Ruminal changes in monensin- and lasalocid-fed XXXX grazing bloat-provocative alfalfa pasture.

@entity291 @entity3265 @entity1735 @entity393 @entity1068
Microbial and fermentation changes in the rumen in monensin- and lasalocid-fed @entity291 grazing bloat-provocative alfalfa pasture were studied using genetically bloat-susceptible, ruminally-cannulated adult @entity291 . Monensin at .66 and .99 mg/kg body weight daily reduced the severity of legume bloat by 41 and 73%, respectively. The same doses of lasalocid reduced bloat by 25 and 12%. Comparison of ruminal contents from animals before treatment with ruminal contents from antibiotic-treated animals showed no differences in pH, @entity3265 , soluble N, soluble @entity1735 , @entity1068 -precipitable slime and anaerobic bacterial counts. Monensin treatment @entity393 and microbial activity, as evidenced by lower gas production from in vitro fermentation of ground alfalfa hay when compared to pretreatment. Lasalocid had no effect on protozoal counts and in vitro gas production. Addition of monensin or lasalocid (12 micrograms/ml) to in vitro fermentation of chopped, fresh alfalfa reduced microbial activity as evidenced by higher soluble N, lower @entity3265 concentration and decreased gas production. Monensin reduced the amount of @entity1068 -precipitable slime and protozoal numbers. Reduction in the severity of bloat when monensin was fed appears to be due to @entity393 , which resulted in decreased gas production. Lasalocid did not reduce legume bloat because of its minimal effect on the ruminal protozoa.
