Help with Endocrinology Lab Results

[Jump314]

My 12 year old Thoroughbred eventer has had some decline in performance over the last two years, loss of topline, and is fuzzier than my other Thoroughbred so I asked my vet to test him for PPID.

The results from Cornell were
ACTH Baseline Equine: 164 pg/mL (reference interval 2 - 30)
Insulin Baseline Equine 29.4 uIU/mL (reference interval 10 - 40)
Leptin Baseline 5.53 ng/mL (reference interval 1 - 10)

He had a low starch grain meal about 2 hours before the blood draw. I trailered him to meet the vet and he was a bit anxious because I also took my other Thoroughbred along, took the other horse out of the trailer first, and the PPID horse has some separation anxiety.

His ACTH is clearly very high, even taking the fall rise into account. I am pretty devastated by the news. My vet is out of town but relayed through his office to start on 1 daily Prascend tablet immediately and we will retest in 1 month. He also said to be very careful with sugars. I have spent hours reading about this and apparently, approximately 30% of PPID horses have insulin disregulation. My question is: how do we know, based on these numbers alone, that my horse has both problems? He has never been laminitic so I’m wondering if I really do need to take him off grass forever or if I should request some other bloodwork to know that for sure.

[Snowdenfarm]

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[JB]

Your guy is currently neither IR, nor leptin resistant which usually accompanies IR

I would start slowly on the Prascend, like 1/4 tab for a few days (or a week), then either 1/2 tab a day or 1/4 tab twice a day for the same, then add another 1/4, and so on until you’re at 1mg. That will minimize the risk of the “pergolide veil” (inappetence, generally feeling puny).

I would treat him more like he’s IR than not, but you don’t necessarily have to go whole-hog into it. Low NSC feeds, 12% or less would be ideal.

Getting his PPID under control will go a long way towards helping prevent also becoming IR.

[lenapesadie]

My old horse is getting the same blood work done tomorrow. His bw was normal in April but since then he’s had a laminitic attack, foundered, had a massive sub solar abscess and an incidental finding of navicular.

Based on my rough understanding, I don’t think your horse is necessarily never going to be able to graze again but caution is warranted.

My vet has instructed me to only allow my horse “grass hay” prior to the blood draw. He’s not even allowed his 1 lb of Timothy based RB breakfast before hand.

[JB]

@lenapesadie

My vet has instructed me to only allow my horse “grass hay” prior to the blood draw. He’s not even allowed his 1 lb of Timothy based RB breakfast before hand.

Yes, these tests should be done on a forage-only “fast”, whatever their normal forage is. Feeding a normal meal could result in a false positive.

[lenapesadie]

My RB does list oats as the third or fourth ingredient. I presume that’s part of why it’s not allowed even though it’s mostly Timothy. Would straight hay pellets impact the results? If they were part of horse’s regular menu. My horses get a bit of alfalfa pellets but I was planning on holding those as well just to be “safe”.

[Jump314]

Thank you all for the information. I’m feeling a bit calmer now since I also didn’t think he had an insulin problem. My vet mostly treats racehorses so I don’t think he has much experience with this. I initially made the appointment for a soundness check but then decided to ask for the blood test. Had I decided in advance, I would have waited to feed that grain meal.

He is currently on free choice orchard/alfalfa at all times, poor grazing for about 15 hours/day (but I have to watch this now) and about 11.5 lbs of 16.5% NSC grain split into three separate meals (Excel Equine’s Animate). He does prelim-level eventing and I-1 dressage so works hard and needs the calories. It seems hard to find low NSC with enough calories. Animate is 1530 cal/lb (and $16.95/ 50 lbs).

Here is what I have found so far:
McCauley’s Alam: 10% NSC, 1300 cal/lb, around $24/50lb bag
Triple Crown Senior Gold: 11.4% NSC, 1800 cal/lb, $33/50lb bag!
Excel Equine Carbolyte: 12.9% NSC, 1350 cal/lb, $15.25/50lb bag
Triple Crown Senior Active: 12.9% NSC, 1535 cal/lb, $33/40lb bag!
Tribute Kalm N EZ: 13.5% NSC, 1470 cal/lb, $23.50/50lb bag

@JB, would you recommend switching to one of these?

