Kris Kohl

ENVIRONMENTAL CONDITIONS IN BEEF DEEP-BEDDED MONO-SLOPE FACILITIES: A DESCRIPTIVE STUDY

In the Northern Great Plains, interest in feeding cattle in enclosed beef deep-bedded mono-slope facilities (BDMF) has increased. Characterization of environmental factors impacting odor and gas emissions, nutrient excretion, and pathogens is needed to develop recommendations for management of BDMF. The objectives of this study were to determine spatial variability of ammonia (NH3) in the air and odorous volatile organic compounds (VOC) in the bedded pack and to quantify environmental factors during various seasons. The effects of environmental factors on concentrations of NH3 and VOC were determined. The nutrient content and occurrence of E. coli O157:H7 and generic E. coli concentrations in bedded pack material were also determined. High spatial variability was observed for steady-state NH3 concentration on the pen surface. Ammonia concentration increased as pack and ambient air temperatures increased (p < 0.01). The temperature humidity index inside the barn was significantly greater than outside the barn during hot and cold months. Concentrations of VOC were highest in transition areas between the bedded pack and the concrete floor. Depth, moisture content, and pH of the bedded pack were poorly correlated to concentrations of NH3 and VOC (r2 < 0.09). Manure from BDMF contained 80% volatile solids. E. coli O157:H7 prevalence and generic E. coli concentrations occurred at high levels in BDMF and varied seasonally. Priority should be given to NH3 and E. coli mitigation during hot months, but location-specific NH3 mitigation will not be effective due to random distribution in the pen. Frequent cleaning of areas surrounding the bedded pack should reduce VOC concentrations.

Economics of Dairy Manure Management in Iowa

Dairy producers have many duties to carry out in their dairy operations, one of which is storing, handling and applying manure. Manure handling ends up being a significant cost on most dairies even when considering the value of the nutrients in the manure. Seldom do producers consider their costs of handling and applying manure on a per hundredweight of milk sold basis like they do with many of their other costs.