What is the Safest Form of Flaxseed – Whole, Ground, Heat Treated or Oil?

Confusion around what form of flaxseed (linseed) is best/safest to feed our horses is nothing new. While many of us thought the concerns around cyanide poisoning for horses were laid to rest, recent safety issues around flaxseed supplementation in human diets, more specifically for toddlers and children, has warranted us to look at this again (EFSA CONTAM Panel, 2019).

There are very few published research studies available in horses around the safety of feeding flaxseed. And there are no published reports of cyanide poisoning that we are aware of. Most safety information is extrapolated from other species including humans, rats, dogs, cattle and pigs. Although information is limited, we aim to answer three questions for you:

  1. Should we be concerned about the potential of cyanide poisoning in horses?
  2. What is the safest form of flaxseed to feed our horses?
  3. Does form then affect the fatty acid composition of flaxseed?

How is Flaxseed commonly fed?

Currently, whole and freshly ground flaxseed are the most common ways of feeding flaxseeds to our horses.

Whole flaxseeds are deemed relatively safe from the point of view of cyanide poisoning as the two things (more scientifically, the precursors for cyanide production; cynanogenic glycosides and the glycosidase enzyme) that combine to produce cyanide are contained separately within the intact whole seed. Once eaten, the chewing action grinding the seeds can allow for cyanide production, but it is thought that this is quickly halted once the flaxseed reaches the stomach and the enzyme becomes deactivated by the gastric acid.

Anecdotally horses owners have found that whole flaxseeds can pass undigested through the gastrointestinal tract presenting in manure, with some finding flaxseed plants growing in their paddocks (great for biodiversity in the pasture, but not so much benefit to our horse in getting those added fatty acids in the diet as we had hoped).

Freshly ground flaxseed has become popular for this reason – with limited time for cyanide to form, preservation of fatty acids and to ensure our horses could access all the goodness within the seed coat freshly ground flaxseed is an excellent option.

Realistically, what is the likelihood of cyanide poisoning in horses?

It appears not likely.

Extrapolated from other species, a horse’s maximum ‘safe’ intake of cyanogenic precursors is 0.4mg/ kg body weight… or 200mg for a 500kg (1100lb) horse (Dusica, I. et al., 2012).

So, even if a flaxseed product contained the highest concentration of cyanogenic precursors reported in the European Food Safety Authority database (407mg/kg) (EFSA CONTAM Panel, 2019), it can be still be safely fed at up to 500g (~1 lb) per day for a 500kg horse.

How much flaxseed can I feed safely?

There is no established recommendation, but we can be guided by amounts that have been safely fed in a few horse specific studies.

In a Canadian study, horses were fed 100g (3.5 oz) per 100kg (220 lb) body weight per day (500 grams for a 500 kg horse). This study looked at the supplementation of flaxseed for reducing skin reactions like ‘sweet itch’ (O’Neill, W. et al., 2002). The authors reported no negative effects of feeding milled flaxseed at this level and reported reduced skin reactions in response to the induced skin irritation in the flaxseed supplemented horses.

Other studies in 2009 & 2012, fed a much lower amount of milled flaxseed, estimated to be 150-165g (5.5-5.8 oz) per day. Between these two studies, positive changes in blood and muscle omega 3 content and improved immune function were reported in those supplemented with flaxseed compared with control groups (Vineyard, K. et al., 2009; Hess, T. et al., 2012).

Based on these few studies and figures extrapolated from other species, up to 100g (3.5 oz) per 100kg (220 lb) or 500 grams for a 500 kg horse per day can be fed safely.

Most horses (65% according to Facebook Poll conducted on the 15 October 2020 by FeedXL Horse Nutrition Calculator) receive 100-250g (3.5-8.8 oz) flaxseed per day.

If you are concerned about cyanide toxicity, what can you do?

Research has shown that heating flaxseed can reduce the amount of cyanogenic precursor present.

One study showed microwaving flaxseed for just over 4.5 minutes on microwave power of 400W reduced precursor by 25% (Dusica, I. et al., 2012). Beware though, you can burn flaxseed in the microwave! Microwave power > 560W for 6 minutes caused samples to burn.

Other studies have also shown that microwave roasting achieved the highest level of precursor reduction (83.3%) in flaxseed (Feng et al. (2003).

Happily, this study also showed that there were no major changes in the main nutrient and fatty acid profile caused by microwave treatment.

Similarly, extrusion (140 degree Celsius) significantly reduced cyanogenic compounds (84%) but did not significantly change the fatty acid content – even after storage for 60 days (Imran, M et al., 2015). Limited information is available on micronized flaxseed specifically.

