EFFECTS OF USING MELATONIN IMPLANTS DURING OUT OF BREEDING SEASON IN TURCANA YEARLING EWES

The current research was carried out during year 2011 in two commercial sheep farms, that were rearing Turcana breed under different production systems. One of the farms provided to the animals high quality cultivated pastures and shade access, while the other farm was rearing the animals under extensive production conditions, with the grazing of sheep on unimproved, natural pastures and no access to shade during summer. On each farm, two groups of Turcana yearling ewes were randomly chosen, experimental and control group, respectively. To the animals included in the experimental groups, one Melovin implant containing 18 mg of melatonin was inserted at the end of May 2011. Implants were inserted subcutaneously, in the peri-auricular area. After testing differences and their significances for the postnatal reproduction indices in Turcana yearling ewes, it was noticed that all reproduction indices were superior (p <= 0.05) in the two experimental groups compared with the control groups from the two farms. By comparing results registered between the two farms, for the animal treated with melatonin implants, it can be noticed that under simulative rearing conditions for both yearling ewes as well as for rams, postnatal reproduction indices are significantly (p <= 0.001) influenced by the production system, with 50.0-57.5% higher than those registered under extensive rearing conditions. Results suggest that throughout the usage of melatonin implants in Turcana yearling ewes, reared under semi-intensive conditions, during out of season breeding, there can be an economical positive response throughout the increase of the conception, prolificacy and birth rates.