Verse 13.1.6.1

vibhūrmātrā prabhūḥ pitreti iyaṃ vai mātāsau pitābhyāmevainam paridadātyaśvo'si hayo'sīti śāstyevainaṃ tattasmāciṣṭāḥ prajā jāyante'tyo'si mayo'sītyatyevainaṃ nayati tasmādaśvaḥ paśūnāṃ śraiṣṭhyaṃ gacatyarvāsi saptirasi vājyasīti yathāyajurevaitadvṛṣāsi nṛmaṇā asīti mithunatvāya yayurnāmāsi śiśurnāmāsītyetadvā aśvasya priyaṃ nāmadheyam priyeṇaivainaṃ nāmnābhivadati tasmādapyāmitrau saṃgatya nāmnā cedabhivadato'nyo'nyaṃ sameva jānāte

Preview of English translation:

1. [The Adhvaryu and Sacrificer whisper in the right ear of the horse, Vajasaneyi Samhita XXII, 19,] “Plenteous by the mother, strengthful by the father,”—its mother, doubtless, is this (earth), and its father yonder (sky): it is to these two he commits it;—“a horse thou art, a steed thou art,”—he thereby instructs it, whence clever subjects (or children) are born to him;—“a courser (atya) thou art, a charger thou art,”—he therewith leads it beyond (ati), whence the horse goes beyond (surpasses) other animals, and whence the horse attains to pre-eminence among animals;—“a runner thou art, a racer thou art, a prize-winner thou art,”—in accordance with the text is (the meaning of) this;—“a male thou art, well-disposed towards man thou art,”—this is with a view to its (or, his) being supplied with a mate;—“Speedy thou art called, Child thou art called,”—this is the horse’s favourite name: by its favourite name he thus addresses it; whence even if two enemies, on meeting together, address one another by name, they get on amicably together.

For a detailled translation, including proper diacritics and footnotes, go the full English translation.