A breastplate (used interchangeably with breastgirth and breastcollar) is a piece of riding equipment used on horses. Its purpose is to keep the saddle from sliding back, and is most helpful on horses with large shoulders and a flat ribcage. It is also a safety feature, especially on cross-country, should a rider's girth or billets break, as she will have enough time to stop the horse and dismount before the saddle slipped off the animal's back or underneath its belly.