrier.

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Table 27. Adjustment factors for 21-day litter weight according to weaning agea

Age weighed, days Factor Age weighed, days Factor

14 1.30 21 1.00

15 1.25 22 .97

16 1.20 23 .94

17 1.15 24 .91

18 1.11 25 .88

19 1.07 26 .86

20 1.03 27 .84

28 .82

aAdapted from National Swine Improvement Federation, 1997.

Table 26. Estimated daily fat-free lean gain (lb/day) using the fat-free lean index and av-erage daily gaina

Fat-free lean index, %

Daily gain, lb 40 42 44 46 48 50 52 54

1.2 .35 .37 .39 .41 .44 .46 .48 .50

1.4 .41 .43 .46 .48 .51 .53 .56 .58

1.6 .47 .49 .52 .55 .58 .61 .64 .67

1.8 .52 .56 .59 .62 .65 .69 .72 .75

2.0 .58 .62 .65 .69 .73 .75 .80 .83

2.2 .64 .68 .72 .76 .80 .84 .88 .92

2.4 .70 .74 .78 .83 .87 .91 .96 1.00

aStarting and final weights are 45 and 250 lb, respectively. Carcass weight is 185 lb.

the basis for the feeding recommen-dations in this publication.

Farm-specific feeding programsfor growing-finishing pigs are bestestablished by conducting growthtrials. Do this by randomly selecting10 to 20 % (equal numbers of eachsex if separate sex feeding is notpracticed on the farm) of the pigsfrom a farrowing group for eachtest. Pigs should weigh between 40and 50 lb at the beginning of thetest. Weigh the pigs and managethem normally to market weight. Toensure that nutrient intake is notlimiting lean growth, feed dietscontaining 10% higher amino acidlevels than those shown for highlean gain pigs in Tables 12 and 13.Terminate the test when the pigsaverage about 250 lb. Repeat thetest quarterly during the first yearand semiannually thereafter. Recordfeed disappearance so nutrientintake can be estimated. Informa-

lb of fat-free lean initially = .95 x [-3.65+ (.418 x live wt, lb)]

For example, assume that agroup of pigs averaging 45 lb ini-tially was tested for 100 days. Atslaughter, the group average for hotcarcass weight and FFLI was 180 lband 45, respectively. What is the av-erage fat-free lean growth rate forthe group?

.95 x [-3.65 + (.418 x 45)] = 14.4 lb of leaninitially

(45/100) x HCWT = 81 lb of lean atslaughter

81 - 14.4 lb = .67 lb of fat-free100 days lean per day on

test

A second and quicker methodof estimating fat-free lean gain isshown in Table 26. Find the pigs’FFLI across the top of the table andaverage daily gain on the left side.For example, a group of pigs hav-ing a FFLI of 45 and an averagedaily gain of 2.0 lb/day will havean estimated fat-free lean gain of.66 lb/day from 45 to 250 lb.

The most accurate method tomeasure the lean growth of yourherd is to determine the leangrowth curve of your growing-fin-ishing pigs. This involves a mini-mum of five ultrasonic scannings atspecific intervals throughout thegrowth phase on a representativesample of pigs. Also, feed intakemeasurements must be obtainedthroughout the growth phase. Thescan data and feed intake data arethen sent to Purdue Universitywhere the specific lean growthcurve for individual farms are gen-erated. While this is the most costlymethod, it also provides one of thegreatest opportunities to formulatediets for a given level of perfor-mance

The equations for calculatingthe FFLI are being revised as thispublication goes to press. We usedthe FFLI provided by the NationalPork Producers Council in 1994 as

tion should be available from atleast three tests before a final deci-sion is made regarding whether toclassify the pigs as high, medium orlow lean gain.

What is the best way to obtain21-day litter weights?

