Nutrition, Digestion, and Feeds

Nutrition is the science that deals with

food and the nutrients it contains that man and animals must have to live and function

Therefore, man is vitally interested in nutrition for

his own sake

However, the animal scientist or livestock producer is interested in nutrition as it

affects the productivity and thereby the profitability of their animals

The meat animal production chain involves

breeding, feeding, management, and marketing

The single most costly category is

feeding

Therefore, a profitable and efficient production program must

consider the efficient use of feeds

To use the various feeds most intelligently, feeders must not only know the various nutrients feeds contain and the function of those nutrients in the animal body but also

be acquainted with the anatomy of the digestive tract of various species

Feeders must know the physical and chemical processes involved in

the digestion and absorption of various nutrients

Additionally, students can learn much information to allow them to understand better

the nutritional needs of and functions of nutrients in their own bodies

If we selected and use feeds more efficiently, we will

have more net income

A lack of knowledge about nutrition can

produce some poor results in animals

Why are some rations pelleted?

The weight of the piles is the same

Classification of Animal Feeds:

Concentrates

Roughages

Animal Feed: Concentrates are

high in energy, low in fiber, easily digestible

Animal Feed: Concentrates can be _ or  _

Carbonaceous, Nitrogenous

Concentrates: Carbonaceous -

low in protein; cereal grain (corn, wheat, oats, sorghum), molasses

Concentrates: Nitrogenous -

high in protein; oil meals (soybean meal, cottonseed meal), fish meal, packing house by-products such as tankage, dairy products

• Important in feeding monogastric animals, companion animals

Animal Feeds: Roughages are

high in energy, low in fiber, less digestible than concentrates

Animal Feed: Concentrates can be __ or __

Carbonaceous, Nitrogenous

Roughages: Carbonaceous -

low in protein; mature grass hay, stover, mature cereal grain silage

Roughages: Nitrogenous - 

high in protein; legume hay and silage, immature grass hay and silage, growing pasture and silage

• Important in feeding ruminant animals (animals who can use the ruffage)

Cross section of a grain kernel

Starch is carbohydrate

Germ is protein

Pericarp needs to be cracked to allow digestion

Nutrients are chemical substances in either mineral or compound form that are

absorbed from the digestive tract into the blood and that function in metabolism of the body

water is the cheapest and 

most abundant nutrient

water is absolutely

necessary for life

An animal will die more quickly from lack of water than

from lack of any other nutrient

How can camels go longer (a week or more) without drinking than we can?

They drink more when it is available (have a large storage capacity in the rumen)

They conserve water better (dry species and concentrated urine)

In a hot environment, a camel can lose 27% of its body weight without observable ill effects

Death occurs after loss of

10%-14% of water in the body

Body temperature fluctuates without causing distress; may fall to

93 degrees F at night and rise to 105 degrees F in the daytime

Minerals regulate

body water

Sources of water

Drinking

Ingested - contained in or on feed

Metabolic - derived from breakdown of nutrients

Functions of water

Transport of nutrients and excretions

Chemical reactions and solvent properties

Body temperature regulation (sweat)

Maintenance of shape of body cells

Lubrication and cushioning of joints and organs

You will die most quickly without 

water

Proteins are composed of

amino acids (are the building blocks) - 22 amino acids

Each amino acid contains nitrogen

Structure of proteins

amino acids > peptide > polypeptide > protein

Classifications of amino acids

Essential

Non-essential

Classification of amino acids

Essential -

essential to animal; must be supplied in diet because body cannot synthesize them fast enough to meet requirements

Memory code: MATT HILL VP for

methionine, arginine, threonine, tryptophan, histidine, isoleucine, leucine, lysine, valine, and phenylalanine

Classification of amino acids

Non-essential -

are essential to the animal, however they are normally synthesized or are in sufficient quantity in the diet and need not be fed to the animal

Protein analysis - determine Nitrogen content and

multiply by 6.25 (average nitrogen content of proteins is 100/16)

Example of protein analysis - If a feedstuff analyzed 1.92% nitrogen,

1.92 x 6.25 = 12% crude protein

Protein analysis - crude protein and digestible protein

The portion of crude protein that is actually digested is digestible protein

Protein quality vs.

protein quantity

Nonprotein nitrogen (NPN) - urea, biuret

If a substance contains nitrogen that is not a part of amino acids, it is called Nonprotein nitrogen (NPN)

Rumen microbes can use this NPN as the nitrogen source for amino acid MFG

Functions of proteins

Basic structural unit of animal body

Body metabolism - enzymes, hormones, immune antibodies, and hereditary transmission structures are composed of proteins

Energy source; excess will be excreted or stored as fat

protein supplements are

expensive

Carbohydrates: Photosynthesis produces

CHO’s: 6 CO2 + 6 H2O + 673 calories of radiant energy from sunlight (Chlorophyll) > C6H12O6 + 6 O2

Carbohydrates are classified by

the number of simple sugars in the molecule

Carbs: Monosaccharides (C6 H12 O6)

one sugar molecule; examples are glucose, fructose, galactose, mannose

Carbs: Disaccharides (C6 H22 O11)

two sugar molecules; examples are sucrose (glucose + fructose), maltose (glucose + glucose), lactose (glucose + galactose)

Carbs: Trisacchariedes

three sugar molecules; examples are raffinose (glucose + fructose + galactose); bacteria in some animal stomachs can degrade

Carbs: Polysaccharides

many sugar molecules; starch, cellulose, lignin, glycogen. amylopectin

• Long chains or branched molecules of several disaccharide subunits

Carbohydrates: Analysis 

determine carbohydrate content of a substance by nitrogen free extract (NFE)

