Factors affecting reproductive performance of zebu and crossbred cows under small-scale dairy farms

Data on reproductive performance of zebu and Friesian x zebu crossbred cows reared under small-scale dairy farms were analysed and the effects of geno type, parity, body condition score (BCS), season, and year of calving were examined for a total of 246 calvings. Uterine involution was completed earl ier in zebu (23.8 +/- 1.2 days) than in crossbred (31.4 +/- 1.3 days) and i n primiparous (25.4 +/- 2.0) than in pluriparous (29.7 +/- 0.8 days) cows ( P < 0.05). Body condition score, season, and year of calving had no effect on uterine involution (P > 0.05). The interval from calving to resumption o f ovarian activity was influenced (P < 0.05) by BCS at calving but not by p arity, season, and year of calving. The interval between calving and concep tion was influenced by genotype (P < 0.05) and was earlier in crossbred (14 8.4 +/- 11.8 days) than in zebu (183.2 +/- 11.7 days). The overall mean for calving interval was 509.7 days and there was an effect of year of calving (P < 0.05). It was concluded that BCS and genotype affected the duration f rom calving to resumption of ovarian activity and conception, respectively.