Clinical, cardiopulmonary and haemocytological effects of xylazine in goats after acute exposure to different environmental temperature and humidity conditions

This study was carried out to assess the influence of xylazine administration on clinical, cardiopulmonary and haemocytological variables after acute exposure to different environmental conditions. Xylazine hydrochloride was administered intravenously at 0.1 mg/kg body mass to 6 clinically healthy, castrated male goats. All animals were exposed for 60 min to 3 sets of climatic conditions: 14 °C, 33 %relative humidity; 24 °C, 55 %RH, and 34 °C, 65 % RH. The variables that were measured for a period of 60 min after xylazine administration were sedation, analgesia, salivation, urination, ventilation rate, heart-rate, mean arterial blood pressure, oesophageal temperature, haematocrit, mean corpuscular volume and mean corpuscular haemoglobin concentration. Xylazine induced sedation, analgesia, salivation and urination independently of the 3 environmental conditions. Environment had no influence on the onset, duration and recovery from sedation. In the 14 °C environment, xylazine resulted in a significant decrease in ventilation and heart-rate from baseline values. Significant changes in mean arterial blood pressure, haemoglobin concentration, mean corpuscular volume, haematocrit and red cell count were observed in the 3 environments. Total plasma protein was significantly altered at 24 °C and 34 °C. Acute exposure of goats to different environmental conditions had no significant influence on the clinical, cardiopulmonary and haemocytological variables. Physiological changes induced by xylazine were therefore independent of the environment.