Hi Melissa!
Texas is in process of re-gaining its TB free status.
Generally, cattle moved across state lines need a Veterinarian's Health Certificate issued which verifies that the animal has been tested within 30 days to be TB and Brucellosis free, as well as doesn't display any obvious symptoms of illness, disease, etc. The TB test requires innoculation with a Tuberculin in the caudal fold of the tail and then the Vet "reads" the site within 72 hours. If the animal comes from a state that has TB and Brucellolis free status, then the Vet will note this on the Certificate. Also, if the Herd that the animal comes from is a certified free herd, then the state certification number for that herd will be entered on the Vet Certificate.
It is also advisable that any animal crossing state lines have their regular vaccinations current along with a current de-worming. This is just additional insurance that the incoming animal has current health status.
After arrival, it is recommended that the new animal be quarantined at the person's (new owner's) facility for at least a week or two so the new owner can observe the animal for any illness or other physical problems. Then, the new animal is gradually introduced to the other animals--first across the fence, then physically in the area with the others. If the purchased animal is shipped with other animals destined for other buyers, then it is recommended that your animals be vaccinated for respiratory diseases and other "shipping" type conditions. I would also recommend de-worming any new arrivals with an injectible wormer such as Dectomax, Ivomec, or Ivermectin related compounds.
Hope this info helps! Good luck!
Bill