Biochemical and physiological parameters and estimated work output in draught horses pulling loads for long periods

A study was undertaken in five draught horses of 648±33 kg body weight to find the effects of continuously pulling loads on their cardiovascular, respiratory and metabolic responses. A cart equipped with an odometer, for measuring distance, and a hydraulic dynamometer, for measuring draught force, was used. Heart and respiration rates and rectal temperatures were recorded. Blood samples for measuring arterial and venous pH and blood gases, haemoglobin, glucose and lactic acid concentrations and the serum activity of the enzymes creatine phosphokinase (CK), lactate dehydrogenase, aspartate aminotransferase and alkaline phosphatase were taken before exercise and immediately after each journey (morning and afternoon) of the daily work.