I'm interested in hearing if anyone has done this! I can't comment on making liquid fertilizer, but I have had good luck with burying raw/cooked meat and letting it
compost that way.
If you want to try burying it, I would recommend picking a spot away from your garden (preferably in a slightly open area) and trying it there to see if anything will dig it up. If something does, then try again burying it deeper (or bury and cover with something that absorbs the smell, like a light layer of woodchips) until you figure out what would work in your garden without attracting animals that would tear your garden apart.
I've found it to be a good use of the rare dead (wild) animal that ends up on our
land, as well as a good way to
reuse any cooked meat that is no longer edible.