Sunan Ibn Majah, Chapter: The Chapters Regarding Zakat

"The Messenger of Allah (saw) said: 'There is no Sadaqah on any less then five camels, or for four. If the number of camels reaches five then one sheep must be given, up to nine. If the number reaches ten, then two sheep must be given, up to fourteen. If the number reaches fifteen, then three sheep must be given, up to nineteen. If the number reaches twenty, then four sheep must be given, up to twenty-four. If the number reaches twenty-five, then a Bint Makhad (a one year old she-camel), must be given up to thirty-five; if there is not Bint Makhad, then a Bin Labun (a two-year-old male camel). If there are more camels then a Bint Labun (a two-year-old she-camel) up to forty-five. If there are more camels then a Hiqqah (a three-year-old she-camel) must be given up to sixty. If there are more camels then a Jadha'ah (a five-year-old she-camel) must be given up to seventy-five. If there are more camels, then two Bint Labun must be given, up to ninety. If there are more camels, then two Hiqqah must be given, up to one hundred and twenty. The for each fifty, one Hiqqah, and for each forty, a Bint Labun.' " Sahih