A pre-synchronization program at early postpartum might increase the chances of <i>Bos indicus</i> cows cycling prior to 50 days regardless of the length of calf separation

Abstract

The aim of this study was to establish if pre-synchronization would enhance the number of animals cycling prior to conventional breeding at 45 days irrespective of the length of calf separation. Multiparous Bos indicus cows were allotted in four groups (n = 10). Control group (C) dams remained with their calves; groups G24, G48 and G72, which were partially weaned for 24, 48 and 72 h, respectively, were estrus synchronized using a controlled internal drug. These procedures were performed at 25 days and again at 45 days postpartum. The number of follicles, presence of a corpus luteum and back fat thickness (BFT) were determined by ultrasound. The proportion of cows with estrus and ovulation at day 25 postpartum was statistically different between the control and treated groups, with the values being 20, 60, 50 and 70 for the control, G24, G48 and G72 groups respectively (P < 0.05). At days 45 postpartum, the proportion of cows with estrus and ovulation was different in group G48 compared with the other groups (P <0.05). The average BFT and body condition score for the four experimental groups in the two periods were similar (P >0.05). Animals with a higher proportion of follicles from 17 to 21 mm, BFT values above 3.5 mm and a regular body condition were significantly different regardless of whether the dams remained with their calves or were separated, regardless of the length of this event. It can be concluded that (1) a pre-synchronization program at day 25 could trigger the onset of ovarian activity and facilitate a breeding program at day 50 and (2) temporary weaning enhances the effect of a pre-synchronization program.

Monitoring changes in back fat thickness and its effect on the restoration of ovarian activity and fertility in Bos indicus cows

“…This is likely the consequence of the time postpartum when the treatment was applied (Rhodes et al., ). In the present study, almost 20% of the cows did not cycle during the duration of the experimental period; similar results have been reported previously (Mondragón et al., ; Pérez‐Torres et al., ). These animals coincidently experienced FAT losses after parturition.…”

“…Previous reports have shown that hormonal treatments prior to 30 days postpartum could enhance the probability of animals becoming pregnant soon after calving either using artificial insemination (Mondragón, Galina, Rubio, Corro, & Salmerón, 2016;Pérez-Torres et al, 2015) or natural mating (Lamb et al, 2008). Nonetheless, the variability of the response could be due to fluctuations in the metabolic profile of the animals.…”

Effect of temperature humidity index on the onset of post- partum ovarian activity and reproductive behavior in Bos indicus cows

“…The percentage of animals starting their cyclicity was 57%. This proportion is low compared to previous reports where values fluctuated between 70 to 92% (Pérez-Torres et al, 2015;Mondragón et al, 2016). On the other hand, 43% of animals did not ovulate.…”

“…On the other hand, 43% of animals did not ovulate. Nonetheless, this percentage is higher than that reported in previous studies where this figure does not exceed 29% (Pérez-Torres et al, 2015). The discrepancies between values could be the result of differences in the high levels of THI that animals were able to tolerate.…”

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

“…Cows that were nursing calves delayed the resumption of ovarian follicular growth, ovulation and establishment of a normal lifespan CL (Abeygunawardena and Dematawewa, 2004). Reducing the time that the cow nurses a calf by partial or total weaning procedures increases the number of animals that resume ovarian activity and ovulate (Perea et al, 2008;Pinheiro et al, 2009;Perez-Torres et al, 2015). Rhodes et al (2003) reported that treating anestrous cows with progestagen plus estradiol induces estrus response and ovulation in almost 90% of the cows.…”