California Code, Business and Professions Code - BPC § 4826.4

(1) Render necessary and prompt care and treatment to an animal patient without establishing a veterinarian-client-patient relationship if conditions are such that one cannot be established in a timely manner.

(2) Dispense or prescribe a dangerous drug or device, as defined in Section 4022, in reasonable quantities where failure to provide services or medications, including controlled substances, may result in loss of life or intense suffering of the animal patient. Prior to refilling a prescription pursuant to this paragraph, the veterinarian shall make a reasonable effort to contact the originally prescribing veterinarian.