Beginning August 9, 2022, Brown Swiss animals will receive CDCB evaluations for disease resistance for six traits: milk fever (MFEV), displaced abomasum (DA), ketosis (KETO), mastitis (MAST), metritis (METR) and retained placenta (RETP).
The new traits will be incorporated into Net Merit (NM$) for Brown Swiss animals, through the sub-index Health $ with the total weight of the six health traits approximately 2%.
These six CDCB health traits have been available for Holsteins since April 2018 and Jerseys since April 2020. After a recent feasibility analysis, the same pipelines and processes used for Holstein and Jersey health traits were expanded to include Brown Swiss. The resulting PTAs are presented as percentage points above or below the breed’s average resistance with more positive values being favorable.
About the CDCB health traits for Brown Swiss:
- Total number of available Brown Swiss phenotypic records by trait ranged from 7,592 for ketosis to 17,391 for mastitis (April 2022)
- Overall incidence ranged from 0.7% for displaced abomasum up to 13.7% for mastitis, similar to incidences in both Holstein and Jersey
- Heritabilities were assumed to be equivalent to those in Holstein, ranging from 0.6 to 3.1%
- Average traditional reliabilities for bulls born since 2000 with ≥ 90% Net Merit (NM$) reliability ranged from 17 to 55%, depending on trait
- Average genomic reliabilities for those bulls ranged from 29 to 57%
- Maximum PTA reliability was 89% for mastitis.
- Among traits such as livability, productive life, and somatic cell score, PTA correlations in young bulls were favorable at 0.74, 0.53, and -0.13, respectively, with the sum of all health traits (Health $).
Provided by CDCB