Any company owning or operating a railroad in whole or in part in this state, which receives livestock for shipment in carload lots, shall be governed and regulated by the following rules and regulations relative to the intrastate rates and minimum weights to be charged in carload lot shipments of livestock:

(A) If such company receives hogs for carload lot shipments in cares:

(1) Of a length of thirty-six and seven-tenths feet or under, the rate charged shall be on a basis of a minimum weight of not more than sixteen thousand pounds for single-deck cars, and twenty-two thousand pounds for double-deck cars;

(2) Of a length exceeding thirty-six and seven-tenths feet, and not more than forty feet, the rate charged shall be on a basis of minimum weight of not more than seventeen thousand pounds for single-deck cars, and twenty-three thousand pounds for double-deck cars;

(3) Over forty feet in length the rate charged shall be on a basis of a minimum weight of not exceeding eighteen thousand pounds for single-deck cars and twenty-four thousand pounds for double-deck cars.

(B) If such company receives for shipment a car containing a mixture of hogs, cattle, and sheep, or any two of them, the freight rate charged shall be based upon the same animal classification as is used to determine the minimum freight weight. The public utilities commission shall enforce this section.