The analgesic and anesthetic effects of Telazol (13.2 mg/kg, IV) and xylazine (0.11 mg/kg, IV)-Telazol (13.2 mg/kg, IV) were evaluated in 6 sheep. Anesthesia was characterized by muscle relaxation and profound analgesia with both regimens, muscle relaxation appeared to be better in sheep receiving xylazine-Telazol. The duration of analgesia was significantly longer in sheep receiving xylazine-Telazol (101.7 +/- 26 minutes) than in sheep receiving Telazol alone (41.6 +/- 15 minutes). Changes in heart rate and respiration rate were transient with both regimens. Apnea occurred in 2 sheep immediately after xylazine-Telazol administration, requiring assisted ventilation, but both sheep resumed spontaneous breathing within 2 minutes. Arterial blood pressure decreased significantly at 45 and 60 minutes after xylazine-Telazol injection. Arousal to standing was smooth, but gradual with no significant difference between the two drug regimens. In conclusion, xylazine-Telazol combination produced better muscle relaxation and longer duration of anesthesia than Telazol alone. The adverse effects induced by xylazine-Telazol were similar to that of Telazol.