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Abstract
The use of color doppler (CD) ultrasound and pregnancy-associated glycoproteins (PAG) as early pregnancy diagnostic tools and predictors of pregnancy loss in Bos taurus beef cattle was evaluated in 392 beef females (214 cows; 178 heifers) were exposed to fixed-time artificial insemination (FTAI; day 0). On days 20 and 22, B-mode and CD ultrasonography were performed to evaluate corpus luteum (CL) morphometries and blood perfusion. Blood was collected on days 25 and 29 of gestation for circulating concentrations of PAG. Conventional ultrasonography on days 29 and 100 was utilized as the gold standard pregnancy diagnosis. Females that experienced pregnancy loss between days 29 and 100 were classified as LEM. Color Doppler accurately recognized most nonpregnant females as early as 20 days post-breeding. Females classified as LEM had decreased concentrations of PAG on day 29. Both blood concentrations of PAG and luteal blood perfusion failed to accurately predict pregnancy loss.