Livestock Studies 1979, Vol 19, Num, 3-4     (Pages: 103-120)

Determination of the duration of oestrus, oestrus cycle and the optimal insemination time in the Karacabey Merino ewes

Kemal ÇETİNKAYA

- This work was carried in Karacabey state farm to determine the durations of oestrus and oestrus cycle of Karacabey Merino ewes and optimal insemination time in the cycle.

All animals were maintained before and during wark on normal rations; usually given in state farm. A total 150 ewes and 8 rams were used. Oestrus control was made using 40 aproned rams.

Oestrus cycle were cheked fourtimes with 6 hours intervals starting at 6 a.m.

150 ewes were divided in to three equal groups and insemination were performed cervically 3, 12 and 26 hours after onset of oestrus for the 1. st, 2. and 3 nd ewe groups respectively.

Oestrus durations varied from 6 to 40 hours averaging 30.09  0.56 hours; and oestrus cycle durations varied from 10 to 28 days averaging 17.6 days. Oestrus duration in 75 % of the ewes was found between 25-33.30 hours. The 81.4 % ewes oestrus cycles were fell between 16 to 18 days.

The none returne rates were found to be 72, 72 and 48 % for inseminations 3, 12 hours after the onset of oestrus. Keywords :