Investigation of serum anti mullerian hormone (AMH) and progesterone (P4) levels from birth to puberty in simmental heifers

Objective: In this PhD thesis, the determination of Anti-Müllerian hormone (AMH) levels in heifers from birth to puberty and its significance in breeding animal selection will be investigated. Progesterone (P4) levels will be used to determine the age at which calves reach puberty. Material and Methods: Ten healthy female Simmental (Fleckvich) combined breed calves were used in the study. In order to determine serum AMH and P4 levels, blood samples were collected from healthy calves on the day of birth, monthly until the fourth month and every fifteen days after the fourth month until approximately the 18th month. Serum samples were stored at -20 °C until mesurments were made. Hormone measurements were performed by ELISA method using a commercial kit. Animals reaching mating maturity were inseminated. Pregnancy scan was performed by ultrasound on the 30th day after insemination. Statistical Package for the Social Sciences 22.0 program was used for statistical evaluations. Results: The mean age at puberty of the 10 calves included in the study was 382.5±14.87 days. When the calves were divided into two groups as early (<400 days) and late (>400 days) pubertal calves, the mean age at puberty was 347.5±4.61 days in the early pubertal group and 435±8.66 days in the late pubertal group. The mean values of AMH before puberty (0.80±.033) were statistically significantly (p=0.006) higher than the mean values after puberty (0.74±0.028). Serum AMH value was 0.82±0.02 ng/ml in the early pubertal group and 0.74±0.01 ng/ml in the late pubertal group. In the statistical evaluation, it was determined that AMH values were higher (p<0.001) in the group reaching early puberty. In addition, in the pregnancy diagnosis performed on the 30th day after insemination, it was detected that 9 of the 10 animals included in the study became pregnant in the first insemination and the other animal became pregnant in the second insemination. Conclusion: It was concluded that in Simmental heifers, serum AMH levels were higher in heifers reaching early puberty than in heifers reaching late puberty; again, AMH values before puberty were higher than after puberty; therefore, it was concluded that follicular reserve started to decrease after puberty when it started to be utilized. Keywords: Antimullerian hormone, Progesterone, Puberty, Simmental Heifer.