Studies on the Reproductive Performance of Jersey X Sahiwal Cows in Chittoor District of Andhra Pradesh

The effect of batch and season of birth was highly significant on age at sexual maturity. Cows born during rainy and winter seasons matured at significantly earlier age (750.18 ± 0.79 and 760.18 ± 0.18 days, respectively). The season of birth, batch and age at sexual maturity had non-significant influence on the gestation period. The overall mean gestation period was 276.89 ± 0.38 days. Age at first calving was significantly affected by season of birth, batch and age at sexual maturity. Lowest age at first calving (1092.46 ± 7.47) was observed in cows born in winter followed by those born in rainy (1134.88 ± 6.47) and summer (1173.95 ± 5.89) seasons. Mean age at first calving ranged from 911.60 ± 4.40 to 1378.37 ± 7.49 days in 1st and 4th groups, respectively. The calves with early sexual maturity (400 to 600 days) had the shortest age at first calving (911.60 ± 4.40 days).