i am fond of animals and want to serve them as a veterinary.what kind of field do i have to opt?

I love animals myself and I think it is a beautiful thought that you want to serve them as a veterinarian

To enter basic requirement is study of Physics, chemistry and biology in class XII.
Veterinary Science like medicine can be pursued after 10+2, Basic requirement is study of physics, chemistry and biology at 10+2 level. For dairy technology and dairy engineering combination with mathematics is required. The course is of 4 1/2 years duration and a year's practical internship is compulsory. The theoretical aspect of the course covers all subjects needed for the understanding of animal health, disease and treatment. M.V.Sc. can be pursued after B.V.Sc. through an All India competitive examination. After B.V.Sc. students can also appear for Biotechnology entrance test for a future in this branch.
B.V.Sc & AH includes the study of animal anatomy and physiology, pathology, pharmacology, and allied subjects. The clinical study comprises of veterinary medicine, surgery, hygiene and pathology. Practical training is an important element of the course.

I wish you all the best