Piebald.

Party-coloured. A corruption of pie-balled, speckled like a pie. The words Ball, Dun, and Favel are frequently given as names to cows. “Ball” means the cow with a mark on its face; “Dun” means the cow of a dun or brownish-yellow colour; and “Favel” means the bay cow. (Ball, in Gaelic, means a mark; ballach, speckled.)