Ruminant Nutrition: Beef - Feedstuffs

An experiment was performed with the objective of evaluating the performance of beef steers on diets consisting of increasing levels of corn milling by-products (BP) (50% wet corn gluten feed, 50%wet distillers grains; DM basis) and different alfalfa hay levels. 280 yearling steers (370 kg BW) were blocked (3 blocks) by weight, stratified within block and assigned to 35 pens (8 steers/pen). Pens were assigned randomly to one of seven treatments (5 pens total/treatment) in a 3 x 2 plus 1 experimental design. Treatments consisted of a control diet (0%BP, 7.5% alfalfa) and three BP levels at 25%, 50% and 75% diet DM, in combination with two levels of alfalfa. Alfalfa level was kept constant at 7.5% of DM or formulated for equal eNDF of control, i.e., 7.5, 5.0, 2.5, and 0% alfalfa for the 0, 25, 50, and 75% BP, respectively. Steers were fed for an average of 113 d and harvested at a commercial abattoir. Interactions were only observed between BP and Alfalfa level (P<0.05) for marbling and YG. Quadratic responses (P<0.05) to the BP level (0, 25, 50, and 75%BP, respectively) were observed for DMI (11.1, 12.0, 11.7, and 10.6 kg DM/d), ADG (1.81, 2.10, 2.07, and 1.77 kg/d), and G:F (0.162, 0.177, 0.176, and 0.167). Improved feedlot performance was observed at the 25 and 50% BP levels, without significant (P<0.05) differences between 25 and 50% BP inclusion. These results suggest that the BP utilization in feedlot diets up to 50% will enhance production performance.