ACTIONS OF XYLAZINE IN YOUNG SWINE

Objective-To determine sedative, analgesic, and basic cardiovascular e ffects of xylazine administered to pigs. Animals-6 two-month-old Landr ace x Large White pigs. Procedure-Xylazine was administered IV at incr easing dosages (1, 2, 4, 8, and 16 mg/kg of body weight) to otherwise unmedicated, conscious pigs, and the aforementioned effects were deter mined before xylazine administration and 2, 5, 10, and 15 minutes late r. Then a higher xylazine dosage was given after the 15-minute measure ments were taken. Results-None of the xylazine dosages induced suffici ent analgesia to prevent painful response to tail clamping; considerab le excitation with vocalization and without appreciable sedative effec t was observed at ail dosages. At lower dosages, cardiovascular effect s were characterized by bradycardia and biphasic blood pressure respon se; initial hypertension was followed by hypotension. At higher dosage s, severe hypotension with moderate bradycardia was followed by marked bradycardia and return to normal baseline values or slight increase i n blood pressure. Conclusion-Xylazine did not induce adequate sedative or analgesic effects in pigs at any dosage tested; however, cardiovas cular effects were considerable. These effects of xylazine differ from those observed in other domestic species.