All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The scholars provided different opinions regarding the Udh-hiyah's milk.
The Maaliki scholars are of the opinion that it is permissible for the owner of the Udh-hiyah to drink from its milk. In Al-Muntaqa, Al-Baji a Maliki scholar, said, "Malik said that it is permissible for one to drink from the milk of his Udh-hiyah."
The Hanbali scholars allowed drinking only what remains after its kid has drunk thereof." The author of Ghayat Al-Muntaha and the book's commentator, Ar-Ruhaybani said, "It is allowed to drink only what remains after its kid has drunk and without causing it any harm."
The Shaafi‘i scholars are of the opinion that the Udh-hiyah's milk should be given in charity. Reporting from Al-Mutawalli, An-Nawawi said, "The milk of an animal allocated for Udh-hiyah is to be immediately given in charity, and it is also permissible to sell it."
Since there is no evidence from the Quran or the Sunnah to support one of these opinions, we view that the soundest is the opinion of the Maliki scholars . This is based on the principle that all things are originally permissible unless there is evidence that proves otherwise. There is no evidence in this regard.
Allaah Knows best.