Effects of xylazine on acid-base balance and arterial blood-gas tensions in goats under different environmental temperature and humidity conditions

The effects of acute exposure to 3 different temperature and humidity condi tions on arterial blood-gas and acid-base balance in goats were investigate d after intravenous bolus administration of xylazine at a dose of 0.1 mg/kg . Significant (P < 0.05) changes in the variables occurred under all 3 envi ronmental conditions. Decreases in pH, partial pressure of oxygen and oxyha emoglobin saturation were observed, and the minimum values for oxygen tensi on and oxyhaemoglobin saturation were observed within 5 min of xylazine adm inistration. The pH decreased to its minimum values between 5 and 15 min. T hereafter, the variables started to return towards baseline, but did not re ach baseline values at the end of the 60 min observation period. Increases in the partial pressure of carbon dioxide, total carbon dioxide content, bi carbonate ion concentration, and the actual base excess were observed. The maximum increase in the carbon dioxide tension occurred within 5 min of xyl azine administration. The increase in the actual base excess only became si gnificant after 30 min in all 3 environments, and maximal increases were ob served at 60 min. There were no significant differences between the variabl es in the 3 different environments. It was concluded that intravenous xylaz ine administration in goats resulted in significant changes in arterial blo od-gas and acid-base balance that were associated with hypoxaemia and respi ratory acidosis, followed by metabolic alkalosis that continued for the dur ation of the observation period. Acute exposure to different environmental temperature and humidity conditions after xylazine administration did not i nfluence the changes in arterial blood-gas and acid-base balance.