Texas Occupations Code - OCC § 801.358. Liability of Veterinarian for Emergency Treatment;  Euthanasia Presumption

(a) A veterinarian who provides emergency treatment to an ill or injured animal on the veterinarian's own initiative, or at the request of a person other than the animal's owner, is not liable to the owner for damages to the animal unless the veterinarian commits gross negligence.

(b) If the veterinarian performs euthanasia on the animal, the veterinarian is presumed to have performed a humane act necessary to relieve the animal's pain and suffering.