Do Joint Supplements work in horses?

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Do Joint Supplements Work in Horses?
By Kentucky Equine Research Staff · October 28, 2014

An even better question than “What came first, the chicken or the egg?” appears to be “Do joint supplements for horses really work?”

According to the latest study1 published on the topic, the answer is no, but other experts suggest there is far more to the story and that we shouldn’t jump to conclusions.

“There are several other studies both in live animals and in a laboratory setting that support the use of various joint supplements, leaving some of us optimistic that joint supplements are important,” says Kathleen Crandell, PhD, equine nutritionist at Kentucky Equine Research (KER).

In the recent study by Higler et al., 24 geriatric horses with “stiff joints and lack of joint flexibility” experienced no increase in stride length after three months of supplementation, whereas horses in the control group experienced increased motion in the knees and forelimb ankles. The authors used kinematic gait analysis when performing the study.

Some interesting things also worth noting were that none of the horses was diagnosed with a specific condition (e.g., fracture, osteoarthritis, tendon, or ligament injury, etc.) and the horses included in the study had very mild lameness—only grade 1 out of 5 using the American Association of Equine Practitioners (AAEP) lameness scale. Further, researchers noted horses were analyzed first at a walk and then at a trot throughout the study, which may have made the horses lose “their starting stiffness.”

Despite the fact that this study joins the “nay” side of the supplement debate, there are other factors to consider when deciding whether or not to use nutritional supplements, such as:

Many studies evaluate proprietary products, and it is well documented that not all nutritional supplements contain either the type or amount of ingredient that is indicated on the product label2, 3;
The study in question only looked at one such proprietary product and didn’t note a significant change in only three months of supplementation; and
The control group of horses in that study actually did experience a significant difference in various outcome measures compared to baseline.
“The significant changes in gait parameters in the control group may indicate the usefulness of exercise regimens in older horses,” concluded the study authors, which is an important finding of its own accord.

Additional details regarding the pros and cons of equine nutritional joint supplements is available online3, including detailed information on how to select a quality equine nutritional supplement.

Read more: Greasing the Joints, Part One and Part Two.

1Higler, M.H., H. Brommer, J.J. L’Ami, et al. 2014. The effects of a three-month oral supplementation with a nutraceutical and exercise on the locomotor pattern of aged horses. Equine Veterinary  Journal 46:611–617.

2Oke, S., A. Aghazadeh-Habashi, J.S. Weese, et al. 2006. Evaluation of glucosamine levels in commercial equine oral supplements for joints. Equine Veterinary Journal 38(1):93–95.

3Oke, S.L., and C.W. McIlwraith. 2008. Review of the potential indications and contraindications of oral joint health supplements. AAEP Proceedings. 54:261–267.

I have read that flaxseed (linseed) meal can generate toxins when fed to horses. Is it safe to feed?

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Q: I have read that flaxseed meal can generate toxins when fed to horses. Is it safe to feed?


A: Flaxseed contains cyanogenic glycosides, which are activated by enzymes in the seed to form cyanide. As long as the seed is intact, there is no cyanide development but when exposed to air or water the conversion to cyanide occurs. The longer the exposure, the greater the time for the reaction to occur.

This is why equine nutritionists recommended that flax be fed as soon as possible once it is ground. In times past when flax (linseed) was an integral part of many equine diets, flax was boiled to soften the hard outer shell. When dropped into boiling water, the enzyme deactivated and no cyanide was produced. On the other hand, if flax is put in cold water and brought to a boil, there will be some cyanide production. Heat and acid exposure deactivates the enzyme.

Whole flax seeds can be fed without any cyanide production because the acid in the stomach will denature the enzymes. Whole flaxseeds are chewed by the horse fairly effectively and may have some effect on keeping the digesta in the tract moving well, as the pectins in the flax form a glutinous gel. Some seeds, however, may escape digestion.

Commercially purchased ground flax will be “stabilized,” a heating process that denatures the enzyme, so they are considered safe to serve as-is. The stabilized product can be refrigerated after opening to extend the shelf life.

