Single melatonin treatment improves reproductive performance of Singharey goats during non-breeding season under sub-tropical condition of North East India

The effect of single subcutaneous melatonin (MEL) administration on reproductive performance in Singharey goats during the non-breeding season was studied. Forty clinically healthy female goats were selected and divided into four groups (control, MEL - 10, MEL - 20 and MEL - 40) of 10 animals each. Treatments were given as single subcutaneous injection of melatonin dissolved in one ml sterilized corn oil in different groups as MEL - 10 (10 mg/animal), MEL - 20 (20 mg/animal) and MEL - 40 (40 mg/animal). Control group was injected with placebo (one ml sterilized corn oil per animal). Oestrus induction response was 20 %, 80 %, 100 % and 30 % in control, MEL - 10, MEL - 20 and MEL - 40, respectively. Time interval to oestrus following melatonin treatment was minimum in MEL - 10 (11.25 ± 0.12 days) and maximum in control group (16 ± 5.00 days). Kidding rate was significantly (P < 0.01) higher in MEL - 10 and MEL −20 as compared to control and MEL – 40 group. Difference in litter size between the groups was non-significant (P > 0.05). Serum MEL concentrations in the treated groups of goats increased significantly and the peak concentration was recorded on day 12 post treatments and thereafter it decreased sharply to reach the basal level on day 40 post treatment. The serum progesterone concentration was significantly (P < 0.05) higher in MEL - 10 and MEL −20 as compared to control and MEL – 40 group of goats during days 16–24 post mating. Total antioxidant capacity (TAC) was significantly (P < 0.05) higher in treatment groups as compared to control. The peak TAC values in all treated group was recorded on day 20 post treatment. The serum malondialdehyde (MDA) concentration showed an abrupt significant (P < 0.05) decline on day 4 post melatonin administrations in all treated groups and the value was maintained up to day 20 post treatment and thereafter it increased till 40 days post treatment. In conclusion, a single subcutaneous injection of melatonin (10 mg per animal) is effective to induce out-of-season breeding in Singharey goats under sub-tropical climatic condition.