Revised:  09/14/2012

Ask the Expert -- Supplements

















Should I feed extra biotin for hooves and the coat?


Do you recommend a biotin supplement for hooves and the coat? If so, in what amounts? Do horses normally make biotin in the body?



Horses' hooves can take a lot of wear and tear and may need something to help maintain a healthy condition. If horses are ridden on a hard or sandy area it can cause trauma to the hoof, making it hard to maintain moisture. Lack of moisture in the hoof leads to brittle and cracked hooves.


Research performed in England shows that supplementing biotin to horses with low quality hooves improves the hooves, making them stronger and less likely to crack. Though many other studies have been performed, most have the same results. The dosage shown to best maintain or improve hoof quality is approximately 15-30 mg/day. It was noted that for the best results, an adequate supply of calcium must also come from the horse’s hay or grain. Results of the supplementation were seen within nine to twelve months due to the fact that horses’ hooves take about a year to grow from the coronary band to the ground.


Though biotin is naturally made in the gut of the horse, supplementing it in the diet will not hurt because it is water soluble and is not stored in the body. Vitamin B-deficient horses especially need biotin in their diet and should be supplemented. Also, horses that are stressed from being transported or stabled for long periods of time also can benefit from a biotin supplement.


While biotin helps with a horse’s hooves, it can also help maintain a healthy coat. The coat is the horse’s largest organ. Biotin helps improve coat sheen, which is a sign that the horse itself is in good health. To enhance coat health, a horse may need only 8 mg of biotin per day. Results are usually visible within about five weeks.


Overall biotin is the best supplement to be used on a horse with brittle or cracked hooves or a lackluster coat. Check with your veterinarian to determine an exact dosage schedule.


This answer was prepared with the help of Samantha Schreiber, Animal Science research student, The School of Environmental and Biological Sciences, Rutgers University.



Are black oil sunflower seeds okay to feed my horse?

I have read that black oil sunflower seeds help the horse’s coat, and that they have natural omega-3 fatty acids. But some say that they can cause impaction and possibly colic in horses. Has there been any official research on feeding black oil sunflower seeds to horses?



To our knowledge there has been no research done on this topic. The seeds do have higher levels of omega-3s compared to corn oil, or other fat sources, which should help horses’ coats, but this has never been tested.


The amount of seeds needed to produce a nice coat shine (I assume no more than 1 cup) would not be enough to create an impaction. Impaction with shelled seeds has been reported, so using unshelled seeds may be a better option. Always make sure the horse has enough water to drink. This will help if impaction is a problem. An associate at my barn has been feeding about 1 cup of black oil sunflower seeds per day for years and has never had a problem.


Another alternative for the coat is to feed oil. Corn, canola, flax or rice bran oil will definitely put a shine on a horse’s coat without risking impaction. You only need to feed ½ to 1 cup per day.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



How do "calming supplements" work?

My trainer has recommended a supplement called Seroquine from Uckele Health & Nutrition. It contains the following ingredients per 30g (recommended dose):

  • taurine 8,000 mg
  • thiamine 1,100 mg
  • magnesium 5,000 mg
  • inositol 4,000 mg

I have a 5-year old Welsh cob in training for combined driving. He has a great temperament but can be skittish when introduced to new stimuli, which occurs on a regular basis. My trainer's experience is that this supplement helps the young horse process things a little better and not be as jumpy. I am having a hard time figuring out what the mechanism might be. Can you help shed some light?


This is a question I am often asked about "calming supplements." Whether or not they work as they claim to is up in the air. I have not seen any research dealing with calming supplements, but there are plenty of people testifying to their effectiveness. Each ingredient has a proposed mechanism. I can shed some light on this; however, use caution when feeding them, as you may be wasting your money.


Taurine: Low taurine and magnesium levels have been found in patients after heart attacks. Like magnesium, taurine affects cell membrane electrical excitability by normalizing potassium flow in and out of heart muscle cells. Taurine functions in electrically active tissues such as the brain and heart to help stabilize cell membranes. Taurine seems to inhibit and modulate neurotransmitters (like glycine and GABA) in the brain and helps to stabilize cell membranes. It also has functions in the gallbladder, eyes, and blood vessels and appears to have some antioxidant and detoxifying activity. Taurine aids the movement of potassium, sodium, calcium, and magnesium in and out of cells and thus helps generate nerve impulses.


Thiamine: Thiamine is very important for the normal function of the citric acid cycle. In this cycle, breakdown products of carbohydrates, fats and proteins are brought together for further breakdown and synthesis. High-grain diets result in a greater requirement for thiamine. Thiamine-deficient animals may be weak with poor appetites, weight loss and incoordination (especially in the hind legs) and exhibit nervousness that contributes to inefficient weight gain. A deficiency in thiamine can result in a number of different nervous disorders and hyper-irritability. Ensuring that thiamine status is optimal is a key step in improving weight gain.


Magnesium: Called the "anti-stress mineral," magnesium aids in relaxing nerves, relieving tension, assisting digestion, activating enzymes important for protein and carbohydrate metabolism, and modulating the electrical potential across all cell membranes. Magnesium is important in the production and transfer of energy, muscle contraction and relaxation, and nerve conduction. It also aids regularity, is necessary to keep vertebrae in their proper position, induces restful sleep, purifies and purges body tissues (by combating acids, toxins, gases, impurities, and neutralizing poisons), and lowers fever. Magnesium is stored in the bowel, nerves and ligaments. Chlorophyll and green vegetables contain large amounts of magnesium.


Inositol: One of the water-soluble B vitamins, inositol is a direct precursor of phospholipids, which are a major component of cell membranes. It helps to maintain proper electrical energy and nutrient transfer across the cell membrane. Studies suggest that inositol is effective in treating depression and may also provide support for people with obsessive-compulsive disorder and those who experience panic attacks. Research also suggests that inositol may be useful in the treatment and prevention of neurological disorders associated with diabetes.


Tryptophan and other B vitamins are also proposed to calm a nervous horse; most of these use their neurotransmitting and nerve-conducting capabilities.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.


What could high levels of cobalt fed to a horse do to their system?

I have a friend who is currently feeding a very high level of cobalt to horses in training. This doesn’t sound like a good idea to me. What effects could this have and are there any negative consequences?




Cobalt is a trace element mineral. It is the central element in Cyanocobalamin, better known as vitamin B-12. Vitamin B-12 is commonly given to racehorses. It is depleted during stress, essential for optimal energy utilization and, though not scientifically proven, thought to have a calming effect in high doses. Deficits cause anemia.


High blood cobalt probably would indicate high doses of B-12 being given (the trace mineral is easier to test than the actual vitamin). The calming effect would be undesirable in a racehorse. It is virtually non-toxic and rapidly excreted through the kidneys if given in large doses, so there is no negative consequence other than possibly a quieter horse. It is recommended to give B-12 to stressed horses at around 30 microgram/kg of feed. There are no requirements for cobalt established for horses so it is uncertain what normal or excessive blood concentrations of cobalt would be. The National Research Council (2007) has set the maximum tolerable intake for cobalt to be 25 mg/kg (ppm) in the total ration but admits they base that decision on data from other species. There is no indication that horses on normal rations need supplemental cobalt.




