This document summarizes the six major classes of nutrients required by livestock: 1. Water is the most critical nutrient and functions in many biological processes. Requirements vary by species from very little for desert rats to 25-29 gallons daily for dairy cows. 2. Carbohydrates are an energy source, building block for other nutrients, and excess is stored as fat. Ruminants can break down fiber while monogastrics cannot. 3. Fats are a dense energy source and provide insulation. Sources include oils, rendered animal byproducts, and fiber reduces dust in feed. 4. Proteins provide amino acids but ruminants can use non-protein nitrogen from microbes while monoga

1. Six Classes of Nutrients
1. Water
The Most Critical Nutrient!
o Functions in transport, chemical reactions, temperature maintenance, lubrication,
etc.
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
o bad taste (high sulfur content)
o don’t know how to use or cannot find waterer
o stray voltage at water source
2. Carbohydrates (CHO)
Functions
o
o
o
energy source
building block for other nutrients
dietary excess stored as fat
Two main components of carbohydrates
o Crude fiber (cellulose mainly)
o Nitrogen-free extract (soluable sugars, starches)
Differences between monogastric, hindgut fermenter and ruminant
o Ruminants 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.
o All livestock are capable of breaking down the soluable sugars and starches.
Management Problems
o poor quality feedstuffs
o improper ration balancing
3. Fats (lipids)
Functions
Energy (stored at higher conc./g than CHO)
Source of heat, insulation, body protection (cushioning)
Essential fatty acids (immune function, CLA-anticancer link?)
Sources
o Oils (soybean oil, corn oil, fish oil)
o By product fats (lard or tallow from livestock rendering)
 provides cheap energy source
 reduces dust in feed manufacturing and animal feeding
 increases feed palatability

2. 4. Proteins
Most expensive ingredient in ration, need decreases as animal matures
Source of Essential Amino Acids (number, type and level of amino acids required varies
with animal species)
o Functions -- basic structural unit, needed in metabolism, hormone, antibody and
DNA production
When fed in exess, converted to energy, fat
Monogastric vs. ruminant
o True protein is composed of amino acids
o Crude protein contains both true protein and other nitrogenous products (nonprotein nitrogen)
o Non-protein nitrogen can be converted by rumen bacteria to true protein (cheaper
source of protein for the ruminant animal)
5. Minerals
Two classes
o Major minerals -- Ca, P, Na, Cl, Mg, K, S
o Minor (Trace minerals) -- Co, Cu, F, I, Fe, Mn, Mo, Se, Zn
 The need for supplementation of minor minerals such as Se and F varies
with the region
Functions -- skeleton, protein synthesis, oxygen transport, fluid and acid-base balance in
body, enzyme reactions
Mineral/mineral and vitamin/mineral interactions
o Ca - Vitamin D
o P - Vitamin D
o Co - Vitamin B12
o Se - Vitamin E
Both deficiencies and excesses can lead to disease
6. Vitamins
Two classes
o
o
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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