The last of my nutrition tidbits

Sorry for the silence - I’ve been writing posts - but they are “special” posts that are being scheduled for the future for moments that are coming up that I don’t want to miss! You’ll understand when you see them go up :).

Let’s get started on more nutrition!

A question that I’ve gotten several times over the years is, “What if my horse hits a wall during our first 50?” or it’s variation: “How do I know whether we are done or if I should work through it?”

I usually give some variation of the this answer:

It's hard to tell whether your horse is done, or if it's just a wall that they will get through. Some people are comfortable asking their horse to push through that wall, and some people have the opinion that if it isn't fun for the horse, than they don't want to ask and would rather pull. For me, asking Farley to push through the wall is a lot like asking her to go out on a conditioning ride. Farley doesn't enjoy conditioning and going away from home early on, she drags and goes SLLLOOOOWWWWW. And sometimes does a silly spook. Or flings her head. Or is just so dull I worry - is she tying up??? Is she lame????? Is she colicky????? Exactly the same things I worry about during an endurance ride when she doesn't want to be forward. I handle it much the same way. If I'm asking for forward and she's dumpy and slow and resistant I do a systems check - are her butt muscles tight? Does she feel sound? Did she eat and drink at the last check? If all the physiological systems are a go, then I insist on forward motion, even if I have to use a crop to reinforce my leg, until she knows I am REALLY serious that she continue to move off my leg. Is there a chance that something is going on that I missed that I've now made worse by my insistence that she move forward? Yes. Is it likely? No. Twice during training there were issues that manifested as slows and resistance. Once, I caught the problem, and once I missed it and didn't catch it until later. But on the one i missed I gave her every opportunity to prove to me something was going on - including lunging her in a roundpen looking for lameness - and when nothing showed, I had to conclude it was a training issue and not a lameness issue. And.....she ended up tying up at the end of that arena session. But, you do the best you can at the time with the information you have. I feel confident enough in my ability to evaluate Farley, and I have enough time with Farley that I know what is likely to be wrong, so I feel very comfortable concluding that the "wall" during an endurance ride is mental and insisting she keep moving after doing a quick "systems check". But on a new horse? I would be more cautious and while a systems check on Farley takes me ~30 seconds, I might take 1-2 minutes evaluating a resistant horse that had less experience.


I think it's still a good answer. But now, based on some new knowledge, I would ask the very important question before going any further:  “Are you carbo loading?”. 

Turns out carbo loading, or including simple carbs and starches in the diet CAUSES HORSES (and humans) TO HIT WALLS.  There’s a place for a higher carb diet but it ain’t in the endurance world.  Carbs ARE indicated for sprinting type horses (quarter horse racing, thoroughbreds) but even they need to be carefully weaned off of carbs before a race to minimize carbohydrate metabolism during the race.

The nutritionist explained to me the mechanism behind how carbohydrate metabolism impacts performance and I *think* it has something to do with increased lactate production which eventually overwelms the body’s ability to use the lactate as an energy source and causes fatigue.....but to be honest, this was 2 weeks ago, and I didn’t write it down right away and now I can’t recall exactly. :(.  If someone REALLY wants me to write the nutritionist an email asking her to re-explain, otherwise I’ll wait ‘til I see her in the spring for my next block.

The bottom line is that feeding carbs (carbo loading the day before, or using carbohydrate rich foods pre race or during the race) will cause an increase in fatigue. 

Oil is still an excellent energy source for endurance horses. It doesn’t have the fatigue effects of carbs, adds lots of calories while minimizing risk to horses sensitive to non-structural carbohydrates, and the research suggests that feeding oil for at least 6-8 weeks prior to an endurance ride can boost aerobic performance. Horses are very good at utilizing fat (as compared to cows), especially if you introduce and increase the amount gradually.  Starting at 1/4 c. per day and increasing it 1/4 cup per week until you reach 1 c. or so is a recommendation I see commonly, and is what I do. Just remember not to use corn oil (pro-inflammatory - and yes, I used to think that was a bunch of BS, but it isn’t and is actually being taught in vetschool :). 

The reason we recommend oil be eliminated from the diet about 1 week before the race is also related to why you want to increase amounts of oil gradually. 

Have you ever accidentally overfed oil?  I haven’t, but I’m told they will get nasty diarrhea.  Oil suppresses the microbes of the hind gut (ie makes them just a bit unhappy).

An excellent way to think of the horse hind gut is the horse’s “rumen” - a giant space where good bacteria and microflora are busy digesting and breaking down nutrients and making food stuffs available to the animal that normally could never be utilized by mammals. Keeping the bacteria in the hind gut happy is PARAMOUNT to keeping the horse happy.  Lots of things can piss the bacteria off - overload grain, not enough forage, too much oil, antibiotics....If you mildly insulting the little buggers perhaps you get some diarrhea.  REALLY pissing them off (which we will touch on in another related nutritional issue) could cause an “environmental” shift where a bunch of the gram negative normal bacteria flora dies, releases endotoxins and poisons the horse as the ultimate act of revenge.

