Comparison of the sedative and cardiovascular effects of the combination of acepromazine-clonidine versus acepromazine-xylazine in horses

The aim of this study was to compare the sedative and cardiovascular effects of the combination of acepromazine-clonidine versus acepromazine-xylazine in horses. Four healthy cross-bred horses were included in the study. They were assigned to two treatments. In treatment I (T1), the animals received xylazine hydrochloride (1.00 mg kg^-1) in combination with acepromazine maleate (0.05 mg kg^-1) intravenously (IV). In treatment II (T2), the animals received intra-gastric administration of clonidine (0.002 mg kg^-1) followed by acepromazine (0.05 mg kg^-1; IV) after 60 min. Head height above the ground (HHAG) and echocardiographic indices were evaluated. In T1, recordings were made 5 min before and 5, 15, 30, 60, and 90 min after drug administration. In T2, recordings were made 5 min before clonidine, 55 min after clonidine administration, and then 5, 15, 30, 60, and 90 min after acepromazine injection. Analyses of the data showed there were not significant differences regarding HHAG and echo-cardiographic indices between two treatments. For sedation of healthy horses, it was concluded that intra-gastric administration of clonidine and IV administration of acepromazine showed similar sedative and cardiovascular effects compared to IV acepromazine-xylazine administration.