Using EPDs in Selection. Edited by: Jessica Hawley & Brandon Freel Originally compiled by Colorado Agriscience Curriculum. Define Expected Progeny Difference. Interpret EPD categories. Analyze EPD variations within breeds. Recognize the importance of EPD use in selection.
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Using EPDs in Selection
Edited by: Jessica Hawley & Brandon Freel
Originally compiled by Colorado Agriscience Curriculum
Phenotype – The appearance of an animal.
Genotype – What genes are present and how they are combined.
(EPD) ExpectedProgenyDifference – A measurement of genetic potential based on the performance of relatives.
(ACC) Accuracy is an important term used in understanding EPDs. It is a measure of expected change in the EPD as additional young are born to the sire. A high accuracy value is better as the chances of the EPD being correct rise.
Common EPDs: Performance-based, Carcass-based, and Ultrasound.
Performance-basedEPDs – Are based on a measurement of how well the bull’s offspring perform. Examples of performance-based EPDs are birth weight, weaning weight, milk and yearling weight.
Carcass-based – Are based on how well the bull’s offspring have performed on the rail. Examples of carcass-based EPDs are Rib-eye Area, Fat (Outer), Retail Product, and % Intramuscular Fat.
UltrasoundEPDs – Done from an ultrasound of the actual bull. Examples of ultrasound EP’s are Rib-eye Area, Fat (Outer), and % Retail Product.
Should include both visual and genetic appraisal
Valuable genetic traits
Depends on producers goal
Culling – Cows should be culled from the herd based on the productivity of their calves.
Evaluation – Cows should be culled based on evaluation of the udders, eyes, skeleton and teeth.
Try to select heifers that will conceive early in the breeding season, calve easily, produce a good supply of milk, wean a heavy calf, make a desirable genetic contribution to your cow herd, and have calves with desirable carcass traits.
Accuracy - The reliability that can be placed on the EPD. Accuracy of close to 1.0 indicates higher reliability.
Herd- Indicate the number of herds from which daughters are reported.
Predictor of a sire’s ability to transmit birth weight to his progeny, compared to the progeny of an average bull for a specific breed; expressed in pounds.
Predictor of a sire's ability to transmit weaning growth to his progeny, compared to the progeny of an average bull for a specific breed; expressed in pounds.
Predictor of a sire's ability to transmit yearling weight, compared to the progeny of an average sire for a specific breed; expressed in pounds.
Predictor of a sire's genetic merit for that part of weaning weight attributed to milk and mothering ability. It is compared to daughters of an average bull for a specific breed.
Predictor of the difference in transmitting ability for scrotal size, compared to the progeny of an average bull for a specific breed; expressed in centimeters.