प्रकृत्याऽऽशिष्यगोवत्सहलेषु

Operational rule vidhi

The word सह retains its original form when the sentence denotes benediction, except when it is गो , वत्स or हल.

Word by word (padaccheda)

With / by प्रकृत्या tṛtīyā · ekavacanaRight context आशिषि saptamī · ekavacanaRight context अ- गो- वत्स- हलेषु saptamī · bahuvacana

With / by Tṛtīyā (3rd case): accompaniment or means.
Right context Saptamī (7th case): "when X follows", the operation applies to what precedes (1.1.66 तस्मिन्निति निर्दिष्टे पूर्वस्य). Also a condition or domain ("in the sense of").

Full reading

प्रकृत्या आशिषि अ-गो-वत्स-हलेषु

Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.

Commentary

The word सह retains its original form when the sentence denotes benediction, except when it is गो , वत्स or हल।
Thus स्वस्ति देवदत्ताय सहपुत्राय, सहच्छात्राय, सहामात्याय ॥ But optionally here, as स्वस्ति भवते सहगवे or सगवे, सहवत्साय or सवत्साय, सहहलाय, or सहलाय ॥ The phrase अगोवत्सहलेषु is no part of the original sutra, but has been added by the Kasika from a Vartika.

Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.