and Implications Ammonia (NH 3 ), temperature, moisture content, pH, pack depth, nutrient composition and concentration of odorous volatile organic compounds (VOC) were measured at 56 locations in each of four pens in two commercial beef deep-bedded mono-slope facilities (BDMF). Areas of high NH 3 concentration occurred randomly throughout the pens. Ammonia concentration increased as pack and ambient air temperature increased. Concentration of VOC was highest in transition areas between the bedded pack and the concrete floor. Depth, moisture content, and pH of the bedded pack did not influence concentration of NH 3 and VOC. Nutrient composition of the manure/bedding material in BDMF is similar to manure in open feedlots, except that in BDMF the volatile solids content is much higher. E. coli concentrations can occur at high levels in BDMF and vary with differences in ambient temperature. Priority should be given to NH 3 and E. coli mitigation during hot months. However, locationspecific NH 3 mitigation will not be effective due to the random distribution of NH 3 in the pen. Frequent cleaning of the area surrounding the bedded pack should reduce VOC concentration.

ABSTRACT. In the Northern Great

and Implications A large pen study was conducted with a commercial feedlot to investigate the influence of corn particle size on performance of steers fed diets containing 35% (DM basis) wet distillers grains plus solubles (WDGS). Feedlot cattle in the Midwest are often fed distillers grains from ethanol production that are low in starch. Therefore, this study was designed to evaluate a practical question asked by producers if feeding moderate levels of WDGS would reduce the acidosis risk and allow fine grinding of corn to improve cattle performance. While fine grinding of corn did not improve performance compared to cattle fed a more traditional particle size of corn, starch digestibility of cattle fed finely ground corn was more favorable.

No abstract