Clinical mastitis associated with abortion in dairy cows

The objective of this study was to assess the association between clinical mastitis and abortion during early gestation in lactating dairy cows. Durin g the study period, there were 2087 cows diagnosed pregnant, 60 cases of cl inical mastitis, and 127 cases of abortion. Logistic regression was used to evaluate the association between the occurrence of mastitis and subsequent abortion. This study found that cows that had clinical mastitis during the first 45 d of gestation were at 2.7 (95% confidence interval = 1.3 to 5.6) times higher risk of abortion within the next 90 d than were cows without mastitis. Cows with a calving to conception interval >174 d were at lower r isk (43%) of abortion compared with cows with a calving to conception inter val <79 d (odds ratio = 0.6; 95% confidence interval = 0.3 to 0.9). Concept ion on a breeding detected by secondary signs of estrus was also significan tly associated with increased risk of abortion (odds ratio = 1.7; 95% confi dence interval = 1.1 to 2.8). No significant association was found between parity, breeding season, or milk production or use of prostaglandin F-2 to induce successful estrus and subsequent abortion.