EN
Milk samples were taken from cows with acute, subacute, chronic, and subclinical mastitis and from healthy cows. The mean activity of lactoferrin (LF) in milk from mastitic cows ranged from 8.9 ±3.0 to 12.1 ±6.9 mU/g protein and was significantly lower than that in milk from healthy cows (29.5 ±15.0 mU/g protein). In group of mastitic cows the highest LF activity was found in cows with chronic mastitis, and the lowest in those with subclinical mastitis. The lactoperoxidase activity in cows with clinical and subclinical mastitis was significantly higher in comparison with healthy cows (1.3 ±1.1 mU/g protein) ranging from 5.5 ±2.6 mU/g protein in subclinical mastitic cows to 8.4 ±5.0 mU/g protein in chronic mastitic cows. Lower LF activities in cows with mastitis than in healthy animals may lead to a decreased antioxidant defence system in mastitic cows.