Free D amino acid content of milk from mastitic udder
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.