Seasonal Changes of FSH, LH, Total and Free Testosterone Hormones in Saanen Bucks

In the study, seasonal changes in follicle-stimulating hormone (FSH), lutein hormone (LH), total testosterone (TTH), and Free Testosterone Hormone (FTH) of Saanen goats were investigated. In order to determine the hormone levels between February 2019 and December 2019, blood samples were taken from bucks (n=6) twice a week during the entire trial. FSH level started to decrease relatively after August and the lowest value was determined as 173.01 mlU/ml in January. The difference between the months in the mean FSH level was found to be significant (p <0.05). The highest LH level was obtained in July (13.12 mIU/mL) and the lowest level (8.02 mIU/mL) was obtained in May. However, during the mating season, the increase in LH level was found to be similar to the FSH level. The difference in LH levels by months was found to be statistically significant (p<0.05). Total testosterone level was similar to FSH and LH levels. The highest and lowest total testosterone hormone (TTH) levels in March and January, respectively; 3.03 ng-/mL and 0.62 ng-/-mL. The highest free testosterone hormone (FTH) level was 119.69 pg/ml in August and the lowest was 29.09 pg/ml in December. The difference between FTH by months was significant (p<0.05). The effect of day length on seasonal variation of reproductive hormones in Saanen bucks is statistically significant (p<0.05). As a result, it was determined that reproductive hormone levels in Saanen bucks depend on the season and the release levels are significantly affected by climatic factors such as day length. To summarize, there is a need for more different studies including sampling frequency, sampling time as well as sample size, and other environmental factors in order to examine the effects of male reproductive characteristics and other important hormones in bucks in more detail to interpret the results more accurately.