Interestingly, the perception that fatty acids in raw ground flaxseed deteriorate quickly is not supported by various studies, all showing minimal difference in fatty acid composition after 2-4 months storage (Khalesi, S., et al. 2011).

What about oil?

The good news is that oil doesn’t contain the cynangenic compounds of whole or ground flaxseed. It can be less stable in terms of fatty acid composition, therefore must be stored correctly and used in a timely manner. But if the reason you are feeding flaxseed is for the oil content, then using the oil may be an option worth considering.

With flaxseed oil products though, you do not get the benefit of other nutrients whole, ground or milled flaxseed provides to a diet including like protein, fibre, minerals & vitamins.

Summary

So, are we any closer to knowing what is the best and safest form of flaxseed to feed our horses? Honestly, we think it comes down to personal preference.

With cyanide toxicity appearing to be less of an issue for horses due to the low amounts commonly fed in comparison to body weight – whole or ground flaxseed is acceptable. Due to anecdotal evidence of whole flaxseeds passing undigested through the gut, freshly ground flaxseed is favourable to ensure fatty acids can be absorbed.

Ground flaxseed also offers the benefit of providing the wonderful fibre and other nutrients along with the omega 3 fatty acids compared with flaxseed oil.

Practically, freshly grinding flaxseed is not for everyone.  If this is the case for you, using a stabilised (pre-heat treated) flaxseed product may be a better option.

If you are still concerned about cyanide poisoning, microwaving your flaxseed  should significantly reduce the cyanogenic precursor and is unlikely to affect the fatty acid content. Be careful microwaving though to make sure you are not burning the flaxseed.

And do your own research on the safest way to microwave them based on your specific microwave. As a guide you should be able to safely microwave them at 400W for 5 minutes. But the quantity you microwave at any one time will have an effect on the appropriate time you should use.

Feeding rates will vary depending on a horse’s energy requirement and amount of omega 3 within the diet however up to 100g per 100kg body weight appears safe…the economics of feeding this much we are less sure about!

 

References

Dusica, I., Kokic, B., & Tea, B., Colovic, R., Vukmirovic, D. & Slavica, S. (2012). Effect of microwave heating on content of cyanogenic glycosides in linseed. Ratarstvo i povrtarstvo. 49. 63-68.

EFSA CONTAM Panel (EFSA Panel on Contaminants in the Food Chain), Schrenk, D., Bignami, M., Bodin, L., Chipman, J.K., del Mazo, J., Grasl‐Kraupp, B., Hogstrand, C., Hoogenboom, L.R., Leblanc, J‐C., Nebbia, C.S., Nielsen, E., Ntzani, E., Petersen, A., Sand, S., Vleminckx, C, Wallace, H., Benford, D., Brimer, L., Mancini, F.R., Metzler, M., Viviani, B., Altieri, A., Arcella, D., Steinkellner, H. & Schwerdtle, T., (2019). Scientific opinion on the evaluation of the health risks related to the presence of cyanogenic glycosides in foods other than raw apricot kernels. EFSA Journal 2019;17(4):5662, 78.

Feng, D., Shen, Y. & Chavez, E. (2003). Effectiveness of different processing methods in reducing hydrogen cyanide content of flaxseed. Journal of the Science of Food and Agriculture. 83. 836 – 841.

Hess, T., Rexford, J., Hansen, D. Harris, M., Schauermann, N., Ross-Jones, T., Engle, T., Allen, K. & Mulligan, C. (2012). Effects of two different dietary sources of long chain omega-3, highly unsaturated fatty acids on incorporation into the plasma, red blood cell, and skeletal muscle in horses. Journal of Animal Science. 90. 3023-31.

Imran, M., Anjum, F., Ahmad, N., Khan, M., Mushtaq, Z., Nadeem, M. & Hussain, S. (2015). Impact of extrusion processing conditions on lipid peroxidation and storage stability of full-fat flaxseed meal. Lipids in health and disease. 14. 92.

Khalesi, S., Jamaluddin, R. & Ismail, A. (2011). Effect of raw and heated flaxseed (Linum usitatissimum L.) on blood lipid profiles in rats. International Journal of Applied Science and Technology. 1(4). 84-9.

O’Neill, W., McKee, S. & Clarke, A. (2002). Flaxseed (Linum usitatissimum) supplementation associated with reduced skin test lesional area in horses with Culicoides hypersensitivity. Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire. 66. 272-7.

Ratnayake, W., Behrens, W., Fischer, P., Labbe, M., Mongeau, R. & Bearerogers, J. (1992). Chemical and nutritional studies of flax-seed (Variety Linott) in rats. Journal of Nutritional Biochemistry. 3. 232-240.