Even though there can be cyanide production when soaking or grinding flaxseeds, the total amounts are not very high. In fact, plant breeders have been working on developing lower glycidic strains of the plant during recent years. As it stands now, a horse would have to eat more than a couple pounds of raw ground flax that had been standing around awhile (or soaked in cold water) to ingest the amount of cyanide to approach having toxic effects. Normal intakes are anywhere from 2 to 8 oz per day and do not come anywhere near the amount that would be considered dangerous.

Please note that flax meal and ground flax are not the same thing. Flax meal is the product left after the oil is extracted from the seed. Ground flax is the whole seed that has been ground so that it has the same fat content as the whole seed.

What’s the Scoop on Carbohydrates in Horse Feeds?

From a plant perspective, carbohydrates fall into three categories: simple sugars active in plant intermediary metabolism; storage compounds such as sucrose, starch, and fructans; and structural carbohydrates such as pectin, cellulose, and hemicelluloses. For the horse, however, it is more appropriate to classify carbohydrates by where and how quickly they are digested and absorbed.

Undigested starch from cereal grains and fructans from pasture are the most likely compounds contributing to lactic acidosis in the hindgut.Carbohydrates can be digested and absorbed as monosaccharides, simple sugars (primarily glucose and fructose), in the small intestine, or they can be fermented in the large intestine to produce volatile fatty acids (VFA) or lactic acid. The rate of fermentation and types of end products produced are quite variable and can have significant effects on the health and well-being of the horse.

Starch is the predominant carbohydrate fraction in cereal grains. Although all starch is made up of glucose chains, the starch molecule is constructed different in various types of grain. These differences in the architecture of individual starches have a large impact on how well they are digested in the horse’s small intestine. Of the grains most commonly fed to horses, oats contain the most digestible form of starch, followed by sorghum, corn, and barley. Processing of grains can have a huge effect of prececal starch digestibility and glycemic index. This is particularly true for barley, sorghum, and corn.

The quantity of blood glucose produced in response to a meal is a useful measure of a feed’s hydrolysable carbohydrate content. The glycemic index of a feed indicates the rate of carbohydrate absorption after the horse ingests that feed. For the purpose of comparison, oats are assigned a glycemic index of 100. Steam-flaked corn has a higher glycemic index of 144, as does sweet feed at 129, indicating that more glucose is derived from their prececal digestion than from oats.  Feeds with lower glycemic indices include cracked corn (90), rice bran (47), alfalfa hay (46), and bluestem grass hay (23).

Rapid fermentation can produce lactic acid, which may lead to a cascade of events culminating in laminitis. Undigested starch from cereal grains and fructans from pasture are the most likely compounds contributing to lactic acidosis in the hindgut. Slowly fermentable carbohydrates from the plant cell wall are absolutely essential to maintain a healthy microbial environment in the hindgut, and provide a major source of digestible energy for many horses.

Obesity is a growing problem in the horse population and is an important risk factor for laminitis through the association with insulin resistance and hyperinsulinemia. Excessive caloric intake can lead to the development of obesity and other clinical signs in horses with equine metabolic syndrome and pituitary pars intermedia dysfunction. Owners should monitor body condition of their horses and should not let them become obese. In general, a horse whose ribs are easily seen may be too thin; a horse whose ribs can’t be felt by pressing the fingertips over the horse’s barrel is probably too fat; and a horse whose ribs can’t be easily seen but can easily be felt with fingertip pressure is at a reasonable weight.

Q&A: Understanding Fiber Types

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The fiber fractions found in plants are cellulose, hemicelluloses, and lignin. Some fiber is digestible (hemicellulose and some of the cellulose), and some is not (lignin). There is currently no exact method of measuring the proportion of digestible fiber (by microbial fermentation) to indigestible fiber in forage. The old “crude fiber” measure is grossly inaccurate. At this time, acid detergent fiber (ADF) and neutral detergent fiber (NDF) are used, and these measure combinations of fractions of fibers.

 NDF: includes low digestibility or indigestible cell wall/structural fiber so includes cellulose, hemicelluloses, and all lignin. High NDF means low digestibility (these are all elements within the cell wall).

 ADF: lignin, cellulose, some ash, and silica. High ADF means low digestibility.  Hemicellulose is estimated by subtracting ADF from NDF (these are elements within the cell wall of the plant).