Litters should be standardizedto between 8 and 10 pigs per litterwithin 24 to 48 hours after birth.Collect litter weights before wean-ing and as near 21 days of age aspossible. Litters may be weighedbetween 14 and 28 days and theweights adjusted to a 21-day basis(Table 27). For example, a litterweighed 120 lb at 19 days of age.The 21-day litter weight would be128.4 lb (120 x 1.07). If creep feed isoffered, it is important that litterweights be obtained by 21 days ofage to minimize the influence ofcreep feed intake on 21-day litterweights. In genetic selection

36

programs the 21-day litter weight isadjusted for parity and number ofpigs after transfer. We do notbelieve these adjustments arenecessary to apply the conceptsoutlined in this publication.

Provide groups of lactatingsows diets containing 1.15% lysineand collect 21-day litter weights.Repeat the test quarterly during thefirst year and semiannually thereaf-ter. Record feed disappearance sonutrient intake can be estimated. In-formation should be available fromat least three tests before a final de-cision is made regarding whether toclassify the sows as capable of pro-ducing litters weighing more or lessthan 120 lb at 21 days of lactation.Amino acid recommendations forlactating sows producing littersweighing less than or greater than120 lb at 21 days are shown in Table14.

How can I estimate feedintake?

Producers who operate build-ings or rooms on an all-in/all-outbasis can use closeout information.Those with continuous flow pro-duction are advised to closelymonitor identified pens of pigs orgroups of sows. To estimate lactat-ing sow feed intake attach a card toeach farrowing crate and record theamount of feed added to the sow’sfeeder daily. General guidelines fordaily feed intake of pigs are shownin Tables 11, 12, 13, 14 and 15.

Methods ofSupplyingNutrients

Making sound decisions aboutthe method(s) used to supply pigsnutrients is an important part offeed program design. However, theterminology used to describe themethods of supplying pigs nutri-

ents often is confused. There arefour basic methods of supplyingnutrients to pigs: 1) purchased com-plete feed; 2) grain plus concen-trate or supplement; 3) grain plussoybean meal and basemix; or 4)grain, plus soybean meal, salt, cal-cium and phosphorus source(s) andpremix. A description of each ofthese options follows.

Complete feed. A ready-to-feedproduct containing ingredientsthat when combined meet thetotal nutritional needs of thepig. The feed manufacturerassumes all responsibilities foringredient quality and mixingerrors. The producer is respon-sible for using the productcorrectly.

Concentrate or supplement. Amixture of ingredients formu-lated to complement nutrientspresent in grain. When it is cor-rectly mixed with grain, theresulting diet will meet the totalnutritional needs of pigs.Typical inclusion rates are 300to 500 lb/ton for all classes ofpigs except starting pigs. Theproducer’s task is to mix thecorrect ratio of concentrate andgrain.

Basemix. A product generallycontaining ingredients rich inminerals and vitamins. Base-mixes correctly mixed withgrain and a protein source(s)will satisfy the total nutritionalneeds of pigs. Some basemixesmay contain crystalline lysineand animal protein products.Typical inclusion rates are 50 to100 lb/ton, although somebasemixes for nursery diets areadded at 200 to 400 lb/ton. Theproducer assumes the responsi-bility for variation in the qualityof the protein source(s) and forcorrect blending of ingredients.

Premix. A product containingsources of vitamins and(or)

trace minerals. The totalnutritional needs of pigs can bemet by combining premixeswith grain, salt and sources ofprotein, calcium and phospho-rus. Typical inclusion rates are 5to 10 lb/ton. Premixes areavailable with trace mineralsand vitamins combined orpackaged separately. Theproducer assumes more respon-sibility for correct diet formula-tion and preparation andvariation in the quality of theprotein, calcium and phospho-rus sources with this optionthan with the three otheroptions.

The example diets shown inTables 19, 21, 22, 24 and 25 arebased on a premix program. We donot necessarily endorse a premixprogram. Our intent is to showcommon ingredients used to sup-ply the major classes of nutrientsnecessary in a diet for pigs.

How does one choose whichmethod to use?

