Poloxalene, a nonionic surfactant, was fed to beef cattle on a legume ration or a high grain ration to observe its effect on bloat. It was also fed to lactating dairy cows to note any effect on yield or composition of milk. Poloxalene was beneficial in the prevention of bloat with both legume and grain rations. It had no effect on per cent fat, protein, solids-not-fat, or yield of milk.