Oxygen uptake and cardiac performance in the sheep.

1. In four ewes no relationship was found between heart rate and oxygen consumption in response to cold stimulus; such a correlation was found in one wether sheep.2. Direct Fick studies of cardiac output showed a significant correlation between heart output and oxygen uptake in two ewes and one wether. The relationship between stroke volume and heart rate was poor in the case of the ewes.3. It is suggested that the 6-month training period which the ewes had received, before the estimates were made of heart rate and oxygen consumption, was insufficient to allay emotional disturbance affecting the relationship between these parameters.