Changes in rumen contents associated with lantana poisoning of sheep.

The effects of lantana poisoning on the microbial populations of the rumen and on fermentation within the rumen were compared to the effects of starvation in sheep. The protozoal and bacterial populations of the rumen were decreased to the same extent by lantana poisoning and starvation. Fermentation appeared to continue for several days in the rumen of lantana-poisoned animals, as shown by the concentrations of volatile fatty acids and ammonia, and the pH and rH of rumen fluid. It is suggested that this was due to retention of plant material in the static rumen of lantana-poisoned animals. It is concluded that lantana toxins do not affect rumen microorganisms directly and that the changes observed in lantana-poisoned animals are probably due to anorexia and rumen stasis.