A comparison of sedative effects of xylazine alone or combined with levomethadone or ketamine in calves prior to disbudding

Objective To compare the sedative effects of intramuscular xylazine alone or combined with levomethadone or ketamine in calves before cautery disbudding. Study design Randomized, blinded, clinical trial. Animals A total of 28 dairy calves, aged 21 +/- 5 days and weighing 61.0 +/- 9.3 kg (mean +/- standard deviation). Methods Calves were randomly allocated to three groups: xylazine (0.1 mg kg(-1)) and levomethadone (0.05 mg kg(-1); group XL), xylazine (0.1 mg kg(-1)) and ketamine (1 mg kg(-1); group XK) and xylazine alone (0.2 mg kg(-1); group X). Local anaesthesia (procaine hydrochloride) and meloxicam were administered subcutaneously 15 minutes after sedation and 15 minutes before disbudding. The calves' responses to the administration of local anaesthesia and disbudding were recorded. Sedation was assessed at baseline and at intervals up to 240 minutes postsedation. Times of recumbency, first head lift and first standing were recorded. Drug plasma concentrations were measured. Results Data were obtained from 27 animals. All protocols resulted in sedation sufficient to administer local anaesthesia and to perform disbudding. Sedation scores significantly correlated with drug plasma concentrations (p Conclusions and clinical relevance Levomethadone or ketamine with a low dose of xylazine produced short but sufficient sedation for local anaesthesia and disbudding with minimum resistance.Peer reviewe