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Q. Do You Need to Get Every Nutrient to 100% On The FeedXL Graph?

A. No. And in fact it would be impossible to create a diet that met exactly 100% of your horse’s requirements for every nutrient shown here.

Q. So if not 100%, where should the nutrient levels be sitting? And what is normal? Because some of the amounts on this graph look really high?! Isn’t that dangerous???

A. Good question! And the answer is it depends on the nutrient. Forages, for example, contain high levels of some nutrients like iron and potassium. Because diets often have lots of forage, these nutrients will almost always be high in the diet.

BUT that doesn’t mean it is dangerous. In fact if you push a nutrient to a dangerous level, the bar for that nutrient will turn red, like this, to warn you that the nutrient is now at its ‘upper safe limit’ and needs to be reduced.

Q. OK, that’s good! So I know if I get a nutrient WAY too high FeedXL will warn me. BUT I still don’t know what is normal for all of the nutrients. Where should I expect to see them?

A. Yep, let me walk you through them all! Let’s use this graph and go through each nutrient.

Digestible Energy

This should sit, for most horses, somewhere between 90% and 105% of requirements. SOME horses have a lower or higher need for digestible energy (calories) so you may see the odd horse sitting below 90% or above 105%.

BUT, if you do enter a horse and the Digestible Energy is low or high and this does not correspond accurately with what you are seeing in your actual horse (meaning if the Digestible Energy is low in the diet you enter into FeedXL, normally you would expect to see weight loss. If it is high, normally you would expect to see weight gain) you MAY need to double check the information you have entered into FeedXL as this is a small red flag that something has not been entered right.

For example, if you have entered bodyweight that is too high, the Digestible Energy level will be low and vice versa. Or if you haven’t weighed your feeds and hay or classified your pasture correctly and you have entered amounts or qualities that are too low, then Digestible Energy will appear low and vice versa.

Quick Tip: If Digestible Energy in your horse’s diet is below 90% or above 105%, check that you have entered your horse’s bodyweight and weights of feed and forages correctly.

Crude Protein

The Crude Protein level in the diet should always be at or above 100%. And it is best to try to keep it less than 200%. For performance horses that are stabled and in work I like to try to keep Crude Protein below 160%, if I can… it is not always possible!

Depending on your forages, you may see Crude Protein go very high (well above 200%). Is this an issue? Generally it’s not, but there are some situations (like very hot, humid climates or when a horse is stabled) that it is not ideal. Sometimes, if it is your pasture for example that is high in protein, there is not a lot you can do about it. If the horse is stabled and fed hay, you should try to switch some of the higher protein forage (e.g. alfalfa/lucerne) for a lower protein forage (like a meadow/grass hay), to bring the overall amount of Crude Protein in the diet down.

For detailed information on whether too much protein is an issue or not read our article here: https://feedxl.com/37-protein-can-you-feed-too-much/

Lysine

Lysine is your indicator of protein quality (you can read about Protein Quality here https://feedxl.com/30-understanding-protein-quality/). Lysine should sit between 100% and 150%. If it is lower, it indicates your protein quality is low and your horse will struggle to do things like build muscle or make milk. In fact, when lysine is low in a diet you will likely see your horse losing muscle over his topline… it’s an important nutrient to get right in the diet.

Lysine may get quite high in some diets depending on the amount and source of crude protein. But if you follow the guidelines above for Crude Protein, you will find Lysine levels will adjust accordingly.

Calcium

Calcium should be at or above 100% in the diet and I like to keep it below 200%. Ideally, I like it sitting below 150% but depending on the feeds and forages being used, it is not always possible to achieve this. The amount in the diet shown here is lovely, more than the horse needs but well below 200%.

It is important with calcium to also check the calcium to phosphorus ratio in the diet (look in the Nutrient Table) to make sure it is within the right limits with phosphorus. And if you like to use the extra ratios, you can also check its ratio with magnesium, which as a guide, should be 3: 1 or less.

Phosphorus

Phosphorus should be at or above 90% and ideally below 150%. You may see some diets with high phosphorus ingredients like Rice Bran pushing phosphorus higher than this. If it is above 150%, be sure to check the calcium to phosphorus ratio on the nutrient table to make sure this is still balanced (there MUST be more calcium in a diet than phosphorus).

NOTE: You cannot calculate the diets calcium to phosphorus ratio off the numbers on the graph. It is always best to read the ratio off the nutrient table. FeedXL will warn you if the calcium to phosphorus ratio is too high or low!