Vineyard, K., Warren, L. & Kivipelto, J. (2009). Effect of dietary omega-3 fatty acid source on plasma and red blood cell membrane composition and immune function in yearling horses. Journal of Animal Science. 88. 248-57.

 

Meet The Author: Samantha Potter, MSc


In 2009, Sam completed a Bachelor of Equine Studies and it was during this time she developed an interest in equine nutrition. Pursuing this passion, Sam went on to complete her Honours followed by her Masters degree in equine nutrition at The University of Melbourne. Since 2015, Sam has worked as an independent nutritionist and enjoys supporting horse owners manage their horse’s nutrition in her role with FeedXL. To learn more about Sam and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.

 

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

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Horse looking out from his stable

Q&A: Original Grain or New Regimen?

Question: I brought a new horse home that has been on grain with his previous owner. I do not feed grain. Instead, I give free choice alfalfa/orchard and grass. Should I continue his old grain or is it ok to keep him on my regime? His body score is low 4 with just a few ribs barely showing. He is an 11-year-old Appendix with no health issues.

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

 

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horse standing at fence

Psyllium Husks

Is your horse in drought conditions? Mine too!

It has been drought here for more than 2 years now… and something I am really, really bad at remembering to do is feeding psyllium husk regularly to clean accumulated dirt and sand out of their gut.

So here is a reminder, feed psyllium husk!

If your horse is in drought conditions or kept in a dry-lot or on very sandy ground, the psyllium will help to shift all the accumulated dirt and sand out of their gut.

If you don’t get it out, it will cause irritation and pain and you may see signs of bloating, diarrhea or colic.

Feed 50 grams per 100 kg of bodyweight (or 2 oz per 250 lb) for 4 days in every month. Add it to a feed your horse really likes, and just damp it down ever so slightly to make the psyllium stick to the feed.

Don’t wet it! It will into a gooey mess your horse probably won’t want to eat (and I can’t blame them).

Consider yourself reminded 😂! My cheeky lot are up to day 3 for this month.

 

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Are Soybean Hulls Safe For Horses?

Are your soybean hulls safe? Because some of them definitely are NOT!

I love soybean! The protein is amazing and year in, year out we feed it to horses with stunning results in muscle, bone quality and milk production.

BUT… it MUST, MUST, MUST be heat treated correctly to make it safe to feed!

Why Must Soybean Be Cooked Before It’s Fed To Horses?

Uncooked soybean has a few anti-nutritional factors. The most significant one is trypsin inhibitor. Trypsin is a protein-digesting enzyme made by your horse. Your horse uses trypsin to cut up protein into amino acids so they can be absorbed.

Trypsin is like a little pair of scissors whose only job is to cut up (i.e. digest) protein. The trypsin inhibitor in soybean effectively ties a piece of string around the end of these protein-digesting scissors so they can no longer cut any protein up.

The end result… decreased protein digestion! So you can be feeding plenty of protein but if any soybean products you are feeding have active trypsin inhibitor, protein digestion will be reduced! A lot! And the problem is it reduces protein digestion from ALL protein in the diet, not just from the ingredient containing the trypsin inhibitor (i.e. the soybean hulls).

How To Know If Your Soybean Product Is Safe For Horses

I recently picked up two samples of soybean hulls from a large riding horse stable. The horses in the stable were being fed two different brands of soybean hull. The stable manager had gone to long lengths to balance these diets using FeedXL. To look at the diets on paper I expected lovely, rounded, well-conditioned horses.

But they weren’t. The horses being fed the most feed had little muscle. Spines were tent-shaped, rumps were flat and shoulders and chests thin and narrow. I was scratching my head. Something was wrong but I couldn’t quite put my finger on what… until I tested the soybean hulls!

Using a rapid colour test to check for likely active trypsin inhibitor, I tested them to make sure they had been heat-treated enough to destroy all trace of trypsin inhibitor. When heat treatment has been done well, the samples tested should show no trace of a colour change. If heat treatment was not done properly, and active trypsin inhibitor is still present, the sample turns pink. How pink determines how active the trypsin inhibitor will still be… more pink = more active trypsin inhibitor (which is not what we want to see).

And the results, to be honest, are scary! The hulls in the photo at the front lit up like a Christmas tree! Bright pink everywhere indicating lots of active trypsin inhibitor. These ones I suspect have received no heat treatment at all and are totally unsuitable for horses. Yet they were packaged and sold specifically for horses.

The ones in the back, you could see had received enough heat on the outside of the pellet to deactivate the trypsin inhibitor. BUT inside the pellets there was still pink indicating active trypsin inhibitor.

