Environmental conditions and gas concentrations in deep-pit finishing cattle facilities: A descriptive study

Authors: CORTUS, ERIN - University Of Minnesota; HETCHLER, BRIAN - University Of Minnesota; Spiehs, Mindy; RUSCHE, WARREN - South Dakota State University

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2020
Publication Date: 1/4/2021
Publication URL: https://handle.nal.usda.gov/10113/7261461
Citation: Cortus, E. L., Hetchler, B. P., Spiehs, M.J., Rusche, W. C. 2021. Environmental conditions and gas concentrations in deep-pit finishing cattle facilities: A descriptive study. Transactions of the ASABE. 64(1):31-48. https://doi.org/10.13031/trans.14040.
DOI: https://doi.org/10.13031/trans.14040

Interpretive Summary: Research information or industry guidance is limited with regard to air temperature, windspeed, and gas concentrations in cattle confinement barns with slatted floors and deep pit manure storage under the barn. Measurements were collected from three barns during summer, fall, and spring conditions. Measurements were taken at the opening in the wall, at the nose level of the cattle, and near the slatted floors. Air temperatures at the wall openings and at cattle nose level were similar to ambient air temperatures, but air temperature at the floor and in the manure pit were lower than ambient air temperature by 2 to 5 °C (3.6-9 F°). Wind speed through the barns were generally about 40% of the ambient wind speed. Ammonia and combined sulfur gas concentrations increased with proximity to the manure surface but varied by barn, pen, and season. Carbon dioxide levels in the barn also varied across barns but were more closely related to whether there were cattle in the barn when the measurements were collected. These data provide a general idea of the conditions within a cattle confinement barn with deep pit manure storage.

Technical Abstract: There is a lack of data to describe the range of environmental and air quality conditions in beef cattle confinement buildings with deep-pit manure storage. The objective of this article is to describe the environmental conditions, manure nutrient concentrations, and aerial gas concentrations for three deep-pit manure storage finishing beef cattle facilities and varying weather conditions. Measurements were collected from three barns finishing beef cattle with deep pits in Minnesota on three sampling days per barn in summer, fall, and spring weather conditions. The air temperatures throughout the barns closely mirrored the ambient temperature conditions, although significantly lower temperatures were sometimes evident at the manure surface or in the inlet opening. However, the manure and floor surfaces had 2°C and 5°C temperature increases over ambient temperatures. Air speeds through the barn openings were generally 40% of the ambient wind speed; at animal level, the average air speed was 1 to 3 m s-1. Manure nutrient distributions were not consistent between the surface and agitated (whole pit) samples, and this was likely due in part to solids distribution in the storage. Total nitrogen levels ranged from 4.5 to 6.7 g L-1, and ammonium-N was 50% to 65% of total N in agitated whole-pit samples. Phosphate and potassium oxide levels ranged from 2.8 to 4.2 g L-1 and from 3.7 to 4.5 g L-1, respectively. Aerial ammonia and combined sulfur concentrations varied by location within a barn, pen, and season. Ammonia and combined sulfur increased with proximity to the manure surface. Higher ammonia and combined sulfur concentrations at manure level and floor level for one of the three barns may have related to water quality and/or feed composition and resulting manure nutrients, in addition to warmer temperatures. At floor level, the greatest average ammonia concentration was 8.5 ppm, and 3.9 ppm at nose level. Maximum combined sulfur levels were a maximum of 270 ppb at floor level in summer conditions in one of the barns, while 52 ppb was the maximum average during spring conditions. Carbon dioxide levels also varied by location within a barn, pen, and season and were related in part to the presence of cattle in the pen. This project is the first to quantify air quality in slatted-floor cattle barns and contributes to a body of knowledge that can be used to develop process-based models for estimating air emissions from cattle facilities.