First time Cushing's!

Rachel Petzold <r.petzold@...>

I need some help/advice/info on my horse's situation. I am a first time horse owner who has never heard of Cushing's Disease until I got my 11 yr old Morgan mare last summer. When I got her she was incredibly overweight and as it turned out later, very lame in her two front feet. I had the vet come out and do xrays and bloodwork, and she put my mare on a very limited diet of grass hay and thyroxin to melt the fat off.
The xrays showed her front left had rotated "a hair", bloodwork showed normal insulin levels, but "on the cusp" of Cushing's disease. When I asked about the Cushing's I was told to get the weight off, keep it off, and my mare, Harley, would be good to go.
So I left it at that.

A year later now and Harley is at a healthy weight, she is sound, and we haven't had any lameness issues! Even all summer when she was on grass for part of the days. Until September came. I noticed that Harley was coming up tender every once in a while, and it has consistently gotten worse the past couple months that she is now more lame than sound. I called my vet to ask about the coffin rotating more, she said no. I asked about tenderness due to wet ground, she said no. I asked about Cushing's and if it can progress at all, and all she said was that it can progress. My vet doesn't seem concerned at all about Cushing's or the fact that she has been sore. But I don't want my horse sore!
I'll be asking my farrier soon, but I need some advice! Should I test Harley again? How concerned should I be? What does "on the cusp" even mean? What should my next step be??

Thank you!!


