Dear enlightened Ardee,
The following verse will address your curiosity.
20:88 Then As-Saamiri made the effigy of a calf. It even brought forth a lowing sound with wind or when blown into it. So they said, "This is your god, and the god of Moses, but he has forgotten.”
[As-Saamiri was not a Sumerian. "Saamiri" in Sanskrit also means a story maker and teller. He originally hailed from northern India. Babu Rajindra’s treatise “Casting of a Caste” shows Saamiri belonging to the ‘Untouchables’. Fed up with apartheid, he tried to lay down the foundation of a new mixed caste that could socialize with all four castes of Hinduism. Consequently, he was exiled by the powerful Brahmins and ended up in Egypt and later followed Moses in the Exodus. Cow worship was running in his blood stream. Side by side, the golden calf of the Israelites symbolized the centuries old Egyptian influence. The Egyptians used to worship the ‘sacred’ bull APIS who was considered to be a god-incarnate. The soul of the sacred bull upon death was supposed to transmigrate into another idol called Osiris (Bull-god) whom they worshiped as God’s son. Recall Uzayr mentioned in the Qur’an (9:30). Some Jews in Arabia, still under the influence of ancient Egyptian traditions during the times of the exalted Messenger, used to believe in Uzayr or Osiris the Bull-god as God’s son. Slaughtering a cow or bull would strike at the root of their SHIRK]