Comparison of running energetics in male and female domestic fowl.

Carbon dioxide production (VCO2) and end-exercise venous lactate concentration were compared in intensively-trained, mature male and female domestic fowl running on a treadmill for 10-min periods at maximal and sub-maximal work loads. The relationship between VCO2 and running speed was linear and had the same slope in male and female birds. However the maximum sustainable running speed of the males was approximately twice that in the females and the maximum weight-specific VCO2 was 60% higher in males. End-exercise venous lactate concentration rose significantly above resting at work loads above 75% maximum in females, but only at work loads above 95% maximum in fully-trained males. The results indicate a greater work capability in male than in female birds in the conditions of the experiments.