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Equine Nutrition

Equine Nutrition

  1. I have an older horse who been showing winter/ cold stress for the past 2.5 winters. The symptom which appears is in the form of intermittent diarrhea, especially occurring when there are ‘cold’ temperature changes; he does have ‘normal manure’ besides this diarrhea throughout the day and if the temperature rises, he doesn’t have any diarrhea! I have been working with my Veterinarian and a Nutritionist. The horse has a good appetite, is not lethargic nor has a temperature, has been maintaining his weight and has continued to perform with as much energy as he does during warmer weather; plus he seems quite content and happy except when he is actually having the diarrhea! He is a 23 yrs old 17.2 hand Holsteiner and Is still happily working in Dressage. Because of the above, neither the Nutritionists, nor the Veterinarian feel this horse displays the signs of having ulcers - stomach or lower intestinal. The question I would like to ask is: Is there any research or helpful information for older horses who become stressed due to temperature changes (display a lack of water absorption in their Lower GIL tract)? Additional Information: We are feeding this horse a senior feed, rice bran and wet hay pellets and plenty of hay. We have tried everything from PeptoBismol, to whole Organic Bananas (with their skins), Prebiotic - ‘Cellminax’ and Probiotics such as ‘Certillus’; We have also tried - Succeed, Proviable, Equiotic..nothing has stopped or prevented the diarrhea that occurs when the temperature drops! (View Answer)

    I commend you for your diligence – your horse is lucky to have such a conscientious owner! I also commend you for working closely with your veterinarian and an equine nutritionist to rule out common causes of loose stool in horses as well as to systematically experiment with a variety of nutritional solutions. If you haven’t already gotten a second opinion from a specialist, that is, a veterinarian who is board-certified in the American College of Veterinary Internal Medicine or ACVIM, then this would be my next step. “Internists” love the challenge of mystery ailments such as you describe and also have access to the latest research.

    It’s noteworthy that your horse developed this condition around when he turned 20; we know that as horses age, some of their body systems (such as digestive) become less efficient, even fragile. In the case of the digestive system, it’s not just the horse’s own tissues that are less resilient, experts believe the “microbiome” or population of bacteria, fungi, and protozoa that live and work in your horse’s gastro-intestinal (GI) also becomes less hardy. So in theory, it’s possible the microbiome is being affected by the cold weather or your horse’s reaction to it. Two things come to mind: 1) provide PREbiotics such as fructooligosaccharies, mannanoligosaccharides, psyllium, etc so that the existing microorganisms in your horse’s gut remain healthy and happy despite external and internal fluctuations, and 2) consider transfaunation to naturally resupply the “good bugs” or microflora to your horse’s intestines. This means taking the manure of a healthy horse, filtering it, then putting this material into your horse’s stomach through a nasogastric tube (like is passed during a colic episode).

    The specialist in internal medicine will have other ideas for treatment after additional diagnostic work. I would be curious what this veterinarian recommends! Lydia Gray, DVM, MA, SmartPak Equine

  2. Beet pulp (unmolassed/unsweetened) for IR horses, yes or no? I'm getting conflicting information depending on who provides the answer: beet pulp manufacturers, commercially-processed horse feed companies, or holistic/homeopathic experts. Some say the sugar content is low enough to be safe for EMS horses and others say there will always be residual sugar so it's not recommended. Who do I trust? (View Answer)

    There’s a long story and a short story. The short story is that all versions of beet pulp range from 10 to 12% sugars and starches. This is at/below the level of simple carbohydrates that most experts recommend for IR horses.

    The long story is that, opposite to what you might think, dried shredded beet pulp WITH ADDED MOLASSES actually has less sugars and starches than dried plain shredded beet pulp. That is, the molasses-added beet pulp averages about 10% simple carbs while the molasses free beet pulp contains more like 12% Turns out that during processing of both types of beet pulp, molasses is added back as a dust control measure but at lower levels.

