Coopers first cycle was almost a non event, but there weren't in intact male around. Part of the problem is that you don't know the female pup well enough to know when she is fertile. I gather that it gets easier after a while. Our first Lab, Ginger, was a rescue who was spayed at 4+ years. Tilly we did at about 7 months and Cooper at about 16 months. We delayed Cooper because of the more recent recommendations to wait until they were pretty much full grown.