Feedlot Bloat Studies. I. Animal and Dietary Factors

Abstract

Experimental frothy bloat was produced in 2 experiments, by using a basal diet composed of 61% barley, 22% alfalfa meal, 16% soybean oil meal and 1% NaCl. No significant differences in the bloating effect of the diet were obtained by substituting corn for the barley, or alfalfa hay for the alfalfa meal. A highly significant difference was noted among animals in their susceptibility to bloat. This difference could not be correlated with their eating habits. In both experiments there was a highly significant increase in the incidence and severity of bloat as the length of time on bloat producing diets increased. Ths increase in the incidence of bloat did not result from an increase in feed consumption. It is difficult to correlate the highly significant increase in the incidence and severity of bloat over an extended period of time with any of the single theories that have been advanced for the cause of bloat. Observations made during the above experiments support the conclusion that an additional factor or factors apart from lack of sufficient coarse roughage is involved in this type of bloat. Furthermore, this factor does not appear to be rumen atony. The bloat encountered in these experiments was of the frothy type, although a variable amount of "free" gas was always found in the rumen. A certain amount of gas could be released with a large sized stomach tube directed toward the dorsal blind sac of the rumen and could always be released from a fistulated animal by slowly opening the pinch cock attached to the cannula stopper.