Free D amino acid content of milk from mastitic udder

Abstract

The California Mastitis Test was used as an indicator of mastitis. Five cows were chosen for each of the five scores from 0 to 4. Milk samples were analysed for free AA and free D- AA. The contents of free AA, free D-AA and the ratio of free D-AA to free AA increased significantly as score increased. The free D-AA content of foremilk (first milk jets) from nonmastitic cows (score=0) was approximately five times that of samples drawn later from the same udders. Contents of free AA and free D-AA were highly associated with score and udder inflammation. Very low concentrations of free D-AA are normal for raw milk. Higher concentrations of free D-AA could be attributed to inclusion of foremilk and milk from cows having subclinical mastitis in the bulk tank milk.