[Fiesta01]

Great suggestions. Weaning onto the Prascend should definitely help prevent the inappetence. It’s frustrating to watch a horse who doesn’t want to eat to begin with (because of the Cushings), then also be deterred from eating by the medicine.

@Jump314. Be patient. If my finicky TB gelding could be weaned onto it, I’m positive yours can, too. Sending jingles your way.

[JB]

@lenapesadie

My RB does list oats as the third or fourth ingredient. I presume that’s part of why it’s not allowed even though it’s mostly Timothy

Yes, if it’s not forage, it should be withheld for the fast.

@lenapesadie

Would straight hay pellets impact the results? If they were part of horse’s regular menu. My horses get a bit of alfalfa pellets but I was planning on holding those as well just to be “safe”.

It’s still forage, and if it’s her regular food, I personally would still feed it as scheduled.

@Jump314

11.5 lbs of 16.5% NSC grain split into three separate meals (Excel Equine’s Animate). He does prelim-level eventing and I-1 dressage so works hard and needs the calories. It seems hard to find low NSC with enough calories. Animate is 1530 cal/lb (and $16.95/ 50 lbs).

At 11.5lb of the current feed, that’s 17,595 cal for a cost of $3.89/day.

Calorie for calorie, it’s 9.78lb of TC Sr Gold, for a cost of $6.45/day (yeah, ouch lol). BUT, you could maybe feed 6lb for $3.96/day and see if you can work in 1c oil for an additional 2000 calories. You may find that with a higher fat and lower NSC intake, you don’t need all 17,000 calories.

I wouldn’t do the TC Sr Active +

Tribute KNE is an option, but you’re reducing calories and spending more, so that’s iffy
Excel Carbolyte is a big drop in calories so not what I’d do

[lenapesadie]

@JB

It’s still forage, and if it’s her regular food, I personally would still feed it as scheduled.

I compromised and just gave a cup of the Alf pellets (instead of his regular 2 quarts). Vet came at 10 am and the horses didn’t seem perturbed by not having a full breakfast. The notes on my invoice say ACTH stim so now I’m not sure if it’s the same bw as OP got or not. Guess I’ll find out when the results come back next week.

I wonder if OP is feeding any supps that the Triple Crown Gold Senior might already have and thus save $ that way.

[Jump314]

@lenapesadie

I wonder if OP is feeding any supps that the Triple Crown Gold Senior might already have and thus save $ that way.

No, that’s a good thought but I’m only feeding Solitude IGR right now.

[Cassi1125]

Went through this with my old gelding (tested initially at age 25 with ACTH of 231; normal insulin and other levels). We started with 1 tablet/day of Prascend, tho had to take him back to 1/2 tablet/day until he got used to it. Later on, was at 2 tablets/day. Never had to restrict his diet, tho I changed his grain first to Nutrena Senior and then later to Triple Crown Senior. He was out on regular pasture and regular hay. He had quite a number of other health issues (grey horse melanomas, Gr. 4-5 heart murmur, mild seasonal heaves managed with oral meds). He never had laminitis issues. YMMV…

[Jump314]

Update: We just retested after being on 1 Prascend per day for about a month. The bloodwork is MUCH better this time:

ACTH 25.4 pg/mL
Insulin 23.05 uIU/mL
Leptin 2.49 ng/mL

I did not wean him onto the Prascend because he has been a good eater. I have not had any problems with inappetence so far and I haven’t noticed any other side effects. He is a bit more alert now with more spooking than before (but nothing at all unmanageable). He didn’t look bad before starting the Prascend, I just had a hunch to test because his topline wasn’t great, but he now seems to be feeling better than before and might be gaining a little muscle.

We are going down to 1/2 tablet per day and will retest again in a month or two.