Copper, Zinc, Selenium and Iodine

I am grouping all of these trace minerals together because they all share the same characteristic that they are almost ALWAYS at low levels in forages. Which means they are nearly always deficient in diets before you add fortified feeds or supplements.

This means that you can aim to keep these nutrients as close to 100% as possible. The diet shown here uses a single vitamin/mineral supplement to meet trace mineral requirements.

This is what the diet looked like before I added the supplement:

You can see these 4 minerals are all low. I used the Supplement Finder (i.e. The BIG PINK BUTTON) to find a supplement that would fill all of these gaps. Ideally what you want to see when you use a single supplement is that at least one of these minerals is sitting very close to 100%. That is your green flag that you have the amount of supplement at the right level. Increasing the amount from this point is just a waste as all requirements are already met, while reducing it would mean the amount of this nutrient (selenium in this example, which is sitting at 101%) would no longer be meeting requirements.

The same rules also apply when using a fortified feed to meet vitamin and mineral requirements. Except that you also have to consider the amount of Digestible Energy the feed is adding.

This is not a super simple concept, so if you are confused, please keep asking questions, as the more you understand this, the easier it will be to use FeedXL effectively.

Quick tip: You can try to keep copper, zinc, selenium and iodine as close to 100% of requirements as possible. If these nutrients are above 200% I would be trying to find ways to reduce them. This may mean switching feeds or supplements!

Manganese, Iron, Magnesium and Potassium

These minerals are almost always HIGH in forages. Therefore you will almost always see them sitting well above your horse’s 100% level in the diet. Is this a concern? No. There are always exceptions, but for the majority of horses, no, it is not a problem when these minerals are well above 200%.

Thing is, because these nutrients are rich in forages, it is almost impossible to get them closer to the 100% mark. You could reduce the amount of forage, but the downside of that (higher risk of ulcers, boredom, compromised hindgut health, higher risk of dehydration and colic) far outweighs any potential upside. In fact unless levels in the forage are extreme and the bar for a nutrient goes red, there really is no upside to reducing forage.

If you are concerned, because sometimes it does look scary, just read the notes in the Nutrient Table or the hover box on the graph to put your mind at ease. For example, Iron in this diet is at 331%. Which seems really high! But, the notes will tell you:

“While Poet’s iron is higher than it needs to be it is still within the safe range. Poet’s upper safe level for iron is 6,019 mg or 943% of his RDI”

So the upper safe limit is 943%. This diet is a long way off that, so even though 331% seems high, it is very much within the safe zone!

For those of you who like to look at the iron: copper: zinc: manganese ratio, it is calculated for you in the Nutrient Table.

Sodium and Chloride

Sodium and chloride are the two components of ordinary table salt. So together they can make a feed taste very salty. If a feed gets too salty your horse may stop eating it, because it simply doesn’t taste good (and can’t blame them!). So I like to keep sodium as close to 100% as I can, by adjusting the amount of salt in the diet.

There are a few exceptions. If your horse is in a very hot and humid climate you may need to feed more (more info here https://feedxl.com/40-electrolytes/) or if you are trying to increase water intake for some reason, more salt is useful. But under normal conditions, sitting sodium at or very close to 100% is best. BUT also always make sure your horse has access to free choice salt!

Chloride is a bit of a lucky dip and its final level in a diet will depend on the amount in your forages. I don’t pay too much attention to where chloride ends up. In fact I don’t think I have ever had to adjust a diet specifically to change the level of chloride (for any dairy nutritionists reading this, it does play a big role in DCAD, but that is another story for another day 🙂 ).

Vitamin A

If you are obsessive about getting nutrients close to 100%, Vitamin A is your friend! You will notice it is nearly always sitting on 100% of requirements. Why?

Well, in forage, the ‘vitamin A’ content is not active vitamin A. It is in the form of Beta Carotene which can be converted to vitamin A IF your horse needs vitamin A. So they will only convert it if they need it.

FeedXL models this physiology and takes into account ALL vitamin A from feeds and supplements as this will be an active form of vitamin A (which can become toxic so we need to count all of it). But then FeedXL will only convert vitamin A to active form from forages IF your horse needs more vitamin A.

For example, if your feed + supplement provides 80% of your horse’s requirement for vitamin A, FeedXL will just top up the remaining 20% of vitamin A from forages to meet 100% of your horse’s requirement. Which is why Vitamin A is very often sitting right on 100%.

