Sahih Bukhari Volume 7, Book 74, Hadith 5610

حَدَّثَنَا أَبُو الْيَمَانِ، أَخْبَرَنَا شُعَيْبٌ، حَدَّثَنَا أَبُو الزِّنَادِ، عَنْ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ نِعْمَ الصَّدَقَةُ اللِّقْحَةُ الصَّفِيُّ مِنْحَةً، وَالشَّاةُ الصَّفِيُّ مِنْحَةً، تَغْدُو بِإِنَاءٍ، وَتَرُوحُ بِآخَرَ ‏"‏‏

Narrated By Abu Huraira : Allah's Apostle said, "The best object of charity is a she-camel which has (newly) given birth and gives plenty of milk, or a she-goat which gives plenty of milk; and is given to somebody to utilize its milk by milking one bowl in the morning and one in the evening."