Pittermann, W. The Isolated Perfused Bovine Udder Skin: A Natural In Vitro Skin Model. Skin Care Forum 1996. 15:1-4.

"As a pure in vitro model the isolated perfused bovine udder skin model makes use of abbattoir material from German Black Pied cows, and therefore completely excludes the involvement of living animals. After the blood has been prevented from clotting immediately after slaughter the undamaged organ is brought to the laboratory, where it is perfused within about 20 minutes. The easily accessible arterial and venous vascular supply system facilitates continuous perfusion and ensures viability under in vitro conditions for at least 8 hours. The acellular perfusion fluid at body temperature (oxygen-enriched Tyrode's solution) is pumped through the organ at constant pressure (80-100 mm Hg; approx. 120 ml/min). The perfusate can be used in the fraction collector as a receptor medium for administered substances. The viability of the organ, including the skin, is checked during perfusion. Lactate dehydrogenase activity, the lactate and glucose concentration in the perfusate, and the surface temperature of the skin are measured. The skin edema formation, which can influence transdermal absorption, is also checked during perfusion."