Bhashya
मानस्य, को नु खल्वत्र ब्रह्मिष्ठ इति विशेषेण ज्ञातुमिच्छा विजिज्ञासा, बभूव ; कथम् ? कःस्वित् को नु खलु एषां ब्राह्मणानाम् अनूचानतमः- सर्व इमेऽनूचानाः, कः स्विदेषामतिशयेनानूचान इति ।स ह अनूचानतमविषयोत्पज्जिज्ञासः सन् तद्विज्ञानोपायार्थं गवां सहस्रं प्रथमवयसाम् अवरुरोध गोष्ठेऽवरोधं कारयामास ; किंविशिष्टास्ता गावोऽवरुद्धा इत्युच्यते- पलचतुर्थभागः पादः सुवर्णस्य, दश दश पादा एकैकस्या गोः शृङ्गयोः आबद्धा बभूवुः, पञ्च पञ्च पादा एकैकस्मिन् शृङ्गे ॥
In plain words
...of Māna. 'Who here is truly the most learned in brahman?' — that particular curiosity, the wish to find out, took hold of him. How did it happen? He found himself wondering: 'Who, really, among these brāhmaṇas is the most learned? They are all learned men — but which one of them stands out above the rest?' Gripped by this question, and wanting a way to settle it, he gathered a thousand cows in the prime of their lives and had them penned up in a cattle-yard. What marked out these particular cows? Here is the answer: a quarter of a pala of gold makes one pāda. Ten such pādas were tied to the horns of each cow — five pādas on each horn.
Close to the Sanskrit
...of Māna. 'Who indeed here is most learned in brahman?' — thus the desire to know in particular, that is, the desire-to-investigate, arose. How? [He wondered:] 'Who indeed, who now, indeed, of these brāhmaṇas, is the most learned? All these are learned; who among them, indeed, is learned to an outstanding degree?' He indeed, this curiosity concerning who was most learned having arisen in him, for the sake of a means to determine that, confined a thousand cows of prime age; he had a confinement made in a cow-pen. Of what distinguishing character were those cows that were confined? It is explained: a quarter of a pala is a pāda of gold; ten pādas each were tied onto the two horns of each single cow, five pādas on each single horn.