Monensin at 300 mg and 450 mg per 1000 lbs body weight reduced the
severity of alfalfa pasture bloat by 41.2 and 73.1 %, respectively. Lasalocid at the
same levels reduced the bloat score by 25.5 and 12.4%. The difference between the
two antibiotics appears to be in their ability to inhibit rumen protozoa. Monensin
reduced protozoal population in the rumen, whereas lasalocid had no effect. A
smaller protozoal population decreases compounds that contribute to frothiness and
also increases substances such as plant chloroplasts, which have antifrothing
properties.