I called the stable feeding these and told them to stop feeding the first pellet immediately. No wonder their horses had no muscle! This product, which they had been feeding for close to 8 months, would have been stopping a lot of protein digestion. And this is not theory… you could SEE how much these horses were deficient in protein, despite their diet containing plenty of it.

The second pellet (in the back) I personally wouldn’t feed either. It will put your horse in a bit of a two steps forward, one or two steps back situation… helping with energy intake but partially blocking protein digestion.

When soybean is PROPERLY cooked, there should be ZERO trace of pink, as shown in the sample on the right here of well extruded full fat soybean. The sample on the left is raw, ground full fat soybean. It is, of course, bright pink… just to show how much the bean itself reacts with this colour test BEFORE it is cooked.

THIS extruded soybean (on the right) is how ALL soybean products SHOULD and in fact MUST look to be safe to feed to horses.

By now, if you are feeding soybean hulls you may be feeling a bit anxious…  wondering if the brand you are feeding is OK or not… it might be, but it may not be either.

How To Test For Trypsin Inhibitor in Soybean

And it is a little bit hard to advise you on what you should do. First step is probably to contact your soybean hulls supplier and ask them to provide any photos they may have of this quick color test check for trypsin inhibitor. Or for a lab analysis for likely trypsin inhibitor activity.

If you are in Australia, Symbio Labs in Brisbane (https://www.symbiolabs.com.au/) can test soybean hulls for you to show you if they have been heat treated enough to be safe to feed.

If you are in North America, you can order a test kit and test your soybean products yourself (https://canadianbio.com/Store) or we can ask around some laboratories for you to see who tests for trypsin inhibitor activity.

If you are elsewhere in the world please get in touch with a local feed or food testing laboratory and ask if they are able to assess soybean hulls for trypsin inhibitor activity.

Unfortunately yet another case of buyer beware. I have contacted the manufacturers of both of these products. Hopefully they will begin to heat treat their products correctly AND take a much more active role in testing products properly before selling them.

 

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

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Grain Free Horse Feed: What Does it Actually Mean?

It can be a bit confusing to get to the bottom of what grain free horse feed really means, especially when you see it printed on a feed bag derived mostly from grain products. In this post we’re unravelling the technical classification of ‘grain free’, and helping you find a suitable feed, even if your horse is grain-intolerant.

How we classify ‘grain free’ in FeedXL

Here at FeedXL we classify feeds in our database as being either ‘grain-free’ or ‘contains grain’, so that if one of our members clicks that their horse is ‘grain intolerant’ they will see the feeds and supplements available to them listed either in black (meaning it is grain free) or ‘red’ (meaning it contains grain).

Occasionally though we are questioned about certain feeds that we have classified as ‘contains grain’ and are sometimes told we have them classified incorrectly because the feed only contains a grain by-product like wheat midds (or bran, pollard, broll, millmix, millrun… many names for similar ingredients).

So does containing a grain by-product mean the feed should be classified as ‘grain-free’ or as ‘contains grain’?

Our position on ‘grain free’ horse feeds

There are companies who make feeds that are almost 100% wheat midds or rice bran and splashed all over the packaging it says grain free! Technically they aren’t but they are classified like this because they only contain PARTS of a grain and no whole grains.

The issue (for us and for horses) is that these by-products, while not whole grains, are derived 100% from grain and still have many of the same characteristics (same proteins, still high in starch, albeit not as high as the whole grains etc). So if someone really needs to avoid wheat or starch for example and they find one of these ‘grain-free’ feeds made with wheat midds there is an issue born from a technical classification that doesn’t tell the full story.

Calling feeds with wheat midds or rice bran ‘grain-free’ would be like saying soybean meal is ‘soybean free’ just because it no longer contains any whole soybeans. Or saying copra meal is coconut free because there are no whole coconuts. Technically yes, they don’t contain the entire original ingredient but for us (and thus FeedXL) we are just not comfortable saying something is grain free when it isn’t.

Imagine the consequences in human foods if manufacturers were allowed to say ‘wheat free’ if a product only contained midds or peanut free if it only contained peanut oil. Much more serious in humans we know but just using them as examples to make the point.

Keep an eye on starch and sugar content!

For horses, what starts to become more important in many cases though is the actual level of starch and sugars in a product. So if we were looking at a diet for a laminitic pony and considering using a feed with wheat midds in it, the important thing is how much starch are those midds contribution to the final feed. If total starch and sugar content is still below 10 to 12% then it should be OK. If it isn’t, then it doesn’t matter how much a feed might claim to be grain free, its analysis says it won’t be safe based on its actual starch and sugar content.