Is Cordyceps sinensis safe to give to racehorses?

I own and race several Thoroughbreds. Recently someone suggested that my trainer use some products containing Cordyceps, a Chinese mushroom. Could you comment on the use of this ingredient in horses?



The full name of the mushroom in question is Cordyceps sinensis. In humans, it has been associated with increased energy levels, reduced fatigue and an enhanced ability to use oxygen. Its proponents claim that it relieves asthma, increases lung function, and improves athletic performance. Many of the available testimonials for Cordyceps are from either geriatrics or people with health problems. It is an expensive supplement – if a dose costs $1.00/day for humans, multiply that by 6 or 7 for horses to get an "effective" dose. There is no proof of safety or efficacy in horses, nor any assurance that the mushroom would not test positive in drug tests as the active ingredient(s) are not yet known. I would be hesitant to use it in racehorses.


Answer provided by Sarah Ralston, VMD, Ph.D., dACVN, Rutgers Cooperative Extension.



Can you comment on the ingredients and efficacy of equine digestive supplements?


Can you comment on the ingredients and efficacy of equine digestive supplements?




Most of these supplements will include probiotics; they include those fermentation-related factors such as naturally occurring live organisms Lactobacillus acidophilus and Bifidobacterium. They are found to be beneficial to the digestive tract because they produce digestive enzymes to help break down proteins, starches, fiber, fats and sugars. They also produce B-vitamins and growth inhibitors against pathogenic microbes and fungi. Carriers consist of nutrient dense fermentation solubles. Probiotics are usually intended for all situations where there is a need to restore, stabilize and maintain optimal level of the gastrointestinal micro flora, such as after antibiotic treatment, illness or surgery or other stressful conditions. They are safe for weaned and pre-weaned foals for maintaining proper digestive balance. Many researchers are simply not certain of the precise bacteriostatic roles played by antimicrobials, lactic acid and hydrogen peroxide. What is certain is that substances produced by Lactobacillus acidophilus do help establish a normal gut microflora. They do so by inhibiting the growth of disease-causing organisms within intestinal tracts. With this being said probiotics will not have much impact on the horse with an existing healthy gut flora.


Yeasts are also found in some digestive aids. In scientific research, yeast has been shown to increase fiber digestion, thereby making more nutrients available for the horse to absorb; increase the availability of dietary phosphorus; normalize problem feces, including diarrhea; stabilize gut pH (acid/alkaline level); reduce level of pathogenic (disease-causing) bacteria; and result in the production of higher quality milk by lactating mares and improved growth rates and health of their foals.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



When should I give my horse electrolytes?

How do you know if your horse needs electrolytes? My Thoroughbred mare sweats quite a bit when ridden during the summer months, but I think that is normal. Our new barn manager keeps telling me that I should be putting electrolytes in her feed daily during hot weather or giving them by syringe. Do I really need to give them to her daily? I also have been having a problem getting my horse to drink at shows. Should I give her electrolytes (via syringe) before the competition? Would that make her drink?


Electrolytes may not be needed daily, but they may be the solution to your horse’s drinking problem. They are only lost when a horse sweats profusely, e.g. during heavy competition, a long hard trail ride, or intense schooling. Daily electrolytes are not usually recommended unless the horse is profusely sweating daily, which is not usually the case.


The easiest way to give electrolytes is with a syringe paste, like a dewormer. These electrolytes are already formulated so that one syringe typically contains several doses. If schooling or at home, a dose after riding will be adequate. If at a show for a day or two and your horse typically doesn't like to drink, you might want to give a dose before leaving for the show (always take your own water), then after the competition is over. Check for signs of dehydration 24 hours after the show (use the skin pinch, capillary refill time and mucous membrane color tests) and if she is looking a little dry give a third dose the day after the show as well. If you had an endurance race or were riding in a competitive trail ride you would probably want to give two more doses on the competition day, however, that again depends on the temperature and humidity outside and amount of sweating.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



Are enteric-coated ingredients in supplements beneficial to horses?

We are presently exploring the possibility of providing enteric-coated ingredients in our joint supplements for equines and canines. Are there any studies that prove enteric-coated ingredients enhance the efficacy of joint support supplements?



After searching through many references, I did not come across any scientific peer-reviewed articles either supporting or refuting the use of enteric-coated joint supplements in equines or canines. Several products in equine supplement catalogs advertised different "absorption catalysts", or different carriers (e.g. an alfalfa base) for the active ingredients in their joint supplements, implying that their product was more readily available to the animal than other products.


More controlled clinical research is needed to investigate the bioavailability of common equine joint support product ingredients. Until we know if, how, and in what form the ingredients are being absorbed, the benefit(s) of enteric-coated supplements is not relevant.


I am not as familiar with canine joint supplement products. However, after reviewing many of the oral products being marketed for dogs, I found many common ingredients between equine and canine joint products. Canine supplements commonly are sold in chewable tabs, powder, or liquid. I did not come across any product claiming enteric coating of their joint support product.


Non-steroidal anti-inflammatory drugs (NSAIDS) are commonly used to treat joint inflammation and pain. Many orally administered NSAIDs have been found to have toxic effects coinciding with chronic use or large doses, including gastric ulceration in both dogs and horses. I am unaware of enteric-coated NSAID products for horses, but I do think there are some for canines.


To the best of my knowledge, it is unknown if the efficacy of oral joint supplements in equines and canines is improved with the use of enteric-coated ingredients.


This answer was prepared with the help of Emily Lamprecht, Rutgers University, Doctoral Graduate Student in Animal Science.



Will feeding supplemental fat to a horse who is an easy keeper have a calming effect?

I have a young Arabian/Paint who is a very easy keeper. He gets adequate grazing time and medium-quality grass hay in addition to 1.5 lbs. of a “lite” pelleted grain daily. I have read that the fats such as corn oil can have a calming effect on horses. I have tried adding one cup to his feed daily for 3 weeks, and so far I see no difference. How much oil can I add to the feed without doing harm to an “easy keeper” horse that weighs about 850 lbs? His “lite” feed is basically given to insure that he is getting his needed vitamins and minerals without adding extra carbohydrates.



Additional fat will only help horses that need to put on weight. Most easy keepers should not get additional fat in the diet if they have a body condition score above 6-7 (I’m just guessing, but I thought a specific range might be helpful). You can feed a 1000 lb horse up to 2 cups of fat (oil) per day. However, I would not recommend this for your horse, because it sounds like he does not need any additional calorie load. Typically, when horses have problems with their energy level and are slightly overweight, they are taking in too much sugar/starch in their meals. The “lite” feed you are giving him is a good food source, because its higher fiber content will dilute out the extra energy he might be getting from other carbohydrate sources.


