Photo of oaten hay

Is Oaten Hay Bad for My Horse’s Teeth?

Oaten hay is commonly fed to horses. Recent research by Jackson et al (2018)1 suggests however that we should be cautious with oaten hay as it may be negatively affecting our horses’ dental health!

The Study

Dr Kirsten Jackson (https://dentalvet.com.au) and her co-researchers found in a study of 500 Western Australian horses, that oaten hay was significantly associated with an increased incidence of dental caries (tooth decay).

Peripheral caries improvement

Image credit: Dr Kirsten Jackson (https://dentalvet.com.au)

How does Oaten Hay do this?

Dental caries form when bacteria in your horse’s mouth metabolise sugars in the hay/ feed and produce the by-product of acid. This acid demineralises the teeth causing decay which in horses generally means the outer layer (cementum) is stripped from the teeth.

Because oaten hay can be so high in water soluble carbohydrates (WSC; also loosely called ‘sugars’) the oaten hay feeds the oral bacteria, a lot… and then they produce a lot of acid… and the acid demineralizes (eats away) the hard part of the teeth.

It is thought that the near constant supply of sugars to the bacteria in the mouth when a horse has constant access to oaten hay, and therefore the prolonged periods of exposure of the teeth to the acids produced by the bacteria is what puts horses on oaten hay at higher risk of disease.

What about other types of hay or pasture?

Dr Jackson reports that in the same study it was found that a meadow hay based diet was protective. And horses with access to good quality grazing all year round were less likely to have peripheral caries than horses that had no access to grazing.

Other similarly high WSC hays like ryegrass hay and other cereal hays like barley and wheaten hay will potentially put horses at the same risk as oaten hay.

What can be done if my horse has dental caries?

The good news is that because a horse’s teeth are constantly erupting, and the acid produced when high WSC hay is fed only affects the part of the tooth that is physically exposed to it (so the tooth below the gumline remains unaffected), dental caries can be treated.

Jackson et al 2021 showed that when oaten hay was swapped for a lower WSC meadow hay, it allowed teeth to start to recover.

The authors note that full recovery generally takes around 2 years.

Peripheral caries improvement

Image credit: Dr Kirsten Jackson (https://dentalvet.com.au)

Should oaten and other high WSC hays be completely avoided?

Not necessarily. It seems in this study that it was horses with free access to oaten hay that were most affected.

If you are in an area where other type of hay is difficult to source and using SOME oaten hay helps to get you through, then using some, mixed with a variety of other hays and/or access to pasture is potentially OK.

Also not all horses on oaten hay were affected so there is some individual variability in susceptibility to the caries so some horses can be ok on oaten but if your horse has caries it is best to avoid it. If your horse is on oaten hay and this can’t be avoided it is probably a good idea you have regular veterinary dental examinations conducted every 6 months.

If you are spoilt for choice with hay and can avoid oaten hay, you are probably best to avoid it completely… especially if you have a thoroughbred as they were also shown to be at higher risk!

References

1. Jackson, K., E. Kelty, and M. Tennant, Equine peripheral dental caries: An epidemiological survey assessing prevalence and possible risk factors in Western Australian horses. Equine Vet J 2018. 50(1):79-84.
2. Jackson, K., E. Kelty, and M. Tennant, Retrospective case review investigating the effect of replacing oaten hay with a non-cereal hay on equine peripheral caries in 42 cases. Equine Vet J 2021. 53(6):1105-1111.

Straw as an Alternative Forage for Easy Keepers

Straw is gaining favouritism among nutritionists and horse owners as part of diets for easy keepers. It allows energy intake of the diet to be reduced without drastic restriction in a horse’s daily feed intake.

This strategy is thought to improve the welfare of easy keepers and reduce the risk of colic and gastric ulceration, all common issues seen with feed restriction.

A recent study that substituted 50% of the grass haylage component of the diet with straw, further supports the use of straw in easy keeper diets.

The main findings in the study (Jansson et al 2021) were that the 50% straw diet had:

  • No effect on squamous or glandular gastric ulcers scores
  • Longer feed intake times and lower energy intakes
  • Lower Insulin concentrations (a positive for those prone to laminitis)
  • A trend for higher serotonin levels (a key hormone that stabilises mood; inhibits aggression, fear and stress; supports intestinal motility; plays a role in fat tissue metabolism)
  • Gut sounds that reflected normal motility patterns and no changes in manure moisture content– indicating no major adverse effects on gut function.

