Breeders or sellers may wish to use a private treaty when they offer different terms for different situations. For example, a breeder may offer their stallion's services to purebreds, part-breds or grade mares, or mares of a specific type or bloodline at different rates. This allows the stallion owner some control over the type of mares they will breed their stallion too. Mares that they favor may be serviced at a lower cost to the mare owner, than those they consider a less desirable match for their stallion.
Sellers too, will sell horses by private treaty, allowing them to tailor the terms of each sale.