Equine Probiotics – Where Are We Now?

The World Health Organization definition of probiotic is a live organism which, when consumed in sufficient amount, confers a health benefit

The microbiome is the microorganisms inhabiting a specific environment, like the gut.

The number, complexity and diversity of organisms in the intestinal tract has captured everyone’s imagination. The idea that they may influence health is both exciting and a little frightening. It’s also the most controversial but everyone can agree the intestinal microbiome is of critical importance to normal function of the digestive tract of the horse.

The upper intestinal tract [stomach and small intestine] is populated primarily by organisms which break down and ferment starch and other simple carbohydrates.  This benefits the horse by reducing the amount of glucose that will be absorbed and by helping to protect the large intestine [cecum and colons] from too much simple  carbohydrate.

Once the large intestine starts, in the cecum, there is known to be an abrupt change in the number and types of organisms. There are two major phyla (Firmicutes and Bacteroides) but many smaller populations as well. The density and diversity of organisms is much greater and while some generalizations can be made it’s also true that every horse has a microbiome that is unique to them.

The hind gut population is capable of breaking down sugars, starch, complex plant carbohydrates, fiber and protein. The organisms often work together. For example, some may ferment sugar and starch to lactate while others use the lactate themselves thus buffering the intestine.

Probiotics have been appearing in basic feeds and all sorts of supplements for about a quarter of a century now.  Supporting normal intestinal function is something everyone can get behind but how are the organisms chosen? Does it matter?

It certainly does matter. While the safety profile of probiotics is quite good, it has been shown that using the wrong strain can have negative GI effects, especially in the fragile gut environment of foals.  For many years the strains used in equine products were largely based on what was beneficial in people and to a lesser extent in other farm animals.  We can now do better.

Recent improvement in genetic techniques has led to a mini explosion of studies on the  makeup of the equine intestinal microbiome.  We can now at least identify the common equine specific species and focus on supplying a blend of organisms that is more appropriate for the horse.

For example, Lactobacilli are in the larger family Firmicutes. They are found throughout the equine intestinal tract but different species are present in the stomach/small intestine than in the hind gut. Lactobacillus acidophilus is one of the most well known probiotic species but we have found many other strains that are specific to horses such as L. reuteri and L. salivarius for the upper part of the digestive tract and L. equi, a horse specific strain in the hind gut.

Other important bacterial strains include Bacilus subitilis which favors the growth of beneficial bacteria over pathogens and Propionibacterium freudenreichii which metabolizes lactate and helps control pH.  The yeast Saccharomyces cerevisiae is perhaps the best researched equine probiotic of all, assists fermentation with any type of diet and should be a prominent ingredient in all equine probiotic products.

Look for these specific organisms and counts in the billions (BCFU = billion colony forming units = billion organisms) to give your horse the most state of the art support possible.

Eleanor Kellon, VMD



Posted in Equine Nutrition | Tagged , , , , , , , , | 2 Comments

Does Your Overweight Horse Have An Insulin Problem?

Easy keepers and overweight horses and ponies have been around forever.  Laminitis has also always been with us, and it’s no secret that overweight animals are at high risk. We now know that the vast majority of laminitis cases are caused by high insulin levels – hyperinsulinemia. Does this mean being overweight/obese causes insulin problems?

It might seem that way superficially but the logic is faulty.

There is an important principle in science which states “Correlation (or association) is not causation”.  Observing that things occur together does not mean one causes the other.  Let’s say that the native horses of the country Muropa are observed to regularly consume the leaves of the Bajunga plant, which only grows in Muropa.  It has also been observed Muropa horses never develop sweet itch.  Does this mean Bajunga protects from sweet itch? While there could be a link, this doesn’t prove it. It could be a genetic  factor protecting them –  or simply that there are no Culicoides midges in Muropa!

Many horses that develop laminitis are overweight or obese. We know that the vast majority of laminitis cases are caused by high insulin levels. The correlation has always been obvious and it didn’t take long for an assumption to arise that obesity is a laminitis risk factor and causes elevated insulin.  There’s just one thing. It’s not true.

