| Abstract: | Six hundred eighty-three mature cows of the Devon, A. Angus, and Hereford breeds were used to investigate the effect of weaning 90 days after calving on the postpartum reproduction (anestrus and pregnancy rate). The calving pariod was 90 days, from September to November (Spring 1976). The breeding period, also of 90 days, began at the end of the calving period and was from December to February (Summer 1977). The calves were separated from their mothers with a mean age of 90 days for the “W” group of cows and 200 days for the “S”.Early weaning increased overall conception in the 90 days breeding period by 43.07% (P < .001) and reduced the postpartum anestrus from 60.42% in the “S” group to 13.79% (difference of 46.63% ? P < .001) in the “W” group. |
