Can a horse stop having Cushings?

[CHT]

A mare that used to be boarded with me was tested positive for Cushings back in 2018, and was put on Prascend. The owner tested the horse regularly, and adjusted her medication as warrented. The horse moved to a different province with less rich hay, and after a little less than a year, her owner noticed she lost considerable weight. She had the BO up the food, and had the vet out to retest. The vet said her blood showed no evidence of cushings and to take her off Prascend. Is this possible?

The horse is now back in this province and in good weight (it didn’t take long). Her owner is worried about why she lost weight before - is there something she should be ask the vet? Should she worry now that the horse is back getting richer hay? Can horses recover from Cushings and no longer need medication?

[Renn_aissance]

Cushings is a disease caused by a tumor on the pituitary gland. The tumor doesn’t go away.

However, the constellation of Cushings symptoms and blood markers can change over time in response to changes in management and other body processes. ACTH also fluctuates seasonally. My horse’s ACTH has been everywhere from 21 to 346 while he’s been on pergolide. 21 is low equivocal for the time of year the test was run and at the time he wasn’t particularly symptomatic- but the tumor hadn’t gone away. The meds and management plan were working.

Although it sounds like there’s a logical reason for the weight loss (change in diet,) it’s also important to know that not all Cushings horses are fat. Some of them become hard to keep weight on. Pergolide can also decrease appetite, so if the horse totally went off her feed, taking her off of Pergolide and reintroducing it gradually might be appropriate. The mare’s owner is right to be thinking about the horse’s overall picture and monitoring her symptoms.

[JB]

@CHT

The vet said her blood showed no evidence of cushings and to take her off Prascend. Is this possible?

No, it means the medication has been keeping her ACTH level in a normal range. That’s not a vet to deal with for this disease

PPID is a progressive disease, there is no cure, it doesn’t spontaneously resolve, unfortunately.

@Renn_aissance

Cushings is a disease caused by a tumor on the pituitary gland. The tumor doesn’t go away.

Or, an enlarging pituitary. I don’t know what % each issue is the cause, but both are causes

[GreyDes]

This seems strange. As @Renn_aissance said, PPID/Cushings doesn’t go away, it’s just managed.

Her numbers are probably in the normal range BECAUSE she is on Prascend. Taking her off will mean they spike back up.

For reference I have two seniors who have PPID and both are on Prascend. My vet tests their levels annually to make sure their dose is appropriate (and would test more frequently if we saw any issues). With treatment their levels have been in the normal or equivocal range, which means the meds are working and the dose is correct for now.

[treebeard]

Agree with other responses.

As for the hay, you may wish to test that rich hay before the mare starts on it. I have a miniature mare with Cushings that will develop laminitis with certain types of hay.

She will lose weight with hay appropriate for her disease and keep weight with the rich hay so I have to manage her with increased horse feed appropriate to her condition to balance things out.

[CHT]

She apparently isn’t IR, so not super high risk for Laminitis. When she was in my care, she was chubby/had fat lumps, but never cresty. She would loose her appetite from time to time, at which point we would lower her dose. At her last situation she was kept in a private pen though, so I would assume the BM would notice if she wasn’t eating? It was just a surprise to see an “easy keeper” quite thin in a short period - possibly a management issue.

her newest barn has a pen specifically for Cushings horses, which I assume has lower sugar hay, but now with her latest blood work she isn’t as sure that her horse will go with that group.

How long would you wait to retest her blood? She was checked a month ago and taken off the Prascend.

It did seem very unlikely to me she could be “cured” but I don’t have much experience with Cushings!

[treebeard]

My wee mare isn’t IR either, and didn’t have issues with hay until last year and she’s 18, so things can change, sadly.

It seems like your former boarder is being managed well to get her Cushings under control and if she’s managed as if she doesn’t have Cushings there very well may be problems.

[GreyDes]

I would strongly suggest re-testing now. You really don’t want to let the Cushings become symptomatic - it impacts the immune system and they can get all sorts of nasty stuff that they can’t fight off.

