Project Number: 6209-31630-003-33
Project Type: Specific Cooperative Agreement

Start Date: Sep 15, 2011
End Date: Sep 14, 2013

Objective:
Obj. 1: Evaluate the impact of feeding low-fat dried distiller's grains (DDG) on dietary net energy and methane production. Technology is being adopted within ethanol plants to extract the germ, thereby reducing the fat remaining in the DDG. The removal of fat during ethanol production will most certainly reduce the energy value of the DDG. The impacts on dietary energy need to be defined before these products enter the marketplace. We have access to a limited amount of low-fat, medium-fat, and high-fat DDG. Calorimetry allows for NEm and NEg values to be defined with limited amount of product. Increasing dietary fiber also has the potential to increase endogenous methane production due to a changing microbial population. Our team has the ability to define both. Obj. 2: Determine the effects of treating distiller's grains with buffered enzymes on digestion and net energy content of the distiller's grains. Improving the digestibility of the fiber in wet distiller's grains plus solubles (WDGS) would improve animal performance. In lab-scaled systems, treatment with buffered enzymes increased DDG digestibility.

Approach:
Exp. 1. Determination of net energy values and enteric methane production via indirect calorimetry. Dietary treatments will include low-fat, medium-fat, and high-fat DDG included at 30% of the diet compared to a steam-flaked corn-based control containing no DDG. Eight steers will be trained to the calorimetry system. Four steers will be fed ad-libitum and four will be limit-fed at maintenance in order to calculate NEm and NEg. Each steer will receive each diet in a Latin Square design. The indirect respiration calorimetry system used will consist of four chambers constructed of a metal pipe frame and Lexan sheets. Air will be analyzed for oxygen, carbon dioxide, and methane. Heat production will be calculated from oxygen consumption, carbon dioxide and methane production, and urinary nitrogen (N) excretion using the equation of Brouwer (1965). Each of the periods of the Latin square will consist of an initial 14-d diet adaptation and 7 d of fecal, urine, and gas exchange collections. Urine and feces from each steer will be weighed daily to determine total tract digestibility. Exp. 2: An individual steer finishing study will be conducted using Calan headgates. Three treatments will be used to determine the effects of treating sorghum WDGS with buffered enzymes on animal performance and carcass characteristics. The treatments will include a finishing diet containing 45% sorghum WDGS, 45% sorghum WDGS treated with enzyme, and 45% WDGS with 10% added limestone (to raise pH), then treated with enzyme. There will be 54 steers and 3 treatments (18 steers per treatment). Steers will be fed for 150 to 200 days.