Matsya Purana — Vrata-Ṣaṣṭhī: The Sixty Sacred Vows
यावत्समा भवेद्यस्तु पञ्चदश्यां पयोव्रतः समान्ते श्राद्धकृद्दद्यात् पञ्च गास्तु पयस्विनीः //
yāvatsamā bhavedyastu pañcadaśyāṃ payovrataḥ samānte śrāddhakṛddadyāt pañca gāstu payasvinīḥ //
Whoever undertakes the milk-vow (payo-vrata) on the fifteenth lunar day and continues it for as many years as he has resolved—at the completion of those years, having performed the Śrāddha, he should give in donation five milk-yielding cows.
This verse does not address Pralaya; it focuses on dharma—specifically, how a vow (payovrata) should be concluded with Śrāddha and prescribed charity.
It presents a householder-style dharma model: observe a disciplined vow, then complete it with ancestral rites (Śrāddha) and public charity (donation of cows), reinforcing social and ritual responsibility.
The significance is ritual, not architectural: the vow’s proper closure requires Śrāddha and a specific dāna—five lactating cows—indicating that completion rites and charity are integral to vrata practice.