1. Nutrient Requirements for Body Functions Topic 3041 Nutrients and Nutrient Requirements Developed by Amanda R. Moore

2. Overview DefinitionsRequirements for: Body Maintenance Growth Fattening Reproduction Lactation Egg Laying Wool Production Work

3. Definitions Metabolism All the chemical and physical properties that take place in the body Anabolism Metabolism that builds tissue Catabolism Metabolism that breaks down materials

4. Nutrient Requirements for Body Maintenance Body Maintenance: A condition in which the body is maintained without an increase or decrease in body weight, and with no production or work being done. Examples: Body tissue repair Control of body temperature Energy to keep vital organs functioning Water balance maintenance

5. Body Maintenance Approximately 50% of feed is used to fill the maintenance requirement This must be met before supplying nutrients for other functions Maintenance needs are related to body size

6. Body Maintenance Maintenance requirement in relation to weight can be expressed as Wt.75 Ie:If a 500-lb animal needs 15 lb of feed per day for maintenance, a 1,000-lb animal of the same type would not require twice as much feed as the first. Instead: 1000.75 shows that this animal requires 1.7 times as much as the smaller animal = (15lb x 1.7 = 25lb)

7. Nutrient Requirements for Growth Growth is the increase in protein over its loss in the animal body. It occurs by increases in cell numbers, cell size or both Growth requires energy, protein, minerals, vitamins and energy Young animals require more protein in order to build muscle and grow Mongastric animals also need certain amino acids for proper growth

8. Growth Young animals also need calcium and phosphorus, salt or a normal sodium level, any mineral that may be deficient in the area the animal lives Iodine and Selenium require special consideration Iodine deficiency in the fetus prevents thyroxine from being produced, causing goiters and eventual death in newborns Selenium deficiency may cause white muscle disease in newborns

9. Growth Vitamins are also required by growing animals Must be supplied to pigs and poultry through feeds (usually vitamin D) Vitamin A is usually the only vitamin commonly fed to ruminants Energy is required to sustain growth, metabolic rate and activities Can be supplied by feeding corn, barley or wheat

10. Nutrient Requirements for Fattening Fattening: Storing of surplus feed energy as fat Results from excess energy from carbohydrates, fats or protein beyond the the maintenance requirements

11. Nutrient Requirements for Reproduction Two categories of requirements: Gamete production Fetal growth in the uterus Fetus requirements are much greater in the last trimester of pregnancy Nutrition of the female must not be inadequate during pregnancy

12. Nutrient Requirements for Lactation Milk production requires considerable protein, minerals, vitamins and energy The need for protein is greater because milk contains more than 3% protein Calcium and phosphorus are the two most important minerals needed for lactation. If absent, may result in decreased lactation, disease or even death

13. Lactation Energy is the most vital requirement for the production of a large quantity of milk High producing dairy cows may need up to four times the energy of a nonlactating cow of the same size.

14. Nutrient Requirements for Egg Laying Egg layers are usually fed free choice (as much as they can eat) It is important that rations have adequate concentrations of energy, protein, vitamins and minerals

15. Nutrient Requirements for Wool Production These are in addition to nutrients needed for maintenance, growth and reproduction Wool fibers are primarily protein, the ration should be adequate in protein Shearing may cause an increase in energy requirements

16. Nutrient Requirements for Work Large amounts of energy beyond the maintenance needs If energy is not sufficient in the ration, the animal will begin to use body fat stores to provide the additional energy needs

17. Resources Taylor, Robert E. and Field, Thomas G. 1998. Scientific Farm Animal Production, Sixth Edition. New Jersey:Prentice Hall Publishing. Desert Roses[online]: www.ag.arizona.edu/desert_roses, 3/14/01