Evaluation of the sedative and physiological effects of xylazine, detomidine, medetomidine and dexmedetomidine in goats

BACKGROUND: Many α(2)‐agonists are commonly used for sedation and analgesia in ruminants. INTRODUCTION: The present study aims to compare the sedative and physiological effects of intravenous (IV) administration of xylazine, detomidine, medetomidine and dexmedetomidine in goats. METHODS: Ten healthy goats aged 6 ± 1 months and weighing 15 ± 2 kg were used in experimental, crossover Latin square, randomised and blinded study. Animals were assigned to five IV treatments: control (normal saline); xylazine (100 μg kg(−1)); detomidine (50 μg kg(−1)); medetomidine (20 μg kg(−1)) and dexmedetomidine (5 μg kg(−1)). The degree of sedation was investigated using a numerical ranking scale of 0–10. Sedation scores were compared at each time using nonparametric (Kruskal–Wallis and Mann–Whitney U) tests. RESULTS: Heart rate (HR), respiratory rate (RR), rectal temperature (RT), ruminal motility and capillary refill time (CRT) were performed before (baseline) and after drug administration. Animals in α(2)‐adrenergic agonist treatments were sedated at 5–60 min. There were no significant differences among α(2)‐adrenergic agonist treatments at 5–60 min in sedation scores. HR significantly decreased from baseline 5–90 min after α(2)‐adrenergic agonists’ administration. Ruminal motility was decreased in α(2)‐adrenergic agonist treatments at 5, 90 and 120 min and absent at 10–60 min. A significant decrease from baseline in RR was detected between 30 and 90 min after α(2)‐adrenergic agonists’ administration. RT was unchanged in any treatment for 120 min. CRT was less than 2 s at all time points following each treatment. CONCLUSIONS: The duration of sedation was up to 60 min after IV administration of xylazine (100 μg kg(−1)), detomidine (50 μg kg(−1)), medetomidine (20 μg kg(−1)) and dexmedetomidine (5 μg kg(−1)) in goats in this study. No significant differences were detected between xylazine, detomidine, medetomidine and dexmedetomidine in goats.