A comparative study of various techniques for diagnosing subclinical endometritis in repeat breeder cows

In the absence of a single trustworthy test, the diagnosis of subclinical endometritis (SCE) is difficult, which leads to many afflicted cows being repeat breeders. This study in 60 repeat breeder cows examined during estrus, investigated twelve distinct laboratory and cow-side tests involving endometrium (uterine lavage cytology), genital discharge (consistency; Whiteside test; pH [pH paper]; qualitative and quantitative microbiology), ultrasonography (endometrial thickness; uterine fluid), and uterine lavage (urinary test strip-based – pH, leukocyte esterase, and protein; pH; uterine lavage sample optical density [ULSOD] at 450 and 620 nm). According to receiver operating characteristics, uterine lavage cytology with a cutoff of ≥2% polymorphonuclear (PMN) cells, sensitivity and specificity of 100% and 55.10%, respectively, was considered as the gold standard for assessing the effectiveness of alternative diagnostic tests. The cytological prevalence of SCE was 56.67%. All other diagnostic methods exhibited low sensitivity (26.5% to 73.5%) and a poor to moderate Cohen’s kappa agreement amongst them (κ: -0.0967 to 0.4042); the greatest being between PMN% and microbial presence. Intrauterine fluid accumulation was absent in all cows. The Whiteside test, with a threshold of ≥2, showed the highest specificity (92.3%) and diagnostic accuracy (56.7%). The protein (test strip) (76.9%) and ULSOD450 (65.4%) tests were the next two best tests. In conclusion, diagnosing SCE in repeat breeders should begin with the cow-side Whiteside test, which, due to its exceptional specificity, can be trusted to exclude the presence of SCE. Uterine lavage cytology is only necessary for cows’ positive on the Whiteside test.