New Trait Released by CDCB The Council on Dairy Cattle Breeding (CDCB) has made available an Early First Calving (EFC) trait for Holsteins and Jerseys. This new health trait is expressed as age in days at first calving. Animals expected to transmit genetics that decrease the age at first calving have a positive EFC value (seen as more beneficial), whereas animals transmitting genetics that increase the age at first calving have a negative value (less beneficial). The heritability of EFC is 2.3%. The average reliability for young genotyped Holsteins is about 66% and about 51% for Jerseys.
CDCB Calculating Crossbred Genetic Evaluations The Council on Dairy Cattle Breeding (CDCB) updated genetic evaluations with the April proofs to include crossbred evaluations. A bull’s Breed Base Representation (BBR) value is used to determine whether he has a blended (crossbred) or single breed genetic evaluation. An animal with a BBR ≥ 90% is evaluated with the breed of its highest BBR. An animal with a BBR < 90% has a genetic evaluation based on a weighted combination of marker effects from the different comprising breeds. Genetic value estimates for crossbreds are less accurate than purebred estimates. The changes noted above are most notably seen on lower BBR sires evaluated on the Jersey base. Any Jersey sire under 90 BBR now has a blended evaluation, more accurately representing the genetic makeup of the animal.
Downward Trend in DPR Seen There was a general downward trend in Holstein and Jersey Daughter Pregnancy Rate (DPR) values with the April proofs. The Council on Dairy Cattle Breeding (CDCB) acknowledged this trend and is looking into the reason. A decrease in DPR negatively impacts a bull’s index values (Lifetime Net Merit, Cheese Merit, TPI® and ICC$™ index). For more detailed information, visit the CDCB website (https:// www.uscdcb.com/news/) for an article entitled “About Fertility Evaluations in April 2019.”
Learn more about crossbred genetic evaluations on the CDCB website: https://www.uscdcb.com/news/
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