So far as I know (he was cauterising) their ears.
Narrated by Anas reported that when his mother gave birth to a child they brought that child to Allah's Messenger (ﷺ) so that he might chew some dates and touch his palate with them. and Allah's Apostle (ﷺ) was at that time in the fold busy in cauterising the animals Shu'ba said: