Effect of reproductive disorders previous to conception on pregnancy attrition in dairy cows

This study was undertaken to determine whether reproductive disorders previous to conception influence pregnancy attrition in dairy cows. Reproductive disorders were registered and pregnancy diagnoses were performed as a part of a reproductive health program at 9 commercial dairy herds in northeastern Spain. Data from 3022 diagnosed pregnant lactating cows were used. Pregnancy diagnosis by palpation per rectum was performed from 33 to 70 d post insemination. Pregnancy attrition was registered when the pregnancy diagnosis was negative at the second palpation carried out between 120 and 150 d following insemination. Data analysis was performed by multiple logistic regression methods. Pregnancy attrition rates were 2.6 and 1.8 times higher in cows with previous pyometra and retained placenta, respectively, than in cows without these disorders. No effect of endometritis, ovarian cysts and repeat breeding was shown on pregnancy attrition. Our results suggest that additional efforts to reduce the risk of retained placenta and pyometra should decrease the incidence of pregnancy attrition in dairy cows.