Using composting to eliminate the remains of dead animals offers lots of positive attributes. But often there’s a lingering skepticism about the processes’ ability to eliminate potential disease carryover.

Researchers J. Garcia Siera, Dale Rozeboom, Barbara Straw, Brad Thacker, L. Granger, P. Fedorka Cray and J. Gray, ran two studies looking at the survival of pseudorabies virus, Actinobacillus pleuropneumoniae, and Salmonella choleraesuis in composted swine carcasses.

In experiment No. 1, pigs were infected with the pseudorabies virus; two days later they were infected with Actinobacillus pleuropneumoniae. The pigs were euthanized 15 to 16 hours later. Carcasses were then composted for 35 days.

In experiment No. 2, pigs were infected with Salmonella choleraesuis and euthanized three days later. The carcasses were composted for 10 days.

Compost piles were constructed inside buildings with concrete floors.

In both experiments, temperatures of the composting piles were monitored daily. Researchers collected samples from the carcasses for microbiologic evaluation at intervals throughout the composting period.

Results showed that the composting piles’ temperatures ranged from 27░C to 51░C in experiment No. 1, and 27C to 62C in experiment No. 2. Composted carcasses degraded rapidly. After seven days, only bones, teeth, large muscles and some of the hide were recognizable. But even those items showed substantial degradation.

In experiment No. 1, tissue samples collected during the composting period on days 7 and 14 were culture negative for PRV and Actinobacillus pleuropneumoniae.

In experiment No. 2, Salmonella choleraesuis was recovered from samples collected during the composting period on days 0, 1 and 3, but not from samples collected on days 7 or 10.

This study suggests that composting can be used to dispose of swine carcasses carrying PRV, Actinobacillus pleuropneumoniae and Salmonella choleraesuis without concern of exposure provided the process is done correctly.