Productivity and Nutrition
The objective of this unit of study is to establish
a common understanding of some nutrition basics and an appreciation for proper livestock
nutrition. Students are strongly recommended to take additional courses in nutrition
for a more complete knowledge of nutitional requirements and techniques used in
formulating and balancing rations. There are six basic classes of nutrients that
must be considered in forumulating diets; water, protein, carbohydrates, fats, vitamins
and minerals. In Frank B. Morrison's Feeds & Feeding, a nutrient is
defined as "Any feed constituent or group of feed constituents of the same
general chemical composition that aids in support of animal life."
A number of factors can make an
understanding of livestock nutrition very confusing.
Many (most) feedstuffs or ingredients in a ration contain
more than one of the six basic nutrients. For instance, a kernel of corn contains
all six basic nutrients:
20-35% field moisture at harvest or if stored as high moisture corn
Commonly used feed ingredients may vary considerably in
the content of the six basic nutrients. The example of corn from above demonstrates
that the water content can vary widely, as can other perimeters. Some varieties of
corn contain high levels of specific nutrients, such as lysine or oil.
The unique physiology and metabolism of different animals
enables some to utilize some feed ingredients to their benefit while other animals of a
different species cannot.
Nonprotein nitrogen sources can be converted to amino
acids and from amino acids to protein by ruminants and hindgut fermenters; monogastric
animals cannot utilize these feedstuffs.
Fiber (roughages - hay, grasses) can be broken down by
ruminants and hindgut fermenters to provide an energy source; monogastric animals cannot
utilize these feedstuffs.
Some feed constituents are essential for
certain species, but not for others. Proline and glycine are essential amino acids
and must be added to poultry diets; other species can synthesize them from other amino
There are "linkages" or relationships between
different basic nutrients.
Selenium (a mineral) is linked to Vitamin E; they share
many "duties" in the body and one can often be substituted for the other.
Fats, carbohydrates and proteins can all be used to
provide energy to the body and can be additive in meeting the energy requirements of an
animal. (Protein will be converted to energy producing subunits if fed in excess of
it's basic metabolic needs.)
Calcium and Phosphorus must be fed at the appropriate
"ratio" for maximal utilization and to prevent interference with other mineral
No single feed ingredient can supply all 6 basic
nutrients an animal needs to survive and be productive.
One must "balance" the ratio
of different feed ingredients to meet the individual animal's needs.
The nutrient needs of an animal varies depending upon the
species, age, stage of lifecycle, etc.
In addition to meeting an animal's basic nutrient
requirements, a diet must also meet the "3 P's" to be useful as a livestock
Palatable -- must be edible,
accepted, and eaten by the animal
Profitable -- if the livestock
producer cannot make a profit feeding certain ingredients, he/she won't be in business
very long. Approximately 75% of the out-of-pocket costs in livestock production is
Productive -- animals eating
the diet must be productive. The least cost ration may just barely
meet the animal's nutrient requirements, but not allow the animal to function at it's most
productive level. The optimal ration is athe ration that can be
produced for the least cost for the benefit returned in animal performance (growth,
productivity, longevity, reproductive performance, etc.)
Six Classes of Nutrients
The Most Critical Nutrient!
Water deprivation ---> dehydration ---> electrolyte imbalance ---> death
Requirements vary from one species to another. For example, the desert rat
requires very little, while the dairy cow
may require 25-29 gallons/day.
Management problems leading to lack of water
- Functions in transport, chemical reactions, temperature maintenance,
- bad taste (high sulfur content)
- dont know how to use or cannot find waterer
- stray voltage at water source
2. Carbohydrates (CHO)
Two main components of carbohydrates
- energy source
- building block for other nutrients
- dietary excess stored as fat
Differences between monogastric, hindgut fermenter and ruminantRuminants and hindgut fermenters have microorganisms in the rumen
or hindgut that can break down crude fiber (cellulose) into useable products; monogastrics
cannot utilize most crude fiber.
All livestock are capable of breaking down the soluable sugars and
poor quality feedstuffs
improper ration balancing
- Crude fiber (cellulose mainly)
- Nitrogen-free extract (soluable sugars, starches)
3. Fats (lipids)
Energy (stored at higher conc./g than CHO)
Source of heat, insulation, body protection (cushioning)
Essential fatty acids (immune function, CLA-anticancer link?)
- Oils (soybean oil, corn oil, fish oil)
- By product fats (lard or tallow from livestock rendering)
- provides cheap energy source
- reduces dust in feed manufacturing and animal feeding
- increases feed palatability
Source of Essential Amino Acids (number, type and level of amino
acids required varies with animal species)
- Most expensive ingredient in ration, need decreases as animal matures
When fed in exess, converted to energy, fat
Monogastric vs. ruminant
- Functions -- basic structural unit, needed in metabolism, hormone,
antibody and DNA production
- True protein is composed of amino acids
- Crude protein contains both true protein and other nitrogenous products
- Non-protein nitrogen can be converted by rumen bacteria to true protein
(cheaper source of protein for the ruminant animal)
Two classesMajor minerals -- Ca, P, Na, Cl, Mg, K, S
Minor (Trace minerals) -- Co, Cu, F, I, Fe, Mn, Mo, Se, Zn
Functions -- skeleton, protein synthesis, oxygen transport, fluid
and acid-base balance in body, enzyme reactions
Mineral/mineral and vitamin/mineral interactions
- The need for supplementation of minor minerals such as Se and F varies
with the region
Both deficiencies and excesses can lead to disease
- Ca - Vitamin D
- P - Vitamin D
- Co - Vitamin B12
- Se - Vitamin E
Water soluble -- B & C
Fat soluble -- A, D, E, K
- Functions -- most vitamins have multiple functions in body involving
metabolism, enzyme reactions, etc.
- Requirements increase with age
- Both deficiencies and excesses lead to disease
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