I hate to say it, but some horses that have extra energy may just need to be exercised more to utilize extra calories. Some horses will not respond to changes in feed, others might respond to a calming supplement with extra B-vitamins and amino acids. No research has ever been done on these products to prove if they are effective, but they may work on a case-by-case basis. There is more information on these supplements at


For your horse, I would recommend discontinuing the corn oil as it may be providing too much energy. Energy from fat will burn slower than that from carbohydrates. This does cause a calming effect, but due to fat’s additional calories this approach might not be appropriate for your horse or any easy keepers. Try increasing his exercise intensity. If this does not work, try a calming product. His high energy may just be his natural behavior. Sometimes an immediate solution is not evident, but over time, a long-term training solution may prove helpful as the horse gets older.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



Can you recommend a good fat supplement?

I have a 24-year-old gelding and a 15-year-old mare, and they are both losing weight. Can you please suggest a good fat supplement for them, or a good sweet feed? I am giving them sweet feed, crimped oats and 2 flakes of hay each day, and I am getting a round bale brought out for them since I am worried that they are not maintaining their weight.


Before I answer your question about the fat supplements, let me first ask you if you have had their teeth checked lately and are on a current de-worming schedule, especially the 24-year-old. If they are in good dental health then I would look at the amount and type of sweet feed and oats you are feeding them now. I worry that 2 flakes of hay daily may not be enough. The round bale will help by allowing free choice access, but it is important that it is kept under cover to prevent mold. If it is left out on the ground I would recommend vaccinating your horses against botulism before starting to feed it. If the 24-year-old is having trouble chewing the forage, try hay cubes that can be soaked in water to form a "mush". There are also complete feeds with increased fiber and lower calorie content meant to be fed in higher quantities to replace the lack of roughage. Most major horse feed companies make these feeds.


If their teeth aren't the problem then they should be better on free choice forage, especially if it is good quality grass hay. I would steer away from a sweet feed in favor of a feed with higher fat and fiber. This will take care of your fat supplement and keep you from having to use a fat source such as corn oil or rice bran (the 2 most commonly used fat supplements). Look for a feed containing about 7% or higher fat, 10-14% protein, and over 8% fiber. Pick one – don't mix and match – and offer this feed without the crimped oats. Be sure to introduce the new feed slowly: substitute a pound of the new for a pound of the old until you get them totally switched over. Without knowing their breeds and how much feed they are currently on, it is hard to estimate the total amount they should get at each feeding. The most an average 1,000-pound horse’s stomach can handle at a time is 5 pounds. So, take a bathroom scale and weigh a scoop of what they are getting now against a scoop of the new feed. If they don't start gaining with just a feed change, you could try adding in a 2- to 3-pound "lunch" or "midnight snack". I think the lack of hay is the primary cause of the problem and simply increasing their forage quantity will help. Give them at least two weeks to adapt to the new hay and feed before you make the decision to increase their grain.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



Is feeding fish extracts to race horses beneficial?

I work with an international racing authority and am in charge of the supply and management of equine feed. I was wondering if there were any benefits or side effects to feeding fish extracts to racing horses.



I have no direct experience with feeding fish extracts to horses, but there should be no risk with this type of product. The protein quality should be fairly high and highly digestible to horses. According to the 2007 NRC (Nutrient Requirements for Horses), fish meals contain 68.5 to 71.2% protein. They are an excellent source of lysine, which is good for growing race horses. They also contain 5 to 10% fat, which is a good energy source for them as well. I was surprised to see the meals are also high in Calcium (4 to 5%) and Phosphorus (2 to 3%), which would also be good for growing bones. (Menhaden and anchovy are the only fish extracts studied in horses.)


All in all, the fish meals would appear to be a good source of desired nutrients for racing/growing horses; if they will eat them. I do not think they would confer an "extra" advantage when racing, other than allowing balancing for optimal nutrient intake.


Answer provided by Sarah Ralston, VMD, Ph.D., dACVN, Rutgers Cooperative Extension.



Is flax seed toxic to horses?

I have fed flax seed in the past: cooked whole seeds, then ground raw flax meal. I have always gotten 25 -50 lb bags. The last time I picked up a bag, I noticed that the label stated, “Not to be fed to horses intended for food. Not for human consumption.” What is the story? Is it toxic raw or ground? Is it worth feeding?


I know many people who do swear by flax seed, however, I do not have any personal experience using it. The raw seeds contain cyanogenic glycoside compounds which, when the seeds are ground, and especially if moistened, will release cyanide! However, this really is not a concern, since the enzymes needed to cause the cyanide release are inactivated by boiling and gastric acids. So, as long as you don't add water before feeding the flax meal, it should not be a problem. If the meal is processed in any way it is also probably totally safe. Read the label again to see if there are other substances added. If not, the warning is probably due to the minuscule risk of cyanide poisoning. But it shouldn’t hurt in small enough quantities.


The presence of cyanogenic glycosides in the diet is significant only in relation to dose and the nutritional status of the consumer. Flax seed meal contains two cyanogenic glycosides, linustatin and neolinustatin. Many foods are slightly cyanogenic (e.g. wheat and barley!), probably as an evolutionary adaptation to discourage herbivory, and our body and our horses have a limited capacity to detoxify low concentrations of cyanide through addition of sulphur (from amino acids). Thus, if the dietary levels of sulphur-containing amino acids are high, the body can resist a low intake of cyanide, but if the diet is low in protein overall, then we see toxicity.


It has been determined that up to 50g high-alpha-linolenic acid flaxseed is palatable, safe and may be nutritionally beneficial in humans by raising n-3 fatty acids in plasma and erythrocytes and by decreasing post-prandial glucose responses. (Cunnane S, et al, (University of Toronto, Toronto, Canada) Br J Nutr, 69:443, 1993)


Answer provided by Sarah Ralston, VMD, Ph.D., dACVN, and Carey Williams, Ph.D., Rutgers Cooperative Extension.



What can I feed my horse that will help her gain weight but won’t make her hyper?

I have a 15 year old Arabian mare that is very hyper. I had her at a full care horse stable but found out that they weren’t feeding her properly. My once plump, sweet horse now has her ribs showing. I had increased her grain from one large coffee can to 1 ½ but now she is out of control and hyper. She won’t eat beet pulp. What can I feed her that is easy on the wallet, won’t make her hyper, and will bring up her weight?


I would try rice bran. It is a high fat/high fiber supplement that is my favorite for putting weight on a horse. It is very palatable, so horses love it, and it is high in fiber, so they get that benefit as well. Make sure when buying rice bran that is it a “stabilized” product. This means that it is balanced for the naturally low levels of calcium found in rice bran.


When starting to feed higher fat supplements you need to start off slowly, read the directions and see how much product is recommended. Start by dropping her grain amount back down to where it was before she was hyper, and slowly increase the rice bran about ½ a cup more every two days until you reach the recommended amount. This process should take 2-3 weeks. Then monitor her weight over the next few months. If she gains, then maintains, you are at a good level. If she is still thin, or keeps gaining too much, add more or back off, but make sure to do so slowly!


