Chapter Six
Feed and Nutrition
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Feed and Nutrition
 Raw materials for growth, maintenance & repair
 Nutrition = food & water requirements & processes to take
in & use food
 Digestion = process food is broken down, absorbed,
distributed & made available to cells
 In cells, chemical reactions break down compounds into
simple molecules, releasing energy and molecules for
synthesizing new molecules like proteins.
 The sum of these intracellular chemical reactions is called
metabolism.
The Nutrients
 Water, proteins, fats, carbohydrates, vitamins &
minerals.
 Carbohydrates, proteins and fats all provide
energy in the form of calories.
 Organisms require energy to operate.
 Require essential and nonessential nutrients.
 Essential nutrients = ones animals can’t produce
in sufficient quantities, must be supplied in diet.
 Essential for some species and not for others.
vitamin C for guinea pigs, NHP & humans
 Some are required in small amounts.
vitamins and minerals
Water
 Water is the most important nutrient.
 An animal can lose reserve carbohydrate and fat
and about 50% of body protein and still survive.
 Without water most animals can survive only a few
days.
 Water is the medium in which all metabolic
reactions and body processes take place and is a
method for distribution of substances throughout.
 A loss of approximately 10 to 20% of body water
can result in death.
Protein
 Complex molecules made up of long chains of
amino acids arranged in a large variety of
sequences
 Proteins are the basic building materials with
which tissues are made.
 Enzymes, some hormones, and hemoglobin are
made of proteins.
 If deficient caloric intake occurs, body protein is
metabolized.
Fats
 Structural components of cell membranes
 More calories than carbohydrates or proteins.
 One function of fat is to supply and store energy.
 Provide thermal insulation, cushion and protect organs,
store and transport fat-soluble vitamins and synthesize
hormones
 Brown fat is found in some animals, and can be
metabolized to provide heat.
 Broken down into units called fatty acids.
Carbohydrates
 Sugars are elementary forms of carbohydrates.
 Glycogen = complex sugars easily broken down
by enzymes, used as an energy source of body.
 Carbohydrate is main energy source in
metabolism.
 Excess carbohydrate is stored as glycogen in
liver and muscle tissue.
 When storage areas are full, carbohydrate is
converted to fat.
Vitamins
 Function to promote chemical
reactions for normal metabolism
 Non-fatty tissues contain watersoluble vitamins (vitamins C & B).
Water-soluble vitamins supplied daily because they are
not easily stored.
 Fat-soluble vitamins A, D, E and K are found in
fatty parts of plants and animals.
Digestion and metabolism of fat supply fat-soluble vitamins.
Fat-soluble vitamins in excess are stored in fat, not excreted.
 Excess or deficiency vitamin = serious disease
Guinea pigs and NHPs get scurvy, a result of feed
stored too long or at too high a temperature.
Minerals
 21 inorganic elements are necessary
to sustain life.
 Ca, P and Na are used as structural
components & as electrolytes in salt balance.
 Minerals are required in trace
amounts, & used in a variety of processes.
 Iron = oxygen carrier in hemoglobin found in RBC.
 Mineral deficiency or excess in the diet can cause serious
disease.
 Ca is necessary for contraction of muscles, including heart
muscle.
 Deficiency in Ca = poor bones
 Bone Ca goes to blood to help maintain heart muscle contraction.
Energy Metabolism
 Diets are formulated for each species.
 Energy is needed to maintain life processes.
respiration, cell metabolism, movement, digestion,
nerve impulse transmission, cell division & growth
 1 calorie is heat necessary to raise temperature
of one gram of pure water at 14.5°C to 15.5°C.
 Feed bag has a chart that tells how many Kcal of
energy contained in the diet.
 can be used to determine how much to feed
 Feeds vary considerably in total caloric content.
 carbohydrates = 4.1 Kcal/gram, proteins = 5.6
Kcal/gram and fats = 9.4 Kcal/gram
(Images) Dog Eating
Feedstuff Evaluation
 Proximate analysis used to formulate diets.
 Analytical tests provide data on a feed sample.
 Consuming proper amount of commercial diet &
water = all nutritional requirements.
 Supplements contribute to daily caloric intake.
