(a) Change of ownership within Texas. All cattle that are parturient or post parturient or 18 months of age and older, except steers and spayed heifers changing ownership within Texas, shall be officially identified with an official eartag or other form of official permanent identification as approved by the commission within seven days of the change of ownership.(b) Cattle that are sold or consigned to move to a state or federally approved slaughter establishment within seven days of the change of ownership, where they are harvested within three days of arrival at the establishment, are exempt from the requirement of subsection (a) of this section.