Mahavira, the founder of Janism was born in 599 BC and died in 527 BC.
Buddha lived between 566 BC and 486 BC
The Rig-Veda (earliest Hindu scripture) was written about 1500 BC but
vegetarian practice amoung Hindus began around 600 BC after the
Upanishads (begun around 800 BC) were made popular.
From: "The Heretic's Feast: A History of Vegetarianism" by Colin Spencer
(University of New England Press, 1995)
Ray Audette
Author "NeanderThin:A Caveman's Guide to Nutrition"
http://www.sofdesign.com/neander