If your feeds and supplements provide more than 100% of your horse’s requirement for vitamin A you will see it above 100%. This is OK, as long as it is within safe limits (though personally I would keep it under 200%).

Vitamin E, Vitamin B1 and Folic Acid

I am grouping these three together because they will often be low in diets before you add some kind of fortified feed or supplement. And they are all relatively expensive nutrients, so for the sake of cost, you want to make sure your horse’s requirement is met, but if levels of these vitamins go above 200%, you may be paying a lot for nutrients your horse doesn’t really need. I like to keep them between 100% and 200% if I can. In the case of this diet, the supplement I used was rich in Folic Acid so it has tipped above 200%, but the E and B1 are at nice levels so I am not going to worry about the Folic Acid in this case.

Quick Tip: Keeping these nutrients below 200% will make sure the diet is not excessively expensive!

Vitamin B2, Niacin, Vitamin B5 and Vitamin B6

This crew are all grouped together because forage is OFTEN high in these vitamins so you will normally see levels WELL ABOVE 100% for all of these vitamins. Is that something you should be concerned about? Not at all. In fact all of these except vitamin B6 are considered non-toxic. And the vitamin B6 upper safe level is very high (in this diet the upper safe limit is 5000%!!).

Quick Tip: I essentially ignore these nutrients as long as they are ‘green’. They will almost always be well above 100%, but it is nothing to be concerned about!

I hope that helps you a little to read the graph and to put your mind at ease about what is and is not normal for certain nutrients. If you have questions, please be sure to ask in the FeedXL Horse Nutrition Forum on Facebook!! We truly want you to know as much as you can about what FeedXL is showing you!

5 Ways One Balanced Diet Can Be Better Than Another

We recently had a member of our nutrition forum ask ‘Can one balanced diet be better than another, or is the key point that it is balanced?’

This is probably the best question I have ever been asked! And the answer is absolutely YES! One balanced diet can be better than another!

BUT, before I explain why, I just want to say that diets balanced using FeedXL will be 1000 (or more) times better than a diet that is unbalanced and not meeting a horse’s basic nutrient requirements. So take heart that if your diet is balanced on FeedXL, you are way ahead in keeping your horse healthy.

So balanced diets that meet all of your horse’s known nutrient requirements are better than unbalanced diets that do not meet requirements.

But, one balanced diet can certainly be better than another.

Here are 5 examples of what makes one diet better than another:

 

Factor OK Option Better Option Why is this better?
Forage Amount Diet just meets the FeedXL minimum forage requirement. Forage is a major component of the diet and is used to meet as much of a horse’s daily digestible energy requirement as possible. The more forage in a diet the better your horse’s gut health will be. If you feed a balanced diet but your horse’s gut is unhealthy, your horse’s overall health will be limited.
Forage Variety You feed only one or two different types of forage. For example Teff hay and alfalfa/lucerne chaff or pellets. Your forage (pasture, hay, chaff, forage pellets or cubes) is made up of several different plant species. For example, your pasture has 3 different grass species plus clover, and you feed a mixed meadow hay plus alfalfa/lucerne chaff. While we know a lot about many nutrients a horse needs (like copper, vitamin E etc) there are MANY nutrients (like the omega fatty acids and most of the essential amino acids) that we know your horse needs. We just don’t know how much he needs. Feeding a large variety of forages improves the chances you will meet requirements for all of these nutrients we don’t understand very well yet.
Uncooked Grains The ONLY OK option for uncooked grain is oats. ALL other grains must be cooked. They are definitely not OK to feed uncooked. All grains are easier to digest when they are cooked (boiled, extruded, steam flaked, micronized). In fact you must only feed barley, corn and rice if it has been cooked. Feeding any of these grains uncooked is going to make your horse sick. The starch from cooked grains can be almost fully digested in your horse’s small intestine. Meaning less starch is allowed to get into your horse’s hindgut to feed the ‘bad’ bacteria. If you do feed raw grains, your horse’s hindgut will become acidic, bad bacteria will flourish and your horse’s gut and overall health will suffer.
Using Oil All oils are ‘safe’ and all provide the same amount of digestible energy in a diet. But, some oils like sunflower and corn oil are extremely high in omega 6 and can unbalance your horse’s omega 3 to 6 ratio. Canola oil provides a good blend of omega 3 and 6 fatty acids and is particularly useful in diets that contain no grain to provide the omega 6 your horse will need. Flax/Linseed oil is very high in omega 3 and is super useful in high grain diets to balance the omega 3 to 6 ratio. If you feed too much omega 6 in a diet it can result in excessive inflammation. Choosing your oils to match your diet (a little like choosing your wine to match your meal) means you will meet omega 3 and 6 requirements and keep the ratio between the two balanced.
Protein Quality As long as you meet your horse’s protein AND lysine requirement in FeedXL you will be doing a good job of providing enough protein and essential amino acids. BUT, not all proteins are created equally. Cottonseed meal, for example, contains lysine, but 60% of it is unavailable for absorption. Or flax/linseed meal is high in protein but it is low in essential amino acids. Choose premium quality proteins for your horse’s diet so that when FeedXL shows you that crude protein and lysine requirements are met, you also have an excellent chance of meeting all requirements for the essential amino acids. This includes choosing things like a component of soybean in preference to an unnamed ‘vegetable protein meal’ and/or using some alfalfa/lucerne together with your grassy forages. When you feed better quality protein you will get more muscle! When you are able to use high-quality sources of protein that meet your horse’s essential amino acid requirements you will have a better chance of 1. Providing enough of the amino acid ‘Leucine’ to switch muscle building on; and 2. Providing the building blocks needed to actually build muscle.

