Quantifying a Technique Using Carbon Monoxide for the Depopulation of Swine

The project demonstrated the euthanasia of mature sows and feeder pigs using carbon monoxide (CO) produced by a 1970 gas grain truck. The gas engine system, with no modifications, had been previously used to euthanize weaned pigs. This project further improved the method by cooling and filtering particulates out of the exhaust gas prior to contact with the pigs. The truck was modified by adding cooling and filtration to the truck, to be completely mobile. The truck then is able to travel from site to site with everything mounted on the truck. This truck can be used in a mass depopulation – pigs can be walked on to the truck and then euthanized while being moved to a dumping location, where the carcasses can be mechanically handled if needed. This method allows for relatively fast turn around and low physical labor to be involved.

A safety checklist was developed for producers while using a system like this. Carbon monoxide is extremely dangerous for human health at these levels. Personal CO monitors should be worn while running the system, especially with those working close to the truck bed.

The materials used to build the system can be found easily; this paper gives the list and methods with pictures to put the system together when needed. Old gas grain trucks can be found across the country; it is necessary to make sure there is no catalytic converter. Each system will be custom depending the truck.

Data was collected on many test (empty) runs and two live animal runs (feeders and sows). The use of an intercooler was very effective at reducing exhaust gas temperatures prior to exposing pigs to the CO. Exhaust gas temperature was reduced to within a couple degrees of outside air temperature consistently. Filtration of particulate matter was accomplished using a V-bank style MERV 14 filter. This data supports the CO model for euthanasia compliance with the AVMA guidelines1.

Contact information – Doug Groth, DVM, phone – 217-357-2811, [email protected]

Key Findings:
• Carbon Monoxide from a gas engine was effective at euthanizing feeder pigs and mature sows.
• Gas engine exhaust can be cooled to ambient air temperature with an intercooler.
• Filtration of engine exhaust with a Hoover vacuum HEPA filter or MERV 14 V-Bank filter reduced particulates.