I'm procrastinating my last PS revisions, so here's some thoughts on yours.
I think it if you spend some time on revisions it could be much stronger. Please don't be offended by my suggestions- I know that writing this sort of thing is REALLY hard for some people, and it has nothing to do with your ability to be an amazing vet!
A couple thoughts on style and content:
1)Use "indoors" instead of inside. I was like, inside what?
2)Try to ease up on the commas; they don't help things flow when overused. If you rearrange a few and diversify your sentence structure, it'll improve the overall style dramatically. For example:
Working inside, as a physician or dentist, is what I thought I would do for a career.
becomes:
"I thought I wanted a career working indoors as a dentist."
I'm NOT saying you should write my example instead, since it's a pretty weak sentence actually. But you might want to change some other sentences in this way.
3)You misuse the semicolon ( ; ) numerous times. It's better left unused than misused.
4)To me, a love of science + air conditioning doesn't equal a lifetime practicing medicine. You might want to expand on this a little, so Adcoms see that you are a thoughtful decision maker.
5) I personally don't think the very beginning of the essay is the place to write about pursuing the wrong career (Dentistry) - what's really important is why you're choosing vet med, not why you didn't choose something else. Not that you should exclude that, but it shouldn't have such a prominent place or length in the essay. Unless of course you had actually practiced dentistry for 10 years....You have great animal experiences. Why not open with something about them? (not everyone grows up around a livestock auction! I went to my first at 26 years old and was totally blown away)
Anyhow, GOOD LUCK! We need more food animal vets, so I'm rooting for you!