Short communication: Influence of subclinical endometritis on the reproductive performance of dairy cows

<p>The aim of this study was to evaluate the influence of subclinical endometritis (SE) on the reproductive performance of dairy cows. Ninety-four dairy cows of parity 1 to 8, distributed in 25 herds, were examined once between 30 and 45 days in milk using transrectal palpation, vaginoscopy and ultrasonography. A cytological sample of the endometrium was taken only from cows with an apparent healthy uterus (n=65). Serum glucose, total cholesterol, triglycerides, non-esterified fatty acids, β-hydroxybutyrate, total proteins, albumin, urea and hepatic enzymes were analyzed. Reproductive indexes were recorded during the next 11 months. Endometrial cytology was considered indicative of SE if percentage of polymorphonuclear neutrophils was superior to 5% of all cells present in the smear, except erythrocytes. Results indicated that 14.9% of the cows sampled for uterine cytology had SE, and that healthy cows become pregnant significantly before than those with SE (hazard ratio=2.35; 95% confidece interval: 1.05-5.3). From all the metabolic and productive variables analyzed, only triglycerides affected negatively to reproduction; serum albumin concentration, body condition score and milk production had positive effects on the reproductive performance. In conclusion, our results indicate that SE has a negative impact on reproductive performance and uterine cytology is necessary to diagnose it since almost 15% of the affected animals were not detected by other diagnosis methods.