INFLUENCE OF MASTITIS ON D-AMINO-ACID CONTENT OF MILK

The California Mastitis Test was used as an indicator of mastitis in t his study. Five cows were chosen for each of the five test scores (fro m 0 = healthy to 4 = severe mastitis). Milk samples were analyzed for free AA and free D-AA. The contents of free AA, free D-AA, and the rat io of free D-AA to free AA increased significantly as the California M astitis Test score increased. The free D-AA content of foremilk (first milk jets) from healthy cows (test score = 0) was approximately five times that in samples drawn later from the same udders. Contents of fr ee AA and free D-AA were highly associated with test score and udder i nflammation. Very low concentrations of free D-AA are normal for raw m ilk. Higher concentrations of free D-AA could be attributed to inclusi on of foremilk and milk from cows having subclinical mastitis in the b ulk tank milk.