High school students interested in becoming veterinarians may find part-time or volunteer work on farms, in small-animal clinics, or in pet shops, animal shelters, or research laboratories. Participation in extracurricular activities such as 4-H are good ways to learn about the care of animals. Such experience is important because, as already noted, many schools of veterinary medicine have established experience with animals as a criterion for admission to their programs. Other methods of exploration include talking to a veterinarian about their career, reading books and magazines about veterinary science, and visiting the Web sites of veterinary associations and veterinary medical colleges. 

Veterinarians care for pets—large and small. They ensure a safe food supply by maintaining the health of food animals. They also protect the public from residues of herbicides, pesticides, and antibiotics in food. Veterinarians may be involved in wildlife preservation and conservation and use their knowledge to increase food production through genetics, animal feed production, and preventive medicine.

About 76 percent of veterinarians are employed in solo or group veterinary medicine practices. Some veterinarians treat all kinds of animals, but more than half limit their practice to companion animals such as dogs, cats, and birds. A smaller number of veterinarians work mainly with horses, cattle, pigs, sheep, goats, and poultry. Today, a veterinarian may be treating llamas, catfish, or ostriches as well. Others are employed by wildlife management groups, zoos, aquariums, ranches, feed lots, fish farms, and animal shelters.

Veterinarians in private practice diagnose and treat animal health problems. During yearly checkups, the veterinarian records the animal's temperature and weight; inspects its mouth, eyes, and ears; inspects the skin or coat for any signs of abnormalities; observes any peculiarities in the animal's behavior; and discusses the animal's eating, sleeping, and exercise habits at length with the owner. The veterinarian will also check the animal's vaccination records and administer inoculations for rabies, distemper, and other diseases if necessary. If the veterinarian or owner notes any special concerns, or if the animal is taken to the veterinarian for a specific procedure, such as spaying or neutering, dental cleaning, or setting broken bones, the animal may stay at the veterinarian's office for one or several days for surgery, observation, or extended treatments. If a sick or wounded animal is beyond medical help, the veterinarian may, with the consent of the owner, have to euthanize the animal.

During office visits and surgery, veterinarians use traditional medical instruments, such as stethoscopes, thermometers, and surgical instruments, and standard tests, such as X-rays and diagnostic medical sonography, to evaluate the animal's health. Veterinarians may also prescribe drugs for the animal, which the owner purchases at the veterinarian's office.

Some veterinarians work in public and corporate sectors. Many are employed by city, county, state, provincial, or federal government agencies that investigate, test for, and control diseases in companion animals, livestock, and poultry that affect both animal and human health. Veterinarians also play an important public health role. For example, veterinarians played an important part in conquering diseases such as malaria and yellow fever.

Pharmaceutical and biomedical research firms hire veterinarians to develop, test, and supervise the production of drugs, chemicals, and biological products such as antibiotics and vaccines that are designed for human and animal use. Some veterinarians are employed in management, technical sales and services, and marketing in agribusiness, pet food companies, and pharmaceutical companies. Still other veterinarians are engaged in research and teaching at veterinary medical schools, working with racetracks or animal-related enterprises, or working within the military, public health corps, and space agencies.

Veterinarians in private clinical practice become specialists in surgery, anesthesiology, dentistry, internal medicine, ophthalmology, or radiology. Many veterinarians also pursue advanced degrees in the basic sciences, such as anatomy, microbiology, and physiology. Veterinarians who seek specialty board certification in one of 40 specialty fields must complete a two- to five-year residency program and must pass an additional examination. Some veterinarians combine their degree in veterinary medicine with a degree in business (M.B.A.) or law (J.D.).

The U.S. Department of Agriculture offers opportunities for veterinarians in the Food Safety and Inspection Service and the Animal and Plant Health Inspection Service, notably in the areas of food hygiene and safety, animal welfare, animal disease control, and research. Veterinarians also are employed by the Environmental Protection Agency to deal with public health and environmental risks to the human population.

Veterinarians are often assisted by veterinary technicians, who may conduct basic tests, record an animal's medical history for the veterinarian's review, and assist the veterinarian in surgical procedures.