The effect of mastitis on the carotenoids, vitamin A and phosphorus compounds of milk

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Abstract
Eight lactating cows with mastitis due to Streptococcus agalactiae were used in the study. The increases of the chloride of the milk were taken as indicators of the intensity of the infection. P was considerably reduced and, since N increased, the ratio of N to P was greater in mastitic milk than in normal milk. The ratio of N to P in the casein of the milk was increased by mastitis. The concns. of total P, ester P, lipid P, casein P of fat and of non-fatty solids were decreased in mastitic milk. The values of the P fractions were negatively correlated with phosphatase, but inorganic P was positively correlated with phosphatase. Mastitis caused a large decrease in the thiamine content of the milk and in the proportion of thiamine present in the cocarboxylase and protein-bound forms. The proportion of thiamine present in the free form was increased. There was a positive correlation between free thiamine and phosphatase but between phosphatase and the cocarboxylase and protein-bound forms of thiamine there were negative correlations. The carotenoid content of the milk fat was increased by mastitis, but the percentage of total carotenoids present in the form of beta-carotene remained unchanged. The vit. A content of the milk fat remained unchanged. The percentage of the vit. A present in the milk in the alcohol form was increased by mastitis. The blood serum of the mastitic cows was found to contain more lipid than that of the normal cows. The beta-carotene content was, however, less in the mastitic than in the normal cows. Neither the vit. A contents of the serum lipids nor the partition of vit. A between ester and alcohol in the serum was affected.