Musannaf Ibn Abi Shayba 18:40

Abu Bakr narrated to us, he said: Muhammad ibn Bakr narrated to us, from Ibn Jurayj, he said: I said to 'Ata', "What is the heavy blood money (tahleez) for camels?" He said: "Forty pregnant she-camels (khalifah), thirty four-year-old she-camels (hiqqah), and thirty three-year-old she-camels (jadha'ah)."