Effect of change in body position on cardiopulmonary function and plasma cortisol in cattle.

The aim of these studies was to investigate the effect of body posture on circulatory and respiratory system function in unmediated cattle. The plasma cortisol concentration was also measured and served as an indication of the level of stress imposed by animal handling and positional manipulation. Six mature, healthy Holstein cows were physically restrained and studied in standing, supine and right lateral postures. The plasma cortisol concentration increased with the change in body position. In a supine position, the value was increased to more than three times the control value (p < 0.001). The arterial oxygen tension and oxygen saturation were significantly decreased (p < 0.001) with changes in body position. The decrease was most pronounced when cattle were restrained in a supine position. Arterial carbon dioxide tension, heart rate, mean arterial pressure and central venous pressure did not change significantly with changes in body posture. Restraining of cattle in a lateral recumbent or supine position without introducing anesthesia was found to exert a strong stress which affected the respiratory function and increased the plasma cortisol level.