As a follow-up, from a recent question I sent to the USDA:
Why Islam: What happens to animals in detail after being stunned unconscious? The directive (http://www.fsis.usda.gov/OPPDE/rdad/FSISDirectives/6900.2Rev1.pdf) describes that animals will be: “shackled, hoisted, thrown, cast or cut”.
USDA: In traditional slaughter the animal is first stunned and rendered immediately unconscious by one of the processes defined in 9 CFR 313.
After the animal is rendered immediately unconscious by stunning the next step is usually shackling and hoisting to facilitate bleeding. Animals are bled by cutting the major vessels in the neck and/or thoracic inlet area (corotid artery, jugular vien, and anterior vena cava). Death results from stunning, stunning and bleeding or bleeding depending on stunning method and the species involved. Regardless of the stunning method, the animal is not allowed to return to consciousness. The next slaughter process steps are hide removal and viscera removal.
Why Islam: The answer included: “Death results from stunning, stunning and bleeding or bleeding depending on stunning method and the species involved. “. How is the result of death dependent on the species involved? What would the result of death be for cows or sheep? Stunning or bleeding?
USDA: Carbon dioxide stunning is death inducing in swine. Bleeding is the primary ultimate cause of death in cattle and sheep.