[Real-time ultrasonic pregnancy diagnosis (B-mode) in sheep. 1. Frequent examinations during the first month of pregnancy].

Transrectal ultrasonography was performed on 63 ewes (four breeds) to determine the earliest day at which pregnancy, the first embryo, the number of embryos, the embryonal heartbeat and placentoms could be detected. The ewes were examined at intervals of two to three days on day 12/13 to 30 post breeding. An Aloka SSD 500 ultrasound unit was used with a 5-Mhz probe. The diagnosis of the pregnant ewes took place on day 17.6 +/- 1.8 p.c. The first embryo was detected on day 20.5 +/- 1.9 p.c., but not all of the embryos were counted accurately until day 26. The heartbeat of the embryos was detected on day 22.9 +/- 2.9 p.c. and placentoms on day 27.6 +/- 2.4 p.c. The influence of the breed on the results will be discussed. The proportion of sheep with a loss of embryos was 24.6% (partial loss of embryos 18.0%, total loss of embryos 6.6%). In conclusion, transrectal ultrasound is a good method to describe the early pregnancy in sheep.