If this does not help, you may need to revaluate her hay ration. Remember, horses should eat a total of 2% of their body weight daily, so make sure she is getting adequate hay. They can actually have free choice access to hay, but it should be of good quality so that she is not just getting fiber, but protein and minerals as well.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



How much garlic should I feed my horse?

I have read on the Internet that garlic can cause anemia. I would like to know what quantities of garlic cause this - at the moment I am feeding my horse 10 ml (2 teaspoons) of dried garlic flakes once daily. Is this too little, too much, or just about right?



In response to your question on garlic I will provide some background and some studies that have shown its effects. Garlic is a plant in the genus Allium. It is given to horses because it is believed to act as an insect repellent, anti-inflammatory, anti-histamine, anti-bacterial, disinfectant and anti-allergic. Garlic is related to onions, shallots, and leeks. Years ago, horses were discovered to become ill after consuming large quantities of wild onion. A study was performed in 1972 to test the effects of onion intake in horses. The horse in the study was fed onion tops in large daily quantities. The horse became anemic and lost most of its red blood cells within 11 days.


The anemia is caused by a specific chemical element of allium plants, N-propyl disulfide. The chemical is responsible for altering an enzyme in the red blood cells of the horses. The changes cause the red blood cells to deform and be removed by the spleen. This type of anemia is called Heinz-body anemia.


The issue with garlic is that it has undergone little testing of its own in regards to horses. Cats, dogs, and other animals are known to have this reaction to garlic as well as onions. Some claim horses have been known to show signs of anemia after an overdose of garlic. The worry is that the same effects could occur with small doses over an extended period of time. Studies about the effects of garlic on horses are only a recent occurrence.


In 2005 a study was published that tested the effects of garlic on horses. A study performed at the University of Guelph in Canada tested 4 horses; two given garlic in their daily diets and the other two with a garlic-free diet. The amount of garlic given was increased daily, reaching a maximum of 5 cups per day. The study lasted for 71 days. The blood chemistry of the garlic-fed horses showed signs of changing within three weeks. The horses did show signs of Heinz-body anemia in reaction to garlic exposure. However, the study gave doses of garlic many times the size of those given to horses in real practice. They estimated that effects would appear if horses were fed 500 grams daily.


If you are feeding 10 ml daily, it would not be a high enough dose to cause harmful effects. However, little is known about the long-term effects of such exposure. Some believe that in the long term, although signs would not readily show, the exposure could cause loss in stamina, energy, and resistance to disease. Plus, these studies are all concerning pure garlic. The garlic found in different horse products is considered less controversial. This is because many of the products that contain garlic lack the active ingredient (allicin) that is the cause for concern. This may cause the products to be less effective than straight garlic, but they are thought to be safe. The studies done to date still have no measure for the correct daily dose of garlic that should be given to horses. Some studies believe that the low-dose, long-term exposure would have the same negative effects as the high-dose exposure in the experiments. Others believe that the low dosage could not build up the same effects.


This answer was prepared with the help of Sonia D’Angio, Animal Science Research Student at the School of Environmental and Biological Sciences, Rutgers University.



Is supplementing a horse's diet with glutamine beneficial?

I know many human athletes are on high protein diets and some supplement themselves with glutamine. Does glutamine have the same benefits in horses if supplemented with higher levels?



Many humans who exercise on a regular basis have a much higher intake of glutamine than the average human due to protein supplements and high protein meals. Recommendations that athletes take glutamine are made due to the belief that glutamine can support immune function and increase glycogen synthesis. Unfortunately, the beneficial reasons for taking glutamine are not backed by controlled research studies.

Glutamine is an amino acid that normally exists in very high amounts in the body, higher than any other amino acid. Because the body can normally make adequate amounts, it is not an essential dietary amino acid. It is stored mostly in muscle and secondarily in the lungs. Glutamine is required to remove excess ammonia, support brain function and digestion, and to support immune function. After exhaustive prolonged exercise, such as running a marathon, glutamine supplementation may be beneficial, but no evidence exists that it aids in repair after less intense exercise.

Glutamine supplements do exist for horses. Manufacturers’ claims are similar to those for human supplements and are equally lacking in any scientific evidence that they are true. Some studies in horses have shown that extreme stress from exercise or infection causes a decrease in glutamine concentration in the plasma; therefore, these horses may benefit from supplementation of glutamine. During severe malnutrition, research has also shown that supplementation of glutamine can aid in the repair of small intestinal mucosa and immune function in some species. However, due to the potential for interference with absorption and utilization of other amino acids that are essential in the diet, it is not recommended to supplement single amino acids on a regular basis.


This answer was prepared with the help of Jessica Caruso, Animal Science Research Student at the School of Environmental and Biological Sciences, Rutgers University.



Are holistic remedies really beneficial?

I recently started feeding my horse holistic remedies to help with various problems. Some of those items were Calendula (marigold), horsetail, plumbum metallicum, and camphora. Are these homeopathic remedies really beneficial?



Because specific problems were not mentioned in the question, the answer provided is generic in nature. There are a few concerns when feeding herbal products: 1) Some herbal products are actually parts of plants that are toxic to horses. Horsetail is a toxic plant that can cause weight loss, diarrhea, and various nervous conditions including lack of coordination if fed in large amounts, 2) Some herbal products have been found to negatively interact with other dietary products and medications; consult with your veterinarian in this case, 3) Many herbal products are on the banned substance list for some show organizations or racing circuits. If your horse is showing, make sure to check the 'banned substance' list, 4) Research on most herbal products has not been conducted in horses. There are very few herbal products that have actually been tested in horses (echinacea, garlic, and various poly-herbal products) and many of these have not been found to be beneficial or have the same proven benefits as in other species.



Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



What should I look for in a hoof supplement?

We have a nine year old gelding, Quarter horse/ Paint, which has brittle cracking hooves. What would you recommend looking for in an oral hoof care supplement? The horse is in great shape, very muscular, and an easy keeper. It is being worked about five times a week in an arena with sand footing and also used for some trail rides. We feed it about five lbs of a commercial grain mix two-times-a-day and free choice coastal bermuda hay.



For dietary hoof supplements to be effective, the problem needs to be due to a nutritional deficiency. From what you say about the horse’s condition and ration fed, it does not sound as if the diet is deficient. Also take into account that genetics and the environment play a role in how a horse’s hooves develop. If you would still like to try a supplement, remember they work from the inside out. Feed the supplement for at least six months before deciding whether it is working or not. The things to look at in a hoof dietary supplement are:

Biotin - a B vitamin activates production of keratin. Provide about 20 mg/day in the supplement.

Iodine - essential for thyroid hormones that develop all tissues. Provide about 1 mg/day in the supplement.

Methionine - responsible for keratin within the hoof. The amount needed to have an effect is not known, but should be at least present in a small amount in the supplement.

