The Messenger of Allah ﷺ, the truthful and trusted, told us, "Selling animals whose milk has been left to accumulate in their udders is deception, and deception is not permissible for a Muslim."
حدثنا وكيع حدثنا المسعودي عن جابر عن أبي الضحى عن مسروق
حدثنا رسول الله ﷺ وهو الصادق المصدوق قال بيع المحفلات خلابة ولا تحل الخلابة لمسلم
Its isnad is daif due to the weakness of Jabir Jafi. Ibn Majah 2:17 also narrated it, from the route of Waki, and we have already pointed to it at 4096.