Comparison of a leukocyte esterase test with endometrial cytology for the diagnosis of subclinical endometritis and correlation with first service pregnancy rate in postpartum Holstein cows
The point toward this study was to determine the diagnostic test characteristics of the leukocyte esterase activity test for subclinical endometritis in postpartum Holstein dairy cows. The objectives were 1) to compare uterine leukocyte esterase activity and the endometrial cytology (EC),  2) to compare leukocyte esterase activity of the cervix (CxLE) and the uterus (UtLE), 3) Compare two methods of assessing the slides (i.e. an exhaustive method and a rapid method). Two hundred eighty five post partum Holstein cows from 5 commercial dairy herds had a post partum evaluation between 21 and 47 days in milk (DIM). Sixty seven cows where diagnosed with clinical endometritis by transrectal and vaginoscopy examinations and were excluded from the study. Two hundred eighteen cows were enrolled for endometrial cytology and esterase activity test. The ovarian status was determined by transrectal examination. Computerized databank, dairy DSA (Dossier de Santé Animale) indexing all the cows was used to retrieve individual information for analysis. The percentage of neutrophils was significantly correlated with the LE from the uterus and cervix. The LE from cervix and uterus decreased significantly with DIM, however, they were not statistically associated with pregnancy risk at 90 DIM (n=186). Between 32-47 DIM, the percentage of neutrophils and risk of pregnancy at 90 DIM were associated (n=94, P=0.04). For the same period, survival analysis identified cows with > 2.6 % neutrophils on EC as subclinical endometritis cows with a prevalence of 56%. The two methods for assessing the slides were correlated by 81%. Subclinical endometritis diagnosed by endometrial cytology  between 32 and 47 DIM was associated with reduced risk of pregnancy at first service.
Subclinical endometritis Endometrial cytology Leukocyte esterase