I shadowed with a DVM/PhD who was in the Army Veterinary Corps. From what I remember, you had to do 3 years of active duty and 5 years of reserve. She said you're actually more likely to be deployed if you're in reserve and have a little bit more say if you stay active duty rather than staying in reserve. Especially if you're at all interested in public health, they really like doing post graduate work and training in stuff like epidemiology and infectious disease.
If you're deployed either to Iraq or Afghanistan, you'll probably be either taking care of the military working animals (mostly the working dogs) and/or helping with food inspection. But that's not the only things, just the most common. When you're stateside, there's a couple things you can do. I would have LOVED to go to Lackland Air Force Base near San Antonio and work with their military working dogs. They also need equine vets to look after their ceremony and parade horses and I think that's somewhere in the southeast.
The vet I shadowed was the head vet for the base at Offutt AFB in Omaha, so she took office calls for vaccinations, wellness checks, allergy consults, that sort of thing. Nothing real difficult. I don't think she said she had to do off hours emergency stuff. If I recall, you go in as a captain with that pay plus an additional salary/stipend. Really good benefits (usually full medical, dental, etc) plus officer housing. But the scholarships are really competitive, or so I heard from the people in my class who applied this year. Three applied and I think only one got it (he was already in the Army before vet school as well). I would have thought about doing it, especially if I would have gone out of state. My father was in the Army for a long time (22 years) and came out of retirement to go back to Iraq, so I know what it's like. My husband didn't want me to though. Ah well...here's the website on it:
http://www.goarmy.com/amedd/vet/index.jsp
