Cardiovascular responses in turkeys as affected by diurnal variation and stressors

Ten hypertensive (hyper) and hypotensive (hypo) turkeys of both sexes were used to evaluate the effect of various stimuli on blood pressure (BP) and heart rate (HR). Blood pressures were recorded from the brachial artery via a catheter and radio telemetric system. After a 48 hr baseline monitoring, the birds were subjected to exercise, fright, and mating and the BP and HR changes recorded. Mean arterial BP was 4.5 mm Hg less during night than day, and the BP of the hyper strain was significantly (P less than or equal to .05) higher than the hypo strain. Tracings from quiescent birds revealed fluctuations in BP that varied by 100 mm Hg. These were unexplainable fluctuations and occurred in both hyper and/or hypo birds at various times. The application of various stressful situations, such as exercise and fright, had little effect on BP but appeared to cause marked changes in HR. The highest recorded BP occurred during one of the mating exercises where systolic BP approached 350 mm Hg and HR increased by approximately 100%. Noises created with dog whistles and a .22 caliber pistol shot did not cause marked changes in BP and HR.