How does the health status of dairy cows affect the composition of milk?

The health status of dairy cows has an influence on milk yield and quality. Sickness often leads to the decrease of milk yield and the change of milk composition, and the degree of this change depends on the nature of the disease. The most common disease of dairy cows is mastitis. According to the severity of mastitis, the milk yield generally decreased 10% ~ 20%, and the contents of casein, β -lactoglobulin and α -lactalbumin decreased. On the contrary, the contents of serum albumin and immunoglobulin from blood sources increased. The pH value of milk and the concentrations of Na+ and Cl- increased, while the concentrations of K+ and lactose decreased. In severe infection, the concentrations of phosphorus and diffused phosphorus decrease, and the concentration of citrate decreases.