Evidence map›Paper›PMID 42549376›Full record

ArticleTranslational animal science2026

The spearmint extract L-carvone as a euthanasia agent in sheep.

Robert J Brosnan, Monica Aleman, Lais Costa, Heather Knych, Adrien Dupanloup, Ujwala Vedavally, Chelsea M Unkel

Abstract read
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Article in Translational animal science, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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4 · The record

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PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors.

Robert J BrosnanDepartment of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, United States.ORCID https://orcid.org/0000-0002-0508-6363
Monica AlemanDepartment of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, United States.
Lais CostaDepartment of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, United States.
Heather KnychDepartment of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, United States.
Adrien DupanloupDepartment of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, United States.
Ujwala VedavallyDepartment of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, United States.
Chelsea M UnkelDepartment of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, United States.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

L-carvone is a natural monoterpene found in spearmint and other foods that can be administered intravenously to euthanize rats. We hypothesized intravenous L-carvone rapidly alters consciousness and produces death in sheep, resulting in tissue L-carvone concentrations that are commonly found in foods. Jugular catheters were placed in five adult Hampshire-Suffolk ewes, and a carotid arterial catheter was inadvertently placed in a sixth ewe. Animals were restrained in a seated position and instrumented with surface electroencephalographic (EEG) and electromyographic electrodes and a two-lead electrocardiogram (ECG) accompanied by pulse and respiratory rate and behavioral monitoring. A 50% solution of food-grade L-carvone administered as a rapid intravenous bolus at a dose of 0.5 mL/kg was followed by bilateral ocular strabismus, loss of responsiveness, shallow breathing, and a 50% reduction in heart rate within 6 ± 4 s (mean ± SD). In 4 sheep, myoclonus and increased muscle tone was present for 15-54 s after injection. Pulses were undetectable within 20 ± 9 s, and animals were apneic in 48 ± 14 s and without cardiac electrical activity 46 ± 19 s after injection. During this time, the EEG spectral edge frequency rapidly decreased, indicative of progressively altered consciousness and deepening anesthesia. Intermittent, large amplitude polyspike waves were observed on the EEGs of most sheep, consistent with seizure activity. Intra-arterial L-carvone injection yielded quantitatively similar results except for persistence of ECG electromechanical dissociation for several minutes after death. Sheep tissues collected after euthanasia were analyzed for L-carvone by liquid chromatography-mass spectroscopy. For intravenous doses, L-carvone concentrations ranged from 283 ± 155 in the kidney to 2.2 ± 1.6 in the semitendinosus muscle. Intravascular L-carvone produces rapid onset of unconsciousness and irreversible death in sheep without contaminating the carcass with non-edible residues. However, increased muscle tone and EEG seizure activity make L-carvone imperfect for euthanasia when administered as a sole agent.

Indexed as

carvoneelectrophysiologyeuthanasiaisoelectricmint

Identifiers

PMID42549376
PMCPMC13431673

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.