A study (Bamford) published in the Equine Veterinary Journal in 2015 fed horses and ponies a control diet or one designed to cause obesity by feeding either excess fat or excess fat and glucose.  The weight gain did not reduce insulin sensitivity in either group.  Dr. Bamford has also clearly shown that insulin responses to oral or intravenous glucose have marked variation by breed in horses of normal weight.  You can read all of Dr. Bamford’s work in detail in his thesis here: https://minerva-access.unimelb.edu.au/bitstream/handle/11343/148423/Bamford%20PhD%20Thesis.pdf?sequence=1.

Selim et al 2015 followed two groups of Finnhorse mares on either native pasture or intensively managed improved pasture. At the end of 98 days grazing, the mares on improved pasture went from a body condition score of 5.5 to 7 and gained 145 pounds but this was not associated with insulin resistance.

If obesity isn’t a cause, why is more insulin resistance seen in obese horses – 25 to  50% IR depending on the study versus 10 to 15% of horses in general?  The answer is simple.  The IR increases appetite and weight gain. Yes, there is an association between obesity and high insulin but obesity is the result, not the cause.

This is more than just splitting hairs.  If you think obesity is a cause then weight control becomes a treatment, even possibly a cure. When you realize it is a consequence, not a cause, expectations for results of weight loss become more realistic.  There are many benefits to weight loss and it should be aggressively pursued but it won’t make insulin resistance go away.  Approximately 50% of IR horses are normal weight.

Eleanor Kellon, VMD






Posted in Equine Nutrition | Tagged , , , , | 4 Comments

Failing Pastures

I’m going to define failing pastures as those that no longer can meet the nutritional needs of the horse.  This can happen a lot sooner than you  might think.

Brown, dormant grass is easy to spot but very mature green grass also lacks sufficient nutrients

Grasses stressed by extremes of weather – drought, heat or cold – will either die or go dormant to protect their carbohydrate reserves until growing conditions improve. They lose their green color because production of chlorophyll and other pigment ceases.

Another pigment is carotene, the precursor of vitamin A, and vitamin A activity in these grasses is low, as is vitamin E and essential fatty acid level. Calories are lower than young green grasses and fiber much higher.  Protein is deficient, typically around 5%.  Even mineral levels may be lower.

You may not think of grass and hay as a source of B vitamins but the fact is they are the horse’s major source and levels are much higher than in concentrates.  The B vitamins are also in their most bioavailable forms, incorporated into active compounds. When metabolic activity slows (maturity) or stops (dormancy or death), levels naturally fall.

Grass hay is best cut right before it starts to set seed. At this stage there has been enough growth for a good yield and the nutritional value of the grass portions above ground is good.  Once the grass has reached full height, set and dropped seed, it’s metabolism slows, fiber fractions rise and protein drops.  The other changes described above for dormant hay also begin.  Significant loss of nutritional value can occur while the grass is still green.

Supplementing protein is the major consideration in all scenarios late in the grazing season. Begin essential amino acid supplementation of lysine, methionine and threonine as soon as grasses go to seed. When grasses begin to brown, start 1/4 to 1/2 lb/day of a 40% protein supplement or 1/2 to 1 lb/day of a 20 to 25%  protein and mineral supplement.

The mixed protein and mineral supplements have to be fed in higher amounts but they are good insurance against drops in mineral levels that can occur.  They will also cover the dropping vitamin A and B vitamin levels.

Maintaining good intakes of omega-3 fatty acids is important for supporting the body’s ability for normal homeostatic balance of inflammatory reactions.  Flax and Chia seeds are the ideal way to do this with omega-6:omega-3 ratios which mimic young green growths of grass.

Dead, dormant and overly mature grasses have a nutritional profile similar to straw. Horses relying on failing pastures for the bulk of their nutrition can still get some caloric value but will encounter significant gaps until they are switched over to their winter rations.  By knowing what the issues are you can target them and support the horse in this transitional period.

