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Article: Genetic Associations Between Clinical Mastitis and Somatic Cell Score in Early First-Lactation Cows
- Article from:
- Journal of Dairy Science
- Article date:
- June 1, 2006
- Author:
CopyrightCopyright American Dairy Science Association Jun 2006. Provided by ProQuest LLC. (Hide copyright information)
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ABSTRACT
The objectives of this study were to examine genetic associations between clinical mastitis and somatic cell score (SCS) in early first-lactation cows, to estimate genetic correlations between SCS of cows with and without clinical mastitis, and to compare genetic evaluations of sires based on SCS or clinical mastitis. Clinical mastitis records from 15 d before to 30 d after calving and first test-day SCS records (from 6 to 30 d after calving) from 499,878 first-lactation daughters of 2,043 sires were analyzed. Results from a bivariate linear sire model analysis of SCS in cows with and without clinical mastitis suggest that SCS is a heterogeneous trait. Heritability of SCS was 0.03 ...