Hi,Connie,
Veterinary medicine, medicine and dentistry courses at university are almost pure science in the first year, and to show that you can cope with the high level of science taught in these courses, coupled with the pressure of applicants to get into them, a very standard is required at A level - As or A*s.
You have no chance of getting into a veterinary school with Cs or Ds in science subjects. You might just get on to a veterinary nursing course.
W