AABP Executive Director Dr Fred Gingrich is joined by Kerry Courchaine, Director of Technical Services for Darling Ingredients Inc. Darling Ingredients is the largest rendering company in the US and was founded 140 years ago. Courchaine discussed the history of rendering the importance of rendering to the livestock industry both in providing a mechanism for utilizing dead stock as well as slaughter offal. Rendering is part of the sustainable food system by utilizing human-inedible components of slaughtered and dead animals to turn it into useful fat and protein material which prevents these products from ending up in landfills. Rendered protein is used as fertilizer, livestock feed and pet food. Rendered fat is used as livestock and pet food as well as in industrial applications such as renewable fuels. In 2015, pentobarbital residues were found in pet foods and after FDA investigations, a zero tolerance for pentobarbital in rendered fat was implemented. The current test detection limit for pentobarbital is 10 ppb and Courchaine explains that one cow euthanized with pentobarbital could contaminate over 1 million pounds of raw material. In addition, cleaning to remove pentobarbital residues from rendering equipment creates a challenge. The positive rate has dropped from around 5% to 3.4% for pentobarbital residues in rendered products. While pentobarbital is an approved method for humane euthanasia of cattle, veterinarians are encouraged to reserve this method as a last resort instead of a routine method of euthanasia due to the high risk of environmental or rendered product contamination. Veterinarians should develop, train and monitor humane euthanasia protocols for all farm clients. If chemical euthanasia is implemented, it is recommended to consider alternatives to pentobarbital such as placing the animal under general anesthesia (i.e., xylazine and ketamine) and the implementing a second step such as exsanguination, intrathecal lidocaine, or IV injection of a saturated salt solution (KCl or MgSO4).  

Links:

AABP Humane Euthanasia of Cattle Guidelines

 Chasity Bagsby, Anita Saha, Granville Goodin, Sheeba Siddiqi, Mary Farone, Anthony Farone & Paul C. Kline (2018) Stability of pentobarbital in soil, Journal of Environmental Science and Health, Part B, 53:3, 207-213, DOI: 10.1080/03601234.2017.1406714