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Objective To evaluate the anaesthetic effects of three different alfaxalone doses to induce anaesthesia in goldfish. Study design Prospective, randomized, clinical study. Animals Thirty goldfish undergoing skin scraping, gill examination and stool collection. Methods Each fish was transferred to an individual 4 L induction tank and randomly allocated into one of three groups (n = 10), in which alfaxalone was administered at concentrations of 6, 7 or 9 mg L–1. The depth of anaesthesia was evaluated by approach reaction, equilibrium, opercular movement and reaction to tactile stimuli. Sedation, light anaesthesia, surgical anaesthesia and recovery times were recorded. Data were analyzed with analysis of variance. A p value Results Surgical anaesthesia was achieved in all fish. Goldfish induced with alfaxalone 7 and 9 mg L–1 showed a mild excitement phase. Time to sedation of the 6 mg L–1 dose (5.89 ± 0.40 minutes) was significantly longer compared to the 7 mg L–1 (3.97 ± 0.40 minutes) and 9 mg L–1 doses (3.94 ± 0.40 minutes). Times to light anaesthesia and surgical anaesthesia of the 9 mg L–1 dose (7.65 ± 1.04 and 9.60 ± 1.84 minutes, respectively) were significantly faster compared with those of the 6 mg L–1 dose (13.79 ± 1.04 and 19.75 ± 1.84 minutes, respectively) and the 7 mg L–1 dose (13.55 ± 1.04 and 21.24 ± 1.84 minutes, respectively). No significant differences were recorded in recovery time. Cessation of opercular movement was recorded in two fish induced with 7 mg L–1 and in two induced with 9 mg L–1. No mortality occurred. Conclusions and clinical relevance Alfaxalone is a reliable agent for immersion anaesthesia in goldfish. Immersion in water containing 6 mg alfaxalone L–1 provided smooth induction of anaesthesia, and no obvious side effects were encountered. Higher doses shortened induction time and caused respiratory depression and excitatory movements.

Objective To evaluate the anti-nociceptive and sedative effects of slow intravenous (IV) injection of tramadol, romifidine, or a combination of both drugs in ponies. Study design Within-subject blinded. Animals Twenty ponies (seven male, 13 female, weighing mean ± SD 268.0 ± 128 kg). Methods On separate occasions, each pony received one of the following three treatments IV; romifidine 50 μg kg − (R) tramadol 3 mg kg −1 given over 15 minutes (T) or tramadol 3 mg kg −1 followed by romifidine 50 μg kg −1 (RT). Physiologic parameters and caecal borborygmi (CB) were measured and sedation and response to electrical stimulation of the coronary band assessed before and up to 120 minutes following drugs administration. Results were analyzed using the Friedman’s test and 2 way anova as relevant. Results When compared to baseline, heart (HR, beats minute −1 ) and respiratory rates (f R , breaths minute −1 ) increased with treatment T (highest mean ± SD, HR 43 ± 1; f R 33 ± 2) and decreased with R (lowest HR 29 ± 1 and f R 10 ± 4) and RT (lowest HR 32 ± 1 and f R 9 ± 3). There were no changes in other measured physiological variables. The height of head from the ground was lower following treatments R and TR than T. There was slight ataxia with all three treatments. No excitatory behavioural effects were observed. The response to electrical stimulation was reduced for a prolonged period relative to baseline following all three treatments, the effect being significantly greatest with treatment RT. Conclusion Tramadol combined with romifidine at the stated doses proved an effective sedative and anti-nociceptive combination in ponies, with no unacceptable behavioural or physiologic side effects. Clinical relevance Slow controlled administration of tramadol should reduce the occurrence of adverse behavioural side effects.