Posts

Black horse on brown pasture

How Stress Affects Your Horse’s Gut

Stress! Did you know stress affects the gut? In pretty dramatic ways!

Prof John Pluske presented a talk at this weeks animal nutrition conference looking at the effect of stress on weanling pigs. Here are some photos from his presentation:

Pigs have a very similar gastrointestinal tract to horses so I often look at pig data when trying to solve problems where there is not enough horse specific information to base my research on.

Prof Pluske showed that stress negatively affects a weanlings pigs gut. With the guts ability to repair itself and it’s effectiveness as a barrier between gut and body both being damaged by stress. Essentially when a piglet is stressed the gut gets damaged. But it then can’t fix itself and it starts to leak.

Which seems relevant to horses. I am sure that we see this in horses too and with the similarities in gut physiology it seems logical… which means we need to be really aware of how we feed and how that impacts on gut health, particularly when a horse gets stressed.

Three things that are really important:

1. Feeding a fully balanced diet that meets all nutrient requirements so the gut has the nutrients it needs to remain intact.

2. Feeding lots of forage. Forage is high in fibre and supports the population of good bacteria in your horse’s gut. These bacteria are very involved in maintaining overall gut health; and

3. Feeding high quality protein. The gut has huge requirements for specific essential amino acids. These amino acids are used by the gut to repair and to produce protective mucus. To provide optimum levels of these amino acids you need to use ingredients with high quality protein.

Protein quality is so important for many reasons. To learn more read our post ‘Understanding Protein Quality’.

Questions? Comments?

Click here to join our Horse Nutrition Forum on Facebook

Horse on summer pasture

What You Should Know About Anaerobic Fungi

Anaerobic Fungi! These little critters live in our horses’ hindguts! And they are responsible for an estimated 30 to 40% of the fibre fermentation that occurs in there! So as well as thinking about how diet might affect our horse’s hindgut bacterial populations we also need to think about how it might affect their anaerobic fungal populations!

Problem is, we know so little about them that we don’t know what is good and what is not so good for them. Information on what we know so far was presented at EEHNC by the incredibly passionate researcher Dr Joan Edwards. Joan described the fungi as having potent fibre degrading enzymes, giving them an important role in a horse’s digestion process.

The fungi can survive outside the horse’s gut too, and are seemingly resistant to both oxygen (which kills many anaerobic bacteria that live in the hindgut) and desiccation (drying out). This makes me wonder if they are part of the reason why my horses will seek out specific dry manure piles and eat them on occasion… maybe?!

Anyway, there is some research published (e.g. https://www.researchgate.net/…/329954798_Anaerobic_fungal_c…)

And more research to come (https://www.wur.nl/en/project/Equine-Anaerobic-Fungi.htm)… so watch this space as we keep learning more.

In the meantime while we figure out how to look after these fungi, I suspect feeding in the way that will look after the bacteria in a horse’s hindgut will also look after the fungi… so keep your horse’s diet high in low fructan forage, keep grain/starch out of the hindgut by feeding only well-cooked grains where necessary and in as small meals as possible and make changes to the diet slowly.

I love info like this as it is exciting to know we are always understanding horses better. Part of me though is thinking great, yet another thing we have to think about! ?

Questions? Comments?

Click here to see this post on the FeedXL Facebook Page

Gastric Ulcer Medications and Their Effect on Digestion

Q: Does gastric ulcer medication reduce nutrient digestion in horses?

Someone asked me this in a recent seminar and it reminded me that when I was studying during my PhD tenure we had looked at the effect of pre-incubating grains in equine stomach fluid on the digestion of starch from those grains.

And what we found was that starch from grains that were exposed to equine stomach fluid before being digested by small intestinal enzymes was between 17% (extruded rice) and 104% (cracked triticale) MORE digested than starch that wasn’t exposed to the stomach fluid. So the stomach fluid was having a definite positive influence on the digestion of starch.

What we can’t say from this research was how much of this increased starch digestion was due to the stomach acid and how much was due to the protein digesting enzymes the are present in stomach fluid that would be starting protein digestion and making access to the grain starch easier for the starch digesting enzymes in the small intestine.

