Uporaba egzogenog melatonina u Ouled Djellal ovaca i ovnova izvan sezone parenja

The study aimed to investigate the effect of exogenous melatonin treatment on the ewe’s and ram’s reproductive activity, out-of-season breeding, usually matching with spring. The eighty four adult ewes and 16 genitor rams of Ouled Djellal breed, taken randomly out of a 176 ovine flock were treated with respectively 1 or 3 melatonin subcutaneous ear implants (Melovine). The 76 non-treated remaining ewes served as the control group. The rams, kept separately from the females, had scrotal perimeters measured before (PS1) and 47 days after (PS2) melatonin treatment, before they were allowed to run with the ewes. The analysis of the lambing rates had not shown anysignificant difference (P>0.05) between the melatonin treated ewes and those of the control group (90.4% vs. 97.3%) which proves that their sexual activity is not under photoperiod control. However, the analysis by the t-test of the paired samples of the ram’s scrotal perimeters had shown a significant difference (P<0.05) between the measurements before and after melatonin treatment in rams which proves the potential effect of this hormone on daily sperm output. During the study period, no effect on female sexual activity has been noted. In Ouled Djellal sheep breed, melatonin use is not recommended in ewes but it can be useful in rams since it enhances sexual capacity during mating.