Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Pregnancy loss in dairy cows: the contributing factors, the effects on reproductive performance and the economic impact | J. Vet. Set. 2007 8 3 283-288 JOURNAL OF Veterinary Science Pregnancy loss in dairy cows the contributing factors the effects on reproductive performance and the economic impact Je-In Lee Ill-Hwa Kim College of Veterinary Medicine Chungbuk National University Cheongju 361-763 Korea This study investigated the effects of the herd cow parity the insemination protocol and season on the incidence of pregnancy loss PL in dairy herds. Furthermore we determined the downstream effects of PL on reproductive performance and its economic impact. The overall incidence rate of PL was in 1 001 pregnant cows and its incidence peaked p during the second trimester of gestation. GLIMMIX analysis revealed that cow parity was the important risk factor for the PL. The odds ratio showed that the likelihood of PL in cows with parities of 1 or 2 was decreased by or fold compared to the cows with a parity of 3 or higher. Following PL the mean rate of endometritis was and endometritis was more common p when PL occurred during the third trimester than during the first and second trimesters. The mean culling rate was and this did not differ with the period of PL. The overall mean intervals from PL to the first service and conception were and days respectively. The mean interval from PL to first service was longer p for cows with PL during the third trimester than for the cows with PL during the first and second trimesters. The economic loss resulting from each PL was estimated at approximately 2 333 and this was largely due to an extended calving interval and increased culling. These results suggest that cow parity affects the incidence of PL which extends calving interval and causes severe economic loss of dairy herds. Key words dairy cow economic loss pregnancy loss reproductive performance risk factors Introduction The fertility of cows plays an important role in the productivity of dairy herds. Pregnancy loss PL is one of the major sources .