The thing to remember though is that the protein digesting enzymes in a horse’s stomach fluid rely on the stomach acid to activate them. So regardless of whether the improved digestion was due to the acid itself or the protein digesting enzymes, if you stop acid production using ulcer medications you will lose both the acid and the enzymes.

So, if we use medications like ranitidine and omeprazole to reduce gastric acid secretion in horses we are very likely reducing the digestion of at least some nutrients further down the gastrointestinal tract.
What to do??? Well, if your horse has ulcers this is by far the most important consideration, you need to medicate to get rid of the ulcers as quickly and as effectively as you can.

BUT, once the ulcers are gone it is recommended you use good management practices to keep your horses chewing, their stomachs full and buffered with saliva and their minds calm instead of constantly using medication to prevent ulcers. That way you are allowing their gastrointestinal tract to function the way it was designed (albeit I would love the opportunity to redesign parts of their gut!) and allowing the digestion process to be as effective as possible.

More info on feeding to prevent ulcers in our article ‘Avoiding Gastric Ulcers’ here https://feedxl.com/8-avoiding-gastric-ulcers/

Happy to share the method for the in vitro assay used to conduct this work with anyone who would like the details!

Click here to see this post on the FeedXL Facebook Page

The Link Between Regular Forage Meals and Gut Health

Poet and I (Nerida) headed out a few weeks ago to do some real work mustering sheep (not that we did anything useful, we were just along for the ride!). There were 5 of us on horses, saddled up by 6:30 am and in incredibly steep, rocky, tough (but stunning!) terrain for 6 hours. At various points we dismounted and slid (feet sideways) down parts of the mountainside because it was too steep to ride. Sheep were tripping and rolling down the hill (amusing! but gives you an idea of how steep it was!!).

Anyway, here is me, very conscious of gastric ulcers, giving my horse lucerne/alfalfa as I saddled up, letting him pick what grass we could find while out riding if we were stopped for any time so he at least salivated a little bit and immediately giving him water and more lucerne/alfalfa on return to where we had saddled up… meanwhile stifling my panic at watching the other horses eating nothing and trying not to think too much about what was going on in their stomachs.

I asked one of the guys, an experienced horseman, if he worried about ulcers, and it soon became clear that there was no understanding of how a horse’s stomach worked and the negative impact of not feeding them for such long (long!) periods of time (his horse had a couple of hours trip home).

I also asked recently at a seminar who could confidently sketch a horse’s gut or explain how it works and no-one was able to. And I get this… I had no idea what a horse’s gut looked like or how it worked the entire time I rode in my pre-nutritionist life!

The thing is, a horses stomach never stops secreting gastric acid. So even when your horse is not eating it is filling the lower part of its stomach up with acidic gastric juices. While the stomach is full this isn’t an issue as the dense matt of fibre in the gut will stop the acid from splashing around and burning the unprotected lining of the upper section of the stomach.

Problems start though when horses are off feed for long periods like this and end up with a pool of acid and an empty stomach. Combine that with the movement of being ridden and you get acid splashing up and quite literally burning holes (causing ulcers) in the top part of the stomach.

So here is my plea! Please help us to educate people on how a horse’s stomach works and what they can do (really simple things) to keep their horse’s stomach and therefore their horse healthy and pain free. Share this article on Avoiding Gastric Ulcers with them and have them understand that a horse’s stomach should never be empty and that as much as is practical you should never work a horse on an empty stomach.

Thank you!! From us and from all of the horses who will be so much better off when their owners understand how they work just a tiny bit better.

The Impact of Proton Pump Inhibitors on Gut Bacteria

An interesting read about the impact of proton pump inhibitors (PPI) like Omeprazole (the major drug we use to treat equine gastric ulcer syndrome) on the gut bacteria in humans! https://gut.bmj.com/content/early/…/12/09/gutjnl-2015-310376

While these drugs are a huge help in setting up an environment in the equine stomach where ulcers can heal, they are overused in many horses (some racehorses are never taken off these drugs) to prevent ulcers in place of management systems that will reduce a horses risk of ulcers (like feeding a forage meal to fill the stomach prior to work).

