The affix kha (īna) comes in the sense of 'who is fit to follow' after the word anugu,
Thus the word अनुगु means गो पश्चाद् ॥ Thus अनुगु पर्याप्तं गच्छति = अनुगवीनः 'who is suited or able to follow after the cows' i.e. a cowherd.,
अनुग्व्-अलङ्गामी
Adhyāya 5 · Pāda 2 · Rule 15