Responses of Swine Carcasses Continuously Exposed to 43°C Inside a Small-Scale Finishing Room

Abstract

Highlights Carcass and room temperatures, as well as CO, CO2, O2, and NH3, were continuously monitored. NH3 release was approximately half when carcass leachate was removed from the shallow pit. Gompertz and logistic models fit data well for daily carcass mass reduction and leachate production. Abstract. A catastrophic mortality event for swine would present numerous challenges with the management and disposal of infected carcasses. This study explored a new strategy for biosecure in-barn processing of swine carcasses as an alternative to traditional management and disposal approaches. A small-scale, mobile laboratory with two discovery rooms (DRs), replicating a swine finishing facility, was constructed to execute tests of in-barn disposal methods. Carcasses were desiccated by subjection to heat at a room air temperature of 43°C (110°F) for 16 days. Three carcasses (average = 82 kg, SE=1.27 kg) were elevated over individual leachate collection systems in DRA, thereby removing leachate from the room. Three carcasses in DRB were placed on concrete slats with cumulative leachate collection in the pit below. Environmental data were collected for DR, outdoor, and slat temperatures; and CO2, CO, O2, and NH3 gas concentrations. Carcasses were characterized by rectal and shoulder temperature monitoring and daily weighing of carcasses and leachate in DRA. The air exchange rate for this unventilated system was quantified based on wind and thermal-driven infiltration. Room environments were compared for thermal performance and gas levels. Carcass temperatures were compared, and data suggested no significant impact of flooring material on internal carcass temperature. Gompertz and logistic models were fit to leachate production data and carcass mass reduction data. Ammonia generation rates were found to have a peak production rate of 96.5 g AU-1 day-1 (15.8 g animal-1 day-1) in DRA and 120 g AU-1 day-1 (19.7 g animal-1 day-1) in DRB. Over the study, the generation of NH3 in DRB (360 g) was nearly twice that of DRA (182 g) due to leachate removal. Further quantification and qualification of in-barn management strategies will better define biosecure disposal approaches in the event of a catastrophic mortality event. Keywords: Ammonia, Catastrophic event, Disposal, Foreign animal disease, Mortality management, Pig.