- The laws of kilayim – forbidden mixtures – do not apply to its wool
- Its wool cannot be used for tekhelet – the special blue thread of tzitzit.
Much of today’s daf (=page) is focused on animals that do not look like their mother. The Mishnah (daf 16b) taught that if a ewe gave birth to what looked like a kid, or a kid gave birth to what looked like a ewe, it is exempt from the law of the firstling but if it possesses certain clear marks resembling the mother it is liable to the law of the firstling.
There are many different breeds of sheep and goats that differ from one another in a number of characteristics. Still, from the descriptions of these animals that are found in the Mishnah and the Talmud it appears that the animals with which the Sages were familiar were similar to today’s common Israeli sheep, the ovis orientalis playtura, while the goats were similar to capra mambrica, today’s common Israeli goat. The wool of the sheep is white, soft and curly, as opposed to the hair of the goat, which is black and hard. The sheep has a long, thick, fatty tail, as opposed to the short, straight tail of the goat. A lamb’s ears are short, while that of a kid are long and dangling. The male goat has a beard, which a ram does not have. The female goat grows horns, which the ewe does not. They can also be distinguished by their bleating voices.
The case of the Mishnah is when an animal is born of one animal that has the characteristics of the other. This is not a discussion of a hybrid, which the Gemara has already discussed (see above, daf 12), but where an animal is born of two animals of the same species that looks like the other.
Such a creature is referred to by the Gemara as a nidmeh – something that “appears” to be something else. The laws of nidmeh extend beyond not requiring it to be set aside as a firstborn; the Gemara lists other unique laws, as well, for example: