578.156.  Interference with the transportation of livestock, offense of — penalties. — 1.  A person commits the offense of interference with the transportation of livestock if the person knowingly does any of the following:

  (1)  Stops, hinders, impedes, boards, obstructs, or otherwise interferes with a motor vehicle transporting livestock regardless of whether the motor vehicle is moving;

  (2)  Provokes or disturbs livestock when the livestock is confined in a motor vehicle regardless of whether the motor vehicle is moving; or

  (3)  Puts or places a compound or substance on, near, or upon such livestock that would:

  (a)  Affect the livestock's marketability or suitability for use;

  (b)  Affect animal or human health; or

  (c)  Result in an unreasonable transportation or shipping delay.

  2.  The offense of interference with the transportation of livestock is a class E felony for a first offense and a class C felony for any second or subsequent offense.

  3.  In a prosecution alleging that a person committed the offense of interference with the transportation of livestock under subsection 1 of this section, the person may assert an affirmative defense of consent.  The person shall prove by a preponderance of the evidence that the person was acting with the consent of any of the following:

  (1)  A person having real or apparent authority to transport the livestock; or

  (2)  The owner of the livestock or any other person having real or apparent authority to possess or control the livestock.

  4.  The provisions of this section shall not apply to any enforcement action or services provided by a law enforcement officer or agency or an employee or agent of the department of agriculture acting under section 267.645.

  5.  As used in this section, the following terms mean:

  (1)  "Livestock", as defined under section 265.300;

  (2)  "Motor vehicle", any self-propelled vehicle not operated exclusively upon tracks and an item attached to the motor vehicle.  "Motor vehicle" shall not include farm tractors and electric bicycles.