Unfortunately, there is nothing. We manage the pathology as best we can and in time, our best is just not enough. So long as his quality of life seems to be adequate, you deal with it as such. At some point, that quality of life will be gone and it is then that we, as responsible stewards of our horses, do the right thing and feel good about having the ability and compassion to remove the pain, remove the suffering regardless of the costs to us personally. Far too often I see people selfishly keeping an animal alive rather than selflessly doing what is right, proper and best for that animal. And I've got a pet cemetary in my back yard that stands in mute testimony with regard to my actions to do what is right for the animals entrusted to my care when, regardless of the personal pain I may suffer, it is time to afford them death with dignity and the dignity of death.