Vegan protesters are calling on Starbucks to take the dairy out of one of the company's most popular cold-weather drinks: the Pumpkin Spice Latte.

A petition on Change.org asking for a dairy-free version of the drink has already collected 1,500 supporters.

Those who order the spiced coffee with soy milk or without the whipped cream, and thought there were no animal byproducts, would indeed be getting a dose of moo in their mugs.

The reason why is that the syrup used to flavor the drinks contains condensed milk, which is just processed milk. While the syrup formula hasn't changed and some vegan blogs discuss this, some customers say they feel duped because there is no information about dairy contained in the drink, which could be a problem for those with an aversion to milk --either due to health or ethical reasons.

One person who commented on the petition page wrote: "Starbucks should service all its customers, including vegans and people wiith (sic) dairy allergies."

Starbucks confirmed to Consumerist.com that Pumpkin Spice Lattes do include some dairy. A spokesman offered an alternative: the Starbucks VIA Pumpkin Spice instant coffee flavor, which can be brewed with soy milk.