The Board, upon a joint petition requesting a referendum being filed with it by at least three of the following: the Virginia Horse Council, Inc., the Virginia Thoroughbred Association, the Virginia Horse Shows Association, the Virginia Quarter Horse Association, the Virginia Farm Bureau Federation, or the Virginia Agribusiness Council, and upon finding that sufficient interest exists among the members of the equine owners in the Commonwealth to justify a referendum, shall authorize the holding of a referendum as set forth in this article. The Commissioner shall thereupon be fully empowered and directed to hold and conduct a referendum, in accordance with the provisions of §§ 3.2-112 and 3.2-1705, on the question of whether or not equine owners in the Commonwealth are of the opinion that additional market development, education, publicity, research, and promotion of the equine industry are required. If approved in the referendum authorized by this section, an assessment of $3 per ton or $0.075 per 50-pound bag of manufactured equine feed shall be established. The cost of conducting a referendum under this section shall be paid from the Virginia Horse Industry Promotion and Development Fund.