The Shetland cow has its history back to the Norse cattle brought to Shetland by the Viking settlers.
The BF of Shetland milk is about 5% - I've seen a demo of making products from the milk and the cheese, butter and so on was lovely. There is however a product made traditionally on Shetland called blaand - it's like the washings after everything else is made - it it truly horrible. Apparently, the fishermen used to take it on the boats - as an alternative to sea water it might be preferable, but that would be the only circumstances
The Shetland is small, cows about 450kg, milky and hardy with a large pelvis that facilitates easy calving - so cheap to run mother that can calve and feed a large X calf. In fact these things make it a super suckler cow and almost caused its demise because so many people crossed them.
Shetlands don't have small feet however, so the weight per square inch of foot is low so they are less likely to poach grass. They are also pretty docile - they are sometimes known as the "clootie coo" because they bond with their owners and when sold, it was traditional to give the new owner a cloth (cloot) with the original owner's scent on it to help the cow settle
I believe that there may be Shetland cattle in France as a breed society member is or has emigrated and taken his cattle with him.