Here at FeedXL, we firmly believe we need to stop confusing horse people with technical classifications to allow loophole claims on feed packaging. This is just our opinion but we have seen pretty devastating effects in horses because they have been fed a feed claiming to be grain-free and therefore their owners believed it would be safe to feed. It is something that shouldn’t happen!

How FeedXL can help you choose the best feed for your horse

When you click ‘grain-intolerance’ in FeedXL you will be able to see which feeds are truly grain free and which are not. If you select that your horse has laminitis or insulin resistance you will see the feed ingredient options classified instead by starch and sugar content.

If you want to save yourself some time finding suitable feeds for horses with conditions that require either grain-free or low starch and sugar feeds give FeedXL a go! Check out our plans and pricing here.

 

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How Long Should You Boil Barley or Corn?

Cooking cereal grains before you feed them to your horse is very important. It improves how easy they are for your horse to digest and drastically reduces the chance of them causing negative effects in your horse’s hindgut.

So if you are cooking your own grains, how long should you cook them for? Are you ready for the answer, it is really very technical …

Cook grains until they are soft and squishy!

Just cook them with lots of water until they are easy to squash between your thumb and index finger. Once they are soft like this their digestibility will be very good.

Want to know why you should cook grains before you feed them? It is all here: https://feedxl.com/18-feed-cooked-grains/

P.S. Don’t just soak them until they are soft, this won’t improve digestion… you must use heat!

 

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Benefits of Oats for Horses

It has been known for a very long time that oats and horses just seem to get along well. Of all of the cereal grains we can feed to horses, oats is the only grain that can be fed safely without being cooked. Why? Horses are able to digest a large portion of the starch that oats contains in their small intestine. Which means only small amounts of starch will be deposited into the hindgut.

Oats vs Other Grains

If we feed corn or barley uncooked, only about 25% of the starch they contain is digested in the small intestine. The rest is fermented in the hindgut.

When starch gets into the hindgut, starch fermenting bacteria ferment it very quickly and cause a build-up of acid and create a condition called hindgut acidosis which has all sort of negative consequences for your horse (including changes in behaviour and laminitis). The balance between fibre fermenting and starch fermenting bacteria is also put out of balance… the ‘good’ fibre fermenting bacterial populations are reduced while the less desirable starch fermenting bacteria increase in numbers.

All of this we have known for a while. More recent research however (Harlow, 2015) has also shown that corn starch is potentially more of a problem in the hindgut than oat starch. This researcher incubated corn and oat starch in test tubes with faecal material from horses and found (briefly) that corn starch caused a significantly greater increase in starch fermenting bacteria than the oat starch and gave rise to higher lactic acid production.

Double Safety Catch in Oats

So oats seems to have a double safety catch built in for our horses. First, most of its starch appears to be digested in the small intestine. Second, if some starch does end up in the hindgut it appears less likely to upset the hindgut bacterial populations present there, which should mean it allows your horse to maintain a healthy population of the ‘good’ fibre fermenting bacteria.

So if you need to feed a grain and either don’t have access to or don’t like ‘cooked’ grains for some reason, go for oats, they are the safest choice for your horse.

 

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

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Chickpeas For Horses: Should They Be Cooked First?

There has been a little bit of discussion of late about chickpeas and whether they need to be cooked prior to being fed to horses. Big apology from me (Nerida) as it seems I have confused the issue and created some angst. So, to clear the waters I have muddied, here is some better information:

4 things to consider when feeding chickpeas to horses

  1. Chickpeas do contain anti-nutritional factors including trypsin inhibitor, which is the same as the main anti-nutritional factor found in soybeans. Trypsin inhibitor does exactly as its name suggests, it inhibits/stops trypsin, an enzyme in the small intestine which chops up protein into smaller pieces so it can be absorbed. Too much trypsin inhibitor in the gut can reduce protein digestion to such an extent that protein deficiency will become apparent. This doesn’t sound good for chickpeas!
  2. BUT, on reading about the amount of trypsin inhibitor in chickpeas it is much, much lower than soybean. I can find published values of 15 TUI (Trypsin Units Inhibited – reflects quantity of trypsin that has its activity inhibited) for chickpeas while values for soybean are more like 80 TUI. Reading papers and interpreting units is proving exceedingly difficult as it seems everyone likes to express their TUI units in slightly different ways so just be careful with this!
  3. Chickpeas have been fed raw to pigs at levels of up to 88% without affecting measured parameters to determine growth and feed conversion. A pretty good indication the anti-nutritional factors aren’t too anti-nutritional as growing pigs will show us very quickly if something is not right. This study did however find that adding additional methionine improved growth performance in chickpeas.
  4. Chickpeas are routinely used uncooked in pig diets in Australia at levels up to 20% of the diet without any ill effect. They typically aren’t fed to younger pigs less than 20 kg bodyweight.

