The Talmud (Shabbat 52a), in discussing what an animal can carry on Shabbat, considers the possibility that an item that is for “Shmirah” (to hold the animal by the strap) is permitted, while an item that is for “Noy” (decoration) is prohibited. As the Pnei Yehoshua notes, this is counterintuitive, when considered against the standard for human beings: carrying in general is prohibited, but jewelry used for decoration (“tachshit”) is permitted. However, as R. Shmuel Rothschild notes (in the journal Kol Torah, #59, “Simchat HaTorah” pp. 24-25), the difference is quite understandable. A person wearing jewelry is enhanced by the adornment, and thus the “tachshit” has a status like clothing; an animal, however, receives no benefit from decoration. Only the owner of the animal gains from its presence, and thus it is as if the animal is carrying on behalf of the owner.