Cats undergoing ovariohysterectomy were assigned into two groups : together with butorphanol [ 0.2 mgkg ( -1 ) intramuscularly ( IM ) ] , group AA ( n = 14 ) received acepromazine ( 0.1 mgkg ( -1 ) IM ) and group MA ( n = 14 ) medetomidine ( 20gkg ( -1 ) IM ) .