Updates in FeedXL…

Based on all of this we have now updated our information in FeedXL to read:

Chickpeas are classified as a pulse, which is a seed from a leguminous plant. Chickpeas are rarely included in horse diets but can be fed as a protein and energy supplement in much the same way lupins or faba beans are used. The protein is of moderate to good quality with good concentrations of the essential amino acid lysine. They may however be too low in methionine for some classes of horses.

Like most pulses, chickpeas appear to contain some anti-nutritional factors including a trypsin inhibitor, which blocks the activity of the protein digesting trypsin enzyme in the gut and can negatively affect protein digestion. The anti-trypsin activity of chickpeas is however much lower than that of soybean, with chickpeas expected to ‘block’ around 15% of trypsin enzyme activity in the gut compared to more than 80% of trypsin activity being blocked when raw soybean is fed.

Chickpeas should therefore be safe to feed without any form of heat treatment to mature horses at levels of no more than 20% of their ‘hard feed’. If larger amounts were to be fed, heat treatment is recommended. Chickpeas would be best heat treated prior to feeding if being fed to horses younger than 12 months of age.

As always our information is quite conservative, but we prefer to play it safe with so many people using our service with so many varied scenarios.

I hope that helps everyone who has had a recent interest in the use of chickpeas in horse rations.

 

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

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Herbs: Where Do They Fit in Your Horse’s Diet?

The use of herbs as a source of compounds beneficial in promoting good health dates back many (many) thousands of years. In the age before ‘synthetic’ drugs, herbs were the only available source of potentially health-enhancing compounds and as such, they were used extensively. But where do herbs fit in a horse’s diet?

With modern day medicine now able to reliably reproduce the specific chemical components of plants that have the desired biological effect, herbs are not so prominent in the treatment or prevention of disease. Herbs are however still enormously popular both in human and equine diets. This newsletter is going to look, in a very broad sense, at how herbs are and perhaps should be used for equines.

‘Herbs are medicine’

The true and traditional role of herbs is to provide biologically active ‘medicines’ to treat or prevent disease states. I am the first to confess I know little about the use of herbs as medicine. A true understanding of how to use herbs effectively to treat or prevent certain diseases requires a full understanding of disease pathophysiology and the chemical actions of the herbs themselves. To understand all of this fully would take many years of committed study.

Herbs can certainly play a valuable role in the treatment or prevention of disease when used together with conventional or complementary medicine, but to use them effectively, they must be used correctly. Discuss the use of herbs or herbal preparations with your trained herbalist and ALWAYS include your veterinarian in these discussions. Quite a few herbs can have interactions with traditional medicines which if not fully explored can result in negative consequences. For example, ginger has been shown to increase bleeding time, so if it was used in conjunction with other anti-clotting drugs or if your vet was unaware your horse was being supplemented with ginger prior to undertaking surgery there may be complications with excessive bleeding.

Natural doesn’t necessarily mean safe

It is common for people to mistakenly believe that because herbs are natural, they are also completely safe. Because herbs contain drug-like components, many of them have the ability to become toxic if fed in too large an amount. Because a horse is such a large animal, the risk is, in reality, probably quite small, but you should always investigate potential toxicity for any herb you are considering to use. Garlic is a good example of a herb that, if fed in too large an amount can have negative consequences, with severe anaemia possible in this case.

Some herbs also accumulate high concentrations of certain minerals, with many plants being selenium accumulators and seaweed or kelp a good example of a group of plants that accumulate potentially toxic levels of iodine.

Additionally, even though some herbs can have positive effects, like nearly every modern medicine available, many also have the potential to cause negative side effects. Ginger, for example, has been shown to reduce post-exercise recovery time, but it is known to cause gastric ulcers in humans (presumably if it is taken regularly or in large doses) and is theorised to do the same in horses.

Herbs as nutritional supplements

Many herbal preparations are sold today as ‘complete nutritional supplements’ and yet are sold without any form of typical analysis to support the claim that they are providing a complete range of nutrients that the horse needs in its diet. Herbs are also used singularly to provide vitamins and minerals to a horse’s diet, but in very few cases are herbs actually able to provide enough of any nutrient to have an impact on your horse’s overall nutrient intake.

Herbs are just plants, and with the exception of selenium accumulating plants, seaweed which accumulates iodine, and perhaps rosehips as a source of vitamin C, herbs really aren’t capable of providing significant amounts of vitamins or minerals in a diet.

