DEUT1170 Several Biblical laws deal with the treatment of animals for agricultural work [This verse] prohibits plowing one's field with an ox and a donkey harnessed together. Being of unequal size and strength, both animals, particularly the weaker one, will suffer; the donkey will experience strain, and the ox frustration. By implication, although the Torah speaks only of a donkey and ox, one should not yoke together any animals of significantly equal unequal strength.