21 CFR Part 530.3 defines the federally "valid VCPR" - A valid veterinarian-client-patient relationship is one in which:(1) A veterinarian has assumed the responsibility for making medical judgments regarding the health of (an) animal(s) and the need for medical treatment, and the client (the owner of the animal or animals or other caretaker) has agreed to follow the instructions of the veterinarian;(2) There is sufficient knowledge of the animal(s) by the veterinarian to initiate at least a general or preliminary diagnosis of the medical condition of the animal(s); and(3) The practicing veterinarian is readily available for follow-up in case of adverse reactions or failure of the regimen of therapy. Such a relationship can exist only when the veterinarian has recently seen and is personally acquainted with the keeping and care of the animal(s) by virtue of examination of the animal(s), and/or by medically appropriate and timely visits to the premises where the animal(s) are kept.”
ELDU for therapeutic purposes only (animal's health is suffering or threatened). Not drugs for production use.Rules apply to dosage form drugs and drugs administered in water. ELDU in feed is prohibited.ELDU is not permitted if it results in a violative food residue, or any residue which may present a risk to public health.FDA prohibition of a specific ELDU precludes such use.