Principles of Animal Nutrition

Objective 13.01: Describe the six functions of a good ration

Six Functions of a Good Ration1. Maintenance of vital body processes to keep animal alive2. Growth by increasing the size of bones, muscles, organs and

connective tissue.3. Fattening by storing nutrients not used for maintenance,

growth or other functions.4. Production of milk, eggs, wool, etc.5. Reproduction – adequate nutrition is necessary6. Work – other needs are met before nutrients are available for

work. Most beef cattle, swine and poultry produced in the U.S. do no work.

*From 1/3 to 1/2 of the ration fed to beef cattle and swine is used for body maintenance, and this function must be met before

nutrients are available for other functions.

Roughages

• 1. Roughages are feeds that contain more than 18% crude fiber when they are dry.

• 2. Examples of roughages– a. hay– b. posture grasses– c. silage– d. hulls– e. straw– f. fodder

Concentrates

• 1. Concentrates are feeds that contain less than 18% crude fiber when they are dry.

• 2. Examples of concentrates– a. grains – corn, oats, barley, wheat, etc.– b. processed by-products – wheat bran, middlings, etc.– c. liquid supplements – molasses, urea– d. animal proteins – meat scraps, tankage, fish and blood

meal– e. plant proteins – cottonseed meal, soybean meal, peanut

meal and linseed meal

Characteristics of a Good Ration

• 1. Balanced – has all nutrients needed in the right amounts and proportions.

• 2. Palatable – tastes good so that animals will eat it.• 3. Low cost – best nutritional value possible at

lowest cost because feed costs are about 75% of the total costs of raising livestock.

• 4. Not harmful to health or quality of animal products• 5. Proper proportions of concentrates and

roughages for type and age of animal.• 6. Uniformly mixed especially micronutrients and

feed additives

Principles of Animal Nutrition

Objective 14.01: Define feed additives and hormone implants used in animal

rations.

Definitions • 1. Feed additives are materials

used in animal rations in small quantities to improve or stimulate performance such as feed efficiency, faster gain and health or production of animal products including eggs, milk, wool, etc. Feed additives are not generally considered nutrients.

• 2. Hormone implants are pelleted synthetic or natural hormones or hormone like compounds placed under the skin or in the muscle of an animal to improve rate of gain and feed efficiency.

• 3. Hormones can also be fed as feed additives in some cases.

Uses of Feed Additives and Hormone Implants

• 1. They are performance stimulants and increase profits because of improved performance.

• 2. Using antibiotics and antibacterials at a lower level than would be used to treat sick animals is subtherapeutic use. A major health concern of this low-level use is that microorganisms that cause diseases may become resistant to the drugs used for treatment.

Hormones (cont)

• 3. Many different antimicrobial drugs are used as feed additives to prevent diseases and to increase performance in livestock and poultry. The greatest return for swine is in young pigs.

• 4. Feed additives are widely used in beef cattle, swine, and poultry.

• 5. The use of feed additives and hormone implants is regulated by the Federal Food and Drug Administration (FDA). Any feed with any drug in it must be labeled as medicated feed.

Mixing Feed with Additives

• 1. The main rule that includes all other rules is “read and follow the label.”

• 2. Uniform mixing of additives in livestock feed is required so that all animals get the correct amounts of the additive.

• 3. To avoid medicated drug contamination of feed, the feed mixer must be thoroughly cleaned.

• 4. It is important that accurate up-to-date records be kept on the use of medicated feed.

Proper Method of Hormone Implantation

• 1. Restrain the animal to prevent head movement.

• 2. Use a sharp needle to eliminate crushed pellets usually caused by dull needles.

• 3. Be sure the needle and the implantation site are clean.

• 4. Select the proper place for the implant on the back surface of the ear in the middle one third of the ear which is 1 1/2” to 2” from the base of the ear.

• 5. Point the implanting instrument toward the head and parallel to the ear, lift the loose skin with the point of the needle and push the needle in being careful NOT to hit a vein or the cartilage.

• 6. Withdraw the needle slightly, start the implant, make certain the pellets have been properly deposited and slowly withdraw the needle. If the needle is removed too fast, the hormone pellets may be crushed or balled up. Crushing pellets causes them to be absorbed too rapidly.

Kinds of Feed Additives

• 1. Antimicrobial Drugs – antibiotics and antibacterials are used to prevent and control diseases.

• 2. Hormones can also be feed additives used to improve feed efficiency and rate of growth, mainly used for beef cattle.

