Behavioral observations, heart rate and heart rate variability in horses following oral administration of a cannabidiol containing paste in three escalating doses (part 1/2)

Fabienne Eichler; Anna Ehrle; Katharina Charlotte Jensen; Natalie Baudisch; Hannah Petersen; Wolfgang Bäumer; Christoph Lischer; Mechthild Wiegard

doi:10.3389/fvets.2023.1305868

Behavioral observations, heart rate and heart rate variability in horses following oral administration of a cannabidiol containing paste in three escalating doses (part 1/2)

Front Vet Sci. 2023 Dec 11:10:1305868. doi: 10.3389/fvets.2023.1305868. eCollection 2023.

Authors

Fabienne Eichler¹, Anna Ehrle¹, Katharina Charlotte Jensen², Natalie Baudisch¹, Hannah Petersen¹, Wolfgang Bäumer³, Christoph Lischer¹, Mechthild Wiegard⁴

Affiliations

¹ Equine Clinic, Veterinary Hospital Freie Universität Berlin, School of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
² Institute of Veterinary Epidemiology and Biostatistics, School of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
³ Institute of Pharmacology and Toxicology, School of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
⁴ Institute of Animal Welfare, Animal Behavior and Laboratory Animal Science, School of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.

Abstract

Cannabidiol (CBD) products have been proposed to exert stress- and anxiety-relieving effects in animals. Despite the increasing popularity of CBD for veterinary use, the available research detailing the effects of CBD in horses is limited. The aim of this study (part 1 of 2) was to analyze stress parameters via behavioral observations and heart rate monitoring in healthy horses following single oral administration of a CBD containing paste in different doses. Study products were two pastes for oral administration, one containing CBD and one containing no active ingredient. Pastes were applied as single administrations in consecutive trials with escalating dosages (doses: 0.2, 1.0, 3.0 mg CBD/kg) to a treatment (trial 1: n = 3, trial 2: n = 3, trial 3: n = 5 horses) and a control group (trial 1: n = 3, trial 2: n = 3, trial 3: n = 6 horses) with minimum wash-out periods of seven days in between. Behavioral parameters were evaluated using video recordings to score the levels of sedation including the horses' reactions to acoustic and visual stimuli. Facial expression was assessed using photographs. Evaluation was based on the previously described facial sedation scale for horses (FaceSed) and the Horse Grimace Scale. For baseline values, identical observations were recorded on the day before each paste administration. Both paste administration and behavioral evaluation were performed double blinded. Cardiac beat-to-beat (R-R) intervals were continuously recorded throughout the trial and assessed using heart rate and heart rate variability parameters. Statistical analysis included comparison between treatment and control group over escalating doses and time points using linear mixed models. The CBD paste was well tolerated, and no side effects were observed. Analysis of sedation scores and facial expressions did not indicate significant differences between treatment and control group over the escalating doses. The heart rate was neither reduced, nor were significant changes in heart rate variability observed compared to the control group. Main limitation of this study is the small sample size. Further research is required to determine adequate doses and indications for the use of CBD products in horses.

Keywords: CBD; FaceSed; Horse Grimace Scale; behavior; equine; sedation score.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The study was funded by the Freie Universität Berlin, the German Equestrian Federation (FN) and the Herosan healthcare GmbH. Herosan healthcare GmbH was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication. We acknowledge support by the Open Access Publication Fund of the Freie Universität Berlin.