Shabbos Chart #9
Chart for Shabbos Daf 53a
DRESSING A DONKEY ON SHABBOS
PAD (MARDA'AS) (4)
(1) This is referring to a situation where the feeding bag is only for the pleasure of the animal and not because the animal is in distress, such as with large animals that are able to bend down easily and eat.
(2) This is done in order to cool off the animal when it gets overheated. (The Sugya concludes that a donkey does not need to be cooled off so much, because its nature is to be cold, and therefore the Rabanan were not so lenient as to permit doing something to cool off the animal.)
(3) This is done in order to warm the animal. However, the saddle (Ukaf) itself does not serve to warm the animal as much as the saddle pad (Marda'as), as is implied in the beginning of the Sugya.
(4) This is done in order to warm the animal.
(5) Initially, the Gemara thought that it was forbidden to place the saddle on the donkey just as it is forbidden to remove it from the animal. However, the Gemara concludes that placing the saddle on the donkey is different, because (a) it is not possible to place it on the animal passively (while it is possible to remove it passively -- by having the animal walk back and forth until the saddle falls off). Alternatively (b) the Gemara answered that removing the saddle was forbidden because the donkey does not need to be cooled off, while donning the saddle is permitted because the donkey needs to be heated. This is the straightforward implication of the Sugya, and this is how the TUR (OC 305) understood the Sugya, as well as many Acharonim (such as the Derishah and Eliyah Rabbah). The Beis Yosef, however, understood that even according to the conclusion of the Gemara, it is forbidden to place the saddle on the donkey, and this is how he rules in SHULCHAN ARUCH OC 305:8, and so concurs the VILNA GA'ON.