Effect of assisted oestrus on the ovulation rate and reproductive performance of Tsigai sheep

Abstract

The aim of the work was to observe the effect of innovated and new methods of assisted oestrus of sheep on basic parameters of fertility and reproductive performance of the ewes raised for the production of slaughter milk lambs and sheep milk for market utilisation. Verifying observation was carried out in the Tsigai sheep in one control flock (n=355) with a traditional Carpathian system of mating, and in 6 flocks with assisted oestrus, where 1528 animals were treated and prepared for mating. Of them the assisted oestrus was used in three flocks for earlier starting of the mating period according to the need of earlier preparation of lambs for an Easter’ market. In the other three flocks the assisted oestrus was verified at the preparation of slaughter milk lambs for a Christmas’ market and subsequent milking for production of sheep milk and its products for a winter tourist season. At the assisted oestrus, of 1528 ewes 1285 ones lambed and 1510 live-born lambs were obtained, which represents 118.2 % natality in conditions of breeding, where in the control flock the average natality was 111.9 %. Valuable information was gained when at assisted oestrus in spring at the preparation for production of slaughter milk lamb for Christmas market the preparation was divided into two stages. Using this method a significantly higher occurrence of twin parturitions and subsequent natality (133.2 %) in comparison with the second stage (102.9 %; P<0.001) was reached. The innovated methods are favourable regarding the environmental and ecological aspects.