Cortisol levels in Puerperal Metritic Cows and Assessing Accuracy Using Receiver Operating Characteristics Analysis

The present study evaluated cortisol levels during peripartum period in crossbred cows that did and did not develop puerperal metritis (PM). Accuracy of cortisol to differentiate the cows at the risk of developing PM from healthy cows was measured by receiver operating characteristics (ROC) analysis. Cortisol concentrations were estimated in blood plasma samples collected from pluriparous Karan Fries crossbred cows (n=20) at wk-2, wk-1, d+1, d+7 and d+14 taking the day of calving as zero. The cows that developed PM (n=8) had significantly (P<0.05) 2.34 time higher plasma cortisol than the normal cows (n=12) on d+1 of calving, however such difference was not observed on any other day of sampling. The ROC analysis revealed that plasma cortisol on d+1 could identify cows that developed PM with 79.17% accuracy (P<0.05). Optimum threshold value of plasma cortisol for early identification of PM was observed to be 27.28 ng/ml (sensitivity=75% and specificity=100%) on d+1. The results of the present study indicated that PM cows had higher cortisol levels immediately after calving, and using cortisol the PM cows could be differentiated from normal cows with moderate accuracy.