it's like... duh...
Remind her that the human slave trade was also justified on the grounds that it was sanctioned by God:
"My own convictions as to negro slavery are strong. It has its evils and abuses...We recognize the negro as God and God's Book and God's Laws, in nature, tell us to recognize him - our inferior, fitted expressly for servitude...You cannot transform the negro into anything one-tenth as useful or as good as what slavery enables them to be.”
"If slavery be a sin, it is not yours. It does not rest on your action for its origin, on your consent for its existence. It is a common law right to property in the service of man; its origin was Divine decree."
God has permitted slavery for wise reasons in order to the accomplishment of some great and important ends.
~ N. L. Rice
“[S]uch is the order of providence that a considerable portion of the human race must necessarily move in a humble sphere and be generally at the disposal of their fellow men.”
~ Richard Furman
Tell them to prove it! don't let them shift the burden of proof on to you
"eating hoofed animals": This is the old testament, before Jesus was born. In the old testament it also talks about sacrificing animals, but after Jesus came along animal sacrifice is no longer needed according to Christian belief. Old Testament vs New Testament is not the same thing, you can Google it its pretty interesting.
Just give them a link to earthlings and ask "Is this what god intended?"
Maybe tell her about the Cristian Vegetarian Association: http://www.all-creatures.org/cva/th-assisi-stfrancis.htm