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F. Guirado Dantas, K. E. Zechiel, S. T. Reese, G. A. Franco, J. D. Rhinehart, K. G. Pohler, 028 Using Pregnancy-Associate Glycoprotein (PAG) on Day 24 as Marker for Pregnancy on Beef Cattle, Journal of Animal Science, Volume 95, Issue suppl_1, December 2016, Page 14, https://doi.org/10.2527/ssasas2017.028
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Abstract
The United States beef industry estimates that reproductive failure results in annual losses of $600 million. Early embryonic mortality between days 7 to 28 range from 20% to 30%. Late embryonic loss (after day 28 of gestation) may account for 3.2% to 42.7% of all pregnancy failures. Bovine pregnancy-associated glycoproteins (PAG) have been identified as an accurate marker of pregnancy around day 30 of gestation. Pregnancy associated glycoproteins have also been shown to increase in circulation in pregnant cattle as early as day 22 to 24 of gestation. The primary objective of this experiment is determine if circulating PAG concentrations on day 24 can be used as marker of pregnancy. Cows (n = 80) and heifers (n = 22) were synchronized using the 7-day CO-Synch + CIDR protocol and bred using fixed time AI. Blood samples were collected via coccygeal vein on day 14 and day 24 after TAI for PAG analysis. Final pregnancy diagnosis was performed on day 54 by transrectal ultrasound. Day 14 PAG concentration was used as a base line and the difference between day 14 and day 24 concentration was used for statistical analysis. Cows diagnosed as pregnant on day 54 had higher PAG concentration on day 24 compared with cows that were diagnosed as non-pregnant (1.69 ± 0.15 ng/ml vs 0.28 ± 0.18 ng/ml, respectively; P < 0.0001). Based on ROC curve analysis, PAG concentration higher than 2.05 ng/ml on day 24 have 95% accuracy in detecting pregnant cows on day 54. Conversely, PAG concentration lower than 0.06 ng/ml on day 24 is 95% accurate in detecting non-pregnant cows. Based on these results, PAG concentration on day 24 might be an early indicator of identifying pregnancy status in cattle; however, more work is needed to determine the efficacy of this test.
