I think pigsfoot is right about why so few apply. Also, from my understanding, it is $$$ for international students!! Compared to what Ontario residents pay, anyway. I'm not sure how that compares to any US school.
It is a very good school - not sure really how they measure that but first (and most importantly, lol) of all U of G has the BEST food of any Canadian school.
Possibly more relevant to vet school - I believe the pass rate for NAVLEs is something like 98%. (It was funny when the people from Grenada came to talk to us about why that school is so great - they were like, we have a pass rate of ~95%, which is better than the rest of the US...then someone pointed out that Guelph's pass rate was even higher than theirs, lol).