 

So if you want the best possible diet, here are my top 5 tips:

  1. Feed as much forage as possible to meet digestible energy requirements.
  2. Use as many different types of forage as possible.
  3. Never feed uncooked grains!
  4. Use oils that have an omega 3 to 6 profile that will complement your horse’s diet; and
  5. Use high quality proteins.

If you can do all of that AND have a balanced diet, your horse will be ready to take on the world!

Is Forage All a Horse Needs?

Pasture or hay is all a horse needs! Or is it?

This is something I often hear… and 99% of the time it is WRONG!

Forages are (almost) always too low in trace minerals to meet a horse’s requirements and leaving them unsupplemented on forage only diets usually results in problems with their hooves, joints, immune system, muscles … everything really!

They may look OK, but there is usually a bunch of stuff going on inside that you can’t see until a deficiency is quite pronounced.

BUT, there are always exceptions to the rule and I have just seen one. As a consulting nutritionist I end up looking at lots (numbering now 1000+) of forage analyses and I have just looked at a pasture from New Zealand that is able to meet all trace mineral requirements without any additional supplementation.

Even for selenium, which is something we don’t expect in New Zealand!

Sodium is a bit low (nothing unusual there) and iodine was not tested, but the fact is it is actually a pasture that horses would do OK on without extra supplementation. Just need a bit of iodised salt!

The horses on this pasture were being fed a selenium-containing balancer pellet and recently tested with blood selenium levels just in the high range (nothing scary, just high). It had us a bit baffled but looking now at the pasture results it makes sense.

The lesson in this, forage analysis is a wonderful tool when assessing your horse’s diet and FeedXL makes it so super easy to really see what forage is providing and what you need to add, which in this case is very little.

If you’d like to have your forage tested, we love to recommend Equi-Analytical.

Not yet a FeedXL member? Click here to get started!

Questions? Comments?

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Don’t Forget the Milk!

If you are looking at your foal’s diet in FeedXL it is crucial you include mum’s milk. It is a goldmine of nutrients for your foal and must be taken into account. Forget the milk and you will end up overfeeding, which will then cause problems with growth that is too fast.

OK you say, I will include the milk, but how? I know right, it’s a bit tricky because the foal just drinks it and you have no way of measuring how much he drinks. But lucky for you, your mare produces a reasonably consistent amount of milk for her foal, so depending on the age of the foal, you can calculate how much milk he is probably drinking. It won’t be perfect, but it is a lot better than not including it at all. 

Here at FeedXL we don’t recommend you balance a diet for a foal until he is at least 3 months of age. Up until this age, his mother’s milk and stores of minerals in the liver will fully meet requirements. So even though he will start to eat with his mother as early as a few days of age he doesn’t need this extra feed to meet his nutrient requirements.

After 3 months of age your foal will start to rely on nutrition outside of milk to meet his requirements, BUT milk still provides a lot of nutrition, so it must be included in his diet in FeedXL.

Here’s how to include milk in your FeedXL diets:

1. Calculate the amount of milk he is getting from his mother. At 3 months of age her milk production will be around 2.5% of her bodyweight per day.