Zinc - contributes to the health of the hoof and reactions controlling metabolism. Provide between 175-250 mg/day in the supplement.



Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



Can you recommend a supplement program to boost the immune system?

My 21-year old thoroughbred gelding is currently hospitalized. Hopefully he will soon be released on a relatively high dose of corticosteroids, which I know are lowering his immune system's ability to support him. He is spiking high fevers with accompanying high respiratory rates. Prior to his hospitalization, he was on Accel, selenium, vitamin E and black oil sunflower seeds. Can you recommend a program of vitamins and minerals that will help boost his immune system?

The selenium and vitamin E you have him on is a good idea. These are both antioxidants that are known to have a protective effect on cell membranes, specifically protecting cells of the immune system. I would definitely keep him on the vitamin E - you could go up to 2500 IU/day on a non-exercising horse. Selenium can be a little harder to supplement because the soil around here is borderline deficient, feed companies add selenium to their products, and the selenium levels in hay will depend on where it comes from. You don't want to supplement too much selenium because it can be toxic to the system at high doses (about 18 mg/day). Just be sure to watch the amounts in all your supplements.


Another antioxidant that you tend to find in mixtures for boosting the immune system is glutathione. This compound is used to protect immune cells as well and also recycle vitamin E after it has been used to fight the harmful damage itself. Vitamin C is good to use specifically around stressful times, but long-term use is not needed since the horse's liver produces its own. However, if your horse has surgery, keeping him on a C supplement (about 7 to 10 g/day) while at the hospital and for about a week after would help him in case he isn’t producing enough to combat the harmful products produced during this stressful time.


When purchasing supplements, make sure you know how much of each component is in the product. Be very cautious about buying a product that claims its ingredients are “proprietary information” or does not list its ingredients. You should at least be able to know how much of each vitamin and mineral is in the mix. You need to know what you are really feeding! Many supplement companies offer ingredient lists on their websites.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



My horse is anemic. Will an iron supplement help?


My horse is anemic; what can I do to treat it? Will an iron supplement help?




Anemia in horses is commonly misdiagnosed. Horses have a spleen, which stores about 1/3 of the body’s red blood cells (RBC). In any time of excitement, e.g. exercise or a sudden spook, the spleen will contract, releasing RBC. To accurately diagnose anemia, it is important to take a blood sample when the horse is at rest. Stall rest will give a lower reading than pasture rest because the horse will not be walking around grazing. You can also take several samples over the course of a few days and average the results. The blood will be analyzed for the packed cell volume (PCV), which should range around 40 %. The horse is considered anemic when the PCV drops below 30 %.


Anemia does not result directly from an iron deficiency. Causes of anemia can include blood loss, parasite infection, and RBC degradation or lack of production. The most difficult obstacle in curing anemia is finding the root of the problem first. Once that is eliminated, the anemia will usually correct itself. Iron supplementation will not help unless you correct the underlying problem of the anemia first. Iron injections are commonly used, but should be given with caution! Iron can be toxic and possibly fatal; anaphylactic shock due to the injection is also possible.


With exercise training and conditioning there will be a natural increase in RBC, so unfit horses may have a lower PCV than fit horses. Conditioning may be a good way to help increase RBC in the borderline anemic horse.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



Are joint supplements absorbed effectively?

My vet says that even if a joint supplement has been tested to show that it is absorbed in the horse’s digestive system, that doesn’t mean that it gets to the joints. Chondroitin sulfate, a joint supplement ingredient, has a very large molecular weight and therefore absorption by the horse is debatable though there are no published studies confirming or denying its absorbability.


Another ingredient, hyaluronic acid, is one of the main components of joint fluid. It has been successfully injected directly into the joint and more recently injected into the blood stream. I’ve been told “the higher the molecular weight of hyaluronic acid, the more effective the product.” However, that seems contrary to what is known about chondroitin sulfate.


Please advise which of these two substances would be most effective as a supplement to prevent joint pain in a mature novice/training level event horse.


I am prohibited from making a direct recommendation of a name-brand product, however, I will provide you with the research that I know of on the following product ingredients, and give you a few other options for your horse. These ingredients can be found in many common joint supplements. All of the joint supplements have had a general lack of sound clinical research on their efficacy, however plenty of testimonials are provided for every type. Always be sure to check your supplements; know your ingredients and don’t administer any product to your horse unless the package clearly lists all of its ingredients on the label.


Ingredients: Glucosamine hydrochloride, chondroitin sulfate, manganese ascorbate
Administration: Oral
Research: Clinical tests showed no benefit to lameness, stride length, carpal circumference, knee flexion, or joint fluid (synovial fluid) parameters from supplementing at the recommended dose for 36 days in horses were observed. Furthermore, results from a clinical study evaluating the availability of oral glucosamine (GC) and chondroitin sulfate (CS) in horses found that these molecules are not absorbed in the intestine and therefore are not available to the synovial joints through the bloodstream. Joint injections of steroids (glucocorticoids) may also be administered by a veterinarian to reduce inflammation and pain, but again long term or chronic use is not recommended. There are a few FDA regulated products.


Ingredient: Polysulfated glycosaminoglycans (PSGAGs)

Administration: Intra-muscular (IM)

Research: These products have been shown to have significant improvements in lameness scores, stride length, flexion, and carpal swelling. It should be noted that while they will most likely help prevent further damage to the articular cartilage, they have not been shown to heal or repair defects already present.


Ingredient: Hyaluronate sodium
Administration: Intravenous (IV); Oral
Research: Clinical research on the efficacy of oral forms of hyaluronan-based supplements has yet to be completed. Intravenous hyaluronic acid (HA) treatment has been shown to improve lameness scores by interacting with cells in the joint fluid and reducing local inflammation and subsequent pain. The best use for HA is thought to be in horses suffering from acute injury or mild to moderate joint inflammation where its anti-inflammatory properties will be the most beneficial/therapeutic.


There is some debate regarding the efficacy of treatment with an intra-articular injection (into the joint) of high molecular weight HA versus low molecular weight HA. Very little clinical research has been conducted on this, and the existing studies do not provide unequivocal evidence that molecular weight has a direct pharmacological effect on efficacy.


Ingredient: Diclofenac sodium

Administration: Topical product (cream applied over the affected joint)

Research: This is another unique ingredient that is worth mentioning. It is brand new and has received FDA approval for the treatment of pain and inflammation associated with degenerative joint disease in horses. Aside from research performed by the company that manufactures the product, outside clinical research has not been published regarding its effectiveness. There have been quite a few horse owners who claim it works well and meets label claims. It can be obtained by prescription only, but it might be a less expensive alternative to other products, assuming your veterinarian has determined that it is an appropriate treatment.


