ASSOCIATION BETWEEN UTERINE HEALTH AND FERTILITY OF POST-BREEDING COWS SUBMITTED TO FIXED-TIME ARTIFICIAL INSEMINATION
Beef cows, uterus, pregnancy rate
The satisfactory restoration of uterine function in the postpartum period is fundamental for the beef cows to present adequate fertility when submitted to fixed-time artificial insemination (IATF) protocols. The objective of this study was to evaluate the relationship between uterine health and fertility of cows submitted to IATF programs initiated between 20 and 60 days postpartum (DPP). This study was performed with 244 Nelore multiparous cows (Bos taurus indicus) in the postpartum period. These bovine females were separated into 3 groups according to the postpartum days (DPP): 1) Group <30DPP (n= 64), composed of cows with DPP between 20 and 30; 2) Group <45DPP (n= 115), composed of cows with DPP between 31 and 45; 3) Group <60DPP (n= 65), composed of cows with DPP between 46 and 60. On day 0 of the IATF protocol endometrial cells samples were collected (cytobrush). Blades with the samples were prepared and submitted to evaluation for polymorphonuclear cell counts (PMN) under microscopy. Cows in the <30DPP group (19/64 = 29.7%) presented a lower (P <0.05) pregnancy rate per AI (P/AI) than cows in the <45DPP groups (52/115 = 45.2%) and <60 DPP (34/65 = 52.3%). Uterine discharge and the proportion of PMN cells decreased with increasing postpartum days. These results indicate that females with higher PMN have healthier uterus and tend to have a higher pregnancy rate / AI, indicating that animals with more than 30 postpartum can be included in the IATF programs. Animals qualified with appropriate ECC by the Vetscore® device (green) had an increase in pregnancy/AI when compared to females in the other categories.