Chapter 6 Livestock Nutrition

Vitamins, Feed Additives and Water

Objectives

• Describe vitamins and feed additives.• List sources of vitamins and feed additives.• Describe the functions of vitamins, feed additives, and

water.• Describe deficiency symptoms caused by lack of vitamin

in the ration.• Discuss the effects of feed additives in the ration.• Discuss regulations on the use of feed additives in the

ration.• Discuss requirements for vitamins, feed additives and

water.

Vitamins Defined

• Vital to health, only needed in small amounts.

• Required for normal growth and and maintenance of animal life.

• Only small amounts are needed because they function as catalysts in metabolic processes.

Composition

• There are 16 vitamins in animal nutrition that are essential.

• They all have different chemical compositions.

• Different from each other in specific functions, but are grouped together because they are all organic, essential in trace amounts.

Naming

• During early research, they were designated by the letter of the alphabet in which they were discovered.

• Vitamin B was actually a number of different substances, therefore they started using subscripts.

• Today they are referred to either by letter designations or chemical names, the latter is used more often.

Solubility

• Some are soluble in water and fat.

• Water soluble include B complex and C.

• Fat soluble fats include A, D, E and K.

• The solubility of a vitamin is related to its function in metabolism.

Ration Considerations

• Some vitamins can be synthesized in the body, therefore do not need to be added to a diet.

• Fat soluble vitamins can be stored in the animals body, reducing the need for daily supply.

• Water soluble cannot be stored therefore need to be supplied on a daily basis.

Ration Consideration

• Vitamin content of feeds varies with the quality of feed.

• A feed may contain an essential vitamin but it may have a low availability in metabolism.

• It is generally recommended that vitamin premixes be used at the appropriate levels in livestock feeding to assure a ready supply of essential vitamins are available.

Ration Considerations

• Specific vitamins have specific functions.

• Involved in a number of metabolic processes and deficiency symptoms are an indication that basic metabolic processes in the body have been disturbed.

Vitamin A

• The product of the conversion in the animal’s body of carotene which is found in feeds.

• True vitamin A is not found in feeds.• Because vitamin A is converted from

carotene, the carotene is regarded as a precursor of vitamin A.

• Beta-carotene is the standard used.

Vitamin A

• Different animal species covert carotene to vitamin A at different rates.

• When the feed source supplied enough carotene, the animal can usually meet its requirements for vitamin A from the diet.

Vit A Functions

• Normal maintenance of the eyes, membrane tissue, respiratory, digestive, reproductive, nerve, and bone growth.

Vit A Deficiency

• Night blindness is a symptom of severe vitamin A.

• Animals may become permanently blind because of a vitamin A deficiency.

• Eye infections and constriction in the optic nerves can be less severe symptoms.

• Excessive watering of eyes. Cornea ulcerations are indications of possible vit A deficiency.

Vitamin A Deficiency• Keratinization of the epithelial tissue, which

causes lowered resistance to infections is common with vitamin A deficiency.

• Diarrhea, reduced appetite, poor growth and weight loss are also indicators of vit. A deficiency.

• Reproductive problems, poor conception, reduced fertility in males, shortened gestation, retained placenta and still born can also be indicators.

Vitamin A Sources• Carotene is found in good quality, fresh,

green forages in amounts generally sufficient to supply the needs of livestock.

• Green, leafy hays that have been in storage less than one year, legume hays, good qulity grass or legume silages.

• Dried sun-cured forages contain less carotene.

• Bleached, low quality forages have little carotene content.

• Yellow corn is a good source of carotene.

Vitamin A Sources

• Carotene content of forages in storage is reduced by exposure to the sun and air, high temperature and long storage times reduce content.

• Mixing the feeds with oxidizing agents such as some minerals or organic acids will also reduce content.

Vitamin A storage

• Stored in the liver and fatty tissues of the body.

• The animal can use this stored vitamin A during periods of feeding when the diet is deficient in carotene.

• A horse can go for 3-6 months when Vit A is deficient, sheep 200 days.

Vitamin A Ration Considerations

• May need to supplement when:• Poor quality or low levels of forage are

available.• Limited amounts of colostrum .• Fed primarily corn silage and low carotene

concentrates.• Grazing during drought, rations of cereal

grains.