Why Should You Consider Including Straw?

It is now widely accepted that horses should be eating a minimum of 1.5% of their bodyweight in forage per day (dry matter basis). This supports natural behaviour and minimises the risk of health complications such as gastric ulcers and colic.

However, for some easy keepers, this amount of forage alone can exceed energy requirements. Therefore, replacing some higher energy forage in the diet with low energy straw can allow owners of easy keepers to reduce the energy content of the diet without restricting intake below 1.5% of bodyweight.

More bulk. Less energy! Happier horses!!

Isn’t There a Risk of Gastric Ulcers on Straw Diets?

A previous study published in 2009 reported the incidence of gastric ulcers (both glandular and squamous) was increased in horses fed straw as their only roughage source. The authors (many of which are the same authors on the above-mentioned paper) suggested that mechanical damage, changes in the gastric contents, specifically the fibre ‘mat’ that forms in the stomach, and reduced buffering capacity due to low calcium and protein content of straw could have been the cause.

However, in the present study the severity and incidence of gastric ulcers decreased over the study period (2 x 21 days). This suggests that including up to 50% of the forage in diets as straw does not increase the risk of gastric ulceration.

And in fact the slower intake of straw is likely to be a good strategy for ensuring horses don’t go longer than 4 hours without feed. Which should then act to reduce the risk of ulcers.

Decreased Feed Intake, No Time Without Forage

The 50% straw diet offered in 2021 study contained the same amount of energy as the haylage only diet. This meant that horses on the straw diet were receiving more forage (based on dry matter) than the haylage diet.

However, the researchers found that the horses on the straw diet actually had leftovers which resulted in them consuming less energy each day (10.7MJ per 100kg bodyweight) compared with the haylage group (12.4MJ per 100kg bodyweight).

This suggests that because horses are ‘fuller’ or more satisfied on the straw diet, they are likely to eat less forage which may decrease energy intake without the need for intake restriction.

Longer Periods Spent Eating

Another benefit of the 50% straw diet was that horses spent more time eating each day compared with the haylage only diet. The authors calculated that the horses on the straw diet spent 11.2 hours per 24 hours eating whereas the control diet horses spent 6.2 hour per 24 hours eating – an 80% difference!

The most likely explanation is differences in palatability or some physiological response as the NDF (measure of the cell wall components such as hemicellulose, cellulose and lignin) content of the two diets was very similar – NDF content is correlated to intake.

The authors noted that interestingly, the horses on the straw diet spent more time pausing their feed intake whereas the haylage diet was consumed almost at all at once.

Lower Insulin Response

Many easy keepers are at increased risk of laminitis. It is therefore in our best interest to feed a low sugar and starch diet which limits glucose and insulin responses.

In the present study, the insulin response was lower on the 50% straw diet than the haylage only diet. The total water-soluble carbohydrate (WSC) intake was significantly lower for the straw diet (60g vs. 75g per 100kg bodyweight) so this was not unexpected but does highlight another possible advantage of including straw in diets.

Be mindful that this cannot necessarily be generalised for all straw and analysis is recommended to determine the actual starch and WSC content of any straw you might consider using.

Also interesting to note that the grass forages used in this study were by no means high in WSC, being 7.7% and 4.9%, as compared with the straw being 0.8%.

Higher Serotonin Levels in Horses on the 50% Straw Diet

This is super interesting and the authors offered the explanation that chewing more and being more satisfied from a hunger perspective is potentially increasing serotonin levels and may be the reason why horses are eating less and taking more pauses between eating when offered the 50% straw diet.
It is well known in humans that spending longer chewing meals reduces hunger levels, with chewing stimulating serotonin.

Does Feeding Straw Increase the Risk of Impaction Colic?

The present study showed no difference in gut sounds between the haylage only diet and the diet with 50% inclusion of straw over the 21-day study periods. Nor did the moisture content of the manure vary between the two groups.

A lack of faecal moisture (or in other words, the presence of dry manure) may indicate increased risk of impaction colic. The authors noted that certain individuals and even some breeds are more prone to impactions and owners should be cautious.

All changes in forages should be made gradually over several weeks to minimise the risk of colic providing a chance for fibre digesting bacteria to adapt.

No More HANGRY Horses?!

Using straw in diets can add another string to our bow for managing the weight and seemingly insatiable appetite of easy keepers.

