Śatapatha Brāhmaṇa ("of a hundred paths") 6.2.2.14

6.2.2.14

tadu vā āhuḥ | vapāyā eva śuklavatyau syātāmetāvadvai paśau śuklaṃ yadvapāśuklavatyau niyutvatyau haviṣo yadeva niyutvadrūpaṃ tasyopāptyā iti

As to this they say, 'It is rather the two (prayers) of the Omentum that should contain (the word) "bright," for so far as the two (prayers) of the omentum containing (the word) "bright" extend, extends what is bright in the animal (sacrifice); and the two (prayers) of the (meat) oblation should contain (the word) "team," for the obtainment of that form of him (Pragâpati) which has a team.'