Principles of Animal Nutrition

Six functions of a good ration• Maintenance of vital body

processes to keep animal alive• Growth by increasing the size of

bones, muscles, organs, and connective tissue

• Fattening by storing nutrients not used for maintenance, growth, r other functions

Six functions of a good ration• Production of milk, eggs, wool,

etc• Reproduction- adequate nutrition

is necessary• Work-other needs are met before

nutrients are available for work • From 1/3 to ½ of the ration fed is

used for maintenance

Roughages

• Feeds that contain more than 18% crude fiber when they are dry

• Examples: hay, pasture grasses, silage, hulls, straw, fodder

Concentrates

• Feeds that contain less than 18% crude fiber when they are dry

• Examples:– Grains- corn, oats, barley, wheat– Processed by products- wheat bran– Liquid supplements: molasses, urea– Animal/Plant proteins

Characteristics of a Good Ration

• Balanced: has all nutrients needed in the right amounts and proportions

• Palatable: tastes good so that animals will eat it

Characteristics of a Good Ration

• Low cost: best nutritional value possible at lowest cost because feed costs are about 75% of the total costs of raising livestock

Characteristics of a Good Ration

• Not harmful to health or quality of animal products

• Proper proportions of concentrates and roughages for type and age of animal

• Uniformly mixed especially micronutrients and feed additives

Feed additives• Materials used in animal rations in

small quantities to improve or stimulate performance such as feed efficiency, faster gain and health or production of animal products including eggs, milk, wool.

• Not generally considered nutrients

Hormone implants

• Pelleted synthetic or natural hormone like compounds placed under the skin or in the muscle of an animal to improve rate of gain and feed efficiency

Use of Feed Additives and Hormone Implants

• Performance stimulants and increase profits because of improved performance

• Sub-therapeutic- Using antibiotics and antibacterials at a lower level than would be used to treat sick animals

Use of Feed Additives and Hormone Implants

• A major health concern of low-level use is that microorganisms that cause diseases may become resistant to the drugs for treatment

Use of Feed Additives and Hormone Implants

• Many different antimicrobial drugs are used as feed additives to prevent diseases and to increase performance in livestock and poultry.

• The greatest return for swine is in young pigs

Use of Feed Additives and Hormone Implants

• Used widely in beef cattle, swine and poultry

• Regulated by the FDA• Must be labeled as medicated

feed

Mixing feed with additives

• Read and follow the label• Uniform mixing is required to

get correct amounts• Avoid contamination by

thoroughly cleaning the mixer• Keep up to date records

Proper Method of Hormone Implantation

• Restrain the animal to prevent head movement

• Use a sharp needle to eliminate the crushed pellets usually caused by dull needles

• Be sure needle and implantation site are clean

Proper Method of Hormone Implantation

• Select the proper place for the implant on the back surface of the ear in the middle third (about 1 ½ inch to 2 inch from the base)

Proper method of hormone implantation

http://www.mycattle.com/health/reports/properimp.cfm

Proper method of hormone implantation

• Point the implanting instrument toward the head and parallel to the ear, lift the loose skin with the point of the needle and push the needle in

• Do NOT hit a vein or cartilage

Proper method of hormone implantation

• Withdraw the needle slightly, start the implant, make certain the pellets have been properly deposited and slowly withdraw the needle.

Proper method of hormone implantation

• If the needle is removed too fast, the hormone pellets may be crushed or balled up

• Crushing pellets causes them to be absorbed too rapidly

Kinds of feed additives

• Antimicrobial drugs- antibiotics and antibacterials are used to prevent and control diseases

• Hormones are used to improve feed efficiency and rate of growth, primarily for beef cattle

Kinds of feed additives

• Anthelmintics (dewormer): used to control worms

• Other additives– Coccidiostats to control

coccidiosis in poultry– Proaxaline to prevent bloat in

beef cattle

Examples• Broad-spectrum antibiotics when

the specific disease is unknown• Melengesterol of MGA to suppress

estrus in heifers• Aureomycin, Terramycin, and

penicillin in swine• Piperizine and Dichlorvos are worm

control additives

General Principles

• Nutrients in the ration should be balanced to meet animal’s needs at the least expense

• The ration should include a variety of feeds to be palatable and to make it easier to balance

General Principles

• Should be succulent to make it fresh and appealing and more palatable

• Should be palatable or agreeable to the taste in order for animals to eat it

General Principles

• Be bulky to satisfy hunger and to help the digestive system function properly

• Slightly laxative to improve feed efficiency and to prevent constipation

General Principles• Be economical

– Price per pound of energy and digestible protein determine if ration is economical

• Should be suited to the species and age of animal– More roughages for cattle, more

concentrates for swine/poultry, higher protein for younger animals

100% Dry Matter Basis

• All moisture is removed form feed

• Formula: Pounds of feed on 100% dry matter basis: Pounds of feed on as-fed basis x % of dry matter in feed

Air dry

• Air dry which means it still has some moisture

• Formula: Pounds of feed on as-fed basis = pounds of feed on 100% dry matter basis/% of dry matter in feed

Other info• The weight of 100% dry matter is

less than as-fed basis because 100% dry has no water

• See table in Gillespie reference shows % dry matter in most feeds

• Storing high moisture feeds will cause them to mold or build up heat

Rules of thumb for beef cattle

• Fattening ration should include 1 ½-2 pounds of air-dried roughage and 2 pounds of concentrate per 100 pounds of body weight

• Cows nursing calves should be fed about 50% more than dry cows

Rules of thumb for swine

• The amount fed depends on size and age of animal and whether sows are nursing

• Pigs under 50 pounds and sows that are nursing require higher percent protein feeds than market hogs

Rule of thumb for poultry

• The ration is about 10% of body weight

Pearson square

• See Gillespie chapter on balancing rations

THE END!!!!!!