Body condition score and serum metabolites and minerals concentrations as indicators of ovarian activity and pregnancy success in goats on rangeland

Aim of the study: To investigate potential differences in ovarian structures relative to serum metabolite and mineral concentrations at mating. Also, body condition score (BCS), serum metabolites, and mineral profiling at mating were compared between pregnant and non-pregnant goats. Area of study: Hot zone of northern Mexico (26 °N). Material and methods: Mixed-breed goats (n= 89) on arid rangeland were exposed to bucks during the non-breeding season. Ovarian structures were recorded at mating and ten days after breeding using ultrasonography. Pregnancy was detected at 30 and 120 days post-mating. BCS, blood metabolites, and minerals were determined at mating. Main results: Pregnant goats had higher BCS at mating than non-pregnant goats. The mean serum glucose concentration was higher (p<0.05) for pregnant goats than that for non-pregnant ones (87.3 ± 12.1 vs. 74.4 ± 11.6 mg/dL). Significantly lower (p<0.01) serum urea nitrogen levels at mating were recorded in non-pregnant (10.7 ± 3.5 mg/dL) than in pregnant goats (12.4 ± 3.7 mg/dL). Lower serum glucose (72.2 ± 6.9 vs. 89.4 ± 11.2) and higher non-esterified fatty acids concentrations (NEFA; 0.43 ± 0.23 vs. 0.18 ± 0.12) were significantly associated (p<0.05) with pregnancy loss. Higher serum total protein concentrations were associated with a greater number and larger ovulatory follicles. High serum phosphorus was significantly associated with larger ovulatory follicles. Goats with ovulatory follicles ≥7.6 mm were more likely (p<0.05) to get pregnant than goats with smaller ovulatory follicles. Research highlights: Monitoring BCS, serum glucose, blood urea nitrogen, and NEFA could be used to identify goats at risk for infertility.