FR 13. Effect of ninety six-hour calf removal on estrus induction and fertility in crossbred aciclic cows

Abstract

A study was conducted to determine the effect of 96 h calf removal on estrus induction and fertility in crossbred cebu aciclic cows suckled twice a day. Cows in moderate (3) to good (4) body condition and over 120 days postpartum were alloted to two groups, CD, with calf removal (n=34) and SD, without calf removal (n=30). Aciclic condition was determined by RIA progesterone measure in milk samples twice a week from day 90 to 120 postpartum. Only cows with progesterone values below 0.5 ng/mL were considered for the study. The percentage of cows showing estrus were CD = 67.6 % (n=23) and SD = 26.6 % (n=8) (P<.001). Fertility after calf removal was 73.9 % (17/23) and 75.0 % (6/8) for groups CD and SD respectively (P > .001) indicating a good level of fertility in cows bred during the first estrus after calf removal. The mean interval between calf removal and estrus was 12.9 ± 8.19 and 19.1 ± 11.4 days for groups CD and SD respectively. The result of this study indicated that 96 h calf removal could be considered an effective way to shorten the calving interval in crossbred cebu cows in the tropics.