Doctor of Vetrinary Medicine 🙂
The answer, as far as I know, would be yes, you can do your MD (MBBS, MBChB, etc), but you would most likely have to do the entire 4-6 years (depending on the program). If you have a BSc and meet the appropriate pre-req's (vary from school to school) you might be able to get into a 4 year program.
And AMERICAN/CANADIAN MD is equivilent to an MBBS, MBChB, MB. BUT, an MD gained from the UK, South Africa, Australia, New Zealand (or really any country that has a MSSB, etc) is more, as it is a RESEARCH degree (equiv. to our PhD).
As for out look...the world will always need physicians, but salary changes depending on specialty. From what I know, a GP in the USA will make more than one in the UK, because the UK is on a National Health Plan (like Canada) and so the government decides your salary. You'd have to do research and look into that. There isn't a 'catch all' answer.
CH