Xylazine was used on 84 occasions to anaesthetise 34 steers, (17 Herefords and 17 Friesians) between 10 and 24 months of age with bodyweights ranging from 209 to 563 kg. Xylazine as a 2 per cent solution was injected intravenously; the mean dose for the Hereford steers was 0.228 mg/kg and for the Friesian steers 0.274 mg/kg. On 21 occasions xylazine only was used. On the other occasions the xylazine was supplemented with local or regional analgesia. The Hereford steers became recumbent after injection of xylazine more readily than the Friesian steers and took longer to recover. In addition the Hereford steers showed fewer reactions to surgical stimulation than the Friesians. It is concluded that xylazine should be supplemented with some form of effective analgesia whenever a surgical operation is performed.