Eleanor Kellon, VMD





Posted in Equine Nutrition | Tagged , , , , , , , , , | Leave a comment

The Lactic Acid Myth

If you’re like most people you have been told time and time again that lactate/lactic acid is the cause of muscle fatigue, “burning” and tying up. You may even have bought supplements for your horse based on claims that they could reduce lactic acid, or changed your horses diet based on similar claims. Truth is, blaming lactic acid for poor performance, fatigue or muscle damage is like looking at the pile of ashes after a building has burned down and assuming that ashes caused the damage.

Muscles produce lactate continuously. It’s generated during the breakdown of glucose as an energy source. If the horse is at rest, or moving very slowly, most of the lactate is further broken down to pyruvate and goes into aerobic (use oxygen) energy pathways in the mitochondria. However, as the horse moves faster and needs to produce energy very quickly to keep up with the demands, the aerobic pathways are too slow and more energy is generated anaerobically, producing lactate.

Lactic acid isn’t a “waste” product or a toxin; it’s actually beneficial. Lactic acid is a buffer – a way that muscle cells can carry harmful acidity (H+ ions) out of the cells. This is because the lactic acid binds the acidifying hydrogen ions and carries them into the circulation – lactic acid + hydrogen ion = lactate. The lactate is then further broken down as a fuel by other cells, or converted back to glucose in the liver.

People who have been used to thinking of lactate as harmful have trouble accepting this concept, but the evidence is impossible to ignore:

  • Sodium bicarbonate is an alkalinizing (anti-acidity) substance that is used to improve performance in racehorses, although now prohibited in most areas. Kesl and Engen from the Veterinary School at Iowa State found that when sodium bicarbonate supplements are used blood is less acid, and muscle recovers from exercise induced acidity quicker, but lactate levels actually are higher
  • Horses that are sugar/starch sensitive and tie up show lower levels of muscle enzyme release, an indicator of muscle damage, when put on lower starch diets but the level of lactate produced is identical with high fat vs high starch feeding. Also, starch sensitive horses exercised on high grain diets show more muscle damage, but their lactate levels are the same as normal horses.
  • Many studies have failed to find any relationship between lactate levels after exercise and poor performance. In fact, it is often found that the superior performing horses are those with the highest lactate levels after exercise.

A similar association between high lactate production and superior performance has long been recognized in human athletes (e.g. Reilly, 1999).

What this all boils down to is that blood lactate after exercise is nothing more than an indicator of how hard/fast the horse worked. It’s not connected in any way to tying up or muscle damage. Instead of being harmful, lactate is actually a source of energy and reduces the acidity inside hard working cells by carrying the hydrogen ions out of the cell. High blood lactate is associated with superior performance, not fatigue. Next time you see advertising for a supplement or grain that claims to make your horse work harder or longer by lowering lactate, pass it up.

Eleanor Kellon, VMD

Posted in Equine Nutrition | Tagged , , , , , , , | Leave a comment

Care of the Mare and Foal at Weaning

With feral horses, by the time weaning occurs naturally both mare and foal are more than ready for it.  When we hasten the process artificially, there is inevitable stress.

Foals depend on their dams for basic survival needs of nutrition and protection from predators or even other horses.  The dam also gives the foal its social status in the band.  Mares fulfill these functions because of the extremely powerful drive of their instincts and hormones.

Interfering with this bond predictably causes anxiety, even anguish.  This means poor appetite, vocalizing, pacing (or running if room allows), poor concentration and diminished awareness of people, other animals, even physical barriers.  In the worst case scenario they may be a danger both to themselves and others.

A variety of methods are used, from gradual lengthening of periods apart to abrupt complete separation.  When separation is final, mare and foal should not be able to see or hear each other. Foals do best either housed in individual stalls or pastured in a group of familiar peers with at least one quiet and tolerant adult baby sitter.

Mares are more likely than foals to end up being stall confined or put in with a group of unfamiliar horses after weaning.  Their stress levels can therefore be higher and individuals may benefit from supplementation geared to help balance these reactions such as Valerian root, thiamine, magnesium and taurine.

