Skandapurana 6.3.146.79

6.3.146.79

piṅgaḥ khuraviṣāṇābhyāṃ sa nīlo vṛṣa ucyate .
yastu sarvāṅgapiṅgaśca śvetaḥ pucchakhureṣu ca .. 146.79 ..

and tawny at the hooves and horns, is called a ‘dark’ (nīla) bull.
One that is tawny throughout all limbs and white at the tail and hooves,