Effect of Temperature and Skin Fold on Blood Flow in the Scrotal Skin of Merino Rams

A technique for cannulating the external spermatic artery was developed and used, together with Krypton-85 clearance, to show that there are two compartments of blood flow (the fast and the slow) in the one region of scrotal skin of Merino rams selected for (Folds Plus) and against (Folds Minus) skin fold. The rate of blood flow of the fast compartment was seven to eight times faster than that of the slow. When the scrotum was heated the fast compartment increased markedly in size, the rate of blood flow (ml/lOOg tissue/min) of this compartment remaining unchanged. As a result of the increase in the size of the fast compartment relative to the slow compartment, mean scrotal blood flow also increased. The mean scrotal blood flows of Folds Plus and Folds Minus rams were similar.