Fermentable NDF and high VFA in hay - good science or bad science


E Sarah Howell
 

I posted a question in the PSSM group last week trying to understand why my, apparently low sugar hay seemed to be causing my horses problems, including apparent symptoms of 'tying up'.  As my follow up Q seems to have a broader relevance, I'm asking it here.  

Recent hay analysis shows amongst other things sugar (as sampled) of 8.5%, starch 0%, NDF 0f 66%, fermentable NDF of 34.2% and VFA's of 1.4% DM.  The following paragraphs are an extract from an email received from the feed company to explain why my horses are struggling with this hay..... 

The protein is high and would be suitable for even harder working horses and there is a good level of fibre present (NDF) with a large proportion of it being fermentable (fNDF). This means calories are there in abundance and are coming from both quick release foregut digestion (which can cause blood sugar spikes) and slower release microbial fermentation in the hindgut -  any good doers will definitely take advantage of this!
 
As a final point the high VFA's indicate that some sort of fermentation has occurred most likely just after baling - it may have been baled a bit too soon - and these VFA's are effectively an energy source which can be used for weight gain. Lactic Acid is also one type of VFA and high levels of lactic acid coupled with high levels of sugar for those very sensitive to it may contribute to tying-up like symptoms and raised muscle enzymes.--

The piece about high NDF seemed to be in direct conflict with what I have understood and I have never of 'fermentable NDF or the existence or risk of VFAs in hay.  I thought that high lactic acid was not a problem - though it is often believed that it is.....

My question therefore is whether the explanation from the feed company is good science or bad science ?  Our miniature horse is in a lot of distress with lots of symptoms suggestive of tying up so am keen to understand what is happening to her and how to help her.  My vet is scratching his head.    

Many thanks for any suggestions our experts might have.  
E Sarah Howell

Cambridgeshire UK
2018
NRC Plus, NAT and NPH 2019


Lavinia Fiscaletti
 
Edited

Hi Sarah,

Sorry your mini is having such a hard time of it.

Would you please post an actual copy of the hay analysis. Was this analysis done by NIR or wet chem?

Can you be more explicit in what you mean by " lots of symptoms suggestive of tying up" ? We really need to see a case history for this mini to be able to help you more fully.

--
Lavinia, George Too, Calvin (PPID) and Dinky (PPID/IR)
Nappi, George and Dante Over the Bridge
Jan 05, RI
Moderator ECIR


Eleanor Kellon, VMD
 

For additional background for those not on that group, Sarah is dealing with 3 horses with elevated insulin (how high, Sarah?) - 2 of them minis.

The CKs are 400 to 700, which is abnormal but not close to the tying-up range of several thousand. Tying-up by definition is cramping and muscle damage caused by exercise. This is something else. Did you have triglycerides checked?

On the other list you said sugar was 6.3 and starch 0.5, confirmed by a second analysis. Is this a different hay? What is the "high" protein? The other one you said was 9.5%.

As for the report you got, something doesn't add up. If there was active fermentation going on the sugar wouldn't be that high. Sugar is the easiest thing to ferment and goes down first. What was the moisture? My first suspicion would be that the hay was baled at higher moisture and they used an organic  acid preservative on it.

As for the rest of it, fermentable NDF refers to the rumen, not horses. Lactic acid is not one of the VFAs. It is also a fermentation product, but not a VFA. Lactate is readily and easily converted to glucose and the liver will quickly grab up any ingested lactate and do just that. If blood glucose is normal, the extra will be stored as glycogen or fat.

Sugar and lactate do not cause tying-up.

What's going on with your mini?


--
Eleanor in PA

www.drkellon.com 
EC Owner 2001


E Sarah Howell
 

Dear Dr Kellon and Lavinia
Thank you so much for your responses and your questions.  I will endeavour to do a CH but, in reality, it is going to take a few days to piece it together as normal life and the day job is going to get in the way !   In the meantime, to answer some of the immediate questions....

The hay came from my usual hay supplier and is a later cut of grass of the same mix which I feed to my other horses.  It came with a photo of the key part of a Forageplus nutrition analysis which showed:
Crude protein 9.8% 
DE  8.79 mj/KG
WSC 11.5%
ESC 6.3%
Starch 0.5%
ADF 38.2%
NDF 62.8%
All results based on DM
I don't know if this was NIR or wet chem.  Nor was DM% visible.  

But on this hay my 3 mares (M a 16.2hh ID and Blossom a 31" miniature horse - both IR and Mandy my 31" mini shetland; PPDI) have not done well.  None have access to grass.  Lab tests last week showed:
  • M (ID mare) insulin 120 ulU/ml cf normal lab range <20ulU/ml.  This is the highest her insulin has ever been recorded.  We have been running with it a 4.5ulU/ml or so for last 2+ years.  She has piled on weight and has a cresty neck but no pulses.  
  • Blossom insulin 83ulU/ml cf normal lab range of <20.  While elevated this is not especially high for Blossom who has seen this at up to 300ulU/ml in the past - but also as low as 4.5 last autumn.  
  • Mandy insulin 45ulU/ml
(for all horses we have now changed hay and are soaking it).

Both littlies just seem stuck;  unable to move; rigid.  Quarters simply don't want to work.  Once she gets going, Mandy will walk around reasonably happily but still looks stiff legged and stiff jointed.  Blossom was doing similarly but in last few days her condition has deteriorated; she does not want to move; fast shallow breathing suggesting pain, sweaty, trembling muscles, almost seemed colicky last night.  But no heat in hooves and no pulses.  No typical rocked back stance and does not react to hoof testers.  So on the face of it while it's easy to say she has laminitis, lots of evidence suggests she doesn't.  

