Iowa Code § 351.42: Exempt dogs.

Dogs that are under the control of the owner or handlers and which are in transit, or are to be exhibited shall be exempt from the vaccination provisions of these sections if they are within the state for less than thirty days. Dogs assigned to a research institution or a like facility shall be exempt from the provisions of sections 351.33 and 351.35, sections 351.36 through 351.41, this section, and section 351.43.