• 3. Anthelmintics are used to control worms

Kinds of Feed Additives

• 4. Other additives– a. coccidiostats to control coccidiosis

in poultry.– b. Proxaline to prevent bloat in beef

cattle

• 5. Some examples– a. broad-spectrum antibiotics when

the specific disease is unknown.– b. Melengestrol of MGA to suppress

estrus or heat in heifers– c. Aureomycin, Terramycin, and

penicillin are antibiotics for swine.– d. Piperizine and Dichlorvos are worm

control additives.

Principles of Animal Nutrition

Objective 15.01: Discuss the general principles involved in

balancing a ration.

General Principles

• 1. Nutrients in the ration should be balanced to meet animal’s needs at the least expense.

• 2. The ration should include a variety of feeds to be palatable and to make it easier to balance.

• 3. The ration should be succulent to make it fresh and appealing and more palatable.

• 4. The ration should be palatable or agreeable to the taste in order for animals to eat it.

General Principles

• 5. The ration should be bulky to satisfy hunger and to help the digestive system function properly.

• 6. The ration should be slightly laxative – To improve feed efficiency and to prevent constipation.

• 7. The ration should be economical because feed cost is about 75% of animal production costs. – Price per pound of energy and digestible protein determine

if ration is economical.

• 8. The ration should be suited to the species and age of the animal. – More roughages for cattle, more concentrates for swine and

poultry, higher protein for younger animals, etc.

Interpreting relationships between 100 percent dry matter and as-feed

basis• 100% Dry Matter Basis

– 1. All moisture is removed from feed

– 2. Formula: • Pounds of feed on 100%

dry matter basis:– Pounds of feed on as-fed

basis x percent of dry matter in feed

Interpreting relationships between 100 percent dry matter and as-feed

basis• Air dry

– 1. Which means it still has some moisture

– 2. Formula: • Pounds of feed on as-

fed basis = pounds of feed on 100% dry matter basis / percent of dry matter in feed

Interpreting relationships between 100 percent dry matter and as-feed

basis• C. Relationship

– the weight of 100% dry matter basis is less than as-fed basis because 100% dry has no water.

• D. Table 48 in Gillespie (G) reference shows % dry matter in most kinds of feed.– 1. 100% dry matter basis of sun-cured hay is about 90% of

as-fed basis.– 2. 100% dry matter basis of most fresh pasture grasses is

about 20-30% of as-fed basis.– 3. 100% dry matter basis of most corn (NOT silage) is about

90% of as-fed basis.

• E. Storing high moisture feed materials will cause them to mold or to build up heat.

Rules of thumb for Rations

• 1. Beef cattle – – fattening ration should include 1 1/2 – 2 pounds

of air-dried roughage and 2 pounds of concentrate per 100 pounds of body weight. Cows nursing calves should be fed about 50% more than dry cows.

• 2. Swine – – the amount fed depends on size and age of

animal and whether sows are nursing. Pigs under 50 pounds and sows that are nursing require higher percent protein feeds than market hogs.

• 3. Poultry – – the ration is about 10% of body weight.

Principles of Animal Nutrition

Objective 15.04: Determine the nutrient requirements from appropriate

tables using the Pearson Square Method.

Reading Nutrient Tables

• A. Reading Nutrient Requirement Tables– 1. Called feed standards.– 2. Watch for Metric or English units of

measurement.– 3. ME means metabolizable energy intake.– 4. The protein, energy, mineral and vitamin

needs of the animal must be met by the ration even if they have to be added as a supplemental mix.

Using the Pearson Square

1. Draw a square with lines connecting the opposite corners and write the percent crude protein needed where the lines cross in the center of the square.

In this example 12% crude protein is needed

12

Using the Pearson Square

2. Write the feeds to be used and their crude protein percents at the left-hand corners of the square with the lower percent feed at the top left and the higher percent feed at the bottom left

12

Corn 8.9

Soybean oil meal 45.8

Using the Pearson Square

3. Subtract the smaller number from the larger number along the diagonal lines and write the difference at the opposite end of each line. The differences are the parts of each feed needed.

12

Corn 8.9

Soybean oil meal 45.8 12-8.9 = 3.1

45.8-12 = 33.8

Using the Pearson Square

4. Divide the parts of each feed by the total parts to determine the percent of each feed in the ration.

33.8 parts of corn / 36.9 total parts = 91.6% corn

3.1 parts of soybean oil meal / 36.9 total parts = 8.4%

soybean oil meal

12

Corn 8.9

Soybean oil meal 45.8 12-8.9 = 3.1

45.8-12 = 33.8

Using the Pearson Square

5. Determine the amount of feed to be mixed and multiply that number by the percent of each feed to find the amount of each feed needed.

In this problem, 1,000 pounds is the amount of corn and soybeans to be mixed.

1000 x 91.6% = 916 pounds of corn

1000 x 8.4% = 84 pounds of soybean oil meal 1000 total feed mixed