Gobhilagrihyasutra 3.6.5

3.6.5

puṣṭikāma eva saṃprajātāsv audumbareṇā 'sinā vatsamithunayor lakṣaṇaṃ karoti, pum̐sa evā 'gre 'tha striyā, bhuvanam asi sāhasram iti;

If he is desirous of thriving (in his cattle), he makes, when the cows have calved, with a sword of Udumbara wood, marks on a male and on a female calf, first on the male, then on the female, with (the Mantra), 'The world art thou, thousandfold' (ibid. 5. 6),