Behavioral manifestations of stress in foals are best handled by management of their environment, keeping them with familiar companions, a stabilizing adult and confined in an area with sturdy and safe fencing. However, there are still often problems with the babies going off feed.  Maintaining adequate nutrition but without excessive calories is also an issue for mares which need to decrease milk production but often are pregnant.

The solution to this problem begins before weaning.  Both the mares and foals have extremely high requirements for protein and minerals compared to adults that are not growing, lactating or pregnant.  They require a diet more dense in protein and minerals per calorie.

The easiest way to achieve this is to provide needed calories with an well balanced adult type concentrate and forage then supplement with a high protein and mineral supplement that can be adjusted to the needs of the stage of growth, pregnancy or lactation.

Look for 25% protein from milk  and high quality vegetable sources with guaranteed lysine and methionine levels. There should be a balanced, high potency mineral profile with 5 to 6% calcium and 500 ppm copper.  Unlike supplements for adults, a moderate level of iron inclusion is advisable for this age group. Fat soluble and full spectrum B vitamins complete the support package.  Because this nutrition is in a concentrated form they are more likely to eat it all.

Weaning is no fun. Reduce physical dangers by careful management of the environment  and nutritional calming support as needed.  Deal with dietary shortfalls caused by poor appetite with the use of a concentrated protein and mineral supplement that is more likely to be completely consumed.

Eleanor Kellon, VMD


Posted in Equine Nutrition | Tagged , , , , , , , , | Leave a comment

The Limitations of Fecal Egg Counts

As concerns grew over emerging parasite resistance to existing deworming drugs, owners were increasingly advised to make deworming decisions based on the results of fecal egg   counts (FEC). While this approach has merit, it’s not foolproof.

Strongyle egg

To be accurate, a sample for parasite eggs should be taken from the rectum or from the   center of a freshly passed pile of manure. A simple technique is to grasp a fecal ball with a gloved hand then turn the glove inside out when you remove it, trapping the sample inside. This should then be placed into a small sealed container and examined immediately or kept cold until it is tested. Samples sent through the mail or allowed to sit around at room temperatures or warmer are not reliable because eggs can hatch. Hatched larvae are not detected by egg flotation techniques.

Egg counts of small strongyles, currently the major intestinal parasite in horses, show a seasonal pattern in temperate areas that have a clear winter and summer.  There is a sharp rise in spring and a smaller secondary peak mid summer, followed by precipitous drops. FECs in late fall and into winter do not reflect the parasite burden of adults or arrested encysted tissue forms.

Large strongyles (“bloodworms”) have the potential to produce even more extensive damage to the horse than the small strongyles. Intensive deworming had all but eliminated them but they are starting to re-emerge now with less frequent treatments. Like small strongyles, the eggs may hatch if manure is not handled properly.

Onchocerca are parasites that live in the nuchal ligament of the neck.  Their larvae can cause intense itching, allergic reactions and midline dermatitis.  They do not have eggs in the feces so cannot be detected with an FEC.

Similarly, bot fly larvae cause erosions in the stomach but never leave eggs in the manure so are undetectable. Tapeworms break off egg packed segments of their bodies into the manure rather than having eggs mixed throughout. It’s sometimes possible to detect tapeworms on a FEC but you have to get really lucky.

Pinworms cause an agonizing itch in the anal area that can drive a horse to rub their tail raw. The eggs are laid on the skin in this area, not in the manure.

Another problem is that the FEC only detects egg-laying adults. By the time you see eggs from roundworms and strongyles, the damage to the intestinal tract, liver and lungs from migrating larvae has already been done. Strongyloides larvae infect foals by migrating to the dam’s udder and getting into the milk. Their migration in the foal damages tissues and is often the cause of “foal heat diarrhea”. The FEC is more a tool for herd health and  monitoring eggs in the environment than it is for monitoring individual health.

