Comparative evaluation of sedative and clinical effects of dexmedetomidine and xylazine in dromedary calves (Camelus dromedarius).

Objective: To compare the sedative and clinical effects of intravenous (IV) administration of dexmedetomidine and xylazine in dromedary calves.

Study Design: Experimental, crossover, randomized, blinded study.

Animals: A total of seven healthy male dromedary calves aged 14 ± 2 weeks and weighing 95 ± 5.5 kg.

Methods: Calves were assigned three IV treatments: treatment XYL, xylazine (0.2 mg kg); treatment DEX, dexmedetomidine (5 μg kg); and control treatment, normal saline (0.01 mL kg). Sedation scores, heart rate (HR), respiratory rate (f), rectal temperature (RT) and ruminal motility were recorded before (baseline) and after drug administration. Sedation signs were scored using a 4-point scale. One-way anova and Mann-Whitney U tests were used for data analysis.

Results: Calves in treatments XYL and DEX were sedated at 5-60 minutes. Sedation had waned in XYL calves, but not DEX calves, at 60 minutes (p = 0.037). Sedation was not present in calves of any treatment at 90 minutes. HR decreased from baseline in XYL and DEX at 5-90 minutes after drug administration and was lower in DEX than XYL at 5 minutes (p = 0.017). HR was lower in DEX (p = 0.001) and XYL (p = 0.013) than in control treatment at 90 minutes. f decreased from baseline in XYL and DEX at 5-60 minutes after drug administration and was lower in DEX than XYL at 5 minutes (p = 0.013). RT was unchanged in any treatment over 120 minutes. Ruminal motility was decreased in XYL at 5, 90 and 120 minutes and absent at 10-60 minutes. Motility was decreased in DEX at 5, 10 and 120 minutes and was absent at 15-90 minutes.

Conclusion And Clinical Relevance: The duration of sedation from dexmedetomidine (5 μg kg) and xylazine (0.2 mg kg) was similar in dromedary calves.