Control of heifer mastitis by nutrition.

Nutritional factors that are linked to mastitis in the mature dairy cow can be associated with mastitis in the first lactation cow as well. However, there may also be risk factors unique to the heifer due to differences in feeding management during rearing or pre-calving. Literature was reviewed to summarize current knowledge regarding links between heifer nutrition and mastitis with the potential to identify areas for future research. The preponderance of data relating nutrition and bovine mastitis involves selected micronutrients. Selenium and vitamin E enhance phagocytic activity and have been associated with decreased clinical mastitis risk. Copper has antioxidant functions and can reduce clinical mastitis in heifers. Zinc is implicated in maintaining the epithelial barriers to infection, but reports vary as to its role in udder health. Vitamin A and beta-carotene aid in maintaining the health of mucosal surfaces, and beta-carotene may also have antioxidant properties. Supplementation with vitamin A and beta-carotene has produced inconsistent results. Vitamin and mineral requirements of dairy heifers are generally influenced by growth rate and body weight relative to mature size, though little specific data is available. From a management standpoint, heifer rations should be supplemented where necessary, and a pre-fresh heifer diet is critical to assure that first lactation animals have adequate stores of minerals and vitamins. Adequate stores are necessary for transfer into colostrum by calving. Additional studies using field data and controlled studies are needed to further define the role of nutrition in animal health and in affecting specific mastitis-causing organisms.