How were the animals in the Temple purchased?
According to Rashi, the general practice in the Temple was to set aside six animals that had been checked and found to be appropriate for sacrifice that would serve the needs of the upcoming communal sacrifices. This way, there was always a reserve of animals available for the Temple’s needs. Tosafot ha-Rosh quotes an opinion which says that it all depended on availability. The kohanimin the Temple tried to always have a reserve of animals, and if a particularly good buying opportunity came up, they would buy a large number of animals.
According to both of these approaches, we can understand the question raised in the Gemara – what was to be done with leftover korbanot (=sacrifices)? With the new year for sacrifices beginning on the first day of Nissan, when the end of Adar arrived there would often be a pool of animals that had been set aside for sacrifices, but could no longer be used, since the new year’s sacrifices had to come from the new year’s donations.
Ulla quotes Rabbi Yohanan as teaching that animals that were set aside to be used as temidim – daily offerings – that were not sacrificed, can be redeemed even though they remain unblemished (ordinarily an animal that had been set aside to be used as a sacrifice could only be redeemed in the event that it developed a blemish that would keep it from being brought on the altar). When Rabbah repeated this teaching, Rav Hisda objected, saying “who will listen to you and to Rabbi Yohanan, your teacher!? Where did the animal’s holiness disappear to?”
The expression used by Rav Hisda is interesting inasmuch as we have no record in the Talmud that Rabbah ever left Babylonia for Israel to learn with Rabbi Yohanan. We do know that Rabbah’s brothers traveled to Israel where they were so taken by Rabbi Yohanan’s leadership that they wrote to Rabbah that he should join them in Israel in order to learn from Rabbi Yohanan. Although, given his age, he could not have spent many years in Israel, it does appear that Rabbah traveled to Israel, as we find a number of places where Rabbah quotes Rabbi Yohanan’s teachings.