The Gemara stated that Rabbi Yehuda HaNasi’s suffering came upon him due to an incident. What was that incident that led to his suffering? The Gemara answers that there was a certain calf that was being led to slaughter. The calf went and hung its head on the corner of Rabbi Yehuda HaNasi’s garment and was weeping. Rabbi Yehuda HaNasi said to it: Go, as you were created for this purpose. It was said in Heaven: Since he was not compassionate toward the calf, let afflictions come upon him.

(2) Further proof that they did not sleep is presented to us by R. Yohanan. He tells us in the name of R. Eliezer the son of R. Yosé the Galilean that because Noah once delayed feeding a lion, the lion bit him so severely that he left the ark crippled, as it is said: And only Noah was left (Gen. 7:23). The word ah (“only,” also “to be afflicted”) indicates that his body was no longer whole. He became, thereby, unfit to bring sacrifices to the altar, and his son Shem had to do it in his stead. Concerning him it is said: Behold, the righteous shall be made whole in the earth (Prov. 11:31).

Moses, too, the Holy One blessed be He tested him only with flocks. Our Rabbis say: When Moses, may he rest in peace, was herding Yitro’s flock in the wilderness, a kid fled from him. He pursued it until it reached cover. Once it reached cover, it happened upon a pool of water, and the kid stopped to drink. When Moses reached it, he said: ‘I didn’t know that you were running due to thirst. You are tired.’ He carried it on his shoulder and was walking. The Holy One blessed be He said: ‘You have the compassion to behave with the flocks belonging to flesh and blood in this manner; by your life, you will herd My flock, Israel.’ That is: “Moses was herding.”

It is also prohibited to kill an animal with its young on the same day (Lev. 22:28), in order that people should be restrained and prevented from killing the two together in such a manner that the young is slain in the sight of the mother; for the pain of the animals under such circumstances is very great. There is no difference in this case between the pain of man and the pain of other living beings, since the love and tenderness of the mother for her young ones is not produced by reasoning, but by imagination, and this faculty exists not only in man but in most living beings. This law applies only to ox and lamb, because of the domestic animals used as food these alone are permitted to us, and in these cases the mother recognises her young.

The Torah forbids us to inflict suffering on any living creature. On the contrary, it is an obligation to remove the suffering of any creature, even if it is ownerless, and even if it belongs to a non-Jew. However, if they are troublesome to mankind, or if they are needed for medical purposes, or for any other purpose, it is permitted even to kill them, and we disregard their pain; for the Torah permits us to slaughter them. Therefore, it is permitted to pluck feathers from living geese [to use as a quill], if you have no other feather [with which to write]. However, people abstain from doing so because of cruelty.

It is permissible to raise pets, such as dogs, cats and parrots...

However, there are some that claim that since these are called impure, it is inappropriate to bring them into the home. Yet this reasoning is not mentioned in the the books of the poskim (decisors). And these animals are [only] called impure because they are forbidden to eat, and one who eats from its meat makes himself impure. But this does not mean that their traits are defective to the point that one who raises them will likely render his soul defective. And it is the opposite, that each animal has its own particular good trait; so the Sages praised also types of impure animals, and noted the loyalty of the dog and the modesty of the cat. Hence it is permissible to raise pets.