Cobalife VB12 Injection for Sheep and Cattle Elanco In the meat and dairy industry, animals are often supplemented with Vitamin B12 due to modern farming practices that limit their natural intake. So people who eat animals are simply taking a Vitamin B12 Injection Side Effects and Safety People love to bring up B12 like it's a reason to eat meat. But here's the irony Even meat eaters can be deficient in B12. That's because B12 comes from bacteria in The B12 Shot: What Every Human Needs to Know About Injectable Vitamin B12 The Advantages of B12 Injections Versus Oral Supplements: Shawn Veiseh, M.D.: Family Medicine