Russian (Rooshan, Rooshian) — esp. of cattle: a beast that is wild or difficult to handle.
With wild cattle you can do nothing. … These wild Russians, as they are called, will … clear at the first leap a stock-yard six feet in height (D. Mackenzie, Emigrant’s Guide). When a real ‘Russian’ happens to be among the mob, circumspection must positively be practised as well as bravery (A. Harris, Settlers & Convicts).