Journal of Animal Science and Products, vol.4, no.2, pp.153-163, 2021 (Peer-Reviewed Journal)
In this study, the effects of melatonin implant treatment before the
breeding season on melatonin (M) and testosterone (T) hormone levels,
and the mating behavior and performance, were determined in Turkish
Saanen goat bucks. Four head of bucks and 50 head of goats were used.
The bucks were randomly divided into two groups and they were treated
with 3 implants with 18 mg melatonin. The half of female goats were
also implanted with melatonin (18 mg/goat). A total of 13 blood
samples 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. Hormone analyses were performed using
ELISA method and in animal species specific hormone kits. Mating was
carried out for 10 minutes, and the mating behaviors of the bucks and
does were recorded. While the treatment (MI) group had an overall
means of melatonin hormone level of 526.3 ng/L, the control (C) group
had a melatonin hormone level of 199.0 ng/L in overall (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 spring than the C group, and significantly higher
testosterone hormone levels in all seasons (P≤0.05). While M hormone
had the highest level of MI and C groups in March, T hormone was
highest of MI group in April and C group in March. Mating behaviors
and the duration of mating were similar in the groups of bucks (P>0.05).
A high statistically significant positive correlation coefficient (r=0.678)
was determined between melatonin hormone and testosterone hormone
(P<0.0001). In addition, there was a significant and positive correlation
coefficient between hormone levels and the frequency of tonguelapping (P=0.0134), sexual vocalization behavior (P=0.0199) in the MI
group. In conclusion, the treatment of melatonin implants before the
breeding season significantly increased the levels of M and T hormones
and positive effects on frequency of mating behavior in Turkish Saanen
goat bucks.