With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: The coat colour of the aurochs can be reconstructed by using historical and contemporary depictions. In his letter to Conrad Gesner (1602), Anton Schneeberger describes the aurochs, a description that agrees with cave paintings in Lascaux and Chauvet. Calves were born a chestnut colour. Young bulls changed their coat colour at a few months old to black, with a white eel stripe running down the spine. Cows retained the reddish-brown colour. Both sexes had a light-coloured muzzle. Some North African engravings show aurochs with a light-coloured "saddle" on the back, but otherwise no evidence of variation in coat colour is seen throughout its range. A passage from Mucante (1596) describes the "wild ox" as gray, but is ambiguous and may refer to the wisent. Egyptian grave paintings show cattle with a reddish-brown coat colour in both sexes, with a light saddle, but the horn shape of these suggest that they may depict domesticated cattle. Remains of aurochs hair were not known until the early 1980s.
text_B: Would a one year old bull have a black coat?
YES.