Carbohydrates: function

provide energy and heat; excess will be stored as fat or excreted

Carbs are a main

energy source

Structure of Lipids (fats and oils)

composed of fatty acids (saturated and unsaturated) and glycerol

Lipids produces 2.25 times more energy (9 calories per gram) than

proteins or carbohydrates (CHOs) (4 calories per gram)

Fats are solid at room temperature; examples are

lard and beef tallow

Oils are liquid at room temperature; examples are

cottonseed oil and corn oils

Lipids (fats and oils) - Fat analysis - either extraction; fat x 2.25 (9/4 = 2.25)

This caloric value difference (9 vs 4) is the reason people trying to lose weight should eat a low fat diet

But total calories, not just fat calories, determine your loss or gain in weight

About 3,000 calories = 1 pound of weight gain

We determine fat content by ether extraction; lipids are soluble in either

Lipids (fats and oils) - functions

Provide energy; excess will be stored as fat or excreted

• Best energy source per gram, if we eat too much it will be stored as fat

Lipids (fats and oils) are sources of 

heat, insulation, and protection

Lipids (fats and oils) are carriers for 

absorption of fat soluble vitamins (D, E, A, K)

Some skin conditions are caused by

a dietary deficiency of these fatty acids (D, E, A, K)

These 3 fatty acids are unsaturated - one valence

of adjacent carbon atoms are not satisfied by hydrogen atoms

Lipids (fats and oils) - digestion coefficient

(in - out) / in x 100

Lipids: Measurement of energy content of feeds

Digestion coefficient = (amount digested / amount consumed) x 100; you multiple by 100 to get percent digestibility

Lipids: Total digestible nutrients (TDN) =

digestible protein + digestible crude fiber + (digestible fat x 2.25) + nitrogen free extract

Components of energy

Gross energy

digestible energy

metabolizable energy

net energy

Lipids give 2.25 times more energy than

carbs or proteins

Vitamins: functions

organic catalysts in biochemical reactions

Needed in small amounts

Vitamins: Classification

Fat Soluble (carried in fats): Vitamins D, E, A, K

Water Soluble: Vitamin C

Water Soluble B-complex vitamins: Thiamin, Riboflavin, Pantothenic acid, Niacin, Pyridoxine (vitamin B6), Biotin, Folic Acid, Vitamin B12, Choline, Inositol, Para-aminobenzoic acid

Vitamin D

Function: Aids calcium absorption from the gut; humans manufacture this if exposed to sunlight

Deficiency: Can be cause of skeletal diseases such as rickets

Vitamin E

Function: Has antioxidant properties; can help reduce free radicals. Research has shown that this may help delay Alzheimer’s effects

Deficiency: Exudative diathesis

Vitamin A

Function: Proper vision, helps eyesight

Deficiency: Night blindness, shortage can cause blindness by constriction of the optic nerve as it passes through the bones of the skull (nerve grows, but bone doesn’t)

Vitamin K

Function: Necessary for blood clotting

Deficiency: Bleeding, if a pet eats rat poison the vet probably will give a large injection of this

Vitamin C

Function: From citrus fruits, functions in collagen formation

Deficiency: Scurvy

Water Soluble B-complex Vitamins: most of these 

vitamins function as coenzymes in oxidative metabolic reactions and prevent several disease conditions

Vitamin Thiamin

Function: Coenzyme

Deficiency: Beriberi, nerve disorder

Vitamin Riboflavin

Function: Coenzyme

Deficiency: Paralysis, curled toe paralysis

Vitamin Pantothenic acid

Function: Coenzyme A

Deficiency: Goose stepping

Vitamin Niacin

Function: Coenzyme

Deficiency: Pellagra, skin eruptions, retarded growth

Vitamin Pyridoxine (vitamin B6)

Function: Coenzyme

Deficiency: Acrodynia, epileptic-like fit

Vitamin Biotin

Function: Coenzyme

Deficiency: Perosis, unclean, hair loss

Vitamin Folic Acid

Function: Oxygen transport

Deficiency: Anemia

Vitamin B12

Function: Only source is meat. Oxygen transport

Deficiency: Anemia, slow growing, rough haircoat, dermatitis

Vitamin Choline

Function: Liver fat metabolism

Deficiency: Liver cirrhosis, spraddled legs

Vitamin Inositol

Function: Lipotrophic action rats

Deficiency: Alopecia

Vitamin Para-aminobenzoic acid

Function: Chick growth stimulant

Deficiency: Graying animal hair

Most B-complex citamins function in 

oxidative metabolism

Vitamins are organic

catalysts

If a small amount of a vitamin is good, is a large amount better?

Not necessarily—while small amounts of vitamins are essential, large amounts can be harmful and may lead to toxicity.

What vitamins are toxic in megadoses?

Fat-soluble vitamins A, D, E, and K are most toxic in megadoses because they accumulate in the body and can lead to serious health risks like liver damage, bone fractures, and bleeding disorders.

Do ruminant and non-ruminant animals have the same vitamin requirements?

No, ruminant and non-ruminant animals do not have the same vitamin requirements due to differences in their digestive systems and microbial synthesis capabilities.

Minerals (ash) are inorganic, required by

animals, both plant and animal sources

The balance among minerals sometimes is as

critical as the amount in the diet

Some minerals are components of hormones and

enzymes

For example, zinc is needed for manufacturing of sex hormones

Minerals help main a cell’s

osmotic pressure

Minerals help maintain a correct

acid : base balance

Minerals are needed for

bones and teeth formation