Relationship of Rumen Gram-Negative Bacteria and Free Endotoxin to Lactic Acidosis in Cattle

Abstract
Feeding grain to animals not adapted to grain resulted in a marked increase in the concentration of free endotoxin in the rumen. Endotoxin concentration increased 15 to 18 times within 12 hr after lactic acidosis was induced through grain engorgement. The increase was accompanied by a shift from predominantly gram-negative to gram-positive bacteria. Data from in vitro fermentations showed that the increase in free endotoxin concentration was not accompanied by a decrease in the number of gram-negative bacteria. The absorption of endotoxin from the rumen was not apparent by the actinomycin D assay procedure because no difference was observed in mice lethality of plasma from control and post-engorgement samples. However, the significant granulocytosis that accompanied acidosis was suggestive of systemic action of rumen bacterial endotoxin. Copyright © 1978. American Society of Animal Science . Copyright 1978 by American Society of Animal Science.