Sayyiduna Usayd bin Hudayr (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) said: "Pray in the sheep pens, and do not perform ablution after drinking their milk; and do not pray in the camel enclosures, and perform ablution after drinking their milk."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 555