Many people deworm once or twice a year using a combination of ivermectin or moxidectin with praziquantel.  This combination gets the bots and tapeworms which do not show up on FEC.  FEC may be checked once or twice a year. For healthy adults with strong intestinal immune systems in a stable, low exposure environment, this can work well.  However, there are many potential scenarios where it won’t be enough, including:

  • Very young or very old horses with poor immunity
  • Mares immediately after foaling
  • High exposure environments at home or horses that travel and may have high exposure
  • Pinwoms
  • Threadworm larvae reactions

Looks for issues such as colic, “pot belly”, weight loss or failure to gain, poor hair coat and slow shedding which can indicate intestinal parasite problems.  Finally, fear of causing dewormer resistance is often behind reluctance to treat the horse but the #1 cause of resistance is underdosing.  If your horse may need deworming, do it and make sure the dose is adequate for weight.

Eleanor Kellon, VMD

Posted in Equine Nutrition | 4 Comments

Chastetree Berry for Horses

Vitex agnus-castus, aka Chastetree, Monk’s Pepper, is a small tree native to the  Mediterranean that produces lilac colored flowers on long stalks which fruit large round berries.

Vitex was mentioned many times in the writings of the ancient Greeks and Romans.  It was also known to 13th century Europe.  The tree grows well in both temperate and subtropical zones.

CTB – Chastetree berries, or simply Chasteberry – have a long traditional history of use to help balance hormonal systems, both male and female. While males and females have different levels of hormones produced by the sex organs, the activity of those organs is influenced by the same pituitary hormones, namely LH and FSH.

Recent research into the actions of CTB extract has shown it supports the activity of dopamine.  Since dopamine regulates LH and FSH secretion, this is believed to be how the plant works.  Dopamine also regulates the secretion of prolactin and hormones from the PPI, the intermediate lobe of the pituitary, i.e. the POMC derived hormones beta-endorphin, alpha-melanocyte stimulating hormone and ACTH.

CTB extract functions as an adaptogen in these hormone systems. Adaptogens are substances that assist in stabilizing physiology and promoting homeostasis.  Homeostasis is a state of equilibrium in which the organism functions optimally.

CTB extract has been well studied for human use and is listed by the German Commission E, a body which provides scientific background on the use of traditional herbal substances.

In horses, CTB extract has the potential to assist the body in maintaining homeostasis in a wide range of situations, including:

  • Ovarian function and female hormone production
  • Lactation
  • Female behavior
  • Male hormone production
  • Male behavior
  • Shedding (under the control of prolactin)
  • Intermediate pituitary lobe hormone production

Vitex agnus-castus is an excellent example of scientific study validating and explaining traditional herbal uses.

Eleanor Kellon, VMD

Posted in Equine Nutrition | Tagged , , , , , , , , , , | 7 Comments

Feeds for Carb Sensitive Horses and Weight Control

By carb I am referring to hydrolyzable carbohydrate digested to glucose in the small intestine. This includes starch and the sugar/ESC (ethanol soluble carbohydrates) fractions on an analysis. These are the carbs that elevated glucose and cause an insulin response. Fiber and fructans are also carbohydrates but do not cause an insulin spike.

Low carb feeds are needed for horses with high insulin related to insulin resistance/metabolic syndrome or PPID (Cushing’s disease) as well as myopathies like EPSM/equine polysaccharide storage myopathy (aka PSSM) and recurrent exertional rhabdomyolysis (RER) – tying up. These feeds are also useful for easy keepers or weight loss as long as there is no added fat, for inactive or injured horses, horses that become too “high” on grains and for horses which develop soft manure when fed grains. Many of the commonly used high fiber ingredients are prebiotic since they are easily fermented and therefore support good populations of those bacteria.

If you think substituting plain grass hay pellets will always keep your bucket meals below 10% you’re wrong.  Young growths of hay are best for pellets because they hold together easier but are also highest in sugar and starch. Beet pulp can be a good choice but may have molasses added or be too high in residual sugars. When using beet pulp, always rinse it well before and after soaking. This will remove extra molasses and sugars.

