Nicking, which is done by mating a stallion to the daughter of another stallion, has been practiced for centuries in hopes of reproducing favorable results from earlier matings. Breeders talk about a "nick" when a sire does significantly better with a particular sire's offspring than  with the females or other sires. In some cases, the offspring of a good nick is said to have been "born again". A good nicking can be highly valuable, since a stallion may mate to a mare of lesser value (and, thus, lower genetic potential) and still get a superior result.