Determining the prevalence and impact of subclinical endometritis in dairy cow with ovarian cyst

The objectives of the study were to the use of endometrial cytology (EC) to diagnose the relationship between subclinical endometritis (SE) in clinically normal postpartum dairy cows with ovarian cyst and to measure the impact of subclinical endometritis on reproductive performance in the cows. The development of cystic ovaries may be related to postparturient diseases and intrauterine infections. Holstein cows from dairy farm were examined after 40 days in milk (DIM) and clinically normal cows (n=36), based on the absence of abnormal discharge on external inspection, were selected. The reproductive tract of selected cows was evaluated by transrectal palpation and EC. The cysts were determined to be follicular or luteal with ultrasonography according to diameter of follicular wall. Endometrial cytology was performed with lavage of uterus after 50 ml normal saline infusion. The collected solution centrifuged and then a drop of precipitate on a slide was stained with giemsa and examined microscopically for percentage of polymorpho nuclear cells (PMNs). All cows in the study were subsequently followed for reproductive performance data for a minimum of 4 months. Ageneralized linear model was used to derive a case definition of subclinical endometritis, based on factors associated with decreased relative pregnancy rate. Positive EC (?3% PMN) was associated with a significant reduction in the relative pregnancy rate and identified cows with ovarian cyst which have subclinical endometritis. Cows with subclinical endometritis had a relative pregnancy rate of 13% (P=0.002), compared to cows without subclinical endometritis. In conclusion, subclinical endometritis in cows with ovarian cyst, diagnosed by EC, was associated with reduced relative pregnancy rate and there was a possible role of intrauterine infection and inflammation in the pathogenesis of ovarian cyst in postpartum dairy cows.