Before getting to ingredients, an important point here is how low is low enough. There is no shortage of feeds claiming to be low or safe, but many are anything but and they may be as high as 25% starch or sugar+starch combined – and that includes “balancers”.  For horses with issues related to high insulin or myopathies, that number should be 10% or lower. If the manufacturer does not volunteer this data in their product information, contact them and ask to see a  typical analysis.

You also want to know if the feed if fixed formula, aka locked formula, which means the ingredients and their relative percentages do not change. Do not buy anything where the ingredients list mentions “products” or “by-products”. Those generic terms can encompass many different ingredients. Take a look at the guarantee analysis. You want to see fiber over 20% and fat no higher than 3%. Ideally, there is no added iron in the formula since metabolic horses are commonly iron overloaded and the base diet already has plenty of iron. Check the ingredients list for items starting with iron or ferrous.

  • Soybean hulls. These are the thin outer coating on the bean, like the skins on peanuts inside the shell. They are an excellent protein source (29% protein), ultra low sugar and starch, easily fermented fiber.
  • Beet pulp. Again, very low sugar and starch, rich in easily fermented fiber. Also holds moisture well if you need to feed wet.
  • Flaxseed. Rich in omega-3 fatty acids lacking in other diet ingredients, low sugar and starch, high levels of easily fermented soluble fiber.
  • Distillers or Brewers dried grains. These are grains that have been fermented for ethanol production. They are high protein, low sugar and starch but high taste appeal.
  • Grass hay or alfalfa meal. Alfalfa can be an issue for some metabolic horses but low levels in a multiingredient feed improve palatability.
  • Wheat middlings. These are a mixture of the most nutritious parts of the grain (e.g. bran, germ) that would otherwise be wasted in the production of white flour. High protein contributes to the amino acid diversity of the feed. Greatly reduced starch.

It takes some time and investigation to find out the details on feeds but the effort is well worth it.  A correctly formulated feed is both safe and appealing to the horse.

Eleanor Kellon, VMD




Posted in Equine Nutrition | Tagged , , , , , , , , , , , , , , , | Leave a comment

Exercise and Gut Health in the Heat

From trail riding to endurance, lessons to racing, exercise in the heat has effects on the digestive tract.

Intensity of work is related to how much heat is generated during exercise but intensity is relative. Activity easily handled by a fit horse may require an extreme effort by one that is not fit. Also, fluid and electrolyte losses in sweat are greater for intense efforts but horses working for prolonged periods at lower levels may accumulate equivalent sweat losses.  An additional factor for horses working for prolonged periods is less opportunity to eat and drink, possible changes in diet.  Horses shipping in hot weather also have less opportunity to drink and their sweat losses in hot trailers can be considerable.

The body and intestinal tract coexist closely but there is normally little exposure of the body tissues/blood to intestinal contents because of proteins located between cells of the intestinal wall called tight junction proteins. It has been shown that increases in body temperature commonly seen with exercise can alter these tight junctions, resulting in cramping and diarrhea. Alterations in tight junctions are also believed to be related to the generally “sick” feeling that athletes can perceive after exertion and contribute to immune dysfunction.

High core body heat can also reduce the number and diversity of organisms in the digestive tract.  Reduced efficiency of fermentation and lowered generation of volatile fatty acid fermentation products means less efficient use of fibrous feeds and less efficient absorption of nutrients and water.

We can’t completely avoid heat having an influence on the GI tract but can take some sensible measures. Make sure your horse has been properly conditioned for the work you do. This is no time of year for “weekend warriors”. Also guarantee adequate intake of salt/electrolytes and constant supply of water to avoid the disrupted intestinal function that comes with dehydration and electrolyte abnormalities.

Supplements containing ingredients like L-glutamine, Marshmallow root, Licorice root, Slippery Elm, sodium copper chlorophyllin and Aloe Vera can help soothe irritated linings while mannanoligosaccharides and beta-glucans provide gentle stimulation for the local gut immune system.

Probiotic supplementation after the horse has been cooled out from exercise could be helpful in restoring beneficial populations.  This supports good fermentation, absorption and immune function.  A blend of Saccharomyces cerevisiae yeast and bacterial species is best.

