BLOAT IN CATTLE .13. EFFICACY OF MOLASSES-SALT BLOCKS CONTAINING POLOXALENE IN CONTROL OF ALFALFA BLOAT

Five experiments were conducted to determine whether molasses-salt blocks containing the bloat preventive agent, poloxalene, might be used successfully to prevent alfalfa bloat in cattle. Rumen-fistulated identical twin Holstein cows, Angus X Holstein steers and heifers, Brown Swiss heifers, and lactating Brown Swiss cows were used. The molasses-salt blocks contained 66 g poloxalene per kg block. The blocks were offered to cattle grazing alfalfa or fed freshly cut alfalfa. Block intakes varied from 0.23 to 0.44 kg per animal per day in the 5 experiments. Intake was not related to body weight and seemed to be affected by weather and managerial factors. While intake fluctuated from day to day, minimum daily intakes were large enough to protect from severe alfalfa bloat when it occurred. Poloxalene block consumption lowered surface tension from 12 to 16 dynes per cm below that of control animals. Surface tension may serve as a simple method to estimate poloxalene intake.