Quantifying the C-reactive protein concentrations of uterine lavage samples in postpartum dairy cows

Changes in the C-reactive protein (CRP) concentration, a non-specific diagnostic biomarker, in uterine lavage fluid and associations with cytological findings were examined following parturition in dairy cows. In postpartum Holstein dairy cows (n = 8), uterine lavage was performed at 3 and 6 weeks postpartum, and polymorphonuclear leukocyte (PMN) ratios to total cells (PMN:ALL) and to lymphocytes (PMN:LYM) and CRP concentrations were determined. Blood samples were collected to monitor the metabolic variables, and plasma CRP concentrations were quantified using samples collected at the same time as the uterine lavage occurred. A cytological examination was performed to determine PMN:ALL and PMN:LYM. The values for metabolic variables were within the normal range throughout the postpartum period. There was a correlation between the PMN:ALL and PMN:LYM, and both ratios were less (P < 0.05) at 6 than 3 weeks postpartum. The mean CRP concentration of the uterine lavage fluid was less at 6 (27.7 ± 9.6 ng/ml) than 3 weeks (60.8 ± 28.1 ng/ml) postpartum, whereas mean plasma CRP concentration was greater at 6 (287.4 ± 34.1 ng/ml) than 3 (254.8 ± 29.4 ng/ml) weeks postpartum. The results of the present study indicate the CRP concentration of uterine lavage fluid decreased in parallel with the frequency of PMN during uterine involution, which leads to the suggestion that uterine lavage fluid CRP concentration could be utilized as a local biomarker for evaluating uterine inflammation in cows.