Hi Rachel,
Welcome to the group!  Really glad that you found us because we can answer your questions and give you some information that you can give to your vet as well.  Unfortunately lots of vets are still a little confused over Cushing's (PPID) and IR (insulin resistance).  They are 2 distinctly different conditions that have some similar and overlapping symptoms.  This group, run by Dr. Kellon, who is well renowned for her work with IR and PPID, has the most cutting edge information available on the 2 conditions.  We follow a philosophy called DDT/E.  That stands for Diagnosis, Diet, Trim, and Exercise.  Getting the Diagnosis right is really key to getting the treatment right.  So, let me explain each aspect and along the way I will try to answer each one of your questions.  What I really need you to do so that we can help you the best is to fill out a case history (CH) on Harley.  You will have to join another group called ECH8, but it should not take long to get approved.  It's our current "filing cabinet" where we store CH's.  Here's a link:  Yahoo's new Neo format has made doing some tasks rather difficult, so if you have any trouble, just let us know and we can help you.
Ok, the DDT/E philosophy....
Diagnosis:  To get a complete diagnosis you need a single blood draw on a NON fasting horse for these 4 tests:  ACTH, insulin, glucose and leptin.  The blood does require special handling (chilled immediately, spun down within 4 hours, etc) and the details can be found on our website here:   That link will take you directly to the "diagnosis" page of the website, but there is so much great information on the whole website that I suggest you read the entire thing!  You need to arm yourself with the information you need to take the best care of Harley!  Our website is also a great place to refer your vet for the latest information on PPID and IR.  Cushing's disease is not that common (though not unheard of) until after the age of 10, so at the age of 11, Harley is definitely in the "at risk" category.  And Morgan's could be the "poster child" for insulin resistance.  So you may be looking at both IR and PPID.  A horse can have just PPID, just IR, or both, or neither, of course.  The tests that I mentioned above help to give a complete diagnosis, which is what you need to know sothat you khow to treat.  PPID is treated with medicine (pergolide) and IR is treated with diet.  A horse that has both IR and PPID would need both pergolide and a carefully managed diet for the rest of it's life.  Yes, both IR and PPID are progressive conditions, but can be managed through the use of pergolide and/or diet, whichever is appropriate.  Since so many PPID horses are also IR, until you get a diagnosis, you should definitely put your mare on the IR diet!  Did your vet start Harley on pergolide back when you initially had her tested and she said Harley was "on the cusp" of Cushings?  I'm not sure what she meant by that, and we would need to see the actual numbers to help you sort that information out.  That's one of the things you will be including in your CH--the actual numbers and normal values of any lab work that you've had done.
One more thing about diagnosis and then I will move on to Diet.  When you had Harley tested and the insulin came back "normal" that does not necessarily mean that your horse is not IR.  The normal ranges that the labs use are too high.  We use this calculator to plug the insulin and glucose numbers in to see if IR is part of the diagnosis:   And one more thing!  I need to address the "seasonal rise" because that may well be what you are dealing with. The seasonal rise is the time of year (fall--August through Nov/Dec) when all horses have a natural rise in their ACTH to prepare for winter.  PPID horses have an exaggerated, and often prolonged rise in their ACTH, which puts them at risk for fall laminitis.  In fact, though there are other symptoms, fall laminitis is often the first sign of PPID.  There's lot of information about the seasonal rise on our website.  You may be surprised, thinking back, that Harley may have had some the more subtle symptoms of PPID.  Here's a link to that part of our website:  Ok, on to Diet! 
Diet:  The diet that you need to start Harley on now is called the emergency diet.  This a temporary diet that you are going to use until you can get your hay tested.  Then you will be able to progress on to a forage based low sugar/low starch (under 10% sugar+starch) and low fat (under 4%) mineral balanced diet.  It's the best diet for an IR horse and also supports a PPID horse as well.  We recommend grass hay, tested to be under 10% sugar + starch with minerals balanced to the hay analysis and then to replace the ingredients that are lost in the hay curing process, we add ground flax seed and Vitamin E.  Until you can get your hay tested, you are going to start the emergency diet.  It won't balance your minerals but it will help with some things that are usually deficient.  The details can be found on the Diet page of our webpage here:  The emergency diet does involve soaking your hay to remove up to ~30% of the sugar content.  You can often see improvement within a few days doing this.   You should feed Harley 1.5-2% of her BW in soaked (an hour in cold water or 30 minutes in hot water) , drained grass hay and then add the other emergency ingredients (iodized salt, magnesium, Vitamin E and ground flax seed) in the amounts as listed for Harley's weight.  We LOVE the small mesh hay nets.  They are great weighing and/or soaking hay, and can really slow down the hay consumption to make that hay last as much of 24 hours/day as possible.. Make sure you dump the dirty, sugary water where the horse(s) cannot get to it!  You can get a fish scale at Walmart for ~$10 to weigh your hay.  As important as not overfeeding is not under feeding.  You want to make sure she gets 1.5-2% of her BW in hay and/or other safe (under 10%sugar/starch) feed.
A very important part of the emergency diet is what you DON'T feed!  No pasture, no sugary treats, including apples and carrots, no grain or products containing molasses.  No red salt blocks as they contain iron and sometime molasses, neither of which you want.  Most IR horse are already iron overloaded, so we want to eliminate extra iron in their diets.  They get plenty in their hay.
To see how to get your hay tested, visit this site:  You want the #603, trainer's package for $54, not the #601.  Once you have your hay tested one of our balancing folks can help you with the mineral balancing part.  I know it all sounds greek now, but it will make sense as you go along!  There is a rather steep learning curve to all of this, but I promise, it does get easier!  It's a rather drastic change in horse keeping practice for a lot of folks, but it's the absolutely best way to feed our "special" metabolically challenged equines!  You've already started some of it with Harley, so you are well on your way! 
It's great that Harley has gotten to a healthy weight!  That's an essential part of the treatment for IR.  You mention that you used thyroxin to help take the weight off.  Is she still on the thyroxin?  Primary disease of the thyroid is very rare in horses, but sometimes an unbalanced diet can make their thyroid levels low.  Once they have adequate amounts of iodine and selenium, the thyroid levels return to normal.  The thyroxin needs to be weaned of slowly because it suppresses the horses own thyroid function.  Weaning it off slowly gives the horse's own thyroid a chance to kick back in.
Ok, on to Trim!
Trim:  A proper trim is toes backed and heels lowered so that the hoof capsule closely hugs and supports the internal structures of the foot.  The trim on a laminitc hoof may not look normal until the part of the hoof with the damaged lamina grows out--could be a year or even more.  You are strongly encouraged to post your xrays and hoof pictures to the PHOTOS section of ECH8.  Here's a site that explains how to take good hoof pictures:  Once you have your pictures and xrays posted, make sure you let us know so that one of our hoof gurus can take a look and see if you have a proper trim in place.  Some farriers are not up to date on the latest trim guidelines for an laminitic or foundered foot, so strongly suggest you follow this step.  Our hoof gurus deal with this problem every day and can offer some "mark ups" for you and your farrier on a proper trim for a laminitic/foundered foot.  When you called your vet with this most recent lameness, did she come out and do more xrays?  Current xrays would also be recommended if it's in the budget. 
Exercise:  The best IR buster there is, but a laminitic horse should never be forced to move!  You are absolutely correct in saying you don't want your horse sore!  Boots and pads are often an essential part getting a laminitic horse comfortable.  In the meantime, you should definitely not be riding Harley.  You can let her move around as she will.  If she is extremely sore, you may need to put her in a deeply bedded stall and/or use boots and pads to protect her feet.  As she becomes able, you can hand walk her in long straight lines with no tight turns.  No lunging, no round pen work.  You don't want to damage the fragile new lamina as they grow in.
So, in summary, you need to:
1) get a diagnosis to see if Harley needs pergolide.  In fact, your vet may even consider a "trial" of pergolide.  Given the fall laminitis, my gut tells me that you are dealing with Cushing's.  If your vet is willing to do a pergolide trial and it helps, you can wait to test until you get her on the pergolide to see if the dose is controlling her ACTH.
2) start the emergency diet! 
3) join ECH8 and get a CH done on her. 
4) stop riding her, if you are, and protect her feet with boots and pads or even duct tape some protection onto her feet.  We've tons of ideas for this--just ask!
Those are the essentials!  Then you need to:
1) get some photos of Harley's feet and post them in the PHOTOS section of ECH8
2) get your hay tested and eventually balanced.
Rachel,  I bet you have a million more questions now!  There is a TON of information on our website and in our files, so definitely read around those places.  I dare say, any question you may have will probably have an answer in those places, but don't hesitate to ask any questions as they come up.  We are here to help you help Harley!  Like I said, the learning curve here is a little steep, but it does all get easier and then eventually just becomes your new way of horse keeping.  People with non-metabolic horses may think you're nuts!  But you will see the positive changes that the DDT/E's make in Harley and you will know that you are doing the right thing!
We ask all members to sign their name (first is fine), date of joining the group, and general location each time they post.  Additionally, once you get Harley's CH done, please put a link to it in your signature as well.  It really helps us to find it faster and consequently answer your questions faster.  Hang in there!
Maggie, Chancey and Spiral in VA
March 2011
EC Primary Response