    To really understand the impact of beet pulp to your horse’s diet though, you must calculate out the sugars and starches into grams and not think of them in terms of percents. That’s because a horse may eat 20 pounds of a 10% total sugar/starch hay but only 1 pound of a 10% sugar/starch beet pulp. Here’s how that looks multiplied through so you can see for yourself the total amount your horse would be getting from each feedstuff:

    10% of 20 pounds of hay = 2 pounds or just under 1 kilogram (0.9kg or 900 grams) of sugar

    10% of 1 pound of beet pulp = 0.1 pound or 0.04kg which is 40 grams of sugar

    Because horses get so much less beet pulp by weight, they are also getting much less sugars and starches. However, if you have a particularly sensitive individual, by all means soak the beet pulp for at least an hour (you’re probably soaking it anyway) then rinse and drain to remove even more of its sugar and starch content. Lydia Gray, DVM, MA, SmartPak Equine

  3. I live in an area where the soil is selenium and magnesium deficient. They are fed grass hay and all receive a ration of senior feed. What would be a good source of supplements that can address the lack of selenium and magnesium What are the daily requirements I should be looking for. Horses range in age of 14 to 30. (View Answer)

    According to the NRC Nutrient Requirements of Horses, an 1100lb adult horse in no work needs 7.5 grams (7,500 milligrams) of the macromineral magnesium a day, with that amount doubling to 15g if the horse is in very heavy exercise. The average size mature horse needs 1mg of the micromineral selenium daily, with even very heavy exercise only modestly increasing the amount to 1.25mg.

    In order to complete and balance the diet of a horse, it is important to know how much of these and other nutrients they are getting from their combined feedstuffs (hay, grain, supplements, etc). The first step is having your forage analyzed – which it sounds like you’ve already done – and the second step is totaling all the amounts to find the areas where the diet is deficient. is an online tool that can easily help you do this, especially since they already have most commercial grains and supplements in their extensive database.

    The third and final step is selecting products that bridge the gaps that you’ve identified. This can be done in a variety of ways, including providing a higher amount of the commercial, fortified grain you are already using; by providing a different commercial, fortified grain; by supplementing with targeted products that provide just magnesium and just selenium, or even by having a company use your feed analysis to custom blend a product just for your horses. Lydia Gray, DVM, MA, SmartPak Equine

  4. What are the best supplements for hooves? How much biotin is needed for strong hooves? (View Answer)

    Studies have shown that continuous dietary supplementation with biotin at a daily dose of 10 to 30mg for not less than 6 to 9 months improves and maintains equine hoof horn quality in horses with less than optimum growth and hardness:

    1. Vet Rec. 1984 Dec 22-29;115(25-26):642-5.
      Clinical observations on the response of equine hoof defects to dietary supplementation with biotin.
      Comben N, Clark RJ, Sutherland DJ.
    2. Equine Vet J. 1995 May;27(3):175-82.
      Hoof horn abnormalities in Lipizzaner horses and the effect of dietary biotin on macroscopic aspects of hoof horn quality.
      Josseck H, Zenker W, Geyer H.

    In horses that do not respond to biotin alone, other nutrients such as the limiting amino acids lysine and methionine, trace minerals such as zinc and copper, and omega 3 and 6 fatty acids may provide additional nutritional support. Lydia Gray, DVM, MA, SmartPak Equine

  5. I have a 10-month-old colt that is being creep fed twice a day and has all the hay he wants, but is getting really thin. He has not been dewormed yet, but will be soon. I don't exercise him anymore except for an occasional walk. Could there be a nutritional deficiency he is missing? He was with a more aggressive colt that would eat his feed, but have since been feeding them separately. Can you provide some suggestions on what I should do to increase his size? (View Answer)

    Separating your colts at feeding time was probably a good idea to ensure that the less-aggressive, thin one is getting his fair share. However, it sounds like it’s time to involve your veterinarian in your overall program to ensure that the nutritional, parasite control and vaccination, exercise, and other components of raising healthy, sound horses are all in order.


    For example, according to the AAEP’s Parasite Control Guidelines, during the first year of life foals should receive a minimum of four dewormings:

    • First deworming: 2-3 months of age
    • Second deworming: 4-6 months of age (just before weaning)
    • Third deworming: 9 months of age
    • Fourth deworming: 12 months of age

    Because your weanlings are behind on the recommended schedule, it is very important to include your vet in their first dewormings, as a heavy burden of internal parasites that are suddenly killed off can have complications such as colic and worse. Parasites may or may not be part of the reason your colt is thin, but they need to get on a good program regardless.


