Detection of embryonic mortality in cattle using sonography]

In 70 pregnant cattle the diameter of conceptus, the size of embryo and corpus luteum were estimated with a 5 MHz-linear array scanner on days 22, 25, 28, 35 and 42 (+/- 1 day) after insemination. Additionally, the milk progesterone level was determined. Embryonic mortality was found in 7 cases, in 3 cows on day 35, in 4 cows on day 42. The lack of embryonic heart beat was the first sign; later in pregnancy significant differences in sizes of conceptus and embryo compared with physiological pregnancies occurred. Membranes and bubble-like structures became visible in the lumen of the conceptus. The conceptus could be detected until the following oestrus, which began 8 to 42 days after embryonic death. The corpus luteum remained until proestrus. This correlated positively with the progesterone levels.