Technical term for a horse coat color, specifically dun, characterized by a light body with darker points. Used in equestrian and veterinary contexts.
その馬の毛色は鼠毛です。
That horse's coat color is dun.
Compound of 鼠 (ねずみ, 'mouse') and 毛 (け, 'hair, fur'), referring to the mouse-like grayish-brown color of a dun horse coat.