Factors affecting the residual blood content of meat

From estimates of the residual blood content of muscles from rats killed while stressed or under barbiturate anaesthesia it appears that, at slaughter, the stress associated with stunning and exsanguination will normally produce peripheral vasoconstriction through the action of released catecholamines. This will result in minimal retention of blood in the skeletal muscles while factors which reduce vascular tone will lead to higher levels of residual blood in meat.