I've had quite a few of my dogs get barbed wire injuries over the years. I sold my last GSP because he tore open his penile sheath on barbed wire. I can no longer lift any dog bigger than a spaniel over fences so I no longer keep large breeds of dogs. I discourage jumping fences unless I specifically command a dog to jump and when I do that it is never over barbed wire fences.
If I habitually train or hunt dogs where barbed wire fences exist I take an army trenching tool with me and dig dog sized holes under the fences. Dogs soon get to know where those scrapes under the fences are and use them.
My cocker Charlie was a nightmare inducing fence jumper when picking up at shoots. He didn't jump fences out on walks etc. but the excitement of retrieves on shoots caused him to make flying leaps at fences in pursuit of shot birds. His method was to dive with head, body and legs fully extended between the top of the mesh fence and the single strand of barbed wire just six inches above the mesh ! He did that for two seasons giving himself many wounds on his head , his neck and his back. On his return with a bird I had by then got myself up to the fence to scruff him and the bird back over all at the same time. Charlie was and still is crazy !
I gave up picking up at that place on the shoot leaving it to other more macho minded pickers-up to cover !

Not once did Charlie's often bleeding little body ever stop working or wanting to work and all I did was to clean the wounds as best I could . There is no way I could have afforded to take him to the vets every second week !
Dogs don't look at wounds and blood as we do so it doesn't bother them too much.
Wullie