USE OF REAL-TIME ULTRASOUND TO IDENTIFY MULTIPLE FETUSES IN BEEF-CATTLE

To examine the feasibility of producing multiple births in beef cattle by means of superovulation, real-time ultrasound was used to identify cows carrying multiple fetuses. Three replicates of the superovulatio n experiment were conducted with groups of 52, 25 and 89 purebred Angu s cows, respectively. Both uterine horns of cows from Replicate 1 were examined via the rectum using ultrasound at averages of 43 (range = 3 0 to 68 days), Sl (range = 38 to 76 days) and 126 (range = 113 to 151 days) days after AI. Cows in Replicate 2 were examined in the same fas hion at averages of 55 and 97 days post insemination. In Replicate 3 t he number of fetuses was estimated on a single date (average number of days post insemination 49 days). Across the 3 replicates, the number of fetuses was most accurately assessed at an average of between 49 an d 55 days post insemination. In most instances for which comparability between ultrasound estimations and calving results was low, the lack of correspondence was likely due to embryo mortality in cows identifie d as carrying multiple fetuses. For all 3 replicates combined, only 1 cow diagnosed with a single fetus produced multiple calves at birth wh en the diagnoses were conducted at 49 to 55 days post insemination. Re al-time ultrasound can be used to accurately identify open cows and to differentiate between cows carrying single or multiple fetuses.