Actress Emily Deschanel is encouraging mums to boycott cows' milk and embrace a vegan diet to show compassion for cattle.

The Bones star has teamed up with staff at animal rights organisation People for the Ethical Treatment of Animals (Peta) for a new video campaign urging women to raise their children on vegan diets and stop supporting the "cruel" dairy industry.

In the video, Deschanel, who has a 20-month-old son Henry, says, "As a mother, I experience the joy of raising my son every day. But not all moms are so lucky. Mother cows on dairy farms have their young traumatically torn away from them shortly after birth so that the milk meant for their calves can be sold to people instead.

"The best way to help cows abused by the dairy industry and keep your family healthy is to stock your fridge with delicious vegan foods. Please join me in standing up for all mothers by refusing to support the cruel dairy industry."

Deschanel is the latest celebrity to promote a vegan diet alongside Peta, following in the footsteps of Joaquin Phoenix, Casey Affleck, Alicia Silverstone and Mayim Bialik.