It is narrated from Abu Amir Huzni, he says: Sayyiduna Abu Kabsha Anmari (may Allah be pleased with him) came to me and said: Lend me your horse for mating, because I heard the Messenger of Allah (peace and blessings be upon him) say: Whoever lends someone a horse for mating, and as a result a horse is born, he will have the reward of seventy such horses that are given for riding in the way of Allah.

It is narrated from Sayyiduna Ali (may Allah be pleased with him) that a male or female mule was given as a gift to the Messenger of Allah (peace and blessings be upon him). I said: What is this? The Prophet (peace and blessings be upon him) said: This is a male or female mule of the breed. I said: How is it produced? The Prophet (peace and blessings be upon him) said: When a donkey mates with a mare, this is produced from them. I said: Then should we not mate such-and-such donkey with such-and-such mare? The Prophet (peace and blessings be upon him) said: No, only those people do such a thing who do not have knowledge.

It is narrated from Sayyiduna Dihyah Kalbi (may Allah be pleased with him), he says: I said, "O Messenger of Allah! Should I not have a mare mated with a donkey for you, so that a mule is produced and you may ride on it?" But the Prophet (peace and blessings be upon him) said: "Those who do not have knowledge do this act."

It is narrated from Sayyiduna Ali (may Allah be pleased with him), he says: The Messenger of Allah (peace and blessings be upon him and his family) forbade us from mating a mare with a donkey.

It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) forbade the castration of horses and other animals. Sayyiduna Ibn Umar (may Allah be pleased with them both) said: Not castrating increases the progeny.