Sayyiduna Anas (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) said: "There is no slaughtering in the name of other than Allah in Islam." Abu Sulayman al-Khattabi (may Allah have mercy on him) said: Some people would slaughter camels in competition and feed people, and whoever outdid the other in slaughtering camels won the contest. He (peace and blessings be upon him) forbade eating the meat of such animals, because this was done in the name of other than Allah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19351