Sensitivity and specificity of pregnancy examinations by means of ultrasound between day 20 and 34 after artificial insemination in dairy cattle

摘要

Cows (1 herd of 800 cows) and heifers (2 heifer rearing units with 300 and 1800 animals, respectively) were examined for pregnancy by ultrasound between days 20 and 34 post insemination (pi) between February and July 1998 (total of 1299 pregnancy tests). The results were compared to those obtained during 1996-98 (2261 pregnancy investigations) in 5 dairy herds (300-1000 cows) by rectal palpation after 35 to 48 days pi. Accuracy was 98% from day 25 and 29 pi in heifers and cows, respectively.