Śatapatha Brāhmaṇa ("of a hundred paths") 3.9.4.11

3.9.4.11

atha yatpañca kṛtvo mimīte | saṃvatsarasammito vai yajñaḥ pañca vā ṛtavaḥ saṃvatsarasya tam pañcabhirāpnoti tasmātpañca kṛtvām mimīte

Now as to why he metes out five times,--the sacrifice is of the same measure as the year, and there are five seasons in the year: he takes possession of it in five (divisions); hence he metes out five times.