By way of a fourth derogation, subject to a maximum of 10 % of adult equine or bovine (including bubalus and bison species) livestock and 20 % of the adult porcine, ovine and caprine livestock, livestock may be brought in, as female (nulliparous) animals, from non organic-production stockfarms per year, for supplementing natural growth and for the renewal of the herd or flock, when organically reared animals are not available, and only when authorised by the control authority or body.