Effect of Once-a-Day Nursing on Rebreeding Efficiency of Beef Cows

Abstract
Two experiments were conducted to evaluate the potential of once-a-day nursing as a tool for decreasing the postpartum interval of Angus cows. In Exp. 1, 96 cows were assigned randomly to two treatment groups. Cows in one group were nursed once daily for 30 min, while those in the second group were nursed normally. Once-a-day nursing was begun 21 days after calving for each cow and continued until the cow exhibited estrus, after which the calf was allowed to nurse normally until weaning. Cows observed in estrus were bred by artificial insemination, and each cow was placed on a 90-day breeding season starting on the day of calving. In Exp. 2, 52 cows were handled in the same way as those in Exp. 1, except that once-a-day nursing began on day 30 postpartum. The postpartum interval to first estrus was 41 ± 2 days for cows nursed once a day and 61 ± 4 days for control cows (P<.05) in Exp. 1. However, there was no difference (P>.05) in postpartum interval to conception between cows nursed once a day (63 ± 3 days) and control cows (68 ± 3 days). In addition, more of the cows that were nursed once a day had short estrous cycles (.05) in the postpartum interval to conception between cows nursed once a day and control cows (65 ± 5 vs 58 ± 5, respectively). Again, a trend toward short estrous cycles was noted among cows assigned to the once-a-day nursing treatment (five vs two in the normally nursed group). Although the difference was not significant, in Exp. 1, weaning weight was 11.5 kg lower for calves nursed once a day than for control calves. Data were not available for weaning weight in Exp. 2. Once-a-day nursing significantly decreased time to the postpartum interval to estrus in Angus cows but did not decrease the postpartum interval to conception. Copyright © 1981. American Society of Animal Science . Copyright 1981 by American Society of Animal Science

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