Effect of melatonin on sperm quality of Taleshi ram during breeding and non-breeding seasons

In this study, nine Taleshi rams (approximately 3 years old and average BW was 55.6±1.57 kg) were selected randomly and allocated into three groups to investigate the effect of melatonin (regulin) on sperm during breeding and non-breeding seasons. The first group (control) did not receive any regulin, the rams of second group received one regulin and finally, the third group received two regulins subcutaneously at the same time. Scrotal circumference (SC), semen volume, sperm concentration, sperm motility and sperm viability of all rams were measured on day zero (regulin implantation day). Scrotal circumference was measured 45 days after regulin implantation and semen volume, sperm concentration, sperm motility and viability were measured 46, 50, 54 and 58 days after regulin implantation. The results indicated that the use of regulin had not any significant effect on the SC and sperm quantity and quality parameters during breeding season (P 0.05). The SC and motility were increased by using two regulins during non-breeding season and this improved sperm viability in comparison to control group (P<0.05). Whereas, the use of regulin had not significant effect on semen volume and sperm concentration (P>0.05). It is concluded that improvement in the ram semen quality was expected with the use of two regulins during non-breeding season.