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.

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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


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.


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 Statistical analysis was performed using Proc MEANS of SAS.


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.


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 (, 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.


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,, 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).

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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

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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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Soft Manure in Horses on Fresh Lucerne/Alfalfa Hay? Try This!

Lucerne/Alfalfa… if it is really fresh and green it will often cause scouring/diarrhea. We don’t know (as far as I’m aware) what causes the scouring, BUT my observation over the years is that once it is stored for a few months the problem goes away (hence the old advice to always feed ‘shedded’ hay)… so whatever it is in lucerne/alfalfa that causes the issue seems to be volatile and disappears after a while.

The issue at the moment for many of us is hay is in such short supply that all we can get is very fresh lucerne! We don’t have the luxury of waiting a couple of months for it to lose whatever it is that makes our horses scour… here is what you can do!

Take your bales, open them up and spread the pieces (biscuits, flakes, leaves… we call them all sorts of funny things depending on where you are in the world!) apart and let them sit for about a week (longer if you have the luxury of time) to air out. You should find that your horse’s gut will be much happier with it once it has had this chance to air out. If your hay seems particularly rich and is making horses scour badly try also sitting it in the sun.

I have dealt with lucerne/alfalfa in a polo stable in Asia actually bursting horses’ stomachs! 😮 was horrible!! But once we got them to start airing and sunning the hay like this (it was imported from the USA) the problem thankfully stopped. Its the only time I have heard of that with lucerne/alfalfa and hopefully the only time!

Anyway, if you are dealing with soft manure in horses on fresh lucerne/alfalfa give this a try. Would love to know what happens if you have time to leave a comment on Facebook.

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Is Grain Free/Low Sugar, Low Starch Always the Way to Go for Horses?

Feeding grain free diets has grown in popularity in the last 10 years and there are certainly many benefits. BUT, need it always be the way to go? The answer is, it depends, but often no.

Horses with conditions like laminitis, PSSM tying up, PPID/Cushing’s, equine metabolic syndrome, insulin resistance etc MUST be fed a low sugar, low starch (or low non-structural carbohydrate; NSC) diet. Usually, to achieve low enough starch and sugar levels, these diets need to be grain free. One of the things FeedXL is great for is to help you sort out which feeds, forages and supplements are safe (low in starch and sugars; NSC) or not safe to feed horses with these conditions.

But for horses that don’t need low sugar, low starch diets to control diseases, as long as grain is FED SAFELY, grains can form a very valuable part of a ration! They are economical compared to high energy fibres like beet pulp (which are expensive in comparison), they provide a source of glucose that horses in heavy work can use to readily replenish muscle glycogen supplies, and they are palatable… horses love grains, so keeping horses in hard work eating on grain based feeds tends to be relatively simple provided the recipe is good!

So, as long as grains are well cooked (with the exception of oats which can be fed uncooked) and as long as you feed them in small meals (no more than 0.5 kg/100 kg BW, 0.5 lb/100 lb BW) they can form a very useful part of a horse’s diet. These are HUGE ‘as long as’ statements too… feed grains in the wrong way and things WILL go horribly wrong. But that is another story for another day.

The moral of this story is don’t fall into the trap of one-size-fits-all when it comes to grain free. 

There is more info here on why we cook grains for those of you who would like the details:

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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.

Teff Hay for Horses

OK, the lowdown on Teff Hay for horses. First, the good!

There is a bit of research looking at the use of teff hay in diets where low sugar, low starch forages are required;

Staniar et al 2010: These authors report non-structural carbohydrate (NSC) contents for teff of 5.4% in the ‘boot’ stage and 8.4% in the ‘late heading stage’ of plant maturity. Both really low NSC levels and well below the 10 – 12% threshold considered safe for laminitic/EMS/PPID/PSSM horses. Variation in NSC levels between samples was also minimal which is also our experience with other C4 Type grasses like Rhodes for example.

Horses in this study ate 1.5% to 1.8% of their bodyweight in teff hay, with the lower intakes being on the more mature hay. Again, this is a good thing as horses on restricted diets are unlikely to eat this hay as fast as more palatable hays like alfalfa, so they should eat for longer periods of time for lower calorie intake.

