Relationship between serum progesterone and estradiol-17_β and embryonic loss in frisian cows under egyptian condition

Association between circulating progesterone and oestradiol-17_β concentrations and embryonic loss in Frisian cows (n=105) under Egyptian condition was investigated. Total embryonic losses in present study were 26.4%. On d25, progesterone (P₄) concentrations and sonography revealed 79.3% cows were continuing gestation and 20.7% lost their pregnancies (early embryonic loss, EEL). Furthermore, 7.4% cows with late embryonic loss (LEL) were detected between d25-42. An increase in P₄ levels started from day 4 to 7 in cows diagnosed pregnant compared to low P₄ in cows that lost pregnancy (p<0.05). Cows with LEL had decrease in P₄ from d28. Estradiol (E₂) concentrations increased (p<0.05) in cows with EEL starting from d4 to 21 after AI compared to cows diagnosed pregnant. Starting from d4 to 40 after AI, P₄/E₂ ratio was higher (p<0.05) in cows diagnosed pregnant compared to cows exhibiting EEL loss, while cows with LEL had highest P₄/E₂ ratio till d25 post-AI and declined from d28 to 40.