In this study, four experiments were conducted to investigate the effect of inclusion level of dry distillers grains plus solubles (DDGS) or modified wet distillers grains plus solubles (MWDGS) (0, 16.7, 33.3, and 50% of ration DM) on performance, carcass characteristics, feeding behaviour, nutrient balance, nutrient excretion, and enzymatic activity using whole corn grain-based finishing diets. In experiment one, there were no effects (P > 0.05) of dietary treatment on final BW, ADG, days on feed, rumen pH at slaughter, dressing %, hot carcass weight, marbling score, lean yield, and lean color. Liver abscess score was lower in steers fed DGS than steers fed the control. Visits of cattle to the feeder (VF) increased when cattle were fed up to 16.7% of DDGS or 33.3% of MWDSG. Number of meals (NM) and eating rate (ER) was greater and time per meal (TM) was lower in cattle fed MWDGS compared to those fed DDGS. Also, increasing the distillers grains plus soluble (DGS) increased daily time at feeder (TF); however, ER decreased when cattle were fed up to33.3% of DGS and after that increased. In experiment two, total tract DM, OM, and starch digestibility decreased with increasing DDGS up to 50%. Daily intake and total excretion of N, P, S, Mg, and K increased linearly with increasing level of DDGS. Nitrogen retention did not change with level of DDGS; however, P retention tended to increase and S retention increased with increasing DDGS. The digestion and retention of Se, Mg, K, and Na did not differ among the treatments. In experiment three, although the pancreatic protein concentration (mg/g) increased linearly with increasing DGS levels, pancreatic mass (g and g/kg BW) did not change. Feeding DGS increased the pancreatic concentration of α-amylase and trypsin activity (U/g) compared to the control diet. Increasing the DGS level increased pancreatic concentration of trypsin activity (U/g). In experiment four, increasing DGS linearly increased kidney weight (g). Hepatic and renal glutathione peroxidases (GPX) activity was not influenced by inclusion level or form of DGS. However, renal GPX activity per kilogram of BW was affected by the form and linear effect interaction. Increasing inclusion level of DGS linearly increased carbamoyl phosphate synthetase (CPS) activity (kU/liver, and U/kg of BW), argininosuccinate synthetase (AS) and ornithine transcarbamoylase (OTC) activity (U/g, kU/liver, and U/kg of BW).The results of these studies suggest that feeding DDGS or MWDGS up to 50% diet DM in whole corn grain-based finishing diets does not negatively affect animal performance, although animals appear to adapt by altering feeding behaviour and nutrient metabolism. However, environmental implications of manure should be considered in the feedlot. / Beef Cattle Research Council, and Ontario Ministry of Agriculture Food and Rural Affairs

Master of Science / Department of Agricultural Economics / Ted C. Schroeder / Very rapid growth in the ethanol industry has led to a void of information regarding price dynamics and utilization of distiller's grains. Understanding market conditions is essential for livestock producers to make informed decisions in the procurement of feedstuffs, especially as grain price levels have recently increased substantially. In this study, distiller's grain price discovery dynamics are evaluated to develop an understanding of spatial price relationships. The knowledge of price relationships reveals that users of distiller's grain should shop around when procuring the feedstuff. Additionally, because animal performance may be altered with increased inclusion of distiller's grains, regional competitive advantages could shift fed cattle production to geographic regions characterized by high of ethanol production plants. Therefore, the cost of current grain processing methods are evaluated to enhance the awareness of regional competitiveness and long term sustainability. The combination of these two objectives allows producers to better realize the implications of the ethanol industry on their ability to maintain their operations into the near future.