The director shall, when livestock is sold, traded, exchanged, or handled at or through a public livestock market, require such testing, treating, identifying, examining and recordkeeping of such livestock by a Washington state licensed and accredited veterinarian employed by the market as in the director's judgment may be necessary to prevent the spread of brucellosis, tuberculosis, paratuberculosis, pseudorabies, or any other infectious, contagious, or communicable disease among the livestock of this state. The state veterinarian or his or her authorized representative may conduct additional testing and examinations for the same purpose.