One method does not consis-tently promote better pig perfor-mance or a lower cost of gain thananother. The major factors we thinkshould be considered in choosing amethod of supplying nutrients to pigsare shown in Table 28. Conveniencerefers to the level of involvement theproducer has in making nutritionaldecisions and feed preparation. Riskis the odds of a diet not containingthe intended concentration of nutri-ents and quality of ingredients. Riskrates the transfer of responsibilityfrom the feed manufacturer to theproducer as the producer assumesmore or less responsibility for properquality control and inclusion ofnutrient sources in swine diets. Ser-vice is the amount of technical advice,farm recordkeeping and other perksoffered. Cost includes costs of ingre-dients and services such as processing, blending, delivery, technicaladvice, etc.

37

Table 28. Considerations in choosing a method of providing pigs nutrients

Method Convenience Risk Service Costa

(Quality)

Complete high low high high

Concentrate

Basemix

Premix low high low low

aIncludes costs of ingredients and services.

↓↓↓↓↓ ↑↑↑↑↑ ↓↓↓↓↓ ↓↓↓↓↓

Producers who put a highpriority on convenience, minimalrisk of having feed quality prob-lems, and ample service will wantto use complete feeds. However,cost is generally higher to justify themanufacturer’s assumption of theserisks and services offered. On theother hand, there is less cost in apremix program, but it is a lessconvenient, higher risk, and lowerservice-oriented program. The risks

associated with feed quality can bemanaged but it takes a commitmentof time and resources. See the sec-tions on Feed Processing andIngredient Quality for details onpreparing quality pig feed. Selectthe method which provides the bestbalance of factors you considerimportant while maintaining acompetitive feed cost per unit ofgain.

What about mixing feed on thefarm?

Choices for producers rangefrom purchasing individualingredients and manufacturingdiets on the farm to purchase anddelivery of complete feeds in mealor pellet form. Compare the fixedand operating costs associated withmanufacturing feed on the farmto custom rates at local feed millsto decide which option to use.Generally, because of problems withstocking several ingredients and thedifficulty in securing and maintain-ing quality, fresh ingredients suchas dried whey and fishmeal, werecommend that most producerspurchase complete pelleted feedsfor starting pigs weighing less thanabout 20 to 25 lb. When feed forpigs weighing less than 20 to 25 lbis made on the farm, we recom-mend it be mixed using a basemixor concentrate that contains manyof the specialty ingredients shownin the example diets in Table 19.

38

Table 29. Ingredient composition (as-fed basis)

Methio- Available Meta-Trypto- Threo- Methio- nine Cal- Phos- Phos- bolizable Crude

Protein Lysine phan nine nine + cystine cium phorus phorus energy Fat FiberFeedstuff % % % % % % % % % kcal/lb % %

Alfalfa meal, dehy 17.0 .74 .24 .70 .25 .43 1.53 .26 .26 750 2.6 24.0Alfalfa hay, early bloom 16.0 .68 .30 .67 .27 .50 1.30 .20 800 2.5 24.0Bakery waste, dehy 10.8 .27 .10 .33 .18 .41 .13 .25 1682 11.3 1.2Barley 11.3 .41 .11 .35 .20 .48 .06 .35 1322 1.9 5.0Beet pulp 8.6 .52 .10 .38 .07 .13 .70 .10 1134 .8 18.2Blood meal, flash-dried 87.6 7.56 1.06 4.07 .95 2.15 .21 .21 886 1.6 1.0Blood meal, spray-dried 88.8 7.45 1.48 3.78 .99 2.03 .41 .30 .28 1338 1.3 1.0Canola meal 35.6 2.08 .45 1.59 .74 1.65 .63 1.01 .21 1200 3.5 11.1Corn distillers grain

w/sol., dehy 27.7 .62 .25 .94 .50 1.02 .20 .77 .59 1282 8.4 9.1Corn distiller’s dried grain 24.8 .74 .20 .62 .43 .71 .10 .40 1234 7.9 11.9Corn gluten feed 21.5 .63 .07 .74 .35 .81 .22 .83 .49 1184 3.0 6.8Corn, high lysine 10.1 .42 .11 .37 .17 .37 .03 .28 .04 1560 4.0 3.7Corn, high oil 8.3 .29 .07 .30 .19 .40 .03 .28 .04 1608 6.5 2.3Corn, hominy feed 10.3 .38 .10 .40 .18 .36 .05 .43 .06 1459 6.7 5.0Corn, yellow 8.3 .26 .06 .29 .17 .36 .03 .28 .04 1555 3.9 2.3DL-methionine — — — — 99.0 99.0 — — — — — —Fats/oils

