A dysplastic dog never gets an off season for conditioning - to do so could mean never getting back to that higher level again. Develop an exercise program that has other activities besides agility. Spend time watching your dog move. Watch it move around the yard, or practice area. Knowing how your dog normally moves allows you to watch for changes or problems.
Nutritional supplements are helpful in lubricating the synovial fluid in the joints.
So with your specialist's advice find the best one for your dog. Train at lowered jump heights,lessening the amount of training time and training intensity. The timing difference for handling can be compensated for by squeezing the course in and having obstacles closer to one another. Don't work dysplastic dogs if the grass or the equipment is wet. Enter fewer classes in competition.