Genetic parameters for cystic ovarian disease in Dutch Black and White dairy cattle

Cystic ovarian disease (COD) is one of the most frequently diagnosed gyneco logical findings in dairy cattle. It causes temporary infertility and is li kely to affect reproduction as well as production parameters in cows. The o bjectives of this study were to investigate the heritability of COD in a Du tch Black and White population and to estimate the genetic and phenotypic r elationships with milk production traits. In the data set used, the overall incidence of COD was 7.7% (1204 COD diagnoses in 15,562 lactations). The f arm incidence varied between 1.9 and 11.3%. The estimated heritabilities on the underlying and observable scales were 0.102 and 0.087, respectively. T he genetic correlations between COD and 305-d milk, fat, and protein yields were 0.345, 0.379, and 0.441, respectively. We concluded that a genetic pr edisposition for COD exists in Dutch Black and White dairy cattle. The gene tic correlations between COD and yield traits indicate that ongoing selecti on for production will increase the incidence of COD.