Beef tallow — — — — — — — — — 3491 100 —Choice white grease — — — — — — — — — 3616 100 —Poultry fat — — — — — — — — — 3718 100 —Restaurant grease — — — — — — — — — 3730 100 —Soybean oil — — — — — — — — — 3818 100 —

Fish meal, menhaden 62.9 4.81 .74 2.64 1.77 2.34 5.21 3.04 2.86 1527 9.4 .9L-Lysine HCl 95.8 78.0 — — — — — — — — — —L-Tryptophan — — 98.0 — — — — — — — — —L-Threonine — — — 99.0 — — — — — — — —Meat and bone meal,

50% CP 51.5 2.51 .28 1.59 .68 1.18 9.99 4.98 4.48 1011 10.9 2.4Meat meal, 55% CP 54.0 3.07 .35 1.97 .80 1.40 7.69 3.88 1180 12.0 2.3Millet, proso 11.1 .23 .16 .40 .31 .49 .03 .31 1340 3.5 6.1Milo, grain sorghum 9.2 .22 .10 .31 .17 .34 .03 .29 .06 1518 2.9 2.2Molasses, beet 6.6 — — — — — .12 .03 1080 .2 0Molasses, cane 4.4 — — — — — .77 .08 909 .1 0Oats 11.5 .40 .14 .44 .22 .58 .07 .31 .07 1232 4.7 10.7Oats, high lysine 12.0 .50 .16 .44 .18 .40 .08 .30 1212 4.1 11.5Oat groats 13.9 .48 .18 .44 .20 .42 .08 .41 .05 1575 6.2 2.5Plasma proteins,

spray-dried 78.0 6.84 1.36 4.72 .75 3.38 .15 1.71 2.0 .2Rye 11.8 .38 .12 .32 .17 .36 .06 .33 1390 1.6 2.2Skim milk, dried 34.6 2.86 .51 1.62 .92 1.22 1.31 1.00 .91 1689 .9 .2Soy protein concentrate 64.0 4.20 .90 2.80 .90 1.90 .35 .81 1591 3.0 3.5Soy protein isolate 85.8 5.26 1.08 3.17 1.01 2.20 .15 .65 1618 .6 .4Soybeans, full-fat, cooked 35.2 2.22 .48 1.41 .53 1.08 .25 .59 1677 18.0 5.2Soybean meal, dehulled 46.5 2.91 .62 1.85 .67 1.37 .34 .69 .16 1536 3.0 3.4Soybean meal, solvent 44.0 2.83 .61 1.73 .61 1.31 .32 .65 .20 1445 1.5 7.3Sunflower meal, 42% CP 42.2 1.20 .44 1.33 .82 1.48 .37 1.01 1243 2.9 15.8Triticale 12.5 .39 .14 .36 .20 .46 .05 .33 .15 1445 1.8 4.0Wheat bran 15.7 .64 .22 .52 .25 .58 .16 1.20 .35 1034 4.0 10.0Wheat, hard 13.5 .34 .15 .37 .20 .49 .06 .37 .19 1459 2.0 2.6Wheat middlings,

<9.5% fiber 15.9 .57 .20 .51 .26 .58 .12 .93 .38 1375 4.2 7.8Whey, dried 12.1 .90 .18 .72 .17 .42 .75 .72 .70 1450 .9 .2

39

Conversion Factors

Multiplied Multipliedby the factor by the factor

Units below equals Units below equals Units(a x b = c)

