Respiratory Rate and Tidal Volume in Healthy Sheep at Different Altitudes in Jos, Plateau State

Respiratory physiology in livestock is influenced by ambient temperature, humidity, altitude, and physical activity. Jos, situated at an altitude of approximately 1200 metres above sea level in Plateau State, North Central Nigeria, presents a unique high-altitude environment where reduced barometric pressure may influence respiratory parameters in sheep. This study measured resting respiratory rate, tidal volume, and arterial oxygen saturation in Yankasa sheep maintained at three different altitudinal zones within Jos Plateau: 900, 1200, and 1500 metres above sea level. Thirty sheep, 10 per altitude zone, were acclimatised for four weeks before measurements were taken. Respiratory rate was counted by costal excursion observation over one minute. Tidal volume was estimated using a portable spirometer adapted for ovine use with a tight-fitting mask. Arterial oxygen saturation was measured using a veterinary pulse oximetry probe placed on the tongue. Respiratory rate increased significantly from 20.3 breaths per minute at 900 metres to 24.6 breaths per minute at 1500 metres. Tidal volume did not differ significantly between altitude groups. Arterial oxygen saturation was significantly lower at 1500 metres at 94.2 percent compared to 97.8 percent at 900 metres, suggesting mild high-altitude hypoxaemia. Haematocrit was significantly higher in sheep at 1500 metres, consistent with polycythaemic adaptation. These findings provide baseline respiratory reference data for sheep managed at altitude in the Jos environment. Keywords: respiratory rate, tidal volume, sheep, altitude, Plateau State.