Hi, from what I have read (I am sure others have read more) while
Cushings is primarily an older horses complaint it can occur much
earlier. It is usuaqlly undiagnosed or misdiagnosed at earlier ages.
Heavy bodied horses are identified as being more prone to it than others
but no one really knows why that is and I don't know if any
comprehensive studies have been conducted to prove or disprove that
theory. Wavy hair coat and retention of winter coat are early signs of
Cushings. If you catch it early enough it is fairly easy to control with
good results. To my knowledge there are not any definitive tests that
conclusively prove a horse is Cushingoid. It is pretty much taking test
results combining them with antedotal evidence and then making a
diagnosis. If it responds to the therapy it's Cushings.
Hope this helps. You might want to check out the archives for previous
more in depth discussions of testing and meds.
Chris in CA