Lab-scale evaluation of on-farm methods to mitigate gaseous emissions from staged swine carcasses

Authors: Trabue, Steven; MURPHY, PATRICK - Digital Agronomy, Llc; Scoggin, Kenwood; RAMERIZ, BRETT - Iowa State University; ANDERSEN, DANIEL - Iowa State University; Pearce, Sarah

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2025
Publication Date: 6/25/2025
Citation: Trabue, S.L., Murphy, P., Scoggin, K.D., Rameriz, B., Andersen, D., Pearce, S.C. 2025. Lab-scale evaluation of on-farm methods to mitigate gaseous emissions from staged swine carcasses. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2025.179958.
DOI: https://doi.org/10.1016/j.scitotenv.2025.179958

Interpretive Summary: Infectious animal diseases and natural and man-made disasters can cause significant problems for the swine industry when managing carcasses. Carcasses may need to be kept at a facility until they can be disposed of appropriately. However, carcasses release gases that can attract scavenger organisms and potentially spread diseases during decomposition. A study evaluated on-farm material and practices that could help minimize gas emissions from decomposing carcasses. The materials tested included tarps, soil, corn stover (CS), and lime. The study found that techniques that reduced oxygen levels slowed the decomposition rate, and reduced emissions of carbon dioxide and ammonia (both attractants for insects). Corn stover dried out carcasses and reduced decomposition. However, a chemical attractant called dimethyl disulfide (DMDS) formed rapidly and uniformly across all treatments, and no technique was found to significantly prevent DMDS gas emissions, not even sealing carcasses in tarp material. This research has implications for growers, scientists, engineers, and veterinary workers in managing animal mortalities, highlighting the challenge of containing gas emissions during disease outbreaks.

Technical Abstract: Animal health emergencies from natural and man-man disasters, including infectious disease outbreaks, may require the depopulation of animals, requiring on-farm carcass retention until disposal methods are available. As carcasses decay, they release gases that attract scavengers and insects that may spread the disease. This lab-scale study evaluated on-farm materials and approaches to temporarily manage carcasses and mitigate gas emissions. Materials tested included tarps, soil, corn stover (CS), and lime. Treatments included the following: 1) control carcasses in a pile; 2) carcasses wrapped in tarp material; 3) carcasses covered with tarp material; 4) carcasses covered by soil; 5) carcasses placed on CS base with tarp cover; 6) carcasses on CS base with CS covering; and 7) carcasses on CS base with a lime covering. Each treatment was run in triplicate using three porcine carcasses per replicate. Carcasses temperatures, headspace air, and leachate were collected over 91 days. Data were analyzed as a completely randomized design with mean comparisons for carcass mass loss and gas concentrations analyzed by regression and ANOVA with treatment as the main effect and time as a covariant. Pairwise comparisons of slopes and means were made when treatments were significantly different. Covering or wrapping carcasses reduced air exchange and significantly (p < 0.05) reduced decomposition rate, respiration (CO2), and ammonia emissions. Corn stover treatments desiccated carcasses significantly (p< 0.05), reducing carcass decomposition. Anaerobic environments significantly (p< 0.05) increased methane, methanethiol, and dimethyl trisulfide emissions. Dimethyl disulfide (DMDS), a significant scavenger attractant, was produced abiotically, the dominant S species produced, and no treatment mitigated its emissions.