III International and XII National Animal Science Conference, Bursa, Turkey, 27 - 28 November 2021, vol.1, pp.87
In this study, the effects of melatonin implant treatment before the breeding season on melatonin (M) and testosterone (T) hormone levels, and the sexual behavior and performance, were determined in Turkish Saanen goat bucks. Four head of Turkish Saanen goat bucks were used. The bucks were randomly divided into two groups and they were treated with 3 implants with 18 mg melatonin. The mating of 50 Turkish Saanen female goats was also observed, half of which were implanted with melatonin (18 mg/goat). All bucks and goats were fed with barley grain feed (flushing) for 60 days. A total of 13 blood serums were collected before the melatonin implant (Day 0) and on the 21st, 42nd, 63rd, 94th, 129th, 157th, 185th, 213rd, 251st, 275th, 307th, and 335th days after the implant. The M and T hormone were determined using the ELISA method in the blood serum. Mating was carried out for 10 minutes, and the sexual behaviors of the bucks and does were recorded. While the treatment (MI) group had an average melatonin hormone level of 526.3 ng/L, the control (C) group had a melatonin hormone level of 199.0 ng/L (P=0.0224). The testosterone hormone level in the MI group was 12.7 nmol/L on average, and it was 6.13 nmol/L in the C group (P=0.2137). The MI group had significantly higher melatonin hormone levels in the summer, autumn, and winter than the C group, and significantly higher testosterone hormone levels in all seasons (P≤0.05). The highest levels of melatonin and testosterone hormone levels were determined in the MI and C groups in April-May. Sexual behaviors and the duration of mating were similar in the groups of bucks (P>0.05). A high statistically significant positive correlation coefficient was determined between melatonin hormone and testosterone hormone (P≤0.05). In addition, there was a significant and positive correlation coefficient between hormone levels and the frequency of tongue-lapping, sexual vocalization behavior in the MI group. Pearson correlation coefficients r=0.487 and r=0.462 were determined between hormone level and frequency of tongue-lapping and frequency of sexual vocalization, respectively. In conclusion, the melatonin implant, which was determined to increase hormone levels significantly, can be used to increase the libido in Turkish Saanen goat bucks.
Key words: Turkish Saanen, melatonin implants, melatonin, testosterone, mating behavior
Note: This work was supported by Çanakkale Onsekiz Mart University, The Scientific Research Coordination Unit, Project number FHD-2019-2842.