Vitamin A Ration Considerations

• Vitamin A, in a stabilized form that is resistant to oxidation may be added to the ration through vitamin premixes.

• Intramuscular injections of vitamin A may be used.

• Stress conditions such as low temperature or exposure to infectious bacteria will increase the vit A requirements.

Excess Vit A in Diet

• Feeding excessive amount of vit A to horse over along period of time may result in fragile bones, thickening of bony tissue, flaking off of the epithelium.

Vitamin D

• Important for calcium absorption, Ca and P metabolism.

• Fat soluble, stored in the body.

• Less critical in mature versus younger animals.

• Most important in animals in the third trimester of pregnancy.

Vitamin D Forms

• Plant forms of vitamin D is ergocalciferol.

• Animal forms of vitamin D is cholecalciferol.

• The liver converts cholecalciferol to 25-hydroxy D3, which is the main form in which the vitamin circulates in the body.

Vitamin D Deficiency

• Development of rickets, because of reduced Ca and P absorption.

• Indicators are decreased appetite, slower growth, digestive disturbances, stiffness in gait, labored or fast breathing, irritability weakness and sometimes the development of tetany.

• Symptoms develop more quickly in younger animals.

Vitamin D Deficiency

• Pregnant animals may give virth to dead, weak or deformed young as a result of a vitamin D deficiency.

Vitamin D Sources

• Diets that include sun-cured forages generally provide sufficient vitamin D.

• Animals regularly exposed to sunlight or ultrviolet light also will not develop symptoms of vitamin D deficiency.

• Green forages, barn cured hay and silages have some vitamin D.

• Grains and grain by products have practically no vitamin D.

Vitamin D Sources

• Vitamin D is more stable than vitamin A, does oxidize, has poor stability when mixed with minerals, especially calcium carbonate.

• Rations with adequate levels of Ca and P will require less vitamin D.

Vitamin D Toxicity

• Extremely toxic to poultry and horses.

• Poultry can withstand 100 times the recommended amounts and horses 50 times.

• Feeding massive doses in the last weeks of dairy cattle gestation has reduced milk fever.

Vitamin E

• Functions as an antioxidant, which helps in the abosorption of storage of vitamin A

• Vitamin E deficiency results in symptoms similar to selenium, whitemuscle, muscular dystrophy.

• Whole cereal grains, green forages, good quality hay all have sufficient sources of Vitamin E.

Vitamin K

• Necessary for the formation of prothrombin, (material that forms blood clots).

• Deficiencies of vitamin K rarely occur because it is synthesized in the rumen.

• Feeding moldy feeds may cause vitamin K deficiency leading to a bleeding syndrome.

• Green leafy feeds, soybeans, fat soluble, solvent process soybean meal are good sources.

Vitamin C

• Necessary for the formation of collagen.

• Normally they synthesize sufficient amounts.

Feed Additives

• Products used in animal nutrition that are not nutrients in the usual sense of the word.

• Promote greater feed efficiency, produce more rapid gains or higher production.

• Types of feed additives include antibiotics and antibacterials, hormones, anthelmintics and other miscellaneous compounds.

• Majority are used when growing and/or finishing livestock.

Health Concerns

• There has been a growing concern in recent ears that the use of some types of additives for livestock feeding may have an imact on human health as well as animal health.

• Antibiotics and animal byproducts are the two most controversial issues today.

Water

• Involved in many of the biochemical reactions in digestion and metabolism.

• Transports nutrients and wastes.

• Regulates body temperature.

• Gives the body form by filling cells.

• Provides lubrication.

• Milk production.

Water

• Animals can survive longer without feed than water.

• Intake of water ranges from three toeight times the intake of dry matter.

• All feeds contain water, 10% for air dry to more than 80% in fresh green forages.

• Clean water should be readily available at all times.

Water

• Temperature of water will effect intake.

• Animals will drink more water if it is warmed slightly above freezing.

• High humidity decreases water intake, while high ambient temperatures significantly increase water consumption.

• Ph levels should be from 6-9.