On long-playing vinyl, there is an unaccompanied performance dating back to before 1960, by Máire Ní Scolaí. This recording can be "heard" as a YouTube video.

https://www.youtube.com/watch?v=_Y1a-H8DIUg

Probably this comes from her broadcast studio recordings for Radio &Eireann/RTÉ. The vinyl LP is "Máire Ní Scolaí," issued by Gael Linn around 1971.

Ní Scolaí sings six verses of "Dónall Óg." I cannot identify her fifth verse; no offense to the singer, as she sings her fifth verse with great dramatic subtlety; can anyone else do more to recognise/identify her Verse 5? Here is an attempt to sum up the verse order from her performance.

Dónall Óg
(traditional)

Verse 1: A Dhónaill Óig, má théir thar fharraige...

Verse 2: Is déanach aréir a labhair an gadhar ort...

Verse 3: Gheall tú dhomsa, is rinne tú bréag liom...

Verse 4: Gheall tú dhomsa ní ba dheacair dhuit...

Verse 5 [fill in the blank]

Verse 6: Bhain tú soir 'gus bhain tú siar dhíom...

(Wow, what a voice she had)