Investigation the effects of melatonin on induction of fertile estrus in anestrus Female dogs

The current study was carried out to investigate the ability of melatonin as subcutaneous (SC), implanted in the induction of fertile estrus in female dogs, and for monitoring serum concentration of estrogen and progesterone before and after induction. 20 adult local dogs involved 4 fertile males; female dogs were divided into two equal groups, as follows: the melatonin group was treated with Melatonin-implant single dose S/C(18mg/animal) for 30 days, and the control group was left without treatment. Before and after treatment, clinical examination and behaviors investigation and hormonal evaluation (estrogen and progesterone), animal response, duration of response, pregnancy rate, and parturition parameters. The results showed that increase significantly (P<0.05) in the concentration of progesterone and estrogen in the melatonin group during anestrus (before treatment) and during estrus (after treatment) as compared with the control group. The results of the clinical examination showed that the animal response recorded 100% and 28.5% in the melatonin and control groups, whereas the duration of response was significantly lowered (P<0.05) in the melatonin group compared with the control groups. Animal’s response recorded a significant increase (P<0.05) in the melatonin group 100% compared with the control group. While the duration of response was significantly longer (P<0.05) in the control group and significantly lower (P<0.05) in the melatonin group. The pregnancy rate was higher in the melatonin group compared with the control group, the number of offspring was 43 and 7 pups, and the sex of offspring recorded 48.24% and 71.4% male, 51.16%, and 28.6% females in female dogs treated with melatonin and control group respectively. In conclusion, the use of melatonin for induction of fertile estrus in anestrus female dogs was effective and safe, with a higher animal response, pregnancy rate, and animal response in melatonin implant groups better than in the control group (non-treatment).