481 Impacts of breeding method on metabolic profile, progesterone concentration, and pregnancy rates in dairy goats

Understanding the distinctions between natural breeding and artificial insemination (AI) in goats empowers farmers and reproductive specialists to make informed decisions regarding breeding management. The precise synchronization of estrous in goats is crucial to achieve proper timing for AI. AI in goats requires technical expertise and can be difficult because goats are not always amenable to synchronization protocols. We previously reported that prostaglandin (PG)F2α alone could be used effectively for estrous synchronization in goats compared with PGF2α plus gonadotropin releasing hormone (GnRH). Our aim was to compare the breeding method (natural breeding vs. AI) on the metabolic profile, progesterone concentrations, and pregnancy outcomes of dairy goats. Mixed breed (Alpine and Saanen) mature does (n = 29; 3.9 ± 0.28 yr of age) were subjected to estrous synchronization by receiving two injections of 10 mg PGF2α on d 0 and d 11 per goat. Thirty-six hours after the second PGF2α injection, goats were either naturally bred (n = 14) with the same breed mature buck or artificially inseminated (n = 15) with frozen/thawed semen using cervical AI. Blood samples were collected on d 12 and 21 post-breeding (PB) for measuring cholesterol, glucose, and triglyceride concentrations. Furthermore, progesterone concentrations were estimated on plasma samples collected on d 3, 9, 15, and 21 PB. Pregnancy specific protein B (PSB) concentrations were also detected on d 28, 35 and 42 PB. Data were presented as means ± S.E. and analyzed by one-way analysis of variance, followed by post hoc Tukey’s test. Results showed that, cholesterol concentrations on d 12 PB was greater (P ≤ 0.05) in natural breeding than AI groups. However, no significant differences were observed in glucose and triglyceride concentrations between the 2 breeding methods. Progesterone concentration was greater (P ≤ 0.05) on d 15 PB in natural breeding than AI groups. PSB was greater (P ≤ 0.05) in natural breeding than AI groups at all time points. Pregnancy rates as detected by ultrasonography on d 50 PB were greater (P ≤ 0.05) in natural breeding than AI groups (71.4% vs. 13.3%, respectively). Furthermore, the kidding rates were greater in natural breeding than AI groups (128.6% vs. 20.0%, respectively). The percentage of female kids was greater than male (66.6% vs. 33.3%, respectively) in both breeding methods. In conclusion, our findings suggest that PGF2α alone as an estrous synchronization protocol