Influence of subclinical endometritis on the reproductive performance of dairy cows

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 methodsXunta de Galicia (Programa Sectorial de Medio Rural, Proyecto Ref. PGIDIT07MRU002E) and FEFRIGA, Santiago de Compostela, SpainS

Validation of a simple method for the interpretation of uterine cytology in cows

One of the main drawbacks of using endometrial cytology in cows is the time required for sample collection and interpretation. It is recommended to count a large number of polymorphonuclear neutrophils (PMN) and to calculate their overall percentage. However, since counting a large number of cells is a laborious method, it would be preferable to simplify the analysis by counting the number of PMN in few microscopic fields. Therefore, the aim of this study was to assess whether a simple test, based on calculating the average number of PMN in 10 fields at 1000×, could be a reliable technique for the diagnosis of endometritis. Two hundred and sixty endometrial samples were taken from Holstein cows at different postpartum stages using an adapted cytobrush. Smears obtained were air-dried for fixing and stained with a Romanowsky-type procedure. To evaluate the counting method, the percentage of PMN in 150 cells was calculated as well as the average number of PMN in 10 fields at 1000×. Receiver operating characteristic (ROC) curves was constructed to evaluate both methods, the percentage of PMN (used as reference) and the average number of PMN. It was observed that the area under the curve is (regardless of cut-off used) higher than 0.99 and the correspondence between both methods were 1.58 PMN/field for the cut-off value of 15% and 2.40 PMN/field for the cut-off value of 20%. These results show that this simple method could be used to determine the percentage of PMN in endometrial cytological samples and to diagnose endometritis in cowsSupported by the Xunta de Galicia (Galician Plan for Research and Technological Development; Grant No. PGIDIT07MRU002E) and the Friesian Federation of Galician, A Coruna, SpainS