Thou shalt have no other gods before me.
Exodus 20:3
--the cow was sacred to Hathor, one of the most widely
worshiped of all female deities of the Nile country,
--while the ram
represented several gods like Khnemu, and the ram-headed Amen, who was
Egypt's chief god in the New Empire period.
Hence, the disease which
slew the animals dedicated to their deities revealed to the Egyptians the
impotence of their gods in the presence of the God of the despised
Hebrews."
Patriarchs&ProphetsAppendix