Effect of dry or temper rolling of high- or low-protein wheat and its impact on rumen parameters, growth performance, and liver abscesses in feedlot cattle

This study assessed the impact of dry-(DR) versus temper-rolled (TR) and low-(13%, LP) versus high-protein (18%, HP) wheat ruminal fermentation, growth, and liver abscesses in feedlot cattle. Crossbred Angus steers (302 +/- 34 kg; n = 160; 24 ruminally cannulated) were used in a backgrounding (BG) to finishing (FN) trial. The BG diet consisted of 60% barley silage, 35% wheat, and 5% supplement, and the FN diet contained 10% barley silage, 85% wheat, and 5% supplement (dry matter basis). Four transition (TN) diets were used to adapt cattle to the FN diet. A numerical increase in large particles and reduction in small particles occurred when both HP and LP wheat were TR, with this response being greater for HP wheat. Steers experienced lower (P < 0.03) ruminal pH with HP-DR and LP-TR than HP-TR wheat during TN. Steers fed HP wheat BG diets tended to exhibit greater (P < 0.09) gain:feed and NEg than steers fed LP wheat. Greater (P = 0.01) average daily gains were exhibited by FN steers fed LP wheat. Liver abscesses were more (P < 0.001) severe with HP wheat. While HP wheat improved the growth of BG cattle, it increased the severity of liver abscesses during FN.