GASEOUS EMISSIONS FROM SWINE FACILITIES FOLLOWING FEEDING OF LOW CRUDE PROTEIN DIETS

Authors: POWERS, WENDY - IOWA STATE UNIVERSITY; BASTYR, SARAH - IOWA STATE UNIVERSITY; HARMON, JAY - IOWA STATE UNIVERSITY; Kerr, Brian

Submitted to: Air and Waste Management Annual Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/21/2005
Publication Date: 6/21/2005
Citation: Powers, W., Bastyr, S.B., Harmon, J., Kerr, B.J. 2005. Gaseous emissions from swine facilities following feeding of low crude protein diets. In: Proceedings of the Air and Waste Management Annual Conference , June 21, 2005, Minneapolis, Minnesota. p. 117.

Interpretive Summary: Animal production is becoming more concentrated and air emissions of potentially harmful compounds such as ammonia, hydrogen sulfide, methane, and odor are under increased scrutiny due to human health and environmental implications. The Environmental Protection Agency and the United States Department of Agriculture are responsible for the regulation of air emissions from animal production facilities. At this time, the health risks and environmental impact have been determined for these compounds, but data relating to the typical levels emitted from livestock operations have yet to be established. Differences that exist from one site to another in diet, manure handling strategies, animal numbers, ventilation, climate, and weather make estimating gaseous emissions from animal facilities difficult. However, determining the 'typical' concentrations and emission rates from similar facilities are necessary before the impact of regulations and the need for regulation can be established. Diet modification serves as an important method of source control for these gaseous emissions. The objective of this paper is to describe a new facility that was constructed for the primary purpose of studying diet modification effects on air emissions and nutrient excretions. The first project conducted in the facility was a swine feeding study to be used as an example to demonstrate the capabilities of the facility. Results demonstrated that the lowest crude protein diet reduced ammonia emissions by 36% with no detrimental impact on animal performance. Hydrogen sulfide emissions were unaffected by dietary treatment. This data can be utilized by nutritionists and environmental management personnel to indicate that changes in the level of dietary crude protein fed to pigs can greatly impact the concentration of ammonia released from swine production facilities.

Technical Abstract: A facility at Iowa State University was constructed to enable evaluation of the impact of diet modification on air emissions. The facility was designed and constructed to have the unique ability to house cattle, poultry and swine by incorporating interchangeable penning and watering systems. Excreta volumes can be measured for group-housed animals. Air emissions are determined by measuring airflow rates into each of the eight animal rooms and multiplying airflow by the concentration of the gas of interest as it is measured in the exhaust air. Rooms are monitored sequentially, for 15 min each, with background measures subtracted from room measures, providing 10-11 observations per room each day. Each room is independently heated or air conditioned based on a temperature set point. Data acquisition is coordinated through software control, including an emergency alarm system should ventilation problems arise. A swine study has been conducted in the facility to evaluate the effect of feeding reduced crude protein diets on air emissions. Results demonstrated that the lowest crude protein diet reduced ammonia emissions by 36% with no detrimental impact on animal performance. Hydrogen sulfide emissions were unaffected by dietary treatment. Findings from the first study conducted in the facility indicate that this facility can discriminate between emissions from animals fed diets that are modified to reduce nutrient excretions while maintaining animal performance.