To calculate 2.5% of her bodyweight:

2.5/100 = 0.025

0.025 x BW = amount of milk per day in kg or lb

So for a 500 kg (1100 lb) mare this would be:

0.025 x 500 kg = 12.5 kg per day
(or 0.025 x 1100 lb = 27.5 lb per day)

2. Create your foal in FeedXL with his correct date of birth and bodyweight. It is so important to get bodyweight correct! The only real way to do this is to weigh your foal (sorry, no easy tricks on this one).

3. Enter your foal’s pasture and/or hay, then add the milk at 2.5% of his mother’s bodyweight using the calculation above.

4. Check the diet to see what is missing and add a balancer pellet or feed to fill in the gaps. TIP: Use the supplement finder to find a product that will top up the required mineral and vitamin levels. 

The images below show a January born, 200 kg thoroughbred foal’s diet with:

Pasture Only – note the LARGE deficit in required digestible energy. If you tried to fill this entire gap with feed you would be feeding waayyyyyy too much and make your foal grow too fast! This is why you need to add the milk!

Pasture + Milk – note now the deficit in digestible energy has been filled by the wonderful milk, so he doesn’t actually need extra calories in the diet. But there remain many mineral deficits. This is what you need to top up.

 

Pasture + Milk + 600 grams of Balancer Pellet (that I found using the Supplement Finder) – and you are done, requirements met without exceeding digestible energy requirement! Note FeedXL may warn you that forage requirement is not met. For foals, you have my permission to politely ignore FeedXL on this one as long as he has constant access to pasture and/or hay!

It is so super important to remember the milk! If you don’t, you run the risk of overfeeding your foal and that will almost certainly cause you to run into issues with developmental disease in the bones and joints.

If you are balancing a diet for your foal with FeedXL and are having trouble getting it right, be sure to pop over to our Facebook Nutrition Forum and ask for help. We are here and we want to help you!

Questions? Comments?

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Adding Your Own Forage to FeedXL

Did you know you can add your own hay with complete data to FeedXL?

The easiest way to do this is to upload an Equi-Analytical XML forage analysis file and FeedXL will add all the data for you.

To learn about Equi-Analytical and their forage analyses, visit their website here. We recommend either the (601) Equi-Tech package ($26/analysis) or the (604) Equine Complete package ($79). When testing pasture or hay, we also suggest you have Selenium tested for an additional $35.

If you have an analysis from another lab or you only have the PDF file from Equi-Analytical, the video below will show you how to add the data to your hay so you can use it in your FeedXL diets immediately (and don’t have to wait for one of us here at FeedXL to enter data for you).

Some things to keep in mind:

  • Use the ‘As Sampled’ data and not the ‘Dry Matter’ data.
  • Watch the per amount unit. The data in this example is given per 1 lb. If your analysis is in a different unit (e.g. per 1 kg) change to the appropriate unit.
  • Watch your units on each nutrient, they can vary.
  • The hay will show ‘Waiting for Data’ in its name until we accept it as a private ingredient. BUT, you can still use the hay in your diets, it will work perfectly!

 

 

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How to Make Sense of Pasture Analysis Results

Have you ever got the results back from a pasture or hay analysis and been left scratching your head trying to figure out what the numbers mean? Frustrating isn’t it!?

That is unless you have a tool (like FeedXL) to interpret the numbers for you.

Let me show you what I (Nerida) mean. The analysis below shows the analysis result numbers for the bottom pasture at our place, but they are kind of meaningless unless we look at them in terms of how much of that pasture a horse eats and how much nutrient is provided compared to the amount of nutrient the horse actually needs.

Take phosphorus for example, the pasture contains 1.45 g/kg of phosphorus, which is only enough to meet 39% of a late pregnant (month 11) mare’s requirement if she was given full time access to this pasture.

Our pasture is native pasture and our soils are low in phosphorus so the pasture is lower in phosphorus than most pastures. BUT, point is 1.45 g/kg of phosphorus was only a number until we put it in terms of what our late pregnant mare needs each day to meet her requirement (note to my husband, we don’t have a late pregnant mare, this is just an example, in case you are panicking right now! No promises for the future though, it’s all part of my professional development right! )

You will also see from the diet readout from FeedXL below that the pasture only diet (bar graph with the green and red bars) is not meeting requirements for multiple other nutrients for this late pregnant mare, which also would have been difficult to determine just from reading the analysis numbers alone.

