When it’s time to preg check your cows, the tools you choose matter — not just for knowing who’s bred, but for making better management decisions across the board. Blood testing might seem easy, but here’s the truth: You’re waiting for the results (minutes to days)… and those results can still mislead you. Studies show that residual pregnancy-associated glycoproteins (PAGs) can trigger false positives weeks or even months after a cow has lost a pregnancy.