Calf presence and estrous response, ovarian follicular activity and the pattern of luteinizing hormone in postpartum Bos indicus cows

Abstract

The main objective of the present experiment was to assess the effect of temporary weaning on the onset of estrus, ovarian follicular activity and secretion of luteinizing hormone in Bos indicus cows. Forty six mature cows were divided into three groups 1) calves were weaned for 72 h allowing auditory, olfactory and visual contact with their dams (VISUAL, n = 17), 2) calves without contact with their dams for 72 h (NC, n = 17) and 3) calves not weaned and in constant contact with their dams (CTRL, n = 12). Estrus was synchronized in all cows using CIDR for 9 days plus 2 mg of estradiol benzoate given at CIDR insertion. The VISUAL group had a greater (P < 0.05) proportion of cows in estrus (76.5%) compared to the CTRL group (16.7%), but no differences were found when compared to the NC group (58.8%). The VISUAL group had a greater proportion of animal that ovulated (76.5%) compared to CTRL (33.3%) and NC groups (64.7%; P = 0.059). Duration of estrus was shorter (P = 0.04) in the VISUAL (8.4 ± 4.4 hours) than in the NC (12.9 ± 13.4 hours) however, CTRL treatment (11 ± 1.4 hours) was not different from either of these two groups. LH concentration after implant removal was similar among treatments and started to increase at 36 h post CIDR removal. Only in the CTRL group was there an obvious increase by 54 h after implant removal. Follicular size increased in diameter from 36 h and were evident in treatments and control groups by 60 h (P < 0.05). The VISUAL treatment increased the number of cows ovulating and shortened the length of estrus. VISUAL and NC groups showed a similar response in follicular growth and pattern of circulating LH because of treatment.

Effects of Separation of Cows and Calves on Reproductive Performance and Animal Welfare in Tropical Beef Cattle

“…There is a considerable number of publications on the subject by Baruselli et al [64]. In a broader sense, drug treatments can be helpful if the animals have adequate body condition, but risks of impaired follicular growth and reduced fertility can be found if animals are borderline in this respect prior to or at the time of treatment [65,66].…”

“…In effect, calf separation for 72 h seems to be the most logical way to mimic the duration of the proestrus phase and thereby achieve more acceptable growth of the follicular milieu. In fact, Mondragón et al [65] and Xavier et al [66] found that follicular diameter can be impaired if suckling continues as compared to calf separation with a possible detrimental effect on fertility.…”

Open Cows in a Beef Cattle Enterprise Managed in a Seasonal Breeding Program? An Appraisal of Their Reproductive Performance Based on Body Fat Reserves

“…Suckling at will, has been shown to be one of the most important deterrents to the onset of ovarian activity after calving [17] [24]. In effect, Mondragón et al [11] have shown that the size of the biggest follicle recorded can be affected by the management of the cows, in fact, a regime of restricted suckling favours the earlier growth of follicles and the prompt restoration of ovarian activity [25]. Equally, Sa Filho et al [18] have reported that fertility is closely related to the size of the follicle following synchronization.…”

The Effect of Maternal Behavior around Calving on Reproduction and Wellbeing of Zebu Type Cows and Calves

“…There seems to be a common agreement that suckling and the presence of the calf impaired the adequate growth of a follicle capable of producing a viable zygote [ 76 ]. This shortcoming is even more evident when the animals are under stress [ 77 ].…”