Pregnancy diagnosis in cows with linear-array real-time ultrasound scanning: a preliminary note

Pregnancy diagnoses were performed under farm conditions in 201 cows (Hungarian Red Pied and crossbreds with Holstein) between 21 and 70 days after last insemination date, using a linear-array real-time ultrasound scanner with a 3.0 MHz rectal transducer. Identification of (a) sharply demarcated black area(s) and/or an embryo within the uterus were used as criterions for pregnancy. Pregnancy was confirmed by rectal examination at 6 and/or 8 weeks after A.I. From the total number of correct positive diagnoses (n = 129), incorrect positive diagnoses (n = 3, made on days 36, 40 and 44 after A I), correct negative diagnoses (n = 62) and incorrect negative diagnoses (n = 7, made on days 25, 28, 28, 29, 30, 31, and 33 after A I), a sensitivity of 94.8%, a specificity of 95,3%, a positive predictive value of 97.7% and a negative predictive value of 89.8% were calculated. From these preliminary results it was concluded that real-time ultrasound scanning is a useful and reliable technique for early pregnancy diagnosis in cows. It is suggested that a combination of milk/plasma progesterone estimation between days 21 and 24 and real-time ultrasound scanning between days 25 and 45 would allow the confirmation and quantification of (late) embryonic mortality in the cow.