Creatine kinase as marker for purulent vaginal discharge and fertility in beef cattle: Using creatine kinase to diagnose purulent vaginal discharge

In beef cows, cycle is expected to resume within 30–35days postpartum. Uterine diseases may delay these processes, extending the partum to conception to 50days. Biomarkers for the diagnosis of Purulent vaginal discharge (PVD) in beef cows remain undefined. Creatine kinase (CK) has been investigated in dairy cows as a marker for clinical endometritis but not in beef cows. Mucus score and blood sampling were performed at 30±5 in 264 non-pregnant Piedmontese beef cows and 28 of them were diagnosed with PVD. Cows that showed no successful conception after more than three AI with no apparent clinical disease were defined as repeat breeders (N=33). Kruskal-Wallis test was used to detect difference in CK between cows with PVD and heathy ones and RB (p = <.001 and p=.048 respectively). No difference was found between healthy cows and RB (p>.05), cows PVD showed lower reproductive performances (PC and n°/IA) than healthy ones. Parity and farm didn’t show differences between healthy and PVD cows. ROC curve was created to define a CK cut-off value for PVD detection (241U/L, Sp 69%, Se 92%, AUC 0.81, Younden Index (J) 0.61) and to determine CK accuracy in predicting infertility at 120- and 150-days postpartum (Sp 77%, Se 42%, AUC 0.57, J 0.19 and Sp 82%, Se 34%, AUC 0.59, J 0.16 respectively). This study underlines the potential of CK as a marker of PVD in beef cows.HIGHLIGHTS Creatine kinase seems to be a useful on field marker of PVD in beef cows Creatine kinase cut-off for PVD is 241 U/L Creatine kinase has low accuracy in prevision of infertility.