Firstly I would like to describe what a VEGAN is. A vegan is someone who avoids eating any animal products including meat (red meat, poultry and seafood), eggs and dairy. Some vegans also avoid the use of honey. Healthy vegans enjoy eating fresh fruits, vegetables, beans, whole grains, nuts and seeds.
Vegans avoid buying and wearing animal products including fur, leather, wool, silk and down. Vegans also avoid using products tested on animals including cosmetics, chemicals and household cleaners.
In Yoga, Patanjali Patabi Jois described the eight limbs of Yoga, which are Yamas, Niyamas, Asanas, Pranayama, Pratyahara. Dharana, Dhyana and Samadhi. The first limb is Yamas, which means Ethical Disciplines. And the first Yama is Ahimsa, which means Non violence. It is in Yamas that Patabi Jois states that Yogis should avoid consumption of meat.
However, when Yoga sutras were written, animal farming was very different back then. Dairy products and eggs were produced in a more environmentally and animal friendly manner. But in todays world, the story is quite different.
Today, dairy cows are impregnated by force, constantly pregnant or lactating until they are no longer of use and then sold and slaughtered for meat, and the male calves are taken away immediately either to be raised and slaughtered for veal or to be raised and slaughtered for beef.
Eggs come from chickens living in tiny cages, several birds stuffed into a cage and smashed up against each other without access to sunlight and room to spread their wings.
So all these are violence against living creatures, so you can find many Yogi who are Vegans and who avoid even consumption of chemicals and follow a veganism as a lifestyle.
So who knows, if only Patanjali was alive now, he would choose Veganism over Vegeterianism. But I believe the right thing to do is to follow a more conscious way of living not only to our inner self but also to our surrounding.