 

So with FeedXL we can see what is not in your pasture that your horse needs. You can then also add other feed ingredients to the diet to meet those requirements.

The second bar graph with the green and blue bars shows a diet I would use for a late pregnant mare on this pasture. The diet uses 2 kg of prime lucerne hay (shown in the darker green) and 3 kg of a commercial broodmare feed (shown in the blue). All requirements are now nicely met!

Pasture analysis made that bit more useful! Using FeedXL to assess your forage analysis also means you will only supplement with the nutrients you need to add, potentially saving yourself a lot of money by not adding unnecessary products and nutrients.

You can upload as many pasture and hay analyses as you like into your FeedXL account, just click the ‘Add my own forage’ link in the Create Forage section of the diet wizard, or directly from the Feeds list (see below). Click here to log in and give it a try!

 

QUESTIONS? COMMENTS?

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Grazing Muzzles

I personally love grazing muzzles. A muzzle means my horses can be out grazing 23+ hours per day. Without them they would be strip grazed (trashing my natives pastures in the process) or locked up for extended periods, which for gut and mental health is not ideal either.

But they come with their challenges. They can rub if they don’t fit properly. If you don’t have one your horse is OK with they can create behavioral issues (rearing while trying to put them on or being impossible to catch to put them on) and I find certain brands can be too hot to wear in hot climates.

And of course there is always that unknown of how long you should leave one on for your particular muzzle+horse+pasture combination (which if you are like me causes a bit of angst for a while until you get it figured out!).

The other thing you need to be really aware of is how they limit normal behavior. My horses love to groom one another, but with muzzles on all the time they can’t do this. So I have to consciously make time to let them have muzzle free time together so they can do some mutual grooming.

Just something to keep in mind for those of you with muzzled horses.

Questions? Comments?

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Iron for Horses: Could Forage Be Enough?

Comparison of equine dietary iron requirements to iron concentrations of 5,837 hay samples

N. Richards and B.D. Nielsen, 2018

Introduction

Iron is essential for the production of red blood cells. According to the 2007 Horse NRC, Fe requirements are 50 ppm for growing foals, lactating and pregnant mares, and 40 ppm for all other classes of horses. The 2005 NRC suggested a maximum tolerable Fe concentration of 500 ppm using data from other species. It is claimed that excess dietary Fe is causative of horses becoming insulin resistant.

Athletic horses, and particularly those in Thoroughbred racing, are often supplemented with Fe in an attempt to improve performance. Supplementation is commonly carried out without any formal analysis of the diet to determine if additional iron is required. Forages are typically high in iron and supply a majority of iron in all equine diets.

This study looks at the iron concentration in forages typically fed to equines and whether iron from forage is enough to meet the iron requirement of an athletic horse.

Methods

Nutrient concentrations from hay samples submitted for analysis in 2017 and for which Fe was measured were obtained from Equi-Analytical, representing 3,060 grass, 1,193 legume, and 1,584 mixed hay samples.

Iron concentration was measured using inductively-coupled plasma mass spectrometry (ICP). Analysis methodology is available from dairyone.com. Statistical analysis was performed using Proc MEANS of SAS.

Results

Iron was highest in Legume and Mixed Mainly Legume Hays and lowest in Grass Hay (Table 1). All hay types had a mean iron concentration more than five times that required by athletic horses and a median iron concentration more than three times.

From all hay samples (n = 5,837), 707 contained Fe at or above the suggested tolerable threshold of 500 ppm, while only 81 contained Fe at less than 50 ppm. Further, only 15 contained Fe at less than 40 ppm.

Discussion

A 500 kg horse in heavy work has an iron requirement of 500 mg/day (NRC 2007; based on a daily feed intake of 2.5% bodyweight and a requirement of 40 ppm). Forage intake is often restricted by Thoroughbred trainers. But even when fed at 1% of bodyweight to a 500 kg horse, these hays will supply an average 1,060 mg to 2,230 mg of iron per day, supplying more than 200% of daily iron requirements in the forage component of the diet alone.

Fortified grain concentrates are fed at an average 2.5 kg/horse per day in Australian Thoroughbred racing stables (Richards 2003). These concentrates have an average iron concentration of 190 ppm (FeedXL.com), adding an additional 475 mg/day of iron to the diet of these horses. Almost 60% of Australian Thoroughbred trainers then add an iron supplement to their horses’ diets (Richards 2003). It is expected similar trends would be found in the USA.

