Influence of suckling time and calving trimester on postpartum ovary activity retake in Bufalipso crossbreds

Resumen

Thirty-four crossbred Bufalipso (Bubalus bubalis) cows were studied. They were multiparous, and had weights and ages between 450-600 kg and 8.8-12 years, respectively. Two experimental groups were formed, according to the suckling times after the milking. The first group remained with the calves one hour after the end of the milking (A, n=17), while the second was kept six hours later (B, n=17). The second study consisted in evaluating the effect of the calving trimester on the reproductive performance. The animals that calved in June, July, and August formed the first group (T1, n=18), while the second grouped the calvings occurred in September, October, and November (T2 n= 16). Every 72 h, each ovary was diagnosed through transrectal ultra-sonography. An analysis of variance was performed, using a
linear model and with adjustment of covariance for the calving number. The first dominant follicle (days), as well as the first and second corpora lutea (days) for the A and B treatments were: 15.81 and 21.11 (P < 0.05), 26.43 and 32.13 (P < 0.01) and 42.93 and 45.50 (P > 0.05), respectively. For T1 and T2, they were of 20.14 and 16.78 (P < 0.05), 45.00 and 32.56 (P < 0.05), and 58.21 and 44.23 (P < 0.05), respectively.
It was concluded that the suckling effect affected the appearance of the first dominant follicle and the first corpus luteum, but did not take part in the appearance of the second, or in the reproductive interval under study. The months of September, October, and November showed, significantly, an earlier retake in all the indicators, compared with June, July, and August, respectively.
Key word: reproductive intervals, ovary activity, river buffalo cows.