Hemodynamics in Normal Cattle

A satisfactory method has been described for conducting hemodynamic studies in cattle. With the animals in normal standing position, and without sedation or tranquilization, cardiac catheterization can be readily performed. With a muzzle mask, ventilatory studies are also feasible. Using this method, each of 10 normal steers was studied four times during a six-month period. This permitted the establishment of normal values for a number of circulatory measurements. In addition, an evaluation of chlorpromazine administration in normal cattle demonstrated some of the numerous complex effects of this drug on the cardiovascular and respiratory systems. These included hemodilution, hypoventilation, and a marked reduction of the arteriovenous oxygen difference.