A comparative study of xylazine-induced mechanical hypoalgesia in donkeys and horses

Abstract

OBJECTIVE: To compare the effects of xylazine on mechanical nociceptive thresholds in donkeys and horses. STUDY DESIGN: Randomized, controlled, crossover, Latin-square, operator-blinded design. ANIMALS: Six 3.1 ± 0.89 year old standard donkeys weighing 145.0 ± 30.5 kg and six 9.6 ± 4.4 year old Thoroughbred horses weighing 456.0 ± 69.0 kg. METHODS: Each animal received one of four doses of xylazine (0.5, 0.7, 0.9, and 1.1 mg kg(-1) ), or acepromazine (0.05 mg kg(-1) ) or saline solution (0.9%) intravenously and mechanical nociceptive thresholds were assessed over 90 minutes. The areas under the threshold change versus time curve values for 60 minutes (AUC(0-60) ) post-drug administration wer..