Nothing in § 55.1-2814 shall repeal the existing fence laws in any county, magisterial district, or selected portion of any county, until changed by the board of supervisors or other governing body, by ordinance and in accordance with the provisions thereof, nor shall the provisions of § 55.1-2814 apply to any county, magisterial district, or selected portion of any county in which the no-fence law is now in force, if such no-fence law exists otherwise than in an ordinance adopted by the board of supervisors or other governing body of such county entered pursuant to § 55.1-2814.