(110) Association Between Circulating Anti-Müllerian Hormone at Birth and Puberty Onset in Holstein Heifers

Jessica C. L. Motta^1,2, Ana C. Carranza-Martin¹, Muhammad Saad¹, Caleb Rykaczewski¹, Alexandria Crist¹, Natalia P. Folchini¹, Rodrigo V. Sala³, Randall Bond³, Pablo J. Ross³, Alvaro Garcia-Guerra¹

¹Department of Animal Sciences, The Ohio State University, Columbus, Ohio, USA;
²School of Food and Agriculture, The University of Maine, Orono, Maine, USA;  
³The Ohio Heifer Center, STgenetics, South Charleston, Ohio, USA

Abstract Text: Anti-Müllerian hormone (AMH) in cattle is positively associated with embryo yield after both in vitro embryo production and multiple ovulation and embryo transfer. In addition, AMH has been suggested as a biomarker for fertility albeit with conflicting observations. Puberty onset is a major reproductive milestone in cattle and earlier puberty onset is associated with improved reproductive performance at first breeding and greater lifetime productivity. Results from recent studies suggest that greater circulating AMH concentrations during the prepubertal period may be associated with earlier puberty attainment in beef heifers. The association of AMH determination early in life and age at puberty onset remains largely unexplored, particularly in dairy cattle. Thus, the objective of the present study was to evaluate the association between circulating AMH concentrations at birth and the age at puberty onset in Holstein heifers. Holstein heifer calves (n = 229) born at a commercial facility in Ohio had plasma samples collected at birth (0 d; range 0 - 2) for determination of circulating concentrations of AMH. In addition, birth weight was retrieved from on farm records. Blood samples were collected at weekly intervals, for determination of circulating concentrations of progesterone (P4), beginning at 168 d of age (range 165 to 171) and until 390 d of age or until heifers were synchronized for artificial insemination or in vitro embryo production, whichever occurred first. Circulating concentrations of AMH and P4 were assayed using ELISA (AL-114, AnshLabs, Webster, TX) and RIA (ImmuChem™ coated tube Progesterone; MP Biomedicals, Costa Mesa, CA), respectively. Puberty onset was defined when circulating P4 ≥ 1 ng/ml. Circulating concentrations of AMH at birth were positively skewed (Skewness = 2.7) with a median of 123.8 pg/ml and a range of 10.1 to 2616.4 pg/ml. Median birth weight was 37.2 kg (range 20.4 – 50.8) and circulating AMH concentrations and birth weight were not associated (r = 0.02; P = 0.71). Heifers were categorized into Low (mean: 40.4 pg/ml; range: 10.1 – 66.2), Intermediate (mean: 130.9 pg/ml; range: 67.7 – 215.1) and High (mean: 732.8 pg/ml; range: 217.3 – 2616.4) AMH concentrations at birth using tertiles. Birth weight was greater (P = 0.01) for Intermediate (38.4 ± 0.5 kg) than Low (36.5 ± 0.5 kg) AMH heifers, while there were no differences (P > 0.30) between High (37.5 ± 0.5 kg) and either Low or Intermediate AMH heifers. The percentage of heifers with puberty onset by 390 d of age did not differ (P = 0.68) among Low (69.7 ± 5.3%), Intermediate (75.3 ± 4.9%) and High (75.0 ± 5.0%) AMH heifers. The hazard ratio (HR; reference low AMH) for time to puberty onset up to 390 days did not differ between AMH classes (P = 0.77; Intermediate HR = 1.15, 95% CI: 0.8 – 1.7 and High HR = 1.06, 95% CI: 0.7 – 1.5). Median and mean (± SEM) days to puberty onset were 325.0 d and 322.9 ± 3.8 d for Low AMH heifers, 326.5 d and 323.7 ± 4.2 d for Intermediate AMH heifers, and 331.0 d and 324.9 ± 7.8 d for High AMH heifers. In conclusion, even though circulating concentrations of AMH at birth varied greatly among heifers these were not associated with age at puberty onset.