Diet can also be very helpful in supporting fermentation and levels of fatty acids as well as promoting good hydration both in the intestinal tract and throughout the body.  Easily fermented and high soluble fiber supplements such as fructooligosaccharides, psyllium husk fiber (always wet before feeding) and beet pulp accomplish this.  Regular use of a supplement with good digestive enzyme (amylase, lactase, cellulase, phytase, lipase, protease) activity can assist with small intestine functions so that the hind gut does not get overloaded.

Exercise and heat effects on gastrointestinal integrity and activity should not be ignored. Solid conditioning, reasonable work expectations and targeted support can make this manageable.

Dr. Kellon

Posted in Equine Nutrition | Tagged , , , , , , , , , | Leave a comment

The Latest Dog Food Scare

Since horselovers are almost universally doglovers as well, I want to veer a little bit off path for this blog and discuss a dog food scare that is currently spreading like wild  fire.

On July 12, the FDA announced they were investigating a possible link between diets containing potatoes or legumes (soy, peas, lentils, etc.) and dilated cardiomyopathy in dogs. It was one of the most confusing and least informative bulletins ever written.

As the word spread, the description of the diets quickly morphed and focus was put on diets that were “grain-free”, “exotic” and “boutique” (meaning not a major name brand).  Owners were advised to feed diets from companies with a long track record using more “typical” ingredients (which in most cases means corn/corn products are a major ingredient).

Dilated cardiomyopathy is one of the most common types of heart disease in small animals. It can be caused by a deficiency of the amino acid taurine which is only found in meat protein. Cats cannot synthesize this amino acid but dogs can; making taurine from the sulfur-containing amino acids methionine or cysteine.

The FDA notice talked about 8 dogs – 4 of which (3 Golden Retrievers and 1 Lab) were taurine deficient and 4 were not.  A retrospective study of DCM cases by Dr. Adin found 22 cases over a 2 year period in dogs on grain-free foods but 27 in dogs not fed grain-free. Furthermore, none of the grain-free fed dogs were taurine deficient.  There is also a large online database of taurine levels in dogs on grain-free diets.  Of 169 dogs when I last looked at it, only 68 had low taurine levels in their blood. Of that 68, 22 had no echocardiogram so DCM status was unknown, 24 were positive for DCM and 22 were normal despite low taurine. Clear as mud!

Historically, taurine deficiency DCM was first reported in Goldens 15 years ago and they were all on big name commercial foods – chicken and corn or lamb and rice based.  Another 15 year old study in Newfoundlands with taurine deficiency DCM found they were fed big name lamb and rice food.  Many lamb and rice based formulas are still on the market and most do not contain added taurine despite the known issue.

It has also been found that foods containing beet pulp and other high fiber ingredients can lower taurine levels by interfering with the intestinal reuptake of taurine from bile salts. (Taurine is a major component of bile.)

Not all DCM cases are diet related. Genetic predisposition has been identified in several breeds. It has also been noted that some dogs (Beagles) can conserve taurine by reducing how much is in their urine when diet supply is low, but others cannot.

In summary, it’s much more complicated than a “boutique” grain-free diet with peas or potatoes is a health risk. Dogs on such a diet may or may not have low taurine – and the same goes for grain-free diets from major companies as well as lamb and rice based diets.  It may well be true that some breeds or individual lines within breeds do have a requirement for taurine and/or higher levels of the taurine precursors and these highly vegetarian based diet ingredients, whether grain or not, are not suitable.

To suggest grain-free diets are more often associated with taurine deficiency, let alone DCM, and that more typical corn based diets are safer is currently premature and speculative. Only formal feeding studies and large scale investigations including many different dog food types in dogs both with and without DCM can provide some answers. Hopefully along the way we may even get some useful information about true nutritional requirements of dogs and how to correctly feed them as the carnivores they are or supplement them to prevent adverse health effects if we don’t.

Eleanor Kellon, VMD

Posted in Cacine nutrition | Tagged , , , , , , , , , | 4 Comments