ABSTRACT
The influence of bovine subclinical mastitis caused by Staphylococcus aureus upon the milk protein fractions was evaluated with the comparison among mammary quarters with subclinical mastits and healthy mammary quarters. The trial was performed in a dairy herd with crossbred Holstein cows and the diagnosis of subclinical mastitis was previously made by California Mastitis Test. The milk fractions as total protein, true protein, casein, whey protein, nonprotein nitrogen, noncasein nitrogen, as well as the somatic cell counts (SCC) from milk were determined. The animals were distributed into two groups in conformity to lactational stage. Group “1” included animals between 10 and 60 days in milk and the group “2” included animals between 61 days and ninth month in milk. The infected quarters SCC in the cows from the two groups was higher than healthy mammary quarters (P < 0.0001). The whey proteins and the noncasein nitrogen in the milk from mammary quarters with subclinical mastitis caused by S. aureus were significantly higher in the cows above 60 days in milk.
KEY WORDS
Protein;
Staphylococcus aureus
; bovine mastitis; milk