Vegetarianism, my friends. A no meat diet. It can be done. Once you give up meat, you don't miss it. Find a safe and hopefully secluded spot with some natural fortification like marshes or a hill, put up a fence, stock the ammo and grow your own vegetables.
Sometimes I cheat with fish and become a pescaterian, though.
Fish is healthier anyway, and it seems to be a more viable option when you have throngs of zombies eating all the cows. Take your gun with you for protection and go fishing for catfish and trout. Cows on your land would attract hungry zombies.