(c x d = e)

lb 453.6 g .0022 lblb .4536 kg 2.205 lbkg 1,000 g .001 kgkg 1,000,000 mg .000001 kgg 1,000 mg .001 gg 1,000,000 µg .000001 gmg 1,000 µg .001 mgmg/kg .0001 % 10,000 mg/kgppm .0001 % 10,000 ppmmg/g 453.6 mg/lb .0022 mg/gmg/lb 2.2 ppm .4536 mg/lbmg/lb 2 g/ton .5 mg/lbmg/g 1,000 ppm .001 mg/gmg/kg 1.0 ppm 1.0 mg/kgg/ton 1.1 ppm .907 g/tonMcal/lb 1000 kcal/lb .001 Mcal/lb

Abbreviations and Symbols

Ca calciumCP crude proteing gramsIU international unitMcal megacalorieME metabolizable energymg milligramsppm parts per millionP phosphorus> greater than< less than

40

Index

Acidifiers, 16Aflatoxin, 13Amino acid antagonism, 12Amino acid balance, 5, 22Amino acid imbalance, 12Amino acid sources, 4-7Amino acid toxicity, 12Antibiotics, 15-16Antioxidant, 3, 17Available phosphorus, 7, 39

Backfat, 3, 32Basemix, 28, 37-38Betaine, 32Bioavailability, 9Breeding boars, 26-30

Calcium:phosphorus ratio, 11Carnitine, 16-17Chelated trace minerals, 7, 9Chromium, 16-17Clays, 13, 16Complete feed, 37-38Concentrate, 37-38Constipation, 30Conjugated linoleic acid, 16-17Copper sulfate, 8, 14, 16Creep feeding, 32-33Crowding, 22Crude protein, 4, 22Crystalline amino acids, 6-7

Daily nutrient intake, 24-27Developing boars, 27, 29Developing gilts, 27-29, 31Digestible amino acids, 5-6Downer sows, 30

Electrolytes, 9Energy sources, 1-4Ergot, 13Example diets, 32-35Extrusion, 19

Fat, 3-4, 30-31Fat-free lean gain, 34-36Fat-free lean index, 34-36Feed additives, 14-17Feed intake, 20-22Feeding value, 2-5Fiber, sows, 30Flavors, 17Flushing, 29Frost-damaged soybeans, 13Fumonisins, 13

Gender, 21Genetics, 21Growing-finishing pigs, 24-26, 31-34

Hammermills, 18-19Health, 22High moisture corn, 13Hydrated sodium calcium

aluminosilicate, 16

Ideal protein, 5-7Interval feeding, 29

L-Lysine•HCL, 6-7Laxatives, 30-31Lean gain, 22-25, 31, 34-36Limit-feeding, 29, 32Litter weight (21-day), 34, 36-37Low protein corn, 4Low test weight grains, 12-13

Medicated early weaning, 22Mineral sources, 7-9Mixing times, 19Mold inhibitors, 17Molds, 13Mycotoxins, 13

Nutraceutical, 14-15Nonstarch polysaccharides, 30Nutrient:calorie ratio, 24-25, 27Nutrient density, 24-25Nutrient interactions, 10-12Nutrient recommendations, 1, 22-28

Particle size, 17Pelleting, 19Phase feeding, 31Phytase, 7, 16Premix, 37-38Probiotics, 15-16Protein sources, 4-7Proteinated trace minerals, 7, 9

Quantifying performance, 34-37

Ractopamine hydrochloride, 16-17Roasting, 19Roller mills, 18-19

Sampling techniques, 14Second generation, 14Segregated early weaning, 22Separate sex feeding, 32Sows, 27, 28-31Starting pigs, 24, 31-32Supplement, 37-38

Temperature, 20-21

Vitamin sources, 9Vomitoxin, 13

Water consumption, 19-20Water quality, 20Water sweeteners, 20

Yucca plant extract, 16

Zearalenone, 13Zinc oxide, 8, 14, 16, 31-32

41

Additional Information Sources

Item Available from

Swine Nutrition (ISBN 0-409-90095-8) CRC Press, Inc2000 Corporate Blvd., N.W.Boca Raton, FL 33431