For example, garlic is commonly fed as a source of copper and selenium. While garlic does contain copper and selenium, horses are so large and the typical dose of garlic so small that adding garlic to a diet has no real impact on the diet. The table below shows the daily contribution of 250 grams of garlic (a massive dose and one that researchers at the University of Guelph, Canada observed to cause anaemia) to the diet of a 500 kg horse in moderate work (shown as percent of Recommended Daily Intake or RDI):

Nutrient % RDI supplied by 250 g/day dried garlic
Calcium 2.8
Phosphorous 3.25
Copper 1
Zinc 1.5
Selenium 2.75
Manganese 2
Iodine 0.0
Iron 1.5

Enter any herb we have in the FeedXL database to your diet and you will see that even in large doses they have little to no useful impact on the nutrient content of a diet.

That is not to say all herbal preparations are not worthwhile. Some well trained herbalists with a good understanding of nutrition have nutritional supplements that contain herbs together with more conventional sources of nutrients to give you supplements that do contain useful levels of vitamins and minerals together with complementary support from the herbs.

If you are buying herbal supplements that are being sold as nutritional supplements ALWAYS request a typical analysis. If one is not available, you should question how the supplier knows it is a nutritional supplement if they can’t even tell you what nutrients it contains. Don’t spend your hard-earned money on supplements that promise a lot without any sort of evidence to back it up.

Balanced diets, best results

As always, a balanced diet should underpin your horse’s entire health regime. While the use of herbs can certainly help support and promote good health or assist in the treatment of disease, if you are feeding herbs on top of diets that contain deficiencies of critical vitamins or minerals their effectiveness will be severely limited. Using FeedXL to first balance your horse’s diet, then working with your trained herbalist to devise a herbal strategy specifically for your horse will give you the best results.

Spice it up!

Herbs can certainly play a valuable role in maintaining or promoting the health of your horse. If you wish to use herbs as part of your horse’s routine health plan, you should keep the following in mind:

  • Use herbs only from trusted suppliers that can guarantee the consistent quality of the herbs.
  • Always discuss the use of herbs with your vet, particularly if your vet is also prescribing modern medicines for the treatment of a particular condition.
  • Understand the herbs you are using, particularly their potential toxicities so that you can use them to good effect without having them cause their own problems.
  • Don’t forget that very few herbs contain nutrients in high enough concentration to contribute substantially to any horse’s diet. If you are buying herbs as nutritional supplements always request a typical analysis for the product.
  • If you are using herbs like seaweed to provide a particular nutrient, always use FeedXL to calculate accurate dose rates to avoid overfeeding and creation of nutrient toxicity.

 

Meet The Author: Dr Nerida Richards


Dr Nerida Richards is FeedXL’s resident equine nutrition specialist. With a degree in Rural Science, a doctorate degree in equine nutrition and nearly 20 years of full time, on the ground experience in feeding all types of horses Nerida is able to help FeedXL members solve any problem they may come up against with feeding their horses. To learn more about Nerida and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.

 

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

 

Garlic cloves

Garlic for Horses: Should You Feed It?

Herbs have been used in some cultures as remedies for disease and illness for more than 5000 years and their effectiveness as part of an ‘integrated system of primary health care’ is well recognised. Given the benefits we see in humans, it is becoming more and more commonplace to use herbs like garlic for horses. However, in many cases for horses, herbs are used not as part of a holistic approach to health care, but rather as a nutritional supplement.

Herbs are commonly added to diets as sources of copper, sulphur, zinc, selenium and iodine. The problem is, most herbs actually contain very little of these nutrients (with the exception of iodine in seaweed). So to supply any real amounts of nutrients, these ingredients need to be fed at high levels … The problem is, some herbal products like garlic can be toxic for horses, especially if you feed them at high rates. So, if you are considering feeding garlic to your horse, you first need to consider the potential benefit to be gained versus the risks involved.

Why is garlic even considered as a feed ingredient?

The answer to this question is likely because we as humans have used it with good effect in our own diets for thousands of years. Traditionally in human medicine, garlic is used as an anti-microbial agent. A compound called allicin, present in garlic, is known to have an anti-microbial effect which (along with some other compounds) is thought to give garlic this property. Garlic also has a well liked taste and smell and is used to give food flavour.

As humans, we all too often fall into the trap of thinking what is good for us must be good for our animals. But take chocolate, macadamia nuts, garlic and onions as an example. All of these foods are eaten extensively by humans and all (yes, even chocolate) have health benefits when eaten in moderation – yet every one of these foods is poisonous to dogs, highlighting that just because we can eat it and receive health benefits, it doesn’t mean that our companions, including our horses can.

