Postpartum subclinical endometritis, its diagnosis and impact on early reproductive parameters in dairy cows

Abstract

The present study was aimed at the diagnosis of subclinical endometritis and its impact on early reproductive parameters in postpartum dairy cows (N=45). The proportion of polymorphonuclear cells (PMNCs-%) and intraluminal uterine fluid (ILUF-mm) was assessed by cytotape and transrectal ultrasonography, respectively, for the diagnosis of subclinical endometritis at 8 weeks post-partum. A receiver operator characteristics curve was used to determine the diagnostic threshold of PMNCs and ILUF. The optimal threshold value for PMNCs was ≥6% (area under the curve (AUC)-0.89; sensitivity-85.71%; specificity-83.33%; P<0.05) whereas it was ≥3.40 mm for ILUF (AUC-0.92; sensitivity-100%; specificity-83.33%; P<0.05). The diagnostic odds ratio (DOR) for the development of subclinical endometritis in cows having a PMNCs percentage and ILUF above the threshold level was 7.70 and 6.00, respectively. Early reproductive parameters, such as days needed for completion of uterine involution (UINV) and first postpartum ovulation (FPO) were studied and were reported to be significantly higher in cows diagnosed with subclinical endometritis based on the percentage of PMNCs (P<0.01; P<0.05 for UINV & FPO, respectively) and ILUF (P<0.05; P<0.01 for UINV & FPO, respectively). Linear correlation analysis showed a significant relationship (p≤0.01-0.05) between the proportion of PMNCs and early reproductive parameters. Similarly, a significant correlation (P<0.01) between ILUF and PMNCs was reported, irrespective of the threshold level. In conclusion, endometrial cytology and transrectal ultrasonography with a threshold level ≥6% for PMNCs and ≥3.40 mm for ILUF, respectively, defined the presence of subclinical endometritis, and this led to a delay in the establishment of subsequent early post-partum reproductive performance.