Immobilization and Exsanguination

The manner in which livestock are immobilized, slaughtered, and exsanguinated can affect final meat quality. The immobilization method should minimize animal suffering as well as prevent excessive struggling which can result in bruising and hemorrhaging. This type of tissue damage can ruin or degrade the meat quality.

In the United States, captive bolt stunning (projectile) stunning is used to immobilize cattle, calves and sheep. Electrical stunning is used for calves, sheep, swine, poultry and fish. Carbon dioxide is also used for swine immobilization.

Most types of immobilization render the animal unconscious but do not stop the heart. The beating heart helps to remove blood from the animal more quickly. Bleeding (also called exsanguination) is important because extra blood in the meat cuts is unappealing to consumers. Rapid bleeding can also help reduce or prevent the small hemorrhages (known as blood splash) that can result in small blood spots in the meat, which cannot be removed. Blood is also an ideal growth medium for the microorganisms which cause meat to spoil so removing as much blood as possible can help increase shelf life of the meat.