《三国志·魏书·乌丸鲜卑东夷传》
当军事发生时，通常要祭天，杀死牛，观察其蹄，用以占卜吉凶。牛蹄崩开表明是凶，牛蹄合拢表示是吉。
有军事亦祭天，杀牛观蹄以占吉凶，蹄解者为凶，合者为吉。
When there was a military action, it was common to sacrifice to the heaven, kill an ox, and examine its hoof to make a divination. The hoof falling apart indicated ill luck, while the hoof closing together indicated good luck.