Can you become a veterinarian with just a GED?

No, just as you cannot become a veterinarian with just a high school diploma. Veterinary medicine is a challenging field to work in and you must have significant college training to do so.

In the United States, you must complete at least 3 years of undergraduate college work plus another four years of vet school. Around the world, most countries require at least six years of post-high school education.