McCown et al 2012: Report that when fed to horses unaccustomed to teff and given a choice of either teff and alfalfa or teff and timothy, their intake of teff is lower than their intake of alfalfa (no surprises there) and timothy. BUT, when given access to only teff, intake was about the same as timothy hay. So they don’t relish teff hay, but truly, this is a good thing as they are less likely to overeat it!

Askins et al 2017: These authors report that horses given free access to teff hay consumed 1.5% of their bodyweight per day which equated to 86% of maintenance calorie requirements. So the finding of lower intake on teff continues … hooray for teff!

This study also reports that resting glucose and insulin levels did not change over 10 days while the horses were fed teff. To keep this in context however, ryegrass hay (which can be very high in NSC) was fed as the control hay in this study and glucose and insulin levels also remained the same on this hay. Unfortunately the NSC content of the hays was not reported (yet!).

DeBoer et al 2017: In another recent study, these authors report that cool season (C3) perennial grasses (in this case orchardgrass, also known as cocksfoot and Kentucky bluegrass) had a significantly higher NSC content than teff pasture in summer and fall/autumn, however actual NSC content was not reported (this is just an abstract, data will be fully published in paper discussed below).

This research also looked at differences in plasma glucose levels in horses grazing either alfalfa, cool season (C3) grasses or teff and found that differences were minimal. However, we know that insulin resistant horses can maintain normal glucose levels, they just need a lot more insulin to achieve this.

DeBoer et al 2018: This is the fully published journal paper of the research above. Authors report that horses grazing teff had significantly lower PEAK insulin levels when compared to horses grazing cool season (C3 Type) grasses in fall/autumn… despite NSC levels not being significantly different between the grasses (the cool season grasses had numerically higher NSC values but when variation was taken into account they were not significantly different). It is worth noting here however that teff was not recorded with an NSC above 10% at any time point where the cool season grasses did reach 12.6% NSC in summer.

All in all, from the research available, teff appears to be suitable for horses who need either a calorie restricted and/or NSC restricted diet. If you are going to feed teff hay though be sure to use FeedXL to balance the diet.

Because here is the not so good!

Teff, being a subtropical/warm season/C4 type grass does contain oxalate which will reduce calcium absorption by your horse and may lead to calcium deficiency if you don’t correctly balance the diets calcium to oxalate ratio (FeedXL will make sure you do this!).

If the calcium deficiency is prolonged your horses will end up with a condition known as secondary nutritional hyperparathyroidism, commonly called ‘Bighead Disease’. You are unlikely to see actual changes in a horses facial/head structure, but you will instead notice general soreness, possibly a shifting lameness, changes in behaviour (horses will often become unhappy and just generally grumpy with a bit of a please don’t touch me attitude) and an intolerance for work (because everything is sore).

To prevent this from occurring you must keep the overall diets calcium to oxalate ratio at or above 0.5 parts calcium to every 1 part oxalate. And with additional calcium being added you will also need to make sure the diets calcium to phosphorus and calcium to magnesium ratios remain balanced. It’s lots of math, but FeedXL does it all for you in the blink of an eye. 

Teff, like almost all forages will also be low in trace-minerals and doesn’t contain great quality protein… so you will have a few other nutrient gaps to fill. Of course testing your specific hay and uploading this to FeedXL will give you the best results in balancing your horse’s diet!

There has been a few reports of teff hay causing behavioural changes in horses and a very alkaline (8+) pH of manure. I have no explanation for this but the people who reported this to me said it occurred repeatedly in multiple horses and that once changed onto a diet of meadow hay, faecal pH and behaviour returned to normal. One of the horse owners reporting this is a knowledgeable and well respected equine nutritionist.

Finally, alfalfa/lucerne hay makes a great forage to feed alongside teff. Alfalfa is similarly low in NSC, but unlike teff is rich in quality protein and high in calcium to help offset the calcium binding tendency of the teff. They complement each other nicely.

