The Mishnah in chapter six of Tractate Bechoros continues to list the blemishes that disqualify an animal, and Mishnah 10 brings the words of Rabbi Chanina ben Antigonus.
"Es sheyesh yabeles be'eino":
A wart that grows in the animal's eye. This refers even to a wart in the white part of the eye (the sclera), even though the Mishnah established earlier in the chapter that the white part does not determine a blemish. The reason for this is that it is not just a wart, but a wart with a hair growing out of it. This defect is so ugly and significant that even in the white of the eye it is considered a blemish that disqualifies the animal.
Additional blemishes listed in the Mishnah:
A missing bone in the leg: An animal that is missing a piece of bone from its front or hind leg. When the deficiency is visible from the outside, it does not grow back, and therefore it is a blemish.
A split jaw: The lower jaw in its mouth is cracked.
One large eye and one small eye.
One large ear and one small ear.
A large eye and a small eye:
The approach of the Bartenura: This refers to one eye that is too large and one eye that is too small, and both are present together. The large one is like the eye of a calf, meaning like a cow's eye, when it should be like that of a goat or a sheep, and the small one is the size of a goose's eye. That is, one is particularly large and one is particularly small.
The approach of the Rash: It seems that he explains it as either this or that - either a large eye or a small eye, provided that it is large or small to the extent that the animal's appearance looks unusual. There is, therefore, a dispute in understanding the words of the Mishnah.
One large ear and one small ear:
That one ear is large and the other is small, but this must be noticeably visible. We do not measure the ears with exact measurements and say that this ear is larger than the other by one centimeter and therefore it is a blemish. Rather, the matter must be such that anyone standing from afar and looking at the animal can see that one ear is particularly large or particularly small.
A dispute regarding the size of the testicles:
Rabbi Yehudah says regarding the animal's testicles that if one testicle is twice as large as the other, it is a blemish. The Sages say that a difference in size between the testicles is not considered a blemish. However, the Gemara explains that if one testicle is so small that it is the size of a bean, it is indeed a blemish. Generally, however, the halachah is that size differences between the testicles do not pose a problem, as long as one has not reached this small size.