Q. We are a family of Bnei Torah but we have had a cat for many years that grew up with our children and is like part of the family. The cat is old and sick, the vet says he has a kind of animal cancer and should be put down. We don’t know if it is suffering or not, should we follow his instructions? The vet says to have the cat cremated, is that correct or should we netter bury it in our back yard? Thanks so much for your advise.

A. Noda Beyihuda (Y.D. 2: 10) maintains that in hunting when it is permitted (not for sport) there is no concern of making the animal suffer, because “to kill animals or all types does not involve the prohibition of tzaar baalei chayim.” the actual killing is not considered causing an animal to suffer, and there is therefore no prohibition. Others disagree, Shoel Umeishiv (2: 3: 65) rules that the prohibition certainly applies to killing. He proves his case from the rationale presented by the Chinuch (440) for the mitzvah of shechitah. A similar principle emerges from the Ri Migash (cited in Shita Mekubetzes, Bava Metzia ).
Chazon Ish is quoted (in Dinim Ve-Hanhagos Mi-Maran Ha-Chazon Ish, 2: p. 40) as having been asked by a member of the family how a dying fly should be treated. The Chazon Ish responded that the fly should be killed, so as to prevent its extended suffering.
Horav Shlomo Miller’s opinion is that in your case, the assessment if the animal is suffering should be better done by the vet, who should also put him to sleep without suffering, when necessary.
As far as how to dispose of the body, the Rov recommends that it should be done in the most environmental friendly and legal way.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a