If you are involved in racing or FEI disciplines you may also need to be careful to not feed too much (or any??) teff because of possible positive swabs for synephrine, which reportedly occurs naturally in teff hay.

If you want to feed teff, our most recent recommendation is to do it carefully, introducing it slowly, feeding it alongside alfalfa and being sure to balance the overall calcium to oxalate ratio of the diet (again, FeedXL will help you to do this).

If you get odd behavioural changes, check faecal pH using a soil pH test kit. If pH is alkaline you may need to reduce the amount of teff you are feeding until this goes back to ‘normal’ (closer to a pH of 7).

Askins M.J., Palkovic A.G., Leppo K.A., Jones G.C. & Gill J.C. Effect of feeding teff hay on dry matter intake, digestible energy intake and resting insulin/glucose concentration in horses. Journal of Equine Veterinary Science 52, 45.
DeBoer M.L., Hathaway M.R., Kuhle K.J., Weber P.S.D., Sheaffer C.C., Wells M.S., Mottet R.S. & Martinson K.L. Glucose response of horses grazing alfalfa, cool-season perennial grasses and teff across seasons. Journal of Equine Veterinary Science 52, 79.
DeBoer ML, Hathaway MR, Kuhle KJ, et al. Glucose and Insulin Response of Horses Grazing Alfalfa, Perennial Cool-Season Grass, and Teff Across Seasons. Journal of Equine Veterinary Science 2018;68:33-38.
McCown S., Brummer M., Hayes S., Olson G., Smith S.R., Jr. & Lawrence L. Acceptability of Teff Hay by Horses. Journal of Equine Veterinary Science 32, 327-31.
Staniar W.B., Bussard J.R., Repard N.M., Hall M.H. & Burk A.O. (2010) Voluntary intake and digestibility of teff hay fed to horses1. J Anim Sci 88, 3296-303.

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How Much Forage Your Horse Really Needs

“You eat like a horse”. There is a very good reason this saying exists; Horses. Eat. A. Lot!!! And a vast majority of horse owners know this, but every now and again I come across a horse owner who is concerned about weight loss in their horse and it is simply because they don’t realise just how much a horse actually needs to eat each day (except my horses, they seem to eat nothing and still get fat!).

So I thought it a timely reminder (with bare paddocks surrounding me in the very drought stricken area where I live) about how much forage a horse needs to eat each day. Traditional recommendations were that horses should receive a minimum of 1% of their bodyweight (1 kg/100 kg BW 0r 1 lb/100 lb BW) of forage per day. More recently however, Harris et al (2016) have increased the recommended minimum to 1.5% of bodyweight. Most good nutritionists will aim for 2% BW of forage in a diet where this is possible.

The amount of forage fed has an impact on the health, welfare, behaviour, gut health and performance of your horse as well as a horse’s risk of colic. Where I see it go horribly wrong is when an owner simply doesn’t realise just how much hay a horse actually needs to eat in a day. Underfeeding hay will often (in everyone else’s horses, mine are still excluded!) result in weight loss and can result in life-threatening colic. The good thing is it is very easily fixed, just feed more hay! 

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How Do You Know if Your Horse is Getting Enough Feed?

Well… happily, this is one of these easiest things to assess in horse nutrition because you can actually SEE if your horse is getting enough feed!

If your horse is getting enough feed he will maintain his weight. If he is not getting enough, he will lose weight. Or if he is getting too much, he will gain weight. Simple huh!

Trick is assessing this consistently so you can adjust how much you are feeding as weight changes. To assess weight gain or loss we use the Henneke Body Condition Scoring System. We have detailed information on using this simple system here:

Here’s a neat (and very colorful) little cheat sheet that you might like to keep handy as well  

Get in the habit of running your hands over your horses and mentally assessing condition. You will find in a very short space of time you will start to pick up small changes in body condition that might alert you to the fact your horse may need an adjustment in his feed program.

I am sure if my horses could talk they’d tell you they are never patted, just condition scored ?… lucky they can’t talk huh!

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