Uterine inflammation did not compromise fertility in young primiparous Bos indicus cows enrolled in postpartum timed AI programs

Although, previous study indicated that postpartum uterine inflammation was more pronounced in young primiparous (YP) Bos indicus cows, no study evaluated the impact of this inflammation on the fertility of these young cows included in timed artificial insemination (TAI) protocols. The objective of this study was to determine the effect of postpartum uterine inflammatory status on pregnancy per artificial insemination (P/AI) in YP Bos indicus beef cows subjected to TAI protocols. Postpartum Nelore Bos indicus YP cows (n = 151), 26.8 ± 1.8 months old were used in this study. On Day 0 of the Timed AI (TAI) protocol, cows were categorized in two groups according to the PMN proportions and vaginal discharge, as follows: 1) Healthy cows (n = 79), cows with ≤ 5% PMN and PVD ≤ 1; 2) Cows with endometritis (n = 72), cows with > 5% PMN and/or PVD > 1. The relative abundance of mRNA transcripts for IL1B was higher (P = 0.02) in cows with endometritis than in healthy cows. The P/AI in healthy cows was 58.2%, and in cows with endometritis was 58.3% (P = 0.99). The results of the study suggest that uterine inflammation at the onset of TAI programs is not detrimental to fertility in YP postpartum Bos indicus cows.