Kislev

Kilayim of animals is the prohibition against crossbreeding two different species of animals. The Torah forbids mating a horse with a donkey, or any other combination of species. This mitzvah applies both in the Land of Israel and abroad, but its primary context is the working of the land in the Land of Israel, where animals are used for plowing and threshing. The Sages also decreed prohibitions related to kilayim of animals, such as not plowing with an ox and a donkey together, and not wearing a garment of mixed wool and linen (sha'atnez).