Metabolic Considerations for Immunity in Transition Cows

Infections of the mammary gland (mastitis) or uterus (metritis) are common sources of inflammation in lactating dairy cows, particularly during the periparturient period. Other health disorders common during this period (e.g., milk fever and ketosis) do not arise from infectious organisms, but instead have metabolic origins. Although the etiologies of infectious and metabolic disorders differ, epidemiologists report a significant association between their occurrences. For example, Curtis et al. (1985) reported that cows with milk fever were more than 5 times as likely to contract clinical mastitis as animals without milk fever. These results do not imply cause and effect; however, they suggest an association between the occurrences of one disease with that of a second disorder. Potential causal relationships between periparturient metabolism and immune function have been investigated for about the last 20 years, but this research has intensified recently. More research needs to be performed, but at this time elevated levels of ketones have been the most consistent metabolic variable to negatively impact immunity. Our group is investigating metabolic regulators that may also be important in the regulation of immune function of the transition cow.