Reproductive parameters of dairy goats submitted to estrus synchronization with prostaglandin F2α associated or not to hCG at estrous onset

Abstract

The objective of this study was to evaluate the efficiency of two doses of PGF associated or not to hCG on the associated reproductive parameters in dairy goats. A total of 29 goats received two doses of 30μg d-cloprostenol latero-vulvar at a 10 day intervals (Day 1 and Day 10). The does were allocated according to body weight and body condition score into two treatments, to receive hCG (250IU) or saline at estrus onset. After the second dose of PGF, estrus was monitored and ultrasound exams were performed twice daily. All does were inseminated 16h after estrus onset. Blood collection was performed every day for progesterone assay. The use of hCG at estrus onset did not affect any studied parameter and therefore the data were pooled.

Reproductive parameters of dairy goats after receiving two doses of d-cloprostenol at different intervals

“…Fonseca et al (2008) also noted that 73.8% of the goats were first observed in estrus in the morning and suggested that in goats, the estrus is predominantly a nightly phenomenon. Likewise, Esteves et al (2013) observed a 91% occurrence of night estrus and a 9% occurrence of day estrus. On the other hand, the 11.5-day protocol evoked estrus predominantly during the day (66.7% first detected at the end of the afternoon) in first trial and in the night (54.8%) in second trial.…”

“…The growth follicular rate in goats is near to of 1 mm/day (Menchaca et al, 2007). It means that for T 7 goats, follicles could reach the ovulatory diameter (Esteves et al, 2013) and adequate estradiol production in three to four days after second d-cloprostenol injection. Goats from T 10 and T 11.5 were more likely in a regression phase in which smaller follicles could originate ovulatory follicles, indicating more time needed to reach ovulatory diameter and estrus onset.…”

“…Siqueira et al (2009) using refrigerated semen stored for 12 h at 5°C reported 55.7% after a single AI performed 12 h after the estrous onset in Toggenburg goats. Likewise, Esteves et al (2013) observed a pregnancy rate of 55% (6/11) in the group treated with human chorionic gonadotropin (hCG) with AI performed 16 h after estrus onset.…”

“…Several studies in our group have recommended the use of two doses of d-cloprostenol (PGF2α) at 10-day intervals (Siqueira et al, 2009;Fonseca et al, 2012;Esteves et al, 2013). However, this protocol does not always achieve the expected success due to the possible occurrence of a short estrus cycle, a reasonably common phenomenon in goats (Camp et al, 1983;Chemineau et al, 2006;Holtz et al, 2008).…”

Effect of two routes of administration of human chorionic gonadotropin upon oestrus induction and reproductive outcomes in adult acyclic mix-breed goats

“…Improvements in the design of oestrus induction protocols have allowed to expand the out-of-season use of artificial insemination, inseminating goats at specific times, while achieving pregnancy rates comparable to those obtained with the use of visual detection of oestrus (Menchaca & Rubianes 2004;Simoes 2015). Common protocols to induce oestrus in acyclic goats include the combined or single use of gonadotropins, gonadotropin-releasing hormone (GnRH), progestins and prostaglandins (Esteves et al 2013;Contreras-Villarreal et al 2016;Sen & Onder 2016).…”