Instructions
Use a firearm of sufficient caliber to cause instant death by physical disruption of the brain stem. A .22 loaded with a soft-nose or hollow-point bullet may be sufficient, but a heavier caliber would be better.
Restrain the cow as firmly as possible to ensure accuracy.
Try to be sure there is something behind the cow to act as a backstop for the bullet, if the shooter should miss or the bullet goes completely through the cow's head. Bales of hay can be used, if the animal cannot be positioned near an earth mound or other natural obstacle.
Face the cow's head and mentally draw an imaginary line across the cow's forehead from the base of one ear to the inner corner of the opposite eye and another line from the base of the other ear to the inner corner of the opposite eye. Aim for a point slightly above where the two lines intersect.
Have everyone else step well out of range.
Hold the weapon 2 to 10 inches from the cow's head. Take careful aim at the target --- point down the line of the cow's back, so that the bullet will enter the brain stem (the beginning of the spinal cord). Then, fire.
Verify death by checking for a heartbeat 5 minutes after the shot is fired. If uncertain of death, fire a second shot.
How to Euthanize a Cow
Emergency euthanasia (mercy killing) of sick or injured cattle can be necessary, if the animal cannot be transported or when the services of a veterinarian cannot be obtained. The only practical method for this regrettable procedure is by gunshot. If euthanasia is not urgently required to relieve severe pain, a veterinarian can euthanize a cow chemically, although this procedure requires large amounts of drugs. A veterinarian can also use a "humane killer" (legally not a firearm) to euthanize the animal. If gunshot euthanasia is necessary, it should be performed by someone trained and experienced in firearm use and safety.