ENDOTOXIN AND ARACHIDONIC-ACID METABOLITES IN PORTAL, HEPATIC AND ARTERIAL BLOOD OF CATTLE WITH ACUTE RUMINAL ACIDOSIS

Ruminal acidosis was induced experimentally with 70 g barley / kg body weight in 2 rumen fistulated cows with chronic indwelling catheters i n the portal vein, in a hepatic vein and the carotid artery. The cows were followed for 24 and 20h after the overfeeding and evaluated clini cally and by clinical chemistry. The 2 cows exerted different response s to the treatment. Both cows showed signs of severe ruminal acidosis. Both cows had endotoxin in portal and hepatic vein blood, but only 1 of the cows convincingly developed a systemic endotoxaemia. A pre-hepa tic release of the stable prostacyclin and thromboxane metabolites, 6- ketoprostaglandin F-1 alpha and thromboxane B-2 was demonstrated in th is cow. The results of the present study show that endotoxin and arach idonic acid metabolites of pre-hepatic origin may be factors involved in the pathogenesis of ruminal acidosis, and that investigation of the factors affecting translocation of ruminal endotoxin and subsequent c learing in the liver, will be of importance.