Euthanasia Drug Found in Carcass Compost

Composting is one option for disposing of a horse carcass after euthanasia. Researchers at West Texas A&M recently conducted a study to determine if residues of sodium pentobarbital might remain in compost as a potential environmental hazard. They presented their preliminary results at the 2009 Equine Science Society Meeting, held May 29-31 in Keystone, Colo.

Horses that had been euthanized by a veterinarian were composted with layers of hay and stall cleanings and mechanically aerated every 90 days (read more).  

After six months, samples from eight different compost piles contained from 0.008 to 3.16 ppm sodium pentobarbital. Lena Cottle, a PhD candidate under the direction of Lance Baker, MS, PhD, is conducting further research to assign relevance to these numbers and learn more about the environmental fate of pentobarbital.

Until this work is concluded, the researchers recommend avoiding the use of potentially contaminated compost as fertilizer. Care should be taken to compost euthanized animals in areas where residues are less apt to leach into ground water or run off into ponds or streams.

Read more about carcass disposal.

About the Author

Kathryn Watts, BS

Kathryn Watts, BS, is the director of research for Rocky Mountain Research and Consulting and a passionate forage researcher. Her web site is

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