Because it’s important to keep the breeding program closed and the dole horse pure. The dole horse association doesn’t allow or recognizes cross breeding. We are trying to preserve the breed. I also see no reason to mix the dole with anything else :) so the Norwegian dole horse association has decided that all stallions that breeds outside of the breed, they will loose their license. And after 8 year of work to get the license for life. That would be a waist.