May result in consuming less than daily diet and
interfere with dietary balance.
 Treats may be a necessity, for delivering
medication or for psychological enrichment.
 Supplementation may be required during rapid
growth, pregnancy, lactation or geriatrics.
Available Forms of Feed
 Ground feed = powdered diet
Commonly used for poultry but OK for other animals.
High dust content may cause respiratory problems in
some species
 Pelleted feed made by grinding and molding into
a variety of shapes & sizes.
High fat content feeds
don’t hold together well.
Abundance of powdered feed
in the feed bag = questionable
quality & should be reported.
Fed to rabbits, guinea pigs, rodents and farm animals.
Available Forms of Feed II
 Extruded = high pressure & heat in tapered mold.
 Semi-moist feed is available for dogs and cats.
High calories = unsuitable for caged animal use.
May contribute to dental problems.
 Canned feed is comparatively expensive.
Can be used to tempt sick animals to eat or deliver
medication by hiding it in the food.
 Hay given to ruminants, rabbits and guinea pigs.
Contaminated hay can affect health.
Hay cubes are a suitable alternative.
Commercial Diets
 Standard diets are available with data on protein,
fiber, fat or other nutrient content
 Certified feed measures pesticides & heavy metal
contaminants.
Contaminants usually certified to be below a particular level.
 Autoclavable and irradiated feed fed to animals in
barrier facilities.
Formulated to account for autoclaving which destroys
significant portions of certain nutrients.
Diets can also be sterilized with radiation.
 Purified diets are made from ingredients such as
starch, glucose, sucrose and casein.
Practical Aspects of Feeding
 Water must be available at all times.
A sipper tube may be plugged preventing animal from
reaching water, so technician quickly learns to identify
such problems and correct them before the animals
demonstrate ill effects.
Addition of substances to water may cause animals to
decrease intake because of taste.
 Feeders designed for a type of feed.
 Feed accessible, clean, uncontaminated.
 J-feeders become clogged with fines.
 Technicians monitor feed intake &
are aware of any variations.
Diet & Water Problems
 Sensitivity to diet changes
often fail to eat or exhibit diarrhea
make feed changes gradually
 Growth and reproduction
two most demanding physiological states
Rodents begin eating feed 10-14 days after birth.
Cats and dogs begin to eat at 3-4 weeks old.
Extra feed should be provided to the nursing female.
Food and Water Intake
 Animals overactive and distressed within
24 hours without water.
 Hair coat appears dull and shaggy.
 Dry food intake decreases dramatically, as does
the production of urine and feces
 Dehydration also due to a disease or faulty watering.
 Decreased food intake = significant
weight loss, obvious overall debilitation, &
prominent skeletal structure.
 Decreased food intake can also be result of an experimental
procedure or a disease process
 In group-housed animals, a dominant animal may prevent
a subordinate animal from reaching food.
Feed Storage & Room Management
 Proper handling vital to health & nutrition.
Direct bearing on economics of facility management.
 Storage environment cool, dry, well ventilated &
no direct sunlight.
 Store on platforms or shelves above floor & at
least 6 inches from the wall to allow for cleaning
& air circulation.
If wood is used, seal to allow proper cleaning.
 Keep open bags in plastic-lined cans w/ tightfitting lids.
Shelf Life
 Milling date = date food was made.
 Feed loses nutritional value after shelf life expires.
 Purified diets & some diets containing vitamin C
have a short shelf life (3 months or less).
Other types can be stored up to 6 months.
Storage under less than optimal conditions (for example,
high heat or humidity) shortens shelf life.
 On receipt, check milling date, mark w/ “use by”
Check: clean, dry, unstained, not torn or damaged
Reject any of these defects as possible contamination.
 Store special feeds w/ drugs or chemicals away
from regular feed storage room.
Store detergents & chemicals separately.
Additional Reading
Frandson, R.D. Anatomy and Physiology of Farm
Animals. 5th ed. Lea and Febiger, Philadelphia,
PA. 1992.
Nutrient Requirements of Laboratory Animals. 4th
ed. National Research Council. 1995.
Jurgens, M.H. Animal Feeding and Nutrition.
Kendall/Hunt, Inc., Dubuque, IA. 1988.