While tail docking is an effective preventive method in some cases, if it is not carried out correctly it may result in other problems such as ill thrift or rectal prolapse. In lambs, tail docking at the distal end of the caudal folds tends to minimize docking effects on incidence of rectal prolapse. Docking at that length has been recommended by the American Veterinary Medical Association. In the UK the law states that for sheep docked tails should at a minimum cover the anus in male lambs, and the vulva in female lambs. These minimum lengths are also recommended in Canada