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Performance Modifiers

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The Problem

•After the realization that animals had a need for protein supplementation the livestock industry was still trying to find ways to increase efficiency and productivity.

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The Solution

• Practical methods of utilizing synthetic or manufactured compounds to enhance growth and efficiency were developed.

• These Compounds:– Performance Modifiers

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What is a Performance Modifier?

• Somatotropins– Proteins that affect the utilization of energy in

the body– Produced in the pituitary gland, located at the

base of the brain.

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Performance Modifiers

• Examples– Injectables

• Bovine Somatotropin (BST)

• Porcine Somatotropin (PST)

– Implants• Growth hormones and steriods

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Bovine Somatotropin (BST)

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BST and the Cow

• Produced naturally in the pituitary gland, located at the base of the brain.

• Causes energy derived from feed to be used for milk production rather than for weight gain.

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Without BST?Energy From Food

• Growth Milk

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With BST

Energy from Feed

Growth Milk

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Genetic Engineering & BST

• The advancement in technology has allowed for the manufacture of “recombinant bovine somatotropin” (rBST)

• The Food and Drug Administration approved rBST for use in November of 1993.

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Administration of BST

• Recommendation:– Injections should begin 9 weeks after the cow

has calved– Repeat injection every 14 days throughout

lactation – Discontinue use 2 weeks before the end of

lactation

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What cows should have BST?

• The cow should be:– In good body condition – Gaining weight– Well managed– Fed a balanced ration with high quality forage

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Which cows should NOT have BST?

• Cows with:– Poor health– Poorly balanced rations– Inadequate feed– High somatic cell count– Stress– Breeding problems

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Benefits of BST?

• Increase milk production – 5 to 15 pounds/day

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Normal +BST

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Is it worth it?

That is for the farmer to determine!

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Porcine Somatotropin (PST)

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What is PST?

A protein produced in the pituitary glandGrowth RegulatorProduction of PST decreases as a pig

matures

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What are the benefits of PST?

Improves feed efficiencyImproves gainDecreases fat deposition

Causing less back fat

Produces more muscle massLeading to a bigger loin eye area

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Making PST Successful

Diet must consist of more protein and amino acids to support the increased growth rate.

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Genetic Engineering & PST

• PST is produced in the pituitary gland at the base of the brain.

• Synthetically producing PST– Scientists have isolated the gene from the pig

and inserted it into E. coli– E. coli then produces PST synthetically– The PST is then isolated and injected into the

pig

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Beef Cattle & Growth Implants

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Growth Implants

• Have been extensively used in beef production for over 30 years

• Can be used in cattle from 45 days old and up– Use of implants in NOT recommended for

replacement heifers or breeding bull calves

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Benefits of Growth Implants

• Suckling Calves– Improved weaning weights of 3-5%

• Feeder calves– Improved feed efficiency and gain of 5-15%

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Implant Use

• Injected into the middle third of the back side of the ear

• Outside the cartilage ring at the base of the ear

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Nutrition Is Key!

• Cattle must have adequate nutrition before the use of implants positively influences feed efficiency and gain

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Problems with Growth Implants

• Carcass Composition– Heavy carcass weight with large frame, exotic

cattle– Poor yield grades in heifers with certain types

of implants– Poor quality grades if implanting schedules are

not managed appropriately

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The key to successful resultsfrom implants depend on…

Good

Management