Genetic association between clinical mastitis occurrence and milk yield in Holstein cows

ABSTRACT:

The objective of this study was to estimate genetic and phenotypic parameters for the occurrence of clinical mastitis (MC) and milk production during lactation (PR305) and study the genetic associations between them, using information from 11,738 lactations of 5,084 Holstein herd cows, that calved from 1995 to 2010. The covariance components were estimated by Bayesian inference using the animal model. Heritability estimates for the PR305 and the MC were 0.16 (0.02) and 0.11 (0.02), respectively and repeatability were 0.34 (0.012) for PR305 and 0.21 (0.02) for MC. The genetic correlation between the PR305 and the MC was negative and of low magnitude (-0.21±0.13). Heritability estimates for PR305 and MC indicate that these characteristics are influenced by environmental factors, however there is enough genetic variability to obtain gains through selection.

Key words:
bayesian inference; genetic correlation; heritability.