Abstract
Interest is increasing regarding use of Cannabidiol (CBD) in companion animals due to anecdotal evidence of beneficial behavioral and health effects. The purpose of this investigation was to evaluate the influence of CBD on behavioral responses to fear-inducing stimuli in dogs. Sixteen dogs (18.1 ± 0.2 kg) were utilized in a replicated 4x4 Latin square design with treatments arranged in a 2x2 factorial, consisting of control, 25mg CBD, trazodone (100 mg for 10–20 kg BW, 200 mg for 20.1–40 kg BW), and combination of CBD and trazodone. A fireworks model of noise-induced fear was used to assess CBD effectiveness after 7 d of supplementation. Each test lasted 6 min, with no noise during the first 3 min and the fireworks track played during the second 3 min. Plasma was collected 1 h before, immediately after, and 1 h after testing for cortisol analysis. Behaviors in each 3-min block were video-recorded, and heart rate (HR) sensors were fitted for collection of HR and heart rate variability parameters. Data were tested for normality using the UNIVARIATE procedure in SAS, then differences examined using the MIXED procedure in SAS with fixed effects of treatment, period, time, and treatment x time interaction. Inactivity duration and HR increased during the first minute of the fireworks track compared with 1-min prior (P=0.0002 and 0.0112, respectively), indicating the fireworks model successfully generated a fear response. Trazodone lowered plasma cortisol compared with control (P < 0.0001), which was attenuated when administered in combination with CBD (P = 0.2379). Neither CBD nor trazodone affected the duration of inactivity (P = 0.9182 and 0.3290, respectively). Trazodone increased time spent with tail relaxed (P = 0.0013). CBD tended to increase HR (P = 0.0930) and decreased the peak of low- and high-frequency bands (LF and HF, P = 0.0107 and 0.0220, respectively). These results do not support an anxiolytic effect of CBD in dogs given CBD at 1.4 mg/kg.
Keywords: Cannabidiol, canine, fear