The results of this study suggest that inclusion of up to 50% of the forage ration as straw does not cause gastric ulcers and may in fact improve the welfare of easy keepers by reducing energy intake on ad lib hay and prolonging the time they spend eating.

Straw in effect lets us feed more bulk, while providing less energy. And keeps our horses fuller, happier, chewing for longer and less stressed!

 

You might also be interested in our article ‘Using Straw to Achieve Weight Loss in Horses’.

 

Full article https://www.mdpi.com/2076-2615/11/8/2197

Jansson, A., Harris, P., Davey, S.L., Luthersson, N., Ragnarsson, S.and Ringmark, S. Straw as an Alternative to Grass Forage in Horses—Effects on Post-Prandial Metabolic Profile, Energy Intake, Behaviour and Gastric Ulceration. Animals, 2021, Issue 11, Volume 8, Pages 2197-2211.

 

Nutritional & Non-nutritional Aspects of Forage

I was honoured to have been part of the team who put together the Veterinary Clinics | Equine Practice book of clinical review articles on Equine Nutrition.

Together with Dr Brian Nielsen (Professor, Michigan State University) and Dr Carrie Finno (Associate Professor, UC Davis) we wrote the chapter ‘Nutritional and Non-nutritional Aspects of Forage’.

Hopefully it will make a great resource for equine veterinarians around the world!

The biggest take-home message…

Forage alone is unlikely to meet all nutrient requirements and some form of supplementation, be it in the form of supplements, balancers or feeds, will almost always be necessary to create a balanced diet!

If anyone would like a copy we would be happy to email it to you.

You can find the abstract here: https://pubmed.ncbi.nlm.nih.gov/33820609/

Richards N, Nielsen BD, Finno CJ. Nutritional and Non-nutritional Aspects of Forage. Vet Clin North Am Equine Pract. 2021 Apr;37(1):43-61. doi: 10.1016/j.cveq.2020.12.002. PMID: 33820609.

DO YOU HAVE A QUESTION OR COMMENT? DO YOU NEED HELP WITH FEEDING?

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Hay and horse in the background

Q&A: Grass and Legume Hays

Question: Can you touch base about grass and legume type hays, what each grass/legume benefits the horse’s overall health. Is a certain mixture better (or preferred) for certain horses; pasture pet, light work, moderate-heavy work, hard keeper, easy keeper, etc.

Example: benefits of having mixtures – pros to having certain types within the mix such as Birdsfoot Tree foil, orchard grass, climax timothy, Kentucky blue grass, spring green felstulolium, brome.

Watch the video below with FeedXL founder Dr Nerida Richards and SmartPak’s Dr Lydia Gray for the answer!

 

Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group

 

Hay for horses on a wagon in a field

Q&A: Alfalfa and the Calcium to Phosphorus Ratio

Question: When feeding a lot of alfalfa, what is the best way to keep a horse’s Calcium to Phosphorus ratio where it should be?

Watch the video below with FeedXL founder Dr Nerida Richards and SmartPak’s Dr Lydia Gray for the answer!

 

Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

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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!

 

Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

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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/

 

Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

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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.

 

Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

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Do High Sugar Forages Make Horses Fatter?

This is a question we are often asked and my standard response has always been ‘well, it depends on the calorie content of the forage’, which has always then made me wonder about the relationship between forage NSC and digestible energy content.

In looking at 13 pasture samples from one farm it seems the higher the NSC content, the higher the digestible energy (calorie) content. The pastures shown here were all sampled between 11 am and 2 pm on the same day. They were all dried at the same time and all were analyzed by Equi-Analytical.

For interest I plotted the Digestible Energy (calorie) value against the pasture non-structural carbohydrate (NSC = starch + water soluble carbohydrates) content and while this certainly isn’t publishable data the trend is pretty clear for this particular set of pastures in that as NSC increases so does digestible energy… which makes very logical sense given the NSC is a source of calories so the more NSC, the more calories.

So perhaps my answer should be ‘yes, high NSC forages will make your horses fatter faster than low NSC forages!’. And therefore yes, it makes sense to feed a low NSC forage when you are trying to achieve weight loss or avoid weight gain in your easy keepers.

For some tips on feeding an easy keeper see https://feedxl.com/11-feeding-the-easy-keeper/

 

Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

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Hay for horses on a wagon in a field

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! It 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.

 

Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

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