It is always a good idea to have your horse examined by a reputable equine veterinarian to determine lameness score and the nature of the injury or chronic disease causing the pain. The use of oral or injectable NSAIDs (non-steroidal anti-inflammatory drugs) such as phenylbutazone or ketoprofin may be used short-term to reduce and initially control inflammation in joints. Long-term usage of NSAIDs is not recommended due to potential toxic effects such as stomach ulcers. A veterinarian’s expert opinion should be sought before administering any sort of treatment and compliance with drug use regulations for any type of competition should be maintained if applicable. In any case, care should be taken not to inappropriately or prematurely return a horse to training and/or competition performance levels even if response to treatment is quick and effective at reducing lameness.


This answer was prepared with the help of Emily Lamprecht, Rutgers University, Doctoral Graduate Student in Animal Science.



What type and amount of joint supplements are the best?

I have a 16-year-old Thoroughbred mare that is doing low-level dressage and some jumping. She is just starting to have some mild arthritis problems in her lower hock joints, so I've started her on a joint supplement. I also have a 27-year-old retired Arabian mare. She has some arthritis problems. Even though she is no longer ridden, she is kept on a joint supplement to keep her comfortable.


I have some questions regarding joint supplements and their ingredients:

  1. Is there any difference in feeding a supplement of glucosamine HCL vs glucosamine Sulfate?
  2. What levels of glucosamine, MSM and Ester-CTM should I look for in a supplement for her? Also does an older horse, not being ridden, need different levels of these ingredients than a horse who is working?
  3. Can feeding yucca really irritate a horse gut? I've noticed it's in many joint supplements.

1. Glucosamine HCl (hydrochloride) and glucosamine sulfate are commonly found in just about every equine joint supplement along with chondroitin sulfate. Glucosamine (GC) is a building block for glycosaminoglycans (GAGs), one of the major components of the articular cartilage around the joint in adult horses. This molecule is naturally made from glucose by the cartilage cells, however if there is enough inflammation or trauma to the joint, glucosamine and other important molecules can become depleted, leaving the cartilage and underlying bone unprotected from enzymes and inflammatory cells that ultimately can cause arthritis and degenerative joint disease. With respect to oral joint supplements, there are two forms of glucosamine commonly listed among a variety of ingredients. Glucosamine HCl is a water-soluble molecule and is said to be more available to the chondrocytes and other target tissues horse than glucosamine sulfate. While results from clinical research studies remain conflicted, there is sufficient anecdotal evidence supporting the anti-arthritic properties of ingredients like glucosamine HCl.


2. Unfortunately, most joint supplements or nutraceuticals out there are not FDA regulated and do not meet AAFCO (Association of American Feed Control Officials) labeling standards. The products often fall short of the claims made on labels and in advertisements, making them a waste of money. Additionally, the effects of ingredients like MSM (methylsulfonylmethane) and antioxidants (vitamin C) can be achieved simply by maintaining your horse on a nutritionally balanced diet without added supplements.


The dosage will depend on the product chosen. However, one particularly popular product recommends that after the initial treatment, the maintenance dosage for an average horse is one to two scoops daily according to the horse’s weight. Each level scoopful (3.3g) contains 1800mg GC HCl, 600mg sodium chondroitin sulfate, and 16mg manganese ascorbate (vitamin C). Treatment and dosage depends on the nature (type) of injury or disease, how advanced it is, and the intended or current use of the horse, not the horse’s age. Unless the horse has special dietary or medical needs, follow label instructions and always seek the expert opinion of your veterinarian before administering any type of drug, nutraceutical, or supplement.


3.Yucca is incorporated into many joint supplements because it is thought to have anti-inflammatory properties. However, there are no clinical research studies on the properties of yucca and its effect(s), or lack thereof, on joint inflammation in horses or if it contributes to gastric upset in horses. Due to a general lack of sound clinical research on its efficacy, I wouldn’t recommend its use.


It is always a good idea to have your horse examined by a reputable equine veterinarian to determine the nature of the injury or chronic disease causing the pain. The use of oral or injectable NSAIDs (non-steroidal anti-inflammatory drugs) such as phenylbutazone or ketoprofin may be used short-term to reduce and initially control inflammation in joints. Long-term usage of NSAIDs is not recommended due to potential toxic effects such as stomach ulcers. A veterinarian’s expert opinion should be sought before administering any sort of treatment and compliance with drug use regulations for any type of competition should be maintained if applicable. In any case, care should be taken not to inappropriately or prematurely return a horse to training and/or competition performance levels even if response to treatment is quick and effective at reducing lameness.


This answer was prepared with the help of Emily Lamprecht, Rutgers University, Doctoral Graduate Student in Animal Science.



Can I feed pine nut oil to my horse?


Would it be safe or effective to feed human grade pine nut oil to my horse to help prevent stomach ulcers?



To my knowledge, pine nut oil has not been specifically tested in horses. Since they can digest and utilize virtually all other edible oils tested, I assume it would be safe in limited (no more than a cup or two per day maximum) quantities if it is introduced slowly to the diet.


There has been research on the efficacy of other edible oils to help with equine gastric ulcers—they do not work. Horses' stomachs are very different from humans’. The best nutritional strategies to prevent gastric ulcers are to give as much turnout as possible, provide free access to forages (with some alfalfa, which seems to be somewhat protective due to its high calcium content) and to limit grain as much as possible, avoiding large meals of sweet or other high-starch feeds.


Answer provided by Sarah Ralston, VMD, Ph.D., dACVN, Rutgers University, Equine Science Center.



Can you recommend any supplements for ponies?

I have a question regarding supplements for my daughter's nine-year-old medium pony. The pony has allergies to alfalfa and soy, she will also frequently tie-up. It has been very hard to find a diet and supplements that suit her. She lives on beet pulp and timothy hay. She does get electrolytes daily, and a joint supplement. I have read that horses with her health issues should be on a good multivitamin. Do you agree with that? Is she getting what she needs on this diet, and if not, do you have any suggestions for supplements?

I usually don't recommend feeding a lot of supplements, especially if the horse/pony is on a good balanced diet. Ponies in general usually only require good quality hay balanced with a mineral supplement. If they are exercising regularly they may require a small amount of grain to provide additional energy. But with her soy allergy I would avoid doing that if at all possible. When you start mixing a lot of supplements you risk throwing your horse/pony's diet out of balance.


In terms of the tying-up I would make sure that the beet pulp you are feeding has no molasses in it. Horses that suffer from tying up need as few sugars in the diet as possible. If horses need extra energy it should be provided as fat instead of carbohydrates. In this situation I would also recommend a vitamin E supplement without selenium. This vitamin is found in very low levels in most grass hay and if she is not on grass at all it might be part of the tying up problem. You can feed up to about 2,500 IU/day for a pony. Horses can get about 5,000 IU/day. Read the supplement label to see how many IU are in an ounce or scoop. Make sure it is a pure E supplement and doesn't have loads of other products in it (especially selenium).


As for the electrolytes, they are only needed when she is sweating profusely, for example, after intense exercise or on a day with 100-degree temperatures. Daily supplementation of electrolytes is of no benefit and may throw off the natural electrolyte balance. The joint supplement could be helpful if she is suffering from a joint problem, however, not all horses will respond the same way. These supplements are not used as a preventative measure for future joint problems.


