A polyol mixture or molasses treated beet pulp in the silage based diet of dairy cows: II. The effect on the lactoperoxidase and thiocyanate content of milk and the udder health

The study investigated the effect of a diet containing either a polyol mixture (polyol group) or molasses (molasses group) on the lactoperoxidase (LP) and thiocyanate (SCN- ) content of milk and the udder health of dairy cows during a 12 week trial period. The control group received no extra carbohydrate feed. On the basis of the weekly milk samples from all test animals the polyol group had on an average the highest LP content (17.8 µg/ml), the lowest SCN- content (0.87 mg/l), and the lowest somatic cell count (152 000 cells/ml). The mean values for the molasses group were; LP: 12.6 µg/ml, SCN- ; 1.01 mg/ml and cell count: 626 000 cells/ml. The same values for the control group were 11,7 µg/ml, 0.91 mg/l and 285 000 cells/ml, respectively. The polyol group yielded milk with an average of 51.5 % more lactoperoxidase daily than the molasses group, and 42.5 % more than the control group. These differences were, however, not found to derive from the different carbohydrate diet, because no significant change in the LP level in any group occurred during the test feeding. The LP and SCN- contents varied considerably from one cow to the other. The degrees of correlation between the factors tested varied markedly among the test groups. The overall values for r were as follows: LP: SCN- = —0.049, LP: cell count = 0.222 and SCN-: cell count = 0.080. On the basis of cell content and the occurrence of mastitis cases, the polyol group had the best and the molasses group the worst udder health. The possible effect of the LP/SCN- /H2O2 antimicrobial system on mastitis resistance is evaluated