Association of subclinical endometritis with acyclia and their additive effect on fertility performance in dairy cows

The aim of this study was to evaluate the relationship between acyclia and subclinical endometritis (SE) and their combined effect on fertility performance in dairy cows. The study was performed on 449 Holstein Friesian cows. The cows were examined in the 4th week postpartum by ultrasound and endometrial samples were collected by cytobrush. Acyclia was defined as the absence of the corpus luteum and follicles > 5 mm on the ovaries. The threshold for SE was set at ≥ 5% of polymorphonuclear neutrophils in endometrial cytology. Intervals calving to estrus and calving to conception, first artificial insemination (AI) pregnancy rate, pregnancy rate 200 days postpartum, pregnancy loss and culling rate were calculated. Acyclia was found in 144 (32.1%) of 449 examined cows. The incidence of SE in acyclic cows was significantly (p≤0.05) higher than in cyclic cows (52.8% vs 36.7%). The intervals calving to estrus and calving to conception were significantly (p≤0.05) longer in acyclic cows with SE than in cyclic cows with SE (99.1 ± 28.9 days vs 77.4 ± 24.3 days and 160.2 ± 60.9 days vs 131.6 ± 46.6 days, respectively). The first AI conception rate was significantly (p≤0.05) lower in acyclic cows with SE than in cyclic cows with SE (17.1% vs 34.8%). The pregnancy loss was significantly (p≤0.05) higher in acyclic cows with SE than in cyclic cows with SE (11.8% vs 5.3%). In conclusion, the study showed that acyclia and SE were associated and had an additive negative effect on reproductive performance in dairy cows.