The Compendium of Kāśyapa 8.3.78

8.3.78

śatike śatādhike vā'pi kṣīrānnādavadiṣyate
jātamātrasya mātrā syāt sarpiṣkolāsthisaṃmitā

For an infant of one hundred [days] or more than a hundred, it is prescribed like for one who eats milk and food. / For the newborn, the dose of clarified butter should be equal [in size] to a jujube stone.