Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated that the Messenger of Allah (peace and blessings be upon him) forbade (eating) mujaththama, drinking the milk of jallalah, and drinking water by putting the mouth to a musk (waterskin).
Hadith Referenceسنن دارمي / من كتاب الاضاحي / 2040
The meaning of "mujaththamah" has already been mentioned previously. "Jallalah" refers to an animal that eats filth, whether it is a goat, cow, chicken, or any other animal. Due to its flesh being impure, it is not permissible to eat it.
Some scholars have said: If the animal is confined for several days and not allowed to eat filth, then its flesh becomes pure.
Drinking water directly from a water-skin by putting the mouth to it is prohibited due to the risk of choking or something getting stuck in the throat, as well as the fear of swallowing something else along with the water. Therefore, it has been prohibited.