[Ultrasonic pregnancy diagnosis (B-mode) in sheep. 2. Comparative studies using transcutaneous and transrectal pregnancy diagnosis].

The aim of this study was to check the earliest time for the ultrasonic pregnancy diagnosis in flock management of sheep after finishing the mating season. Therefore a transcutaneous pregnancy diagnosis (5 MHz) took place on a total of 1060 German merino-mutton sheep between day 10 and 90 after mating (a.m.) and a transrectal diagnosis (5 MHz) took place on a total of 1442 German merino-mutton sheep between day 10 and 70 a.m. At the beginning of the third week a.m. the accuracy of transrectal diagnosis was over 95% and increased to 100% on day 35 a.m. At that time the accuracy of transcutaneous diagnosis was 80% and reached 100% on day 60 a.m. Considering the reached accuracies the pregnancy diagnosis should not take place before day 35 after the end of the breeding season. After day 35 a.m. it is advisable to combine the transcutaneous and the transrectal pregnancy diagnosis. That means that at first all animals are examined by transcutaneous sonography and in the second step the so-called "non-pregnant sheep" are checked by transrectal ultrasound. From the beginning of the third month a.m. a single transcutaneous pregnancy diagnosis is sufficient.