Increased Feedlot Bloat from Feeding Soybean Oil in a Mixed Ration to Steers

Abstract
Thirty steers were used to study some of the factors involved in the development of feedlot bloat. During a 105-day preliminary period, the steers received a bloat-producing ration in order to determine their bloat potential or susceptibility. Steers were then divided into outcome groups and allocated into three equal groups of ten steers each on the basis of bloat history. One group was continued on the basal bloat-producing ration, the second was fed the basal ration with 4% soybean oil replacing an equal weight of grain, and the third group received the basal ration with 8% soybean oil. These treatments continued for an additional period of 105 days. Feeding soybean oil resulted in a highly significant increase in feedlot bloat. Furthermore, there was a greater incidence of bloat among steers fed twice-a-day than among those allowed to eat ad libitum. Out of several rumen traits studied during the experiment, only the stable ingesta volume was increased significantly by feeding soybean oil. None of the ruminal volatile fatty acids was highly correlated with bloat. Observations on ruminal microorganisms suggested a relationship between the presence of certain ruminal bacteria and feedlot bloat. Copyright © . .