Cardiopulmonary, hemocytologic and biochemical effects of xylazine in goats

Intramuscular administration of xylazine at the rate of 0.22 mg/kg body weight caused a significant reduction in respiratory rates. Mean arterial blood pressure and rectal temperature were not altered. Preadministration of atropine did not affect the depth and pattern of respiration; however, the heart rate increased. A significant reduction in pH and arterial oxygen tension and an increase in carbon dioxide tension was observed after xylazine and xylazine following atropine treatment. Hemocytologic changes included a decrease in total erythrocytes, leukocytes, hematocrit and hemoglobin concentration and a rise in neutrophils with relative decrease in lymphocytes. Biochemical changes included a slight rise in potassium and a decrease in sodium concentration. Glucose level was significantly increased at maximum depth of sedation. The changes in hemocytologic and biochemical parameters returned to near preadministration level in 24-72 hours. No alteration was observed in the electrocardiogram. Xylazine was well tolerated, and the sedation was rapid in onset and lasted for about 30 minutes. The recovery was uneventful.