I saw that in your previous post right after I posted my reply.  We've had exactly the opposite experience.......had several Aussies in a row with an Aussie/hound mix thrown in for good measure. (If you think that was a handsome dog, you'd be wrong.  But he was a heckuva hog dog)  All fixed, and all consistent as all get out about marking everything they saw.  Good dogs, lovable, but annoying beyond belief.