So.  Happy microbes = happy horse. 

If you’ve fed oil properly, you’ve slowly built up the amount over time without the microbes protesting - they’ve adapted to each weekly increase. 

The problem is, even though there’s no overt signs of unhappy microbes, feeding oil/fat is still slightly “depressing them”.  The benefits that you get feeding oil is worth this, and at home during normal training and athletic effort this minimal amount of depression isn’t worth a second thought. 

However, when you go to do 50 or 100 miles, it is crucial that all the systems of the horse - including the critically important microbe community of the hind gut - are in absolutely the best shape they can be - and that means pulling the horse off oil for the week prior.  Fortunately, even though the horse isn’t consuming oil in that last week, you still retain all the benefits of feeding oil over time on race day :).

Moving on to particle size. 

The “length” of forage or feed that your horse eats is important.  In the horse gut, large particles “pass” (ie go into poop) and small particles “stay”.  (FYI in cattle it’s the opposite - large particles stay in the GI tract while small particles pass - which makes sense if you think about the difference the length of fiber you find in each species’ poop, but I digress).  Various parts of the horse’s gut have these “saculations” or pouches.  Small particles settle out into these saculations and create a little micro acidic environment, while the larger particles keep moving down the GI system. 

Accumulate enough of these small particles and you will create a more and more acidic environment within the gut.  Note that this isn’t a systemic acidic effect - this is localized within the gut.  At some point the pH drops (acid) enough that it makes the gut environment less hospitable to the normal bacteria/microflora....which start to become unhappy.  The “new” lower pH of the gut makes it much MORE hospitable to DIFFERENT bacteria that LIKE this new lower pH and decide to make it even LOWER - which of course makes the old resident bacteria even LESS happy and they die. 

This is not good because the old resident bacteria are mostly gram negative which have  “endotoxin” as part of their outer membrane which is then released as they die.....Endotoxin is a potent stimulator of the immune system and unfortunately horses are EXQUISITELY sensitive to endotoxin. 

It’s the revenge of the microflora :).

During this whole process of a new lower pH, the GI tract lining is also becoming ulcerated, which allows the dying gram negative bacteria and the endotoxin to be released systemically. 

And then you have a dead horse.

Well, not actually - I’ve just spent 2 weeks learning how to deal with endotoxemia in horses - all of which bores me and so I will not bore you with it. 

The moral of the story (besides don’t piss off the bacteria in your gut) is that feeding little particles of forage is not as good as feeding it in a longer form.  Obviously pasture forage or baled forage is good, but how small is too small? When you do you have to start worrying about how small the particles are?

Apparently cubes contain fiber lengths that are borderline OK.  Pellets are too small.

I immediately started thinking about all the pelleted mashes my horse gets leading up to a ride and at a ride. There are some folks who won’t let their horses eat hay at all during the last section of a 100 because of worrying about choke and their horses only eat pelleted mashes at that point.  Am I acidifying my horse’s gut and setting it up for GI ulcers and potential microflora issues?  On top of all the other stressors the horse experiences at a 100?

I asked the nutritionist specifically about this situation and she said because I am suspending the small particles in an emulsion (ie a mash) that the impact of small particles on the gut was less, and because I only fed mashes over a very short period of time (only at rides, mostly in a 24-48 hour window), that in her opinion I wasn’t causing an issue. It would be more of an issue if I was feeding significant amount of mash made with pelleted feeds daily. Like most things in nutrition, there doesn’t seem to be any hard and fast rules - more general guidelines that are applied to individual situations after weighing the available options.  I do give a pound or two (works out to about 1-2c) of soaked pellets daily for vit E administration etc.  but I think that is a small enough amount, combined with a diet that is almost 100% forage (makes the microbes very happy!) that I won’t worry about it.  But it’s something I’ll definately keep in mind if I find myself feeding more mashes than usual for some reason. And because there ARE additional stressors on the gut at ride, even more reason to wean off that oil during rides so the microflora are as healthy as possible.

It’s quite interesting (and difficult!) to stay up on what’s happening in the nutritional world, but I’m always so grateful when I get to have a conversation with some one that does it for a living.  I always learn so much and come away with some many tidbits that are practical and I can use to tweak my horse management.

It can be easy to get lost in the sea of information, but I think if you start with some basic fundamentals (ideally horses should live on a large amount of acreage and eat good quality pasture forage), it gives you something to base the new information in, and help you make a decision of whether it’s something makes sense and might be worth implementing.

The oil is counterintuitive to me - but there’s a large enough body of research on the subject, that I’m willing to do it. 

The rest of the new information makes sense to me if I look at horse management as “managing a horse that is varying degrees from the ideal (ie on pasture)”. The further from the ideal, the more intensively the horse probably needs to be managed and the more attention to detail is needed.