Breast collars and pulling collars are designed to stop the saddle from slipping rearwards while riding. Saddles can slip towards the rear while going through hilly terrain, when girths loosen or by the action of the rider's seat in the saddle. Breeching and cruppers are designed to stop the saddle from slipping forward while riding. Saddles can slip forwards rear while going through hilly terrain, when girths loosen or by the rider's seat in the saddle. Mutton withered and round barreled horses and mules often benefit from breeching or a crupper.