To date, no single factor has been reported to be responsible for the immune dysfunction that cows experience around the time of calving.
Experimental models of under-nutrition have generally failed to reproduce the typical problems seen during this period. But, aspects of energy metabolism, especially ketones, have been reported to negatively impact immune function, according to research presented by Matt Waldron, University of Missouri dairy nutrition specialist, at the 4-State Dairy Nutrition and Management Conference in early June.
Although not as well understood, high levels of circulating NEFA and calcium metabolism may also contribute to immunosuppression around the time of calving. In addition to metabolites, many dietary nutrients, like vitamins C, D and E, as well as trace minerals like zinc and selenium, are involved in immune protection. Some of these nutrients are involved in immune cell function, but many others serve to minimize damage during the immune response by limiting inflammatory damage. Much of the potential damage caused during inflammation is due to oxidative stress, or the reaction of unstable oxidizing molecules with tissue lipids, proteins and DNA. Many of the micronutrients that are important for immune function and health also serve as antioxidents to protect tissue. Careful nutritional management to provide highly bio-available nutritional profiles and to maximize metabolic health is currently the best strategy to maximize immune function.