Asim bin Kulayb narrates from his father, and he from a man (may Allah be pleased with him) of the tribe of Juhaynah or Muzaynah, that they were with the Messenger of Allah (peace and blessings be upon him) a day or two before the sacrifice, and they used to give two goats in exchange for one musinnah. The Messenger of Allah (peace and blessings be upon him) said: "The jadha'ah, i.e. of sheep, suffices in place of a musinnah animal."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19071