Comparative study on the sedative effects of morphine, methadone, butorphanol or tramadol, in combination with acepromazine, in dogs.

Objective: To compare the effects of morphine (MOR), methadone (MET), butorphanol (BUT) and tramadol (TRA), in combination with acepromazine, on sedation, cardiorespiratory variables, body temperature and incidence of emesis in dogs.

Study Design: Prospective randomized, blinded, experimental trial.

Animals: Six adult mixed-breed male dogs weighing 12.