119 Anti-Müllerian hormone as an endocrine marker of fertility in Bos taurus heifers

Abstract

The objective of the study was to determine the relationship between the serum concentration of anti-Mullerian hormone (AMH) and fertility indicators in Bos taurus heifers subjected to breeding. From a group of 40 Simmental heifers (15–18 months of age, body condition score of 5 to 7; weight 350–400 kg) that received a single dose of 25 mg of dinoprost, 23 females entered oestrus and were artificially inseminated 14–16 h after onset of the oestrus. If the females returned into oestrus, they were inseminated until conception was confirmed by ultrasonography (30–33 d after IA). On Day 4 of the oestrous cycle, a blood sample was collected from each animal, and serum AMH concentration was determined using an ELISA. The AMH levels were classified as normal (AMHn, <0.4 ng mL⁻¹) or high (AMHh, >0.4 ng mL⁻¹) and were correlated with the number of follicles (NF) and the sampling-to-conception interval (SCi). The number of follicles (antral follicles of 3 to 8 mm) in each female was counted at the onset of the recruitment phase during the oestrous cycle. A linear model included AMH level as a fixed effect to analyse NF and SCi. The AMH level was correlated with NF (r = 0.8; P < 0.001) and SCi (r = −0.61; P < 0.05). The AMHh category produced a higher NF (27 ± 3.06 vs. 16 ± 1.85 follicles; P < 0.05) and fewer days of SCi (18.22 ± 2.97 vs. 76.30 ± 14.41 days; P = 0.03). In conclusion, high AMH levels were related positively with the number of follicles and higher fertility in Bos taurus heifers.