Animal Science Department


Date of this Version

Fall 12-3-2010


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Animal Science, Under the Supervision of Professor Galen E. Erickson and Terry Klopfenstein. Lincoln, Nebraska: December, 2010
Copyright 2010 Amy R. Rich


Two experiments were conducted to determine the effect of feeding wet distillers grains (WDGS) at 70% and wheat straw at 25% (DM basis) on finishing steer performance and N mass balance in open feedlot pens. Four treatments were tested as a 2x2 factorial with factors being diet and pen cleaning frequency (monthly or at the end of the feeding period). In both experiments the CON treatment (corn based diet) had greater DMI, ADG, HCW, marbling and fat depth. There was greater N intake and N excretion for both the WINTER and SUMMER experiments on the WDGS. Not all the additional N excreted by feeding WDGS above the animal’s requirement was lost: some was removed in the manure during pen cleaning. Evaluation of nutrient mass balance experiments in feedlots will help minimize the negative impact of feeding those ingredients on the environment. The influence of feeding high levels of wet distillers grains plus soluble (WDGS) with wheat straw or on performance and carcass characteristics on feedlot steers were evaluated in one experiment. Economical analysis was performed on all seven treatments. No cases of polio were observed when feeding WDGS diets with no inclusion of corn however, feedlot performance appeared to be negatively impacted when WDGS was fed above 77% DM or wheat straw was increased in the diet above 10%. Feeding WDGS at 40% of diet DM resulted in improved ADG, G:F, and greatest profit. Feeding diets including high levels of WDGS and wheat straw resulted in lower feedlot performance which resulted in higher cost of gain (COG) and less profit.

Advisors: Galen E. Erickson & Terry Klopfenstein