Hilchos Issurei Mizbeiach 4:2

If an animal or bird had relations with a human, was the object of relations from a human, or killed a human, it is executed by stoning so long as the deed was observed by two witnesses. It is prohibited to derive benefit from the executed animal’s flesh, and it goes without saying that such an animal is prohibited for the altar. The statement that such animals are prohibited for the altar was said in a case where the animals were permitted for basic use, such as if there was only one witness to the sin and the animal’s owner remained silent, or if the owner testified regarding the sin but there no witnesses. If one witness observed the sin and the animal’s owner contradicts him, the animal remains permitted, even for the altar.

Hilchos Issurei Mizbeiach 4:3

If an animal is used in the ring [like bullfighting] and is trained to gore until it kills, it remains fit for the altar because it is considered to have been coerced to kill. An animal is not disqualified for having relations with or receiving relations from a male under the age of nine. An animal is disqualified for the altar if it was the object of relations from a Jew, a non-Jew or a servant, since a human had relations with it. If a human was the object of relations from an animal, the animal is not disqualified unless the female recipient was at least three years of age or the male recipient was at least nine years of age.