It is a little different with horses. Inbreeding is sire to daughter, son to dam, or full siblings. LIne breeding is breeding grandsons and daughters to grand sons or daughters. When you see the same sire appear on the top and bottom of the papers, we call it line breeding. This can still concentrate recessive bad traits, Line bred Poco Bueno horses have a better chance of having HERDA. Line bred Imprsseive horses stand a better chance of being HYPP positive. For most commercial producers, you will be a lot better off to not breed your bull to his daughters.