Thanks for the link. That’s pretty cool. I’ve noticed the problem with the handle being not hand-friendly. I may modify it this winter, before the zombies thaw.
FAO (UN) On Destroying Animals - scroll down for diagrams of where to aim with a firearm.
I am realizing now that this might be considered veterinary advice, and I am not a vet, just another person who is upset at the thought of being unable to help a dying animal.
BTW, cutting the trachea is pretty much useless in and of itself – it gives them one MORE hole to breathe through and is done on purpose sometimes. To kill an animal with exsanguination, you need to transect one or both jugular veins and/or carotid arteries. These lay above the trachea and below the muscle mass of the neck (in some animals, there is a visible groove or depression); the jugular is right under the skin, being more superficial closer to the head and deeper closer to the chest, and the carotid runs underneath the jugular. They are somewhat separated in the upper neck and closer together in the lower portion of the neck.
I would not mess around with trying to restrain the legs, as you are likely to get kicked unless you really know what you are doing. Stay on the spine side of an animal lying on its side, do what you need to do, and get away as soon as possible, especially with a wild animal. A large towel would work better than wrestling with a burlap sack to put over its head.
Putting a knee on the neck of an animal right behind the head (when approaching from the back) will keep it from lifting its head; taking the animal’s nose and tilting it towards the sky (so that their poll is kept down) is even better. Horses are usually unable to get up from this position, but I think cattle are capable of starting to get up and flinging you off (I haven’t worked with them as much). With horses, I haven’t worked at all with deer, but they are much smaller than horses or cattle, so I would expect them to be easier to restrain with brute force and no drugs, although they will fight harder than something used to human contact. All in all, though, it would be hard to restrain them in such a way as to make it safe to wield a sharp knife on a flailing animal.