Makes me wonder what PPIs may be doing to the equine gut bacterial populations… one study I can find (https://onlinelibrary.wiley.com/doi/pdf/10.1111/eve.07_12792) shows no impact on equine fecal bacterial populations, but use of omeprazole in these horses was only short term and the study doesn’t specify the dose used. The fecal microbiota also aren’t necessarily reflective of what is happening further up the gastrointestinal tract.

Something to keep in mind if you have a horse on a PPI medication long-term. Needs some more research!

Click here to see this post on the FeedXL Facebook Page

Hindgut Ulcers

There has been a bit of talk about hindgut ulcers in recent years; do they exist, what impact are they likely to have on a horse, how should we treat them, how do we even know if they are there… lots of questions, not a lot of answers.

But here is something for you to consider… I just spent the end of last week in a room full of dairy (as well as pig and poultry) nutritionists. They spoke a lot about sub-acute rumen acidosis (SARA) and part of that discussion was around the health of the rumen wall and the impact that SARA has on it. Essentially if you make the rumen acidic (in the same way we can make a horses hindgut acidic when we feed raw grains like corn/maize), you start to damage the gut wall. Initially this will reduce the gut linings ability to asorb nutrients (which is a huge problem in itself). BUT, make it bad enough and ulcers will appear!

The photos here (from https://vet.uga.edu/…/digest…/week02/forestomach/rumen06.htm) show rumens that have been affected by acidosis. The first (black) shows ulcers in the lining. The second shows a healed ulcer and the long term damage done.

Scary huh!!! Please when you feed think about how what you are feeding is going to affect your horse’s hindgut health. It is possibly the single most important thing to consider when feeding!

For more on feeding for hindgut health have a read of our newsletter Keeping the Hindgut Healthy at https://feedxl.com/15-keeping-the-hindgut-healthy/

Click here to see this post on the FeedXL Facebook Page

How to ‘Measure’ Gut Health

Gut health! It’s so important but also really hard to ‘measure’. One way to get a bit of an indication of what your horse’s hindgut health is like is to check faecal pH.

A healthy hindgut will stay at quite a neutral pH, close to 7. At this pH the good fibre fermenting bacteria will be living happily ever after and doing an amazing job of digesting fibre for your horse.

A high pH (over 8) may indicate that there is not a lot of fibre fermentation happening in the hindgut for some reason, while a low pH (less than 6.5) may indicate that there is too much fermentation of starch and sugars happening. The good fibre fermenting bacteria don’t like living in these lower pH conditions and will be starting to shut down. If pH goes below 6.2 you can be almost certain that a lot of your good fibre fermenting bacteria will be starting to die and your horse will lose the ability to digest fibre (which then causes all sorts of problems including weight loss and vitamin deficiency).

So if you want to do a quick check on hindgut health, grab a ‘soil pH test kit’ (google that, you will find plenty of options for inexpensive kits) and use it on a fresh pile of your horse’s manure. You might find that pH is just right, or you may just find that something is a little out of kilter and you need to adjust the diet to get it back to a more neutral pH.

Have fun! I spent three years of my life measuring faecal pHs, fond memories! ?

Click here to see this post on the FeedXL Facebook Page

Enzymes, What Do They Do for Your Horse?

When a horse eats, much of its feed is made up of LARGE carbohydrate, fat and protein molecules. The horse can only absorb tiny little molecules from its gut (because if big stuff was able to cross from the gut into your horse’s body all sorts of bacteria, toxins and general muck would pass into the body and cause disease havoc!).

So before absorption from the small intestine can occur, the big stuff must be chopped up into little stuff. And it is enzymes in your horse’s gut that do this chopping.

It is easiest to think of digestive enzymes as little pairs of scissors. Let’s look at starch as an example. Starch (found in cereal grains like barley and corn/maize) is made up of lots of glucose molecules, all joined together. The job of the starch digesting enzymes in your horse’s small intestine is to cut starch into single pieces of glucose. Then it is the glucose that your horse is able to absorb.