In light of all this I sent a hay sample off for a 'quick and dirty' test to get a sense check.  It went to a different lab which just reports 'sugars' and does not break it down into ESC, WSC.  All I was after was a 48hr turnaround to help to tell me if I was going nuts of not - the horses should not be reacting to this hay as they have done.  

My sample was taken with a hay corer from 12 different bales and results were as follows:
DM 84.7% - it feels pretty dry but not dusty.  Maybe surprised this isn't a little higher.  
CP  13.9%
DE 10.4 mj/KG
'sugars'  8.5%
Starch 0%
ADF  32.8%
NDF 66%
All results on DM basis
The extract from the email - in message above - was from the feed company which organised this test.  
So quite a few differences from the test I was provided with and a significant difference in the DE in particular.  But still, on the face of it, a 'low sugar/starch' hay. Significant differences too on CP -but still not what I would think of as a 'high protein' hay.   

Vet is back in the next day or so and will test triglycerides.  AST and CK were both elevated - but, as Dr Kellon says, not alarmingly so.  GGT Liver function test was bang in middle of normal range and kidney tests both normal.  Vets seem at a loss to know what is going on and default is to say simply laminitis though they confess that the picture is not clear.  

In meantime, I have sent the hay back to the supplier (with a health warning) and am sourcing some low s/s from Forageplus.  Certainly, the clinical signs that I am seeing in my horses do not correspond to the hay that I thought I had !  
I'd be happy to attach copies of the analyses (and blood test results) but confess I have got no idea how to !!  Sorry.  

Moral of the story is never to accept a hay test result that you are given.....

With very many thanks as always and best wishes.
--
E Sarah Howell

Cambridgeshire UK
2018
NRC Plus, NAT and NPH 2019


E Sarah Howell
 

It's been some weeks, but I think we may at last have an answer to what is going on.  At least it is a working hypothesis.

Since my last post, M remained the same but Blossom and Mandy continued to go downhill.  Eventually both ponies went to our local veterinary hospital where they were diagnosed with active laminitis and some rotation.  

The conclusion that we have reached is that all three were being affected by toxins in the bedding.  The ponies had been stabled  for many many weeks because we haven't got Mandy's PPID under control (despite pleas to the vet to increase her dose) and of course are close to the ground so inhale dust.  M is out at night, comes in during the day and sleeps flat out every day, with her head on the bedding.  We have 3 other horses, all apparently unaffected; but none of them lie down.  

Our working hypothesis, therefore is as follows:
  • Mandy's PPID is not under control which has caused her insulin to be high
  • Blossom's is elevated (but for her not particularly high) because her body is under stress from toxins in the bedding
  • M's is as Blossom, and her endocrine system is impacted by toxins in the bedding.
The bedding that we have is made from straw pellets but since November has been made from miscanthus due to a shortage of straw in the UK.  Perhaps the straw / miscanthus is sprayed with pesticides, either during its life or to desiccate it prior to harvest ?  Perhaps there is something in the manufacture process to turn straw and miscanthus to pellets ?   

We have changed all bedding, reverting to wood shavings and have persuaded the vet (at last !!!) to increase Mandy's prascend dose.  After 2 weeks all three are much much better.  Ponies are walking and trotting around well.  M's coat is better, she looks more healthy and less 'puffy' and has begun to lose weight.  My vet, who saw her on Tuesday, reports that her whole body and system is much less toxic.  

My trimmer has today told me of another mini which she has seen with active laminitis.  It is on soaked hay, no access to grass but has been stabled on straw (for a reason I do not know) since Christmas. The laminitis has developed in recent weeks.  

I appreciate that to consider toxins in the bedding as the cause of the problems is a controversial hypothesis,  But we have no other sensible explanation.

I'd be interested if anyone has ever come across a similar experience.


--
E Sarah Howell

Cambridgeshire UK
2018
NRC Plus, NAT and NPH 2019


Eleanor Kellon, VMD
 

Except for black walnut, which causes problems within 24 hours, I don't know of any toxins in any type of bedding that cause laminitis. There could be toxins we don't  know about but a dead giveaway is elevated GGT and yours were normal.

Early Spring (March and sometimes into April) can be difficult for some IR mares because of the tendency to develop cystic follicles. Once their ovaries straighten out, the foot pain abates.

--
Eleanor in PA

www.drkellon.com 
EC Owner 2001


 

Hi Sarah, 
There are also straws which test higher in sugars and starches than our 10% cut off for safe hay and the ponies bedded on that straw will eat it preferentially.  Not sure about miscanthus but it seems to be a grass and I saw a report that it is related to bamboo and sugar cane.  Something to consider.
--
Martha in Vermont
ECIR Group Primary Response
July 2012 
 
Logo (dec. 7/20/19), Tobit(EC) and Pumpkin, Handy and Silver (EC/IR)

Martha and Logo


 
 


E Sarah Howell
 

Hi Martha
Just to clarify, the bedding is from straw (or miscanthus) pellets.  Not edible and not being eaten.  
--
E Sarah Howell

Cambridgeshire UK
2018
NRC Plus, NAT and NPH 2019


Kirsten Rasmussen
 

Hi Sarah,

How can you be certain your ponies were not eating it?  One of the reasons straw pellet bedding is used is because it is said to be safe IF the animals do happen eat it.  Of course it might not be safe for all equines if the ESC and starch in it are high. It would not take much to cause laminitis.  Whether it's straw or miscanthus, did you ever test the bedding for ESC and starch?

--
Kirsten and Shaku (IR) - 2019
Kitimat, BC, Canada
ECIR Group Moderator
 
Shaku's Case History
Shaku's Photo Album