Clinical effects of two doses of butorphanol with detomidine for intravenous premedication of healthy warmblood horses

Objective: To compare the effects of two different doses of butorphanol combined with detomidine administered intravenously (IV) on quality of sedation, degree of ataxia and anaesthetic induction in horses. Study design: Randomized, blinded, clinical study. Animals: A total of 40 client-owned healthy warmblood horses scheduled for elective surgery under general anaesthesia. Methods: Horses were randomly allocated to be administered 8 μg kg–1 detomidine IV plus either 20 or 50 μg kg–1 butorphanol IV, with the principal investigator blinded to group allocation. Head height was measured before drug injection and 2 minutes thereafter. Data were compared using unpaired t test. Horses were filmed and scored using Simple Descriptive Scales for sedation (2 and 15 minutes after IV injection), ataxia (at walk, immediately after the 2 minute time point) and quality of swing-door induction following diazepam and ketamine administration. Data are shown as median (and range where appropriate). Scores were compared using chi-square tests (p