In this paper, data from real-time ultrasound pregnancy diagnosis carried out in 45 sheep flock during six reproductive seasons are presented. A total of 27089 ewes from commercial flocks, mated during autumn, were scanned. The mean pregnancy percentage(PP) found was 81.6% showing a variation from 77.3 to 89.9%. Mutton breed flocks (Hampshire Down, Suffolk and Texel) showed the highest PP of 85.6%, followed by cross breeds, with a PP of 82.9%. The PP of wool breeds flocks (Australian Merino, Corriedale and Polwarth) was 80.8%. The causes of low PP founded on some flocks is presented and discussed.
sheep; pregnancy percentage