We dealt with multiple eye infections on one of mine when he was first diagnosed and we were working through dosing. It was not fun and I highly recommend she work with a vet that understands what a Cushings/PPID diagnosis means and how to treat it. As many of us have said - it does not go away, it’s just managed.

[CHT]

I think she is going to go see her horse this weekend and will talk to the barn. I am not that familiar with the vets in her area to know who to recommend, but hopefully her barn has someone good they use. It did seem unlikely a horse could spontaneously recover from Cushings.

[LookinForSpace]

@CHT

At her last situation she was kept in a private pen though, so I would assume the BM would notice if she wasn’t eating? It was just a surprise to see an “easy keeper” quite thin in a short period - possibly a management issue.

Management may well be a good thing to double-check. A change in diet may account for the weight loss as you noted, and maybe more exercise even just how much walking around she does, and possibly stress associated with the recent move, but also keep in mind that herd dynamics could be affecting her access to hay in the paddock. Hopefully, the owner can visit her mare frequently enough to check on her weight loss and feed situation.

An easy-keeper losing a significant amount of weight in a short period of time after moving to a new barn could be an issue of food access/amount fed.

[CHT]

She was actually in a private pen when she lost weight and it was before her most recent move. It was as she came out of winter. The horse has to be blanketed pretty much 24/7 in summer, so I think the BM just didn’t notice the loss until the owner was out and noticed, but this is a horse that is more prone to obesity. She looks good three weeks after her recent move.

[Jump314]

@CHT

The horse has to be blanketed pretty much 24/7 in summer

Blanketed? Do you mean that the horse wears a fly sheet?

[LookinForSpace]

@CHT

She was actually in a private pen when she lost weight and it was before her most recent move. It was as she came out of winter. The horse has to be blanketed pretty much 24/7 in summer, so I think the BM just didn’t notice the loss until the owner was out and noticed, but this is a horse that is more prone to obesity. She looks good three weeks after her recent move.

Well, good, that takes that possible concern off the list.

[CHT]

Usually a KoolCoat or a fly sheet. She is prone to sunburn.

[BroncoMo]

I assume you’re talking about a healthy amount of weight loss? as Renn_aissance said, not all cushingoids are fat. I had one who was an easy-ish keeper but not fat by any means. She ate high quality 2nd or 3rd cutting alfalfa and a ration balancer to keep a nice “weight” but her topline was trashed. Two winters ago she lost a ton of weight on a lesser quality alfalfa and I never could get it back on. After some blood testing, we believe a type of cancer was the cause of her weight loss.

I agree with JB that this is not a vet to be dealing with a cushingoid. The disease only gets worse over time, not better. Mine got to the point, around the time of her cancer “diagnosis”, that even marginally higher doses of pergolide could not keep her ACTH levels down. High levels with minimal/no clinical symptoms can be ok.

[RMJacobs]

My horse with Cushings got very thin, even though he was eating well and taking his meds. I had the vet out, and we agreed to increase his pergolide. Unfortunately, he died two days after that visit, when I’d put the order in for pergolide. He was very old (into his 30s), and the vet thought there could be other things going on with him on top of Cushings.

[RedHorses]

Something to know (direct from a B-I vet) is that if a horse has their PPID well controlled with Prascend and is then taken off the drug for a longish period, that horse may need an increased dose to get back to where they were before the break. I don’t think he gave a time frame, but I would guess long enough for the numbers to start climbing again.

My horse tests within normal range every time, with a couple of exceptions (when administration was in the feed - numbers went down once we went back to syringe and water). The vet reaction is basically “Good. Keep doing what you’re doing.”

[CHT]

That is interesting and makes some sense.

Her horse was never particularly symptomatic, but I am worried about what I think is bad advice. Hopefully I can convince her to get the vet out sooner than later - I think she is just appreciating that her horse doesn’t need medication so it is hard to be objective.

[RedHorses]

If it helps, my horse was diagnosed in 2014 age 16, and started Prascend in 2015, age 17. He is now 27, still tests within normal range, and still has only the one symptom that prompted the original testing (lack of topline muscle despite good feed and correct work). As PPID is a degenerative disease, using the drug early significantly slows the process of degeneration- meaning a healthier horse for more of their life.