Effect of exercise on cardiac output and other cardiovascular parameters of heavy turkeys and relevance to the sudden death syndrome.

The cardiovascular response to treadmill exercise was studied in 14-to-18-week-old male and female heavy turkeys. Arterial blood pressure, cardiac output, body temperature, and heart rate were measured before and during each period of exercise. Total peripheral resistance, stroke volume, and stroke index were calculated from those parameters. Systolic, diastolic, and mean blood pressures significantly decreased during exercise. Cardiac output increased during exercise in males and females by 64% and 23%, respectively, while total peripheral resistance fell by approximately 40% in both sexes. Exercise had no significant effect on stroke volume and stroke index. The cardiac functional capacity of the heavy turkey in response to mild exercise appears very limited. This failure of the cardiovascular system to adequately respond to increased metabolic needs suggests that hemodynamic failure is a major component in the pathogenesis of sudden death syndrome of turkeys.