The Oestrous Behavior of the Karayaka Sheep in Turkey

Abstract

In order to verify the estrus activity of the Karayaka ewes reared under natural conditions of the Black Sea Region of Turkey throughout year, ten, 3 years-old Karayaka ewes with an average weight of 46 +/- 7.9 kg and with two lambing record, were used. In this experiment four climatic seasons were considered; winter, spring, summer and autumn. Behavioral oestrus was monitored twice a day (7: 00 and 15: 00) during all the experiment by using two teasers rams. The oestrus cycles were quantified within each season and classified as short (<= 14 days), normal (15-20 days) and long (or anoestrus, >= 21days). The percentage of ewes in oestrus was higher (p<0.05) in the autumn than in the winter and summer seasons and the percentage never exceeded 40% in each season. The minimum length of short cycle was 11 days while maximum length of anoestrus was 87 days and the average length of normal cycle was 17.3 +/- 1.06. During the experiment, there were 11.9% short cycles, 35.8% normal cycles and 52.3% anoestrus. The percentages of abnormal cycles (short and anoestrus), in relation to total cycles monitored in each season were 87.4, 88.5, 90.9 and 35.5% for winter, spring, summer and autumn, respectively. It can be concluded that Karayaka ewes maintained on rangeland show a low seasonality for oestrus behavior. Thus, in this oestrus pattern, mating may occur from late spring through to late autumn taking into account demands for slaughter lambs and/or feeding of lambs in rangeland.