 ADF and NDF measurements of fiber content give an indication of digestibility and palatablilty of forage.

 NDF is a measure of the plant’s cell wall content where the higher the value, the less the horse will eat of the hay (less digestible).

 ADF is a measure of the fiber concentration shown as a percent where, as ADF increases, digestibility and nutrient availability decreases.

Hays with ADF levels above 45% have little nutritive value (lower than 31% are excellent).  Hays with NDF values of 65% or greater are not very palatable (below 40% are excellent).

Essentially, the change that you are seeing from one hay test to the next has to do with the maturity of the hay at the time it is harvested. Different cuttings throughout the year will have different fiber fractions relative to the maturity of the plant at the time of cutting.  With alfalfa, the detergent fiber levels (ADF and NDF) will increase with an increase in the amount of stems in the hay. Consequently, the more stems, the more lignin (an indigestible fiber component), which gives stiffness to the stems, and the less digestible fiber will be present.

Understanding Analysis for Horse Forages | Equinews

Understanding Analysis for Horse Forages | Equinews

Mobilization of Horses after Musculoskeletal Injury

Long periods of stall rest used to be part of the healing process after musculoskeletal injury or surgery. This regimen allowed healing but also resulted in bulky scar tissue, adhesions, and losses in range of motion, flexibility, balance, and muscle strength.

Each horse and injury must be evaluated on an individual basis to determine the best course of treatment and recovery.

Newer advice is to put recovering horses back into light work at a much earlier point. Though a short period of immobilization is important immediately after severe tears and fractures, early mobilization has been shown to increase blood and lymph flow, and the tissue tension caused by movement stimulates soft tissue repair and improves fiber alignment in healing tissues. In one study, there was a 60% improvement in tendon Type 1 collagen deposition and a 20% improvement in range of motion and the ability of an injured tendon to handle ground reaction forces. Also, long immobilization doesn’t guarantee a better outcome, and early mobilization doesn’t lead to an increased rate of reinjury.

While it’s difficult to quantify the psychological effect of stall confinement, some horses seem to become depressed while others show increased agitation when they are kept in stalls with no company, turnout, or exercise. Each horse and injury must be evaluated on an individual basis to determine the best course of treatment and recovery.

Monitoring Equine Parasites Via Fecal Egg Per Gram Counts

Fecal egg per gram (EPG) counts are valuable to actually determine the number of worm eggs in a horse’s manure. Routine fecal floats determine if parasite eggs are present but cannot differentiate a heavy-shedding horse from one shedding fewer worm eggs. Manure for EPG determination is weighed, floated in a standard volume-of-egg flotation solution, and worm eggs are counted under a microscope using a special slide.

The most commonly observed worm egg is called a typical strongyle-type ova (eggs) because the eggs of small and large strongyles look alike. Small strongyles are the most common internal parasite of horses. Roundworm eggs are also observed, especially in younger horses. Tapeworm eggs are seldom seen, even when horses are infected with large numbers of tapeworms.

An excellent study from Denmark found that horses tend to be consistent in the amount of worm eggs shed in their manure. Less than 200 EPG is considered a low level of shedding. Horses that had two previous EPG counts performed six months apart that were both less than 200 EPG had an 84% chance that their third EPG count would also be low. Similarly, if a horse had two previous EPG counts greater than 200, the chance of being greater than 200 EPG on the third count was 59%. This demonstrated that horses with low EPG counts tend to keep low EPG counts and those that are high also tend to stay high.

These findings help to target deworming to reduce resistance and allow for the classification of horses into low or high EPG shedders. Horses that consistently have low EPG counts do not require frequent deworming, and deworming twice a year is probably sufficient. Horses that have a consistently high EPG count can be segregated to reduce overall pasture parasite egg contamination, and these horses may benefit from more frequent deworming.

Your veterinarian can perform EPG counts and is the best source of information to tailor a deworming program that is best for your farm. EPG counts also help slow the development of resistance to dewormers, and less frequent deworming reduces costs.

Reference: Nielsen, M.K., N. Haaning, and S.N. Olsen. 2006. Strongyle egg shedding consistency in horses on farms using selective therapy in Denmark. Veterinary Parasitology 135:333-335.