Mechanisms of Bacterial Injury

The medicine and epidemiology of bovine respiratory disease in feedlots

“…Endotoxin has an array of toxic effects including initiation of complement and coagulation cascades. 34 These result in increased vascular permeability and coagulation leading to accumulation of inflammatory cells, oedema and both intravascular and extravascular fibrin deposition in the lung. 34 Endotoxin activates granulocytes and macrophages that help protect against bacteria that contain endotoxins but also lead to increased tissue damage.…”

“…34 These result in increased vascular permeability and coagulation leading to accumulation of inflammatory cells, oedema and both intravascular and extravascular fibrin deposition in the lung. 34 Endotoxin activates granulocytes and macrophages that help protect against bacteria that contain endotoxins but also lead to increased tissue damage. M haemolytica produces a ruminant specific leukotoxin active against phagocytes that impairs phagocytosis and kills macrophages.…”

“…M haemolytica produces a ruminant specific leukotoxin active against phagocytes that impairs phagocytosis and kills macrophages. 34 M haemolytica and P multocida can also affect neutrophil defence of the lung. Extracellular fractions of M haemolytica kill bovine neutrophils 35 and a capsular fraction of P multocida inhibits bovine neutrophil function.…”

Effects of injectable vitamins A, D, E and C on the health and growth rate of feedlot cattle destined for the Australian domestic market

“…Cattle on high grain diets are most likely capable of meeting their vitamin C requirements from endogenous production of vitamin C unless challenged with severe stress and/or disease. Much of the pathology of bovine respiratory disease (BRD) is due to inflammation that involves oxidative challenge 9 . Therefore, concentrations of the antioxidant vitamin C may be reduced by BRD, 10 and being water soluble, vitamin C is rapidly excreted.…”

“…Much of the pathology of bovine respiratory disease (BRD) is due to inflammation that involves oxidative challenge. 9 Therefore, concentrations of the antioxidant vitamin C may be reduced by BRD, 10 and being water soluble, vitamin C is rapidly excreted. Accordingly, we examined the effects of injectable vitamin C administered at the time of treatment of cattle for BRD with an antibiotic.…”