EFFECT OF ACUTE HEAT EXPOSURE ON BLOOD-FLOW AND ITS DISTRIBUTION IN THE UNRESTRAINED LAYING FOWL (GALLUS-DOMESTICUS)

1. The effect of heat exposure (air temperature 35-45-degrees-C) for 1.5 h on blood flow distribution between the abdominal viscera and the muscles of abdominal wall and hind leg was investigated in unanaesthetised, unrestrained laying fowl. 2. Heat stressed fowl showed a significant hyperthermia (+ 1.3-degrees-C), rapid shallow breathing (229 breaths/min) and significant hypocapnia (- 8 Torr). 3. Significant increases in absolute blood flow (ml/g per min) were measured in the kidneys, spleen, liver and duodenum during hyperthermia, but there was no change in the absolute blood flow to the reproductive tract or the relative perfusion of the reproductive tract compared with the other tissues sampled. 4. We conclude that in these acute conditions of heat exposure, blood flow to the reproductive tract of the laying fowl is not compromised by any simultaneous thermoregulatory needs.