We had to have the vet in to a lambing the last time Schmallenberg was here. The lamb had a twisted spine and my daughter noticed it wasn't breathing properly. The vet euthanased it and did a PM on the spot, to find part of its lower rib cage on one side was missing. He took the lamb away and Schmallenberg was later confirmed. It can present in different ways but it's something to bear in mind if you have trouble getting a lamb out - if the lamb isn't the "right" shape it may be that that's causing the problem.