Pork Industry Handbook Media Distribution Center301 South 2nd StreetLafayette, IN 47901-1232

Alfalfa in Swine Diets (G117) Local Extension Offices in Nebraska or:Mixing Quality Pig Feed (G892) BulletinsFull-Fat Soybeans for Pigs (G994) P.O. Box 830918Weaned Pig Management and Nutrition (G821) Lincoln, NE 68583-0918Conducting Pig Feed Trials on the Farm (EC270)Altering Swine Manure by Diet Modification (G99-1390)Nebraska Swine Reports http://www.ianr.unl.edu/pubs/

NRC Nutrient Requirements of Swine (ISBN 0-309-05993-3) National Academy Press2101 Constitution Avenue, NWLockbox 285Washington, DC 20055

http://www.nap.edu/bookstore

Nontraditional Feed Sources for Use in Swine Production(ISBN 0-409-90190-3) Butterworth Publishers

80 Montvale AvenueStoneham, MA 02180

Diseases of Swine (ISBN 0-8138-0338-1) Iowa State University PressAmes, Iowa 50014

http://www.isupress.edu

Swine Production and Nutrition (ISBN 0-87055-450-6) AVI Publishing Company, IncWestport, Connecticut

425M copies printed at no cost to the state. Partial funding provided by a grantfrom the South Dakota Pork Producers Council. January 1990.

South Dakota State UniversitySouth Dakota State UniversitySouth Dakota State UniversitySouth Dakota State UniversitySouth Dakota State UniversityIssued in furtherance of Cooperative Extension work, Acts of

May 8 and June 30, 1914, in cooperation with the USDA.Mylp A. Hellickson, Director of CES, SDSU, Brookings.

SDSU is an Affirmative Action/Equal Opportunity Employer(Male/Female) and offers all benefits, services, education,and employment opportunities without regard to ancestry,

age, race, citizenship, color, creed, religion, gender, disability,national origin, sexual preference, of Vietnam Era veteran

status.

University of Nebraska-LincolnIssued in furtherance of Cooperative Extension work, Acts ofMay 8 and June 30, 1914, in cooperation with the U.S.Department of Abriculture. Elbert C. Dickey, Interim Directorof Cooperative Extension, University of Nebraska, Institute ofAgriculture and Natural Resources.

University of Nebraska Cooperative Extension educationalprograms abide with the non-discrimination policies of theUniversity of Nebraska-Lincoln and the United StateswDepartment of Agriculture.

Item Available from

Swine Nutrition (ISBN 0-409-90095-8) CRC Press, Inc2000 Corporate Blvd., N.W.Boca Raton, FL 33431

Pork Industry Handbook Media Distribution Center301 South 2nd StreetLafayette, IN 47901-1232

Alfalfa in Swine Diets (G117) Local Extension Offices in Nebraska or:Mixing Quality Pig Feed (G892) BulletinsFull-Fat Soybeans for Pigs (G994) P.O. Box 830918Weaned Pig Management and Nutrition (G821) Lincoln, NE 68583-0918Conducting Pig Feed Trials on the Farm (EC270)Altering Swine Manure by Diet Modification (G99-1390)Nebraska Swine Reports http://www.ianr.unl.edu/pubs/

NRC Nutrient Requirements of Swine National Academy Press(ISBN 0-309-05993-3) 2101 Constitution Avenue, NW

Lockbox 285Washington, DC 20055

http://www.nap.edu/bookstore

Nontraditional Feed Sources for Use in Swine Production Butterworth Publishers(ISBN 0-409-90190-3) 80 Montvale Avenue

Stoneham, MA 02180

Diseases of Swine (ISBN 0-8138-0338-1) Iowa State UniversityAmes, Iowa 50014

http://www.isupress.edu

Swine Production and Nutrition (ISBN 0-87055-450-6) AVI Publishing Company, IncWestport, Connecticut

Additional Information Sources

swine - animalscience.unl.edu · figure 1. factors that were considered when developing nutrient...

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