Based on this broad diet analysis, forage is able to meet the daily iron requirement of athletic horses. When iron from fortified feeds and supplements is added, there would be few racehorses receiving less than 300% of their daily iron requirement. It’s not unexpected that many horses would be receiving in excess of 500% of their daily iron requirement

What About Insulin Resistance

Given the dearth of Thoroughbred racehorses that are insulin resistant, despite Fe supplementation in combination with diets that can easily supply amounts beyond requirements, it seems unlikely excess Fe causes insulin resistance. However, it is recognized insulin resistant horses may have elevated serum ferritin.

References

Council NR. Nutrient Requirements of Horses: Sixth Revised Edition. Washington, DC: The National Academies Press, 2007.

Richards N, Hinch G, Rowe J. The effect of current grain feeding practices on hindgut starch fermentation and acidosis in the Australian racing Thoroughbred. Aust Vet J 2006;84:402-407.

FeedXL Nutrition Software, https://feedxl.com/, 2018.

HUGE THANKS to Equi-Analytical for providing the data to write this paper, which was presented as a poster at the recent International Conference on Equine Exercise Physiology (ICEEP).

Questions? Comments?

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Setaria Grass and Bighead: What You Need to Know

Setaria should really be classified as toxic for horses. It is a subtropical pasture with such high levels of oxalate that it makes it almost impossible to prevent Secondary Nutritional Hyperparathyroidism (Bighead disease) in horses grazing this grass.

Grasses like kikuyu and buffel grass readily cause bighead disease with an oxalate content of around 15 g/kg. Setaria contains anywhere between 30 and 80 grams of oxalate per kg of (90% dry matter) pasture… which translates to HUGE amounts of calcium being needed to balance the calcium to oxalate ratio to prevent bighead.

I have seen horses go from normal to severely affected in a matter of months on setaria. So if you have setaria in your pasture you need to be very aware of what you are feeding and how well this is meeting calcium (as well as phosphorus and magnesium) requirements.

FeedXL will help you in calculating the calcium to oxalate, calcium to phosphorus and calcium to magnesium ratios to keep your horse healthy. BUT, the first step is identifying that you have this grass in the first place so you know you need to be on your game with managing nutrition!

I took the following photos of setaria on the NSW mid-north coast… setaria was everywhere! Please take a look at the photos and then in your paddocks to see if you have setaria. And if you do, please do something sooner than later to prevent severe and often life-threatening calcium deficiency.

There is more information on Bighead here too if you need it at https://feedxl.com/25-bighead/

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Teff Hay vs Rhodes Grass Hay

Teff Hay seems to have suddenly appeared as a hay option for many horse owners and because it is sold as a low starch low sugar hay it is starting to be recommended in place of Rhodes Grass Hay.

BUT, if you are lucky enough to have access to Rhodes Grass Hay, I wouldn’t be eager to swap. Here is why:

1. Rhodes Grass Hay is low in oxalate, containing approximately 2.5 to 3 g/kg of oxalate.

Teff Hay is moderate to high in oxalate at 10 to 12 g/kg. This means Teff needs careful supplementation of calcium, phosphorus and magnesium to prevent it from causing Bighead Disease. With Rhodes being so low in oxalate Bighead is not an issue (though you do still need to make sure you correctly balance the diet for minerals and vitamins as forages rarely contain enough to meet a horse’s requirement).

2. Rhodes Grass Hay is more reliable and consistent when it comes to the low starch, low sugar characteristic.

From the analyses we have seen coming through here at FeedXL Teff can be high in starch, with one analysis sent through showing an as-fed starch content of 7.1% and total NSC of of 13.7% which for a laminitic horse is going to be too high. While soaking would more than likely bring this non-structural carbohydrate (NSC) level back down to safe levels it makes for much more time consuming feeding… so if you have access to Rhodes Grass it would be much easier to use this.

3. Teff Hay causes some odd behavioural issues in some horses and this is normally associated with an alkaline fecal pH.

We have no way of explaining this, and it doesn’t happen with all horses on Teff so I don’t know if all Teff Hay is the same or if there is a certain variety that causes this issue.

So while Teff gives people in cooler climates a low NSC option which is welcome, it is not yet well understood and not without its issues. If I had a choice between Teff and Rhodes I would go with Rhodes Hay every time.

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