Terms used in §§ 5-5-10.2 to 5-5-10.4, inclusive, mean:
(1) "Animal unit," one cow and calf, one horse, five sheep, or five goats;
(2) "Annual animal carrying capacity," the number of acres needed for one animal unit to subsist on natural forage, on a given tract of land for one year;
(3) "Rental rate," twenty percent of the average price of one calf as sold in South Dakota for the last reported five years based on the weight of a four hundred twenty-five pound calf.