I did ours in the practice at 2-6 days (recommended to be between 2-7) old.
I gave them all anaesthetic gas as the local anaesthetic doses required for kids are very close to dangerous levels, and an anti-inflammatory painkiller injection (the boys were also rubber ringed while under).
They were disbudded in a similar way to calves, with care taken to make sure the burner wasn't applied for too long as they have thin skulls there, and all buds scooped out with the dehorning iron, then blue spray applied.
All were none the worse for wear, and bouncing around back in the field in the afternoon.
Hope that helps
Suzanne