Canola screenings as a fiber source in barley-based feedlot diets: effectson rumen fermentation and performance of steers

Two experiments were conducted to determine the feeding value of canola scr eenings in combination with barley grain for beef steers. Four dietary trea tments were used. These included canola screenings:barley grain ratios of 1 00:0; 75:25, 50:50, and 25:75 (as-fed basis). In a metabolic trial, the eff ects of dietary treatment on ruminal fermentation parameters were determine d in a 4 x 4 Latin square design experiment using four ruminally fistulated steers. Tn a production trial, 66 individually fed steers were used in an 83-d finishing trial to determine the performance and carcass characteristi cs of feedlot cattle fed different levels of canola screenings. A barley gr ain/barley silage-based control diet was also fed for comparison purposes. Ruminal pH decreased (P < 0.05) while total volatile fatty acid concentrati ons increased (P < 0.05) as the level of barley grain in the diet increased . Ruminal NH3-N followed a pattern (P < 0.05) similar to that of pH. Inclus ion level of canola screenings had no effect on DM intake. However, ADG and feed efficiency increased (P < 0.05) as the level of barley grain in the d iet increased. Increasing the level of barley grain in the finishing diet d ecreased (P < 0.05) lean meat yield and increased (P < 0.05) carcass fat. I t was concluded that canola screenings can be included as a source of fiber in barley-based diets. However, levels in excess of 500 g kg(-1) reduced t he performance of feedlot steers. Performance and cost of gain with 250 and 500 g kg(-1) canola screenings in barley-based finishing diets were compar able with those fed an 800 g kg(-1) barley grain and 200 g kg(-1) barley si lage diet.