Glutathione peroxidase activity and its relationship with somatic cell count, number of colony forming units and protein content in subclinical mastitis cows milk

This study was conducted to determine the relationship between milk and blood glutathione peroxidase (GPx) activity, casein concentration, somatic cell count (SCC) and colony forming units (CFU) in cows with subclinical mastitis. Following these tests carried out on 84 lactating cows, 10 of them were classified as cows with subclinical mastitis (SCC values above the limit of 400,000 cells mL - 1 ) and 74 as normal. After microbiological processing of the subclinical mastitis milk samples, nine microorganism species have been isolated, represented by seven bacteria and two types of fungi. Comparative analysis of GPx activity in milk revealed significant differences (p = 0.0013), the average of this parameter is higher for mastitis than normal milk. GPx activity in blood shows no significant changes in cows with subclinical mastitis compared to healthy ones. The average quantity of caseins in mastitis milks was lower compared with regular milks, the difference being significant (p = 0.0007). Mastitis milk GPx activity was directly correlated with the total SCC (r = 0.019) and CFU (r = 0.1785). Correlation coefficient between GPx activity and caseins in mastitis milk showed indirect trend (r = - 0.2606). The positive correlation between SCC and GPx activity suggests that this enzyme may have potential to detect subclinical mastitis in dairy cows.