It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When you say Bismillah (while slaughtering), then also say Allahu Akbar." That is, over the slaughtered animal.
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Uthman bin Sa'd except Muhammad bin Humran; al-Shadhakuni is alone in narrating it."