We really don’t know the answer to this question. There is also a question over whether it kills off beneficial bacteria in the horse’s gut, which the horse relies on to digest fibre. I guess the real question is WHY do we want to feed a horse an anti-microbial agent all the time? It would make more sense to only feed one when the horse is at risk of microbial infection. We would never consider giving antibiotics all the time, so why is garlic any different. Perhaps the perception that it is ‘natural’ makes us feel more inclined to use it all the time rather than just when it may be needed. Sometimes it is fed all the time in a horse’s diet not as an anti-microbial, but as a nutrition supplement, raising the question of whether it is useful for this purpose.

Does garlic provide a horse with beneficial nutrients?

As a nutritional supplement to supply vitamins and minerals, garlic rates poorly. Feeding 100 grams of dried garlic per day (which is far more than I suspect any of you would be feeding) provides the following nutrients for a 500 kg horse in moderate work (shown as percent of Recommended Daily Intake or RDI):

Nutrient % RDI supplied by 100 g/day dried garlic
Calcium 1.1
Phosphorous 1.3
Copper 0.4
Zinc 0.6
Selenium 1.1
Manganese 0.8
Iodine 0.0
Iron 0.6

As you can see from the table above, garlic provides less than 2% of a horse’s daily requirement for these minerals and as such is virtually useless as a ‘mineral supplement’.Try this in your own horse’s diet in FeedXL, enter 100 grams of garlic in the diet and look at the graph to see what it contributes to the diet; its nutritional effect is virtually nil.

Is garlic safe for horses?

There is much debate over whether or not garlic is safe to feed horses. A study conducted by Wendy Pearson at the University of Guelph, Canada in 2005 found that when fed at high levels (250 g/day for a 500 kg horse) garlic caused an array of changes in the horse’s blood including an increase in mean corpuscular volume (MCV), decreases in red blood cell count and blood haemoglobin concentration. These changes eventually led to a condition known as Heinz Body Anaemia. While the dose rate they used was high, the researchers note that currently a safe dose rate for horses is unknown. Because research has not been carried out looking at feeding lower doses of garlic over a long period of time we don’t know ‘scientifically’ if it is safe or not.

Onion, a close relative of garlic and containing the same toxic component (n-propyl disulfide) is also known to be toxic to horses, with research conducted in 1972 showing that consumption of onion tops caused severe anaemia. Again, this study used large amounts of onion tops to produce life threatening anaemia within 11 days, meaning the question of whether onions and garlic would be safer at lower levels still remains. However, US veterinarian Dr Karen Hayes notes in her article “Feeding Garlic – The great garlic debate” that she sees a handful of cases of Heinz Bodied Anaemia every year resulting from horses consuming wild onions in amongst their pasture or in horses who have raided a compost or garden and eaten garlic or onions, suggesting perhaps that the dose doesn’t need to be high for effects to occur. In any case, the effects the researchers have observed when feeding garlic or onions at high levels have been severe. While feeding garlic at lower levels over long periods of time may not cause a life-threatening anaemia, it may be causing anaemia that is mild enough not to be overtly noticed, but prevalent enough to reduce your horse’s stamina and performance and Dr Hayes suggests it may even affect a horse’s ability to resist disease.

If you do feed garlic and wish to continue feeding it, it would be a good idea to run a blood analysis on your horse to make sure their mean corpuscular volume, haemoglobin and packed cell volume levels are in the normal range and that no Heinz Bodies are present.

So should you feed it or not?

My normal stand on feeding garlic to horses is unless there are DEFINITE and DEMONSTRATABLE benefits associated with feeding garlic to your specific horse, don’t feed it. While it is true that it hasn’t been proven that lower dose rates of garlic will harm your horse, it also hasn’t been proven that feeding garlic to your horse provides any specific benefits. We also don’t know what garlic does to horses when fed consistently at low feeding rates.

Next time you go to tip garlic into your horses feed just take a moment to consider why you are feeding it, what benefit the horse is getting and whether it is worth taking the potential risk, even if it is only a small one. There is no doubt herbs can make valuable nutraceutical additions to diets but if you are considering using them as nutritional supplements, use FeedXL to see what it is they are actually adding to the diet.

 

Meet The Author: Dr Nerida Richards


Dr Nerida Richards is FeedXL’s resident equine nutrition specialist. With a degree in Rural Science, a doctorate degree in equine nutrition and nearly 20 years of full time, on the ground experience in feeding all types of horses Nerida is able to help FeedXL members solve any problem they may come up against with feeding their horses. To learn more about Nerida and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.

 

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

 

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