My final recommendation is this: back down on the electrolytes and check your joint supplement to see if it is necessary. If so, give only a pure supplement (only glucosamine, chondroitin sulfate, or MSM; it may have some magnesium or vitamin C) along with a multivitamin formulated for horses/ponies. Check the vitamin E content of this supplement as well. Most don't have more than 100 IU/scoop, so I would still recommend the straight E supplement. However, if all your supplements have additional or superfluous ingredients, you may be overdoing vitamins and minerals unnecessarily and I would not give the multivitamin.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.


How much psyllium is good to feed horses with insulin resistance?

I have been advised by my veterinarian to feed psyllium to my horse to help remove sand in his gut and treat insulin resistance. He will not eat any of the psyllium supplements available, except the one with lots of sugar. I would like to try 100% organic psyllium husk. This horse has a history of choke due to bolting feed which we solved by wetting his feed. He eats a mash of timothy hay pellets and a ration balancer. If psyllium is okay for this horse, and do I give it every day? Is there a difference in the amount given for sand and treating insulin resistance? If psyllium is not appropriate for this horse, is there any supplement to help with sand removal and insulin resistance?

The dose of psyllium that is reported to help with insulin resistance is less than 1/5 of that used for sand clearance (90 g daily versus 500 g for a week for a 500 kg horse). See the research reference: Moreau et al, Journal of Equine Veterinary Science, Volume 31, Issue 4, Pages 160-165, April 2011. If your horse will eat the organic psyllium husk, you can certainly try it, but be aware that the actual efficacy of psyllium in clearing sand from the gastrointestinal system of horses is somewhat debatable.


The best treatment for both conditions is to feed grass hay in feeders that are on platforms or mats that are kept clean. This way the horses are not getting high grain rations or scrounging for morsels on the sandy ground. Ideally the hay should be fed free choice, but if your horse is overweight, feed whatever hay it is allotted (should be 1.5 to 2.0% of body weight), divided into at least three, but preferably four, separate feedings.



Is it okay to feed rice bran in the winter?

Is it okay to feed my healthy four-year old mare rice bran pellets during the winter months? I also feed her rolled oats and grass hay. The mare is starting to lose weight and I am just not sure what she should be eating during the winter.



Assuming your horse is already getting free choice hay, rice bran is a great fat supplement because horses rarely reject it. Rice bran is also high in calories and fiber. Many horses do lose condition in the winter and need extra energy to maintain their ideal body weight. Adding rice bran will increase the calorie content in the feed and will create more energy for weight gain without the effect of a high-sugar diet (hyperactivity). Your horse could probably get about one-to-two pounds per day (based on a 1000 pound horse), but it is best to follow the recommendation on the bag since various products differ somewhat. “Stabilized” rice bran is fortified with a higher level of calcium. Natural rice bran is typically low in this mineral while being very high in phosphorus. Remember, one needs to be careful when adding fat to the diet. It needs to be introduced slowly. For example, start with about ¼ lb and increase the amount slowly over the course of one-to-two weeks. This is the standard time for any change in feed.


Try this for a few weeks to one month and monitor the body condition. As with any horse, one should not be able to see its ribs, but should be able to easily feel them when running a hand down its side. The top line (withers and loin area) should have fat cover without bulging or rippling. If your mare is not on free access to hay, increase hay intake before going to the more expensive supplements.




What nutrients are best for strengthening hooves?

My daughter’s gelding Thoroughbred (10 years-old) has relatively delicate hooves. In fact, he had to use glue-on shoes while we were correcting some farrier trimming mistakes, and aluminum shoes were used for a while as a transition. Fortunately, he’s back to wearing normal shoes, but his hooves aren’t very strong. What ingredients should we be looking for in feed supplements, and are there any special (external) treatments that would be helpful in toughening up his hooves? Is there any correlation between hoof color and strength? I was once told that white hooves were always a problem.


This is one of my favorite questions! I will answer your last question first. I have asked more farriers and vets than I can count what the correlation is between white hooves and problems. There is no correlation. A lot of people think that there is, but it has never been proven to be true. As for internal supplements to help hoof growth, I can recommend four different ingredients:

  • Biotin is a B vitamin that helps to activate production of keratin, which is the major component of the hoof.
  • Iodine is essential for thyroid hormones that help develop all body tissues, including hoof tissue.
  • Methionine is responsible for helping with the production of keratin.
  • Zinc contributes to the health of the hoof and reactions in controlling metabolism.

Each of these ingredients has been studied as to its most effective dose. It is advisable to look at supplement labels when purchasing hoof supplements because many supplements do not contain the appropriate amounts. Biotin should at 20 mg/day, iodine should be 1 mg/day and zinc should be between 175 and 250 mg/day. Amounts for methionine are unknown in terms of hoof health. Just be careful if you are already adding supplements to the diet that contain these products. Excessive iodine and methionine could cause more problems than going without the supplement altogether. You should choose a supplement that is most important to your horse if you have more than one with these ingredients.


Another caution with feeding hoof supplements is that while they are proven to help horses with problem hooves, they have never been shown to improve hooves that are not in need of extra help. Also these supplements take a long time to show any benefits. Hooves grow from the coronet band down, which takes about 1 year to grow from the top until it is trimmed off at the bottom. So give these supplements at least six months to see if they are making an impact on the quality on the hoof as it grows. Some studies have also shown that horses on a good balanced diet are getting just as many benefits as with an added hoof supplement, but that will depend on the horse and the hoof problem. Higher fat diets have also been shown to help with hoof condition as well (if at least 10% fat).


As for any topical solution for hoof strength, any farrier you ask will tell you something different, but the one that most will usually tell you works is venice turpentine. Venice turpentine is a viscous resin from the European Larch, a pine tree. It is used for lithographic work, as a sealing wax, and in varnishes. Horsemen have used it for years as a salve for cuts and as a hoof dressing. The stuff is very sticky, and messy, and applied to the bottom of the hoof, but for horses with thin soles or helping hooves strengthen after an abscess, this seems to work. Many hoof hardener products will include this in their list of ingredients. In most instances an iodine solution will also work if you coat the bottom of the hoof. A lot of the hoof conditioners out there will just put a shinny coat on the hoof and are not really doing much good otherwise. You can apply both of these products as necessary, but usually weekly works unless the conditions are very wet where he is stabled, than daily might be more appropriate.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



What does sulfur and copper supplementation do for a horse? Are there toxic effects?

What would adding sulfur (in a yellow powder form) and bluestone (copper sulfate) to a horse’s diet do? What are the beneficial effects? Do these supplements have any adverse effects? Also, can you indicate if there is a known amount of recommended supplementation, or known toxicity rate for either of these components?


