Energy Cost of Inflammation in Dairy Cows

摘要

Metabolic maladaptation to lactation (ketosis) and heat stress are two economically devastating hurdles to profitability. Heat stress and ketosis affect herds of all sizes and almost every dairy region in the world. The biology of ketosis and heat stress has been studied for almost a half century, but the negative impacts of both are as evident today as they were 30 years ago. Our recent discoveries suggest that endotoxin is the common culprit in both disorders and the intestine appears to be the etiological origin of both metabolic disorders. Endotoxin stimulates the immune system and activated leukocytes switch their metabolism away from oxidative phosphorylation to rely more on aerobic glycolysis. In multiple species, we estimate that immune activation consumes about 1 g glucose/kg BW0.75 or about 2 kg glucose/day in an adult lactating dairy cow. Thus, an activated immune system reprioritizes nutrient partitioning away from the synthesis of economically valuable products.