Nutrient Requirements for Body Functions

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Nutrient Requirements for Body Functions

• Topic 3041 Nutrients and Nutrient Requirements
• Developed by Amanda R. Moore

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Overview

• Definitions

• Requirements for
• Body Maintenance
• Growth
• Fattening
• Reproduction
• Lactation
• Egg Laying
• Wool Production
• Work

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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

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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

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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

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Body Maintenance

• Maintenance requirement in relation to weight can
  be expressed as Wt.75
• IeIf 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)

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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

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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

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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

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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

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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

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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

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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.

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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

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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

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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

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Resources

• Taylor, Robert E. and Field, Thomas G. 1998.
  Scientific Farm Animal Production, Sixth Edition.
  New JerseyPrentice Hall Publishing.
• Desert Rosesonline www.ag.arizona.edu/desert_ro
  ses, 3/14/01