Copper sulfate can be used as a supplement to provide the trace mineral copper to horses. Copper is a necessary component of the equine diet. It is needed for enzymes that structure collagen for connective tissue, cartilage, and bone. Copper can be found in many tissues in the body, specifically the liver, brain, heart, kidneys, the pigmented part of the eye, and the hair. Important functions of copper include red blood cell formation, bone formation, and hair pigmentation. Copper is also important in the hoof health of horses.


The current National Research Council (NRC) equine copper requirement is 10 parts per million (ppm) for horses of all ages, although that requirement is raised slightly for growing or pregnant horses. This being said, horses can tolerate a dose of up to 800 ppm without adverse effects, but above this amount could be unsafe.


The greatest concern with horses is not copper toxicity, but rather copper deficiency. Copper deficiencies can be seen clearly in the wool of sheep, although in horses the deficiency is not so easily visualized. Some signs of equine copper deficiency include a loss of black pigment in the hair, causing a brown “spectacled” appearance of the hair around the eyes, and a coarse hair quality. A horse with a copper deficiency has a tendency to arterially rupture and develop chronic anemia. In addition, copper deficiency in the horse results in bone abnormalities. The cartilage matrix fails to mineralize properly, so the cortex of long bones will be thin, leaving them more likely to be brittle and easily breakable.


Inorganic sulfur (in forms such as a yellow powder) has not been shown to be essential, although organic sulfur (in forms such as sulfur-containing amino acids found in organic protein sources) is necessary to the equine diet. It is necessary for synthesizing cartilage and other organic components in the body, as well as being an essential component in blood clotting.


Equine sulfur requirements have not been established, but the NRC states that .15% of the diet is adequate. Sulfur toxicity is not a major concern in horses. Excesses of all amino acids cause anorexia and growth depression, but this is not necessarily a concern relating to organic sulfur in particular. Elemental sulfur is actually viewed as one of the least toxic elements.


Sulfur is usually available in the horse’s forage, however if this is not the case there may be a need for a very small amount of sulfur supplementation in the diet. This should occur in the form of an organic source to ensure that the sulfur is absorbed and utilized most effectively. Interestingly, sulfur combined with molybdenum can interfere with copper absorption, causing either copper toxicity or deficiency. A horse that has a high intake of sulfur from any source is at a risk of a copper deficiency. If the sulfur amounts in the diet are below 2200 parts per million (ppm) toxicity will not be a concern.


This answer was prepared with the help of Diana Malyshko, Animal Science Research Student at the School of Environmental and Biological Sciences, Rutgers University.



How much is too much Vitamin A and D?

I show cutting horses that are under a heavy workload (worked 5-6 times a week). What is the daily recommended requirement of vitamins A & D for this performance level? I use a supplement that has a guaranteed analysis of 62,500 IU vitamin A and 12,500 IU vitamin D per 10 oz serving (10 oz. per day) for my show horses which weigh around 1100 lbs. I also feed 7.5 lbs/day of a feed with 3,000 IU/lb of vitamin A and 670 IU/d of vitamin D. With the combination of the two, is there a potential toxicity level of vitamins A & D? How much is too much of each vitamin?


An 1100 lb horse under heavy exercise requires 22,500 IU of vitamin A and 3300 IU of vitamin D per day, which is significantly below what your horses are receiving in the supplement alone. The upper safe limit reported by the National Research Council’s nutrient requirements for horses for vitamin D is 44 IU/kg of body weight per day; or for the 1100 lb horse about 22,000 IU/d.
The level for vitamin A is 16,000 IU/kg of diet intake, or roughly 160,000 IU/d. Since the concentrate you feed has 3,000 IU of vitamin A per lb and 670 IU of vitamin D per lb, your horse is getting 22,500 IU/d of vitamin A and 5,025 IU/d of vitamin D from the feed alone. This is not taking into account any of the forage sources your horses eat, including pasture and hay which are typically excellent sources of vitamin A. If your horses are in the sunlight for at least 3 to 4 hours a day they do not need a dietary source of vitamin D since they can synthesize it in the body. It is not necessary to use supplements as an A or D source, especially if your horses have access to fresh pasture and sunlight. With that being said, you are still lower than the upper safe limit; keep this in mind if you decide to add another supplement to the diet. It is best to not purchase several supplements that have the same nutrients in them. It is good that you are taking the proactive approach to find out if there is a problem.



Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



My horse is on a high Vitamin E supplement and has high blood levels of E; is
this a problem?


My horse is a 15-year-old Quarter Horse gelding that is used for English riding and light jumping. About a year ago he had muscle soreness, stiffness, poor performance under saddle, and difficulty with his hind legs while being shod. He was looked at by a vet using Nuclear Scintigraphy, with no significant findings. He has also tested negative for Lyme disease on multiple occasions.


We recently tested him for levels of vitamins E, A and Selenium. The results showed an elevated E level, a low A level, and a selenium level within normal range.


We made some adjustments to his saddle and initiated a high fat diet with a high vitamin E supplement. The horse is currently doing extremely well, looks very good clinically, and has substantially improved with his hind legs. However, we are concerned regarding the high E level. Should we specifically supplement this horse with vitamin A?


It all depends on what level of E you are giving. I usually recommend that horses with muscle problems be given a 5000 IU/day supplement of E. (Watch that selenium is not increased this much as well.) Studies have shown that groups of horses given vitamin E supplements of 10,000 IU/d had decreased beta-carotene levels compared to groups of horses given a lower (5000 IU/d) dose and control groups (not given a supplement). The levels of beta-carotene were not shown to be deficient (as no deficiency level has been determined), but they could eventually affect vitamin A levels.


I would try to see if your horse could go with 5000 IU/d and still maintain his soundness without muscle problems. If your horse needs 10,000 IU/d of vitamin E, I recommend making sure he consumes good quality pasture or gets a beta-carotene or vitamin A supplement.


I would also consider asking your vet to take a muscle biopsy and test for Polysaccharide Storage Myopathy (PSSM). It sounds like he might have a mild case since he responded so well to the high fat and high E supplementation.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



Can a horse get enough vitamins from an apple or carrot a day?


Do you feel that feeding a horse a carrot or apple a day will provide it with enough vitamins?




A general multi-vitamin and mineral supplement for horses or plenty of fresh pasture grass would be better than a daily carrot or apple. The reason for this is because the concentration of vitamins and minerals that horses need in their diet is much greater than what can be provided in 1 carrot or apple per day. Plus, these natural sources are not balanced for a horse where most commercial companies specifically formulate their products for the needs of a horse. With this being said, if a horse is on good quality forage (i.e. hay or pasture) there is typically not a need for other supplements as they get most of what they need from green leafy forages. That is their source of vegetables!


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



The material provided on this site is for educational purposes only and is not intended to diagnose, prevent, or treat any illness. Any recommendations are not intended to replace the advice of your veterinarian. Any products mentioned are not intended to diagnose, treat, cure, or prevent disease. Mention or display of a trademark, proprietary product, or firm in text or figures does not constitute an endorsement by the Equine Science Center or Rutgers University and does not imply approval to the exclusion of other suitable products or firms.







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