Reference for Shabbat 5:2
חֲמוֹר יוֹצֵא בְמַרְדַּעַת, בִּזְמַן שֶׁהִיא קְשׁוּרָה לוֹ. זְכָרִים יוֹצְאִין לְבוּבִין. רְחֵלוֹת יוֹצְאוֹת שְׁחוּזוֹת, כְּבוּלוֹת וּכְבוּנוֹת. הָעִזִּים יוֹצְאוֹת צְרוּרוֹת. רַבִּי יוֹסֵי אוֹסֵר בְּכֻלָּן, חוּץ מִן הָרְחֵלִין הַכְּבוּנוֹת. רַבִּי יְהוּדָה אוֹמֵר, עִזִּים יוֹצְאוֹת צְרוּרוֹת לְיַבֵּשׁ, אֲבָל לֹא לְחָלָב:
An ass goes out with a pack-saddle, [which is kept on it the entire day to keep it warm], when it is (already) tied to it on Sabbath eve, [for he knows that the ass requires it for warmth, as people say: "An ass is cold even in the summertime" — so that it is not a burden. But it is forbidden to tie the pack-saddle on the ass on Shabbath. For it is impossible to tie it except by bracing oneself against its side, which constitutes (forbidden) use of an animal. And if he transgressed and tied it, it may not go out with it.] Males go out with levuvin [leather tied against their genitals so that they not mount the females.] Ewes go out shechuzoth, [which hold their tails high so that the males can mount them], kevuloth, [which clamp their tails against their legs so that the males not mount them], and kevunoth [They would tie a cloth around lambs on the day they were born so that their wool not become soiled.] Goats go out [with their udders] tied, [sometimes, to dry up their milk by pressing forcibly against them; sometimes, tied as a "pocket," so that the milk not drip to the ground and be lost.] R. Yossi forbids it with all, [regarding them as burdens], except with the kevunoth lambs, [in which instance, keeping their wool from being soiled, it is like an ornament]. R. Yehudah says: Goats go out tied for drying (of the milk), but not for (catching) the milk. [R. Yehudah holds with the first tanna, that it is not a burden. For drying, there is no reason to decree lest it fall and he come to carry it, but for (catching) milk, where it is not tied tight, it is forbidden. We fear that it might fall and that he might come to carry it. The halachah is in accordance with the first tanna].