Oxygen transport chain in double-muscled blue Belgian cattle.

The physiological peculiarities of the oxygen transport chain in double-muscled Blue Belgian cattle are described. The investigations performed at several levels of the oxygen transport chain suggest that the increased susceptibility of these cattle to stress, resulting mainly in respiratory diseases, is due to an insufficient functional reserve capacity mainly involving the pulmonary and cardiovascular systems. The resulting lack of 'functional hardiness' of the oxygen transport chain is seen in those double-muscled cattle which do not react in an appropriate or predictable way when submitted to a hostile environment.