Abstract #281

# 281
Extending genomic evaluations to direct health traits in Jerseys.
L. Jensen*1, K. L. Parker Gaddis1, H. D. Norman1, 1Council on Dairy Cattle Breeding, Bowie, MD.

The Council on Dairy Cattle Breeding (Bowie, MD) initiated evaluations for 6 direct health traits in Holsteins in April 2018. Currently, there are no health evaluations for Jerseys, the second largest dairy population in the United States. An increasing number of health records are being submitted to the cooperator database for Jerseys, doubling in the past year. The objective of this research was to determine the feasibility of providing accurate genetic predictions of direct health traits for disease resistance in Jerseys. We retrieved producer-recorded health trait observations in Jerseys from the cooperator database including milk fever (MFEV), displaced abomasum (DA), ketosis (KETO), mastitis (MAST), metritis (METR), and retained placenta (RETP). After extensive editing, records ranged from 39,716 for KETO to 97,507 for MAST, resulting in 134,403 total phenotypic records from 79,334 animals with 35–45% of animals providing multiple observations. Data were from 213 herds with 88% of the records submitted in the past 5 years. Incidence rates were lowest for MFEV (1.3%), highest for MAST (10.2%), and comparable to those observed in the Holstein population. In all traits, excluding METR, incidence rate increased with each consecutive lactation. However, METR had the highest incidence rate in the first lactation. Traditional PTA were calculated for approximately 6 million Jerseys using the same linear animal model as applied in routine Holstein evaluations. Effects accounted for in the model included year-season, age-parity, herd-year, and permanent environment, in addition to a regression on inbreeding. Although traditional reliabilities reached 90% for some traits, the mean reliabilities of bulls with progeny were 12–22%. Genomic PTA were calculated using 79k markers for 310,232 Jerseys. Mean genomic reliabilities were higher and ranged from 29 to 35%, depending on the trait. This is approximately 15 points lower than the average for Holsteins, but as more health records are accumulated, Jersey reliabilities will increase. With these genetic predictions, Jersey producers will have a growing arsenal of tools for breed improvement.

Key Words: Jersey, genetic evaluation, health