Jaiminīya (Talavakāra) Brāhmaṇa 20.96

He pronounced over it:
'The young mother bears the child hidden, wrapped up; she does not give it to the father;
people do not perceive his face, resting in front in the fire-drill.
What is this child, O young woman, which you, a tormentress, bear? The queen has brought him forth;
for many autumns the embryo grew; I saw him born when the mother brought him forth.
Agni shines out with great light, making all things visible by his might;
he overcomes hostile, ill-willed wiles; he sharpens his horns to pierce the rakṣas.
And may the roars of Agni be in heaven, with sharp weapons to slay the rakṣas;
even in his exhilaration his flames shatter; the godless obstructors do not ward him off.'
Thus the heat of this fire, rushing upwards, completely burned her up.
Thereupon they distributed the heat of Agni according to their proper places;
Agni cooked for them in the proper manner.
This is a sāman of splendor and spiritual luster.
By it, indeed, they found the departed heat of Agni.
Splendid, possessing spiritual luster, and radiant does he become who knows thus.
It has a base of one and a half Iḷās; it is the visible form of the Śakvarī verses on the Śākvara day.
Thereby it is endowed with form.
Because Vṛśa saw it, therefore it is called the Vārśa.

'Soma, pressed by the pressers,'—

this is the form of the boundaries.

'Over the backs of the sheep,'—

thus [verses] containing 'cow' and 'cattle' occur for the securing of cattle,