R’ Ḥiyya bar Ashi said that Rav said: One may hang a basket with fodder around the neck of an animal on Shabbat, and by means of an a fortiori inference, derive that one may place a saddlecloth on an animal’s back on Shabbat. What is the a fortiori inference? Just as there, placing the basket of fodder so that the animal can eat without bending down, which is done for the animal’s pleasure, is permitted; here, placing the saddlecloth, which is done to prevent the animal from suffering from the cold, all the more so should be permitted.
Some commentaries suggest that Rav permits hanging a basket of fodder around the neck of an animal on Shabbat, even though this seems to contradict the baraita that was taught previously. Rav holds that cruelty to animals is a Torah prohibition. The Sages would not have issued a decree that would lead to violation of a Torah prohibition. Therefore, he makes no distinction between causing the animal to suffer and withholding pleasure from the animal (Rabbi Elazar Moshe Horowitz).
Another discussion relates to ornamental objects placed on an animal. The Gemara teaches:
A horse may neither go out into the public domain on Shabbat with a fox’s tail that is placed as a talisman to ward off the evil eye nor with a string of red wool that is hung between its eyes as an ornament.
Some suggest that a fox’s tail and red wool were not ornamental but served as a talisman to ward off diseases or the evil eye (Me’iri). Some commentaries deduce from here that all animal ornaments have the legal status of a burden; therefore, the animal may not go out with them on Shabbat. Other authorities distinguish between ornaments like these, which are not universally placed on animals and are considered a burden, and a standard ornament such as a bell, which is not a burden and is permitted (Rashba).