IMMUNITY IN DAIRY CATTLE: WHAT'S A HEALTHY COW?

摘要

The maintenance of health for a dairy cow requires the interaction of multiple physiological systems during dynamic shifts in tissue and organ function. Stable immune function during these shifts provides the animal the foundation for health and optimal performance. Health and immune function can be impacted by physiological strain induced from many factors including environment (heat), pathogen challenge and nutritional imbalance. The reaction in the animal is either induction or repression of immune function, both of which can cause inflammatory cascades that can compromise health and productivity. The dairy cow possesses several unique characteristics that make it an ideal livestock species for analysis of the regulation of immune function. Dairycows have distinct developmental, management and production cycles that last weeks to months and biological samples can be collected repeatedly during these cycles. In addition, dairy cows are exposed to metabolic, environmental and nutritional challenges induced by calving, lactation and housing. Balance of these challenges to maintain health is key to productivity. Measurements that provide a real-time index of health or possibly a predictive index of health would be of great value for all levels ofdairy production. The ability to strive for optimal dairy cow production and health requires a repeatable, nondirected analytical approach to identify pathways and markers of known importance in cow immune function as well as shifts in the relative abundance of these markers. This approach may provide an analytical definition of a "healthy cow". Progress is being made in this direction, but a thorough understanding of the inputs needed for the optimal productive and healthy cow is ongoing.