Each nutrient has its own specific set of enzymes in your horse’s small intestine. So there are specific enzymes to digest/chop up starch, protein and fats/oils.

To learn more about enzymes and your horse’s digestive system, read https://feedxl.com/31-the-gastrointestinal-tract/

Click here to see this post on the FeedXL Facebook Page

Gut Bacteria, Vitamin B1, and Behaviour: Are They Linked?

The short answer is yes! Here is how:

Vitamin B1 has been observed to have an influence on behavior in multiple animal species, including horses. A horse will meet its vitamin B1 requirements via the vitamin B1 it eats in its diet and from vitamin B1 produced by the bacteria in its hindgut.

There are two main families of bacteria living in your horse’s hindgut:

1. The fiber fermenting bacteria who love to ferment fibre from the forage your horse eats. These little critters are the ones we consider the ‘good bacteria’; and
2. The starch and sugar fermenting bacteria who prefer to ferment starch and sugars. These we generally consider to be the ‘bad bacteria’.

The good bacteria PRODUCE vitamin B1 that your horse can then absorb and use.

On the other hand, the bad bacteria produce a compound called ‘Thiaminase’ that actually destroys vitamin B1 (also known as thiamine) that is in the gut, making it useless to your horse.

If your horse has too many bad bacteria, and not enough of the good ones your horse may not get enough vitamin B1 and behavioral changes may occur.

How do you avoid this? Keep your horse’s hindgut healthy with an abundant population of good bacteria. The main two things you should do to achieve this are:

1. Feed lots of forage!; and
2. Never feed uncooked grains (with the exception of oats for some horses)

For more tips on keeping your horse’s hindgut healthy head on over to https://feedxl.com/15-keeping-the-hindgut-healthy/

Click here to see this post on the FeedXL Facebook Page

Meal Size: Why Should it Be Little and Often?

We have all been told ‘Little and often’ when it comes to feeding horses. But why?

Well, when you consider horses are ‘grazers’ and their gut has been designed to work best with small amounts being consumed constantly over long periods of the day and night (they eat for up to 17 hours a day, can you imagine having to do that!) it makes sense that they should be fed small meals frequently.

But let me give you a visual (in words) on why it is best to feed little and often… In the horse’s small intestine there are things called enzymes, which are like tiny pairs of scissors. An enzymes job is to cut big things like protein, starch and fats up into very small things like amino acids (the building blocks of protein), glucose the building block of starch) and fatty acids (a building block of fats).

Unless the enzymes chop protein, starch and fat up they will not get absorbed as they are far too big to cross the intestinal wall intact. So for absorption to occur, these little enzymes MUST chop the big stuff into little stuff!

Now, imagine I was to give you a pair of scissors and then held up a long piece of ribbon. If I walked past you very, very slowly holding this ribbon and said ‘chop the ribbon into small pieces’, you would have plenty of time to chop the ribbon multiple times into small pieces. This is what happens in the gut. If a piece of protein for example goes moving through the small intestine very very slowly, the little enzymes have plenty of time to chop it up into amino acids so it can be absorbed.

Now imagine if I held up another piece of ribbon, exactly the same as the first, but this time I RUN past you and tell you to chop it up… you might get one shot at it (I am not very fast!) before it is gone. And this is exactly what happens in the gut. If feed is moving too quickly through the gut the poor little enzymes simply don’t get enough time to chop anything up. Meaning it simply won’t be absorbed.

So back to meal size and the little and often concept… when you feed small meals, the feed will move nice and slowly through the gut and the enzymes will be able to do their job and fully digest it so your horse gains full benefit.

Feed large meals and all of a sudden you increase the speed with which it will travel through the gut and reduce the amount of time the enzymes have to do their cutting… meaning your horse misses out on a lot of the value from that feed. It will be digested to some extent in the hindgut but a lot of value is lost.

So while not the only reason you should feed little and often, it is a really important one to keep in mind.

If you have a horse struggling to gain weight eating huge feeds, you might find you get better results by feeding less! Something to consider 

Click here to see this post on the FeedXL Facebook Page

© FeedXL