I know it's not much of an answer, but the income gap varies by species and specialty, as well as academics vs private practice, region, etc. It seems to be even less consistent than, say, the variations in human medicine. An equine vet who is not board-certified but who owns a private practice in an area with well-paying clients (e.g. NE East Coast, CA, FL, KY) may well pull in more at the peak of their career than someone in an academic setting, although the academic will earn more than someone in a rural practice, etc. There are also disparities in the temporal patterns of earning -- equine vets tend to earn less (sometimes a lot less!) when they first graduate than SA, but they may end up earning more than their SA counterparts a couple decades down the road. At least in equine, I think some of the best paid people in the field are surgeons at large practices with wealthy client bases.
I don't know a ton about small animal practice, but my impression is that radiologists are most likely to serve as consultants to other practices, work part time at a couple different SA practices, maybe work full time for a very large practice, or work in academic settings. Since many vets perform and read their own radiographs and U/S, there's not as big a niche for radiologists to own their own practices as in human medicine. I'm not saying it couldn't happen, but I'd be surprised if it were at all common. Cardiologists, ophthalmologists, etc., may own their own specialty referral practices or work at someone else's practice seeing in house and referred patients. Internal medicine and surgery people may be at referral practices or at general practices. Any of the above may be found, of course, in an academic setting.
Wow, that was long. I hope it made at least some sense.
