Editorial Type:
Animal Welfare

Evaluation of squeeze-induced somnolence in neonatal foals

Balazs Toth Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Monica Aleman William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Robert J. Brosnan Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Peter J. Dickinson Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Alan J. Conley Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Scott D. Stanley CAHFS Equine Analytical Chemistry Laboratory, University of California-Davis, Davis, CA 95616.

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Nora Nogradi William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Colette D. Williams William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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John E. Madigan Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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DOI:
https://doi.org/10.2460/ajvr.73.12.1881
Volume/Issue:
Volume 73: Issue 12
Online Publication Date:
01 Dec 2012
Restricted access
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Abstract

Objective—To test the hypothesis that application of a rope restraint device would result in behavioral, electroencephalographic, and humoral changes consistent with sleep and analgesia in neonatal foals.

Animals—8 healthy neonatal foals.

Procedures—Following acclimatization to experimental conditions, each foal underwent a series of assessments before and during or at the end of a period of restraint via application of a restraint device (soft linen rope). Assessments included measurements of heart and respiratory rates, rectal temperature, and circulating β-endorphin and steroid hormone concentrations and evaluations of mentation and body position (behavior), electroencephalographic patterns, and pain tolerance.

Results—All foals were lively with apparently normal behavior prior to restraint. During application of the restraint device, foals assumed lateral recumbency with relaxed, somnolent behavior. Heart and respiratory rates and rectal temperature uniformly decreased as a result of the procedure. Electroencephalographic recordings (completed for 3 foals only) revealed patterns consistent with slow wave sleep. Plasma ACTH, dehydroepiandrosterone sulfate, and androstenedione concentrations significantly increased during restraint, compared with prerestraint values. The foals' tolerance to noxious stimuli significantly increased during restraint; however, this was independent of the concentration of circulating β-endorphin.

Conclusions and Clinical Relevance—In neonatal foals, the evaluated form of restraint resulted in a decrease in heart and respiratory rates and rectal temperature. Squeeze-induced somnolence may resemble the effects of compression of the fetus in the birth canal and lead to inhibition of voluntary activity. Use of this technique to safely restrain neonatal foals during minor procedures warrants further evaluation.

Abstract

Objective—To test the hypothesis that application of a rope restraint device would result in behavioral, electroencephalographic, and humoral changes consistent with sleep and analgesia in neonatal foals.

Animals—8 healthy neonatal foals.

Procedures—Following acclimatization to experimental conditions, each foal underwent a series of assessments before and during or at the end of a period of restraint via application of a restraint device (soft linen rope). Assessments included measurements of heart and respiratory rates, rectal temperature, and circulating β-endorphin and steroid hormone concentrations and evaluations of mentation and body position (behavior), electroencephalographic patterns, and pain tolerance.

Results—All foals were lively with apparently normal behavior prior to restraint. During application of the restraint device, foals assumed lateral recumbency with relaxed, somnolent behavior. Heart and respiratory rates and rectal temperature uniformly decreased as a result of the procedure. Electroencephalographic recordings (completed for 3 foals only) revealed patterns consistent with slow wave sleep. Plasma ACTH, dehydroepiandrosterone sulfate, and androstenedione concentrations significantly increased during restraint, compared with prerestraint values. The foals' tolerance to noxious stimuli significantly increased during restraint; however, this was independent of the concentration of circulating β-endorphin.

Conclusions and Clinical Relevance—In neonatal foals, the evaluated form of restraint resulted in a decrease in heart and respiratory rates and rectal temperature. Squeeze-induced somnolence may resemble the effects of compression of the fetus in the birth canal and lead to inhibition of voluntary activity. Use of this technique to safely restrain neonatal foals during minor procedures warrants further evaluation.

Contributor Notes

Drs. Toth and Nogradi's present address is Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906.

Supported by an anonymous private donation.

Presented in abstract form at the 57th Annual Convention of the American Association of Equine Practitioners, San Antonio, Tex, November 2011.

The authors thank Dr. Janet Roser, Lillian Sibley, Dr. James Jones, Dr. Barry R. Tharp, and John Doval for technical assistance.

The authors have declared no conflict of interest.

Address correspondence to Dr. Toth (toth4@purdue.edu).
Cover American Journal of Veterinary Research
American Journal of Veterinary Research
Publication Date:
01 Dec 2012

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