Sahih Muslim
The Book Pertaining to Clothes and Decoration (Kitab Al-Libas wal-Zinah)
Book Number: 024 / Hadith Number: 5286
Anas reported that when his mother gave birth to a child they brought that child to Allah's Messenger (may peace be upon him) so that he might chew some dates and touch his palate with them. and Allah's Apostle (may peace be upon him) was at that time in the fold busy in cauterising the animals Shu'ba said: So far as I know (he was cauterising) their ears.