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Determining the Persistence of Xylazine and Ketamine in Cattle Tissue Following a Simulated Rendering Process
Scott A Fritz1, Michael D Kleinhenz2, Steve M Ensley1
1Department of Anatomy and Physiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA.
Veterinary Sciences
|August 28, 2025
Summary
Xylazine and ketamine, used in animal euthanasia, persist in tissues even after simulated rendering. Drug residues were found in all tissues, with the highest concentrations in rendered kidney. This impacts pet food safety.
Area of Science:
- Veterinary Pharmacology
- Food Safety
- Animal Science
Background:
- Humane euthanasia is a critical endpoint for production animals.
- Drug residues from euthanasia agents can enter the food chain via rendering.
- Understanding drug fate in rendered products is crucial for food safety.
Purpose of the Study:
- To quantify xylazine and ketamine concentrations in food animal tissues.
- To determine the stability of these drugs after a simulated rendering process.
- To assess the implications for pet food safety.
Main Methods:
- Twelve cattle were administered xylazine or xylazine and ketamine.
- Tissue samples (muscle, fat, liver, kidney) were collected pre- and post-simulated rendering.
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for drug analysis.
Main Results:
- Xylazine and ketamine were detected in all tested tissues, both raw and rendered.
- Highest drug concentrations were observed in rendered kidney tissue.
- Lowest concentrations were found in rendered fat (xylazine) and raw fat (ketamine).
Conclusions:
- Xylazine and ketamine residues can remain in animal tissues after simulated rendering.
- Kidney tissue showed the highest potential for accumulating these drug residues.
- The presence of these drugs in rendered products warrants further investigation for pet food safety.
