Relationship of acidosis to other feedlot ailments.

Laminitis often follows lactic acidosis and is accompanied by increased blood and rumen histamine. However, since histamine is poorly absorbed and absorbed histamine is rapidly metabolized, and since high levels of oral histamine have not produced laminitis, it is unlikely that ruminal histamine causes laminitis. Lactic acidosis leads to rumenitis, which, in turn, leads to liver abscesses because the causative microorganism can now cross the rumen wall into portal circulation. In cattle, hair ingested during grooming may penetrate the rumen wall and aid in this passage. Immunizing cattle against liver abscesses may be possible. Polioencephalomalacia occurs because an enzyme, thiaminase, develops in the rumen, catalyzing the production of a thiamin antagonist. Lactic acidosis may set up ruminal condit ions that encourage this chain of events. (