When hiking in Switzerland we noticed some very funny looking cows in the pasture:
Yup. Those are standard sized donkeys right in amongst the cows. Are they work animals? Possibly, but a more likely explanation is that they're stock guardians.
Three species are generally used as stock guardians - a more aggressive animal put in with the livestock to deal with predators and other threats (there aren't officially wolves in that part of Switzerland. Officially). Traditionally, dogs were most often used - the Great Pyrenees and Bernese Mountain breeds were both created for this purpose. Dogs have the downside of needing to be fed, however. Modern farmers are more likely to use either donkeys or alpacas, which enjoy the same grass as the animals they're protecting.