The use of darkness apllication in the out-season heat synchronization in akkaram sheep

The aim of this study is to investigate the possibility to synchronization of oestrus by applying darkness at out-season in Akkaraman sheep. In this study, 3-4 aged were used 50 Akkaraman sheep as animal material. The study was conducted in April. Forty-eight hours prior to estrus synchronization application, intramuscular injection of 1 cc PGF2α was performed to lutalyse the corpus luteum on the ovary in all ewes. 48 hours after the injection, vaginal implant device CIDR (0.30 g progesterone) in all sheep was used for return to the beginning of the follicular development (0.day). The sheep were randomly divided into two groups. A group of sheep (control; n = 25) were synchronized by using natural and synthetic hormones. The other group (dark; n = 25) was exposed to darkness in a fully controlled sheep housing during 13 hours. For all animals was taken blood in a specific program and melatonin hormone concentrations were determined in Elisa device. At the beginning of the experiment, there was no difference in melatonin hormone concentrations between the groups (P>0.05). At the end of darkness application, melatonin hormone concentration in darkness applied group (90.83 ± 29.27 pg / ml) was higher than control group (66.58 ± 21.05 pg / ml) (P <0.01). At the end of the experiment, melatonin concentration was higher in the darkness applied group (89.30 ± 29.57 pg / ml) than the control group (54.44 ± 22.97 pg / ml) (P <0.01). Reproductive charactersitics was not difference between the groups (P> 0.05). According to these results, it has been shown that melatonin hormone concentrations can be changed with the application of darkness in out-breeding season in sheep, and therefore heat synchronization can be realized.