Cytological endometritis diagnosed at artificial insemination in repeat breeder dairy cows

Contents This study aimed to (i) assess the prevalence of cytological endometritis ( CYTO ) diagnosed at artificial insemination ( AI ); (ii) evaluate the effect of CYTO on the pregnancy outcome of the same AI sample; and (iii) determine the risk factors associated with CYTO diagnosed at AI in repeat breeder ( RB ) dairy cows. We analysed the productive and reproductive performances of 146 RB Holstein‐Friesian cows. To obtain a CYTO sample at AI , we used the cytotape technique. Generalized mixed effect models were computed to find the risk factors associated with the pregnancy and CYTO outcome. Based on ≥1% PMN cut‐off point, the CYTO prevalence at AI in RB cows was 25.3%. The overall pregnancy at AI was 44.2%. The conception rate in CYTO ‐positive ( n  = 37) RB cows was 29.7% versus 49.5% for CYTO ‐negative ( n  = 109) cows. A RB cow diagnosed CYTO positive at AI had 0.47 [odds ratio ( OR )] odds to become pregnant in comparison with a CYTO ‐negative cow. Cows that produced more milk than their counterparts in this study had increased odds ( OR  = 1.01) to be CYTO positive at AI . A novel risk factor positively associated with CYTO diagnosed at AI in RB cows was the level of daily milk urea ( OR  = 1.11). To conclude, CYTO at the moment of AI had a significantly negative effect on the pregnancy outcome in RB dairy cows. However, as only one of fourth of RB cows is affected with CYTO at AI , it may not be considered a key element associated with the RB syndrome.