because of a cat which she confined until it died: she neither fed it nor let it loose to eat from the vermin of the earth.” (1)

His statement, “whatever is needed for their wellbeing,” means whatever protects them from harm. Thus, he is obliged to keep them under a shelter that protects them from heat or cold, if they are affected by heat or cold. If they are not affected, then this is not obligatory upon him.

His statement, “whatever is needed for their wellbeing,” also includes the case in which the animal has a wound or something causing it pain, and he is able to treat it: he is then obliged to do so. This is why people have needed veterinarians, for he cannot leave it suffering when he is able to remove its pain. Indeed, its need to have what harms it removed may be greater than its need for food and drink.

His statement, “nor burden them with what they are unable to bear,” means that he is likewise obliged not to load them with what they cannot bear, because placing upon them what they cannot bear causes them hardship. But how do we know that this causes them hardship or is beyond their capacity? We know from the condition of the animal itself: sheep cannot carry what a cow can carry, cattle cannot carry what camels can carry, and the weak among them cannot carry what the strong can carry. This is something known from outward circumstances, and so he must show them mercy.

His statement, “what they are unable to bear,” did not say, “nor should he load them with that which it is not customary to load them with.” Accordingly, it is permissible to make them carry something that they are not customarily made to carry—for example, using cattle for carrying loads, camels for ploughing, and goats for children to ride. There is no harm in this, provided that it does not cause them hardship.