Get a medium to Large breed that is fairly agile, can keep up with you in the field, and is fiercely loyal to you. Raise them and train them up from a pup. Northern breeds are good for their work ethic and genetic ability to stay warm. They are quiet when you need them to be if you know what I mean. Most of them are used to water, too. Pit bulls are the worst SHTF 4-legged companion I can think of. They can't take cold weather (humans fare better) and will give away your position at the most inopportune time. I had an Irish Wolfhound that would follow he though the thickest brush and bramble absolutely silent. He got into a fight with 2 pit bulls, won both times and left them bleeding. He lived to be almost 15.
