Paraoxonase-1 activity and lipid profile in dairy cows with subclinical and clinical mastitis

The aim of this study was to investigate serum paraoxonase-1 (PON1) activity and lipid status in cows with subclinical and clinical mastitis in order to evaluate systemic inflammatory and oxidative stress responses. The study was conducted on a total of 90 Holstein-Friesian dairy cows kept in farms in eastern Croatia. Cows were assigned into three groups: the cows suffering from clinical mastitis (CLM), the cows with subclinical mastitis (SCM) and control (CTL) group. In collected sera, PON1, lipid status and calcium concentration were measured. Total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C) and calcium concentrations were significantly lower in the CLM group of cows compared to the SCM and CTL groups (P < 0.05). There were no significant differences in the lipid status and calcium level between the CTL and SCM groups. PON1 activity was significantly lower in both the SCM and CLM groups compared with CTL indicating that PON1 could be considered as a potential biomarker for the diagnosis of subclinical form of the disease.