Who makes these rules??? Maybe that's an antiquated criteria for generating graduates? Would someone be just as good if they only had an associate degree before entering vet school?
from a google search: looks like every state requires certain levels of education to get licensed.
Will I Need a License?
You must generally earn a license before you can practice veterinary medicine in the United States. However, some government employers may not require a license. Although licensure requirements vary by state, they usually include graduating from an approved veterinary medicine program and passing the North American Veterinary Licensing Exam. Depending on your state, you may be required to take additional examinations, such as a state jurisprudence exam or a clinical competency exam.
To gain admission to a veterinary medicine program, you must first complete undergraduate prerequisite courses, which may include inorganic and organic chemistry, biology, physics, nutrition, microbiology, genetics, social science, English and mathematics. Many schools also require that you gain experience working with animals. Since admission to veterinary school is highly competitive, it is recommended that you earn a bachelor's degree as well. You will also need to take an admissions exam, which, depending on the school to which you apply, could be the Veterinary College Admission Test (VCAT), the Graduate Record Examination (GRE) or the Medical College Admission Test (MCAT).
While enrolled in a veterinary medicine program, you will take courses in anatomy, physiology, pathology, immunology, microbiology, pharmacology, nutrition and ethics during your first two years. During your final two years, you will receive clinical training in surgery, anesthesia, dermatology, ophthalmology, radiology, critical care and euthanasia. You will be exposed to different types of veterinary medicine, such as companion animal, food animal, wildlife and equine medicine. Some programs allow you to concurrently conduct research and prepare a thesis. Upon completion of your program, you will earn a Doctor of Veterinary Medicine (D.V.M.) or Veterinaria Medicina Doctoris (V.M.D.) degree.