Transrectal real-time ultrasound scanning for diagnosing pregnancy and for monitoring embryonic mortality in dairy cattle

Abstract

A total of 309 ultrasonographic tests was performed on 100 inseminated dairy cows during the course of the first trimester of pregnancy and on 13 noninseminated controls. The reliability (defined as the proportion of cows pregnant or nonpregnant by rectal palpation at 60–90 days compared to those diagnosed as pregnant or nonpregnant by ultrasonography) and accuracy (defined as the proportion of cows correctly identified as pregnant or nonpregnant) of the ultrasonographic results at different intervals after A.I., are reported. It was found that near 100% reliable results could be obtained for positive diagnosis from 45 days onwards and that the ultrasonographic results were 100% reliable for negative diagnosis from 40 days onwards. Furthermore, 7 out of 100 inseminated cows which were diagnosed as negative by early pregnancy diagnosis 21–24 days after A.I. were found to be positive at the ultrasonographic test after 30 days but interestingly enough failed to carry the conceptus until rectal palpation occurred (60 days). The total late embryonic mortality was 23%.