FACTORS AFFECTING RETENTION OF PLACENTA AND ITS INFLUENCE ON POSTPARTUM REPRODUCTIVE PERFORMANCE AND MILK PRODUCTION IN FRIESIAN COWS

Abstract

A total of 1243 records of 585 dairy Friesian cows collected through 8 years (1997-2004) were used to study factors affecting retention of placenta and its influence on reproductive performance and milk production. The obtained results showed that the per - centage of retained placenta averaged 24.90%, the highest percentage was in the year 1998 (46.3%) and it increased significantly (P<0.05) with increasing body weight of cows, parity and body weight of calves born. The percentage of retained placenta was significantly higher (P<0.05) in spring and summer seasons (28.0 and 27.70%, respectively) and also with twining in comparison to single calving (37.90 vs. 24.20%, respectively). There were no significant differences in the percentage of retained placenta between winter and summer feeding as well as between male or female birthings. Retained placenta resulted in an increase (P<0.05) in the period from parturition to first estrus (25.90 vs. 20.50 days) and first serv - ice (56.90 vs. 47.20 days), service period (57.70 vs. 46.10 days), open days (106.90 vs. 92.70 days), number of services per concep- tion (3.50 vs. 2.60) and calving interval (395.20 vs. 372.90 days). Moreover, it reduced the conception rate (66.70 vs. 74.10%) and average daily milk yield (13 vs. 14 kg) compared to normally calved cows.