Relationship of some hormone levels and some biochemical parameters with parity in repeat breeder dairy cows

Abstract

The aim of this study was to determine the role of anti-müllerian hormone (AMH), progesterone, insulin, thyroid stimulating hormone (TSH), triiyodotironin(T3), tiroksin(T4), non-esterified fatty acids (NEFA), beta hydroxy butyrate (BHBA) and glucose concentrations in the etiology of Repeat Breeder (RB) cows. In the study, 60 RB Holstein cows, all housed on the same farm and receiving identical care, feeding, and reproductive management, were inseminated at least three times but did not achieve pregnancy and were confirmed to have no gynecological problems through ultrasonographic examination. Were categorized into three groups based on parity: Group I (1-2 lactation), Group II (3-4 lactation), and Group III (5-6 lactation). During estrus, 10 ml blood samples were collected from all the animals in the study. Blood samples collected on the day of estrus were used to assess serum levels of AMH, insulin, BHBA, NEFA, glucose, T3, T4, and TSH. Additional blood samples were taken on days 9 and 17 post-mating for serum progesterone (P4) analysis. The serum samples were separated and stored at -80°C until analysis. T3, T4, TSH, AMH and insulin levels were measured using an ELISA device, and serum progesterone, NEFA, BHBA and glucose determination were measured using an autoanalyzer. When comparing the results of hormone measurements across lactation groups, it was observed that T3 levels were highest in Group II and lowest in Group III. As for AMH, T4, TSH, insulin, and progesterone hormones, no statistically significant differences were found among the groups. Group I exhibited significantly lower NEFA levels compared to the other two groups, while Group I also had significantly higher glucose levels than the other two groups. In Group II, a statistically significant negative correlation of 69.7% was observed between T4 and AMH. In conclusion, this study determined that T3 hormone, NEFA and glucose levels may play a role in the etiology of RB cows, while AMH and other parameters do not seem to be effective.