Mastitis, Mammary Gland Immunity, and Nutrition

Although intensive research and prevention measures have been carried out for decades to control bovine mastitis, it continues to cause the biggest economic impact to the dairy industry worldwide. Severe economic losses, which are estimated to be approximately $200/cow/yr in the United States, are due to reduced milk production, discarded milk, replacement costs, extra labor, treatment, and veterinary service costs (Smith and Hogan, 2001). In addition, mastitis increases the risk of antibiotic residues in milk due to treatments and decreases milk quality due to an increase in somatic cell count, as well as proteolytic and lipolytic enzymes, which increase the enzymatic breakdown of milk protein and fat (National Mastitis Council, 1991).