Page 28 - MWC 3-10-2022s

The Midwest Cattleman · March 10, 2022 · P28

IGS CARCASS EPD UPDATES

By Randie Culbertson, PhD

Carcass records on terminal cattle remain
rare and highly sought-after phenotypes for
National Cattle Evaluation. As the number of
carcass phenotypes are limited in the National
Cattle Evaluation, IGS uses breed effects from
the USDA Meat Animal Research Center to
adjust genetic predictions for various breeds.
Programs like the Carcass Merit Program
and Carcass Expansion Program are adding

valuable terminal records and genomic
information to the genetic evaluation.

As with any trait under may see a shift in the EPD within contemporary groups, and often from herds with
selection, breed effects value but the bulls still have using field data (i.e. IGS breeding systems designed
will change over time. As a the same rank among other data) can lead to unreliable specifically to obtain these
result, US-MARC updates bulls with the same breed estimation of breed effects. breed effects. In the case of
their breed effects annual- percentage. However, rerank- In those carcass trait breed differ-
ly and the IGS Multi-breed ing occured when comparing cases, breed effects from ences, the IGS Multi-breed
Genetic Evaluation recently one breed to another as well scientific literature are Genetic Evaluation uses the
updated the breed effects in as different percentage com- often used. The advantage breed effects derived from
the published EPDs (as of posites. of using breed effects from US-MARC.
12/20/21). The implementa- An ongoing challenge of literature is that the effects
tion of these updated breed estimating carcass EPDs are derived from “clean” data
effects caused some changes is the lack of carcass phe-
in carcass EPDs. The adjust- notypes. This lack of pheno-
ments are set to an Angus types creates a real challenge
base and are applied depend- for the genetic evaluation
ing on the breed percent of to appropriately account
the animal. When comparing for breed differences. With
the rank of bulls with a high traits that have limited re-
percent of a breed, breeders cords and breed comparisons