Using EPDs in Using EPDs in SelectionSelection

Stolen and edited by: Brandon Freel Stolen and edited by: Brandon Freel and Daniel Powelland Daniel Powell

Originally compiled by Colorado Originally compiled by Colorado Agriscience CurriculumAgriscience Curriculum

ObjectivesObjectives

►Define Expected Progeny Difference.Define Expected Progeny Difference.► Identify terms associated with EPD’s.Identify terms associated with EPD’s.► Interpret EPD categories.Interpret EPD categories.►Analyze EPD variations within breeds. Analyze EPD variations within breeds.

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You must first look at breeding You must first look at breeding values.values.

PhenotypePhenotype – The appearance of an – The appearance of an animal.animal.

GenotypeGenotype – What genes are present – What genes are present and how they are combined.and how they are combined.

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How are Breeding Values How are Breeding Values Reported?Reported?

((EPDEPD) ) ExpectedExpected ProgenyProgeny DifferenceDifference – – A measurement of genetic potential A measurement of genetic potential based on the performance of relatives.based on the performance of relatives.

((ACCACC) ) AccuracyAccuracy is an important term is an important term used in understanding EPDs. It is a used in understanding EPDs. It is a measure of expected change in the measure of expected change in the EPD as additional young are born to EPD as additional young are born to the sire. A high accuracy value is the sire. A high accuracy value is better as the chances of the EPD being better as the chances of the EPD being correct rise.correct rise.

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How are Breeding Values How are Breeding Values Reported?Reported?

Common Common EPDsEPDs: : Performance-basedPerformance-based, , Carcass-Carcass-basedbased, and , and UltrasoundUltrasound..

►Performance-basedPerformance-based EPDsEPDs – Are based on a – Are based on a measurement of how well the bull’s offspring perform. measurement of how well the bull’s offspring perform. Examples of performance-based EPDs are birth weight, Examples of performance-based EPDs are birth weight, weaning weight, milk and yearling weight.weaning weight, milk and yearling weight.

►Carcass-basedCarcass-based – Are based on how well the bull’s – Are based on how well the bull’s offspring have performed on the rail. Examples of offspring have performed on the rail. Examples of carcass-based EPDs are Rib-eye Area, Fat (Outer), carcass-based EPDs are Rib-eye Area, Fat (Outer), Retail Product, and % Intramuscular Fat.Retail Product, and % Intramuscular Fat.

►UltrasoundUltrasound EPDsEPDs – Done from an ultrasound of the – Done from an ultrasound of the actual bull. Examples of ultrasound EP’s are Rib-eye actual bull. Examples of ultrasound EP’s are Rib-eye Area, Fat (Outer), and % Retail Product.Area, Fat (Outer), and % Retail Product.

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How to Compare EPDsHow to Compare EPDs

EPDs can be useful for comparison. Look at the Select Sires EPDs can be useful for comparison. Look at the Select Sires Explanation for how EPDs are measured. For example Birth Explanation for how EPDs are measured. For example Birth Weight is in pounds.Weight is in pounds.

BWBW WWWW MilkMilk YWYW MarbMarb REAREA FATFAT %IM%IMFF

RERE FATFAT %RP%RP

Bull Bull AA

-0.5-0.5 +61+61 +15+15 +11+1111

+.20+.20 +.19+.19 +.01+.0177

+.50+.50 +.22+.22 +.00+.0044

+.28+.28

Bull Bull BB

+0.1+0.1 +50+50 +21+21 +51+51 +.20+.20 +.44+.44 +.01+.0177

+.26+.26 +.66+.66 -.046-.046 +.28+.28

How much more will Bull B weigh at birth than Bull A? Answer: .6 pounds.

How much more will bull A weigh at weaning than Bull B?Answer: 11 pounds

Which bull would be a better bull for heifers?Answer: Both would be fine. But smaller calves would come from

A.Which bull has a bigger Rib-eye Area?

Answer: Bull B

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Selection of CowsSelection of Cows

CullingCulling – Cows should be culled from – Cows should be culled from the herd based on the productivity of the herd based on the productivity of their calves.their calves.

EvaluationEvaluation – Cows should be culled – Cows should be culled based on evaluation of the udders, eyes, based on evaluation of the udders, eyes, skeleton and teeth.skeleton and teeth.

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Selection of HeifersSelection of Heifers

► Try to select heifers that will Try to select heifers that will conceive early in the breeding conceive early in the breeding season, calve easily, produce a good season, calve easily, produce a good supply of milk, wean a heavy calf, supply of milk, wean a heavy calf, make a desirable genetic contribution make a desirable genetic contribution to your cow herd, and have calves to your cow herd, and have calves with desirable carcass traits.with desirable carcass traits.

AccuracyAccuracy

The reliability that can be The reliability that can be placed on the EPD. Accuracy of placed on the EPD. Accuracy of close to 1.0 indicates higher close to 1.0 indicates higher reliability.reliability.

HerdHerd

► Indicate the number of herds from Indicate the number of herds from which daughters are reportedwhich daughters are reported..

BirthBirth WeightWeight

Predictor of a sire’s ability Predictor of a sire’s ability to transmit birth weight to to transmit birth weight to his progeny, compared to his progeny, compared to the progeny of an average the progeny of an average bull for a specific breed; bull for a specific breed; expressed in pounds.expressed in pounds.

WeaningWeaning WeightWeight

Predictor of a sire's ability to Predictor of a sire's ability to transmit weaning growth to transmit weaning growth to his progeny, compared to his progeny, compared to the progeny of an average the progeny of an average bull for a specific breed; bull for a specific breed; expressed in pounds.expressed in pounds.

Yearling WeightYearling Weight

Predictor of a sire's ability Predictor of a sire's ability to transmit yearling to transmit yearling weight, compared to the weight, compared to the progeny of an average progeny of an average sire for a specific breed; sire for a specific breed; expressed in pounds. expressed in pounds.

Maternal MilkMaternal Milk

Predictor of a sire's genetic Predictor of a sire's genetic merit for that part of merit for that part of weaning weight attributed weaning weight attributed to milk and mothering to milk and mothering ability. It is compared to ability. It is compared to daughters of an average daughters of an average bull for a specific breed.bull for a specific breed.

Scrotal CircumferenceScrotal Circumference

Predictor of the difference Predictor of the difference in transmitting ability for in transmitting ability for scrotal size, compared to scrotal size, compared to the progeny of an average the progeny of an average bull for a specific breed; bull for a specific breed; expressed in centimeters.expressed in centimeters.

ObjectivesObjectives

►Define Expected Progeny Difference.Define Expected Progeny Difference.► Identify terms associated with EPD’s.Identify terms associated with EPD’s.► Interpret EPD categories.Interpret EPD categories.►Analyze EPD variations within breeds. Analyze EPD variations within breeds.