    It’s also a good idea to have your vet thoroughly examine both colts, including performing a body condition score (BCS). Experts agree that growing horses should be maintained at the ideal BCS of 5 – not too thin and not too fat – so that they reach their mature size and weight safely and avoid bone, joint, or other disturbances. Your vet can help you determine their current status, review your feeding program, and make suggestions for what might need to be changed in order to get them back on track safely. For example, it’s possible that the amount or type of hay and grain needs to be adjusted so that you’re meeting the NRC’s requirements for young, growing horses.


    There are some excellent articles on this very website that can get you started on reviewing your nutritional offering and I encourage you to check them out:


    Feeding Young Horses: It’s Not the Protein!

    Help Your Foal Grow with Proper Nutrition

    Foal Growth: Special Care and Nutrition


    Lydia Gray, DVM, MA, SmartPak Equine

  6. What conditions benefit from Vitamin B in horses? (View Answer)

    The Vitamin B family is made up of several compounds that serve many important roles in the body: protein, fat and carbohydrate metabolism; energy production; proper nerve cell transmission; and cell reproduction and division (especially rapidly dividing ones such as red blood cells). B-vitamins include Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid (B5), Pyridoxine (B6), Folic Acid (B9), and Cyanocobalamin (B12). Choline, Biotin, Inositol, and a few others are sometimes referred to as B-vitamins.


    For most of the B-vitamins, microorganisms in the large intestine make all the horse needs. Only Thiamine and Riboflavin have NRC dietary requirements. However, research suggests B-vitamin supplementation may be beneficial to stabled horses with little access to fresh pasture, heavily exercising horses, pregnant and lactating mares, horses with GI conditions that may interfere with normal gut flora, and any periods of stress (injury, illness, shipping, old age, etc.). Lydia Gray, DVM, MA, SmartPak Equine

  7. How do you tell if a colt has ulcers? Can you treat them with better nutrition? (View Answer)

    If you suspect your horse has gastric ulcers, no matter the age, it’s always best to schedule a visit with your veterinarian so that a full physical examination and tests can be performed, leading to an accurate diagnosis. There are several reasons for this:


    1) some signs of ulcers overlap with other, more serious conditions

    2) better to know what you’re dealing with and be managing it correctly than guessing, which could take longer (and wind up costing more in the end!)

    3) knowing the severity of the problem will help your vet formulate the most appropriate treatment and management plan.


    In general, horses demonstrate discomfort from gastric ulcers in three areas: physical signs, personality changes, and performance issues (not really a factor in a colt).


    Physical signs: mild recurrent colic, a lack of energy, weight loss/poor condition, dull hair coat,

    lack of appetite


    Personality signs (again, more common in mature horses): agitation at feeding time, irritability,

    resistance, poor attitude


    Interestingly, young horses may exhibit two signs that mature horses often don’t: teeth grinding or bruxism and dog-sitting.


    If gastric ulcers do turn out to be the culprit, the treatment and management plan will hinge upon how severe your vet determines them to be. It’s possible that in less severe cases, he or she will simply recommend a nutritional approach to support stomach health that includes feed changes and the addition of supplements. However, for higher grades of severity, it’s likely that medications will be prescribed to treat and heal the lesions.  Lydia Gray, DVM, MA, SmartPak Equine

  8. I have a 17-year-old Warmblood with a history if colic surgery and gastric ulcers. He has mildly elevated cortisol levels with no physical signs of Cushing’s disease, but is on pergolide. These levels are soon to be retested. He has bouts of impaction colic, thought to be possible entrapment. The veterinarian thinks he may have hindgut ulcers now. What is the appropriate diet for such a situation? (View Answer)

    I have a 17-year-old warmblood with a history of colic surgery and bouts of colic too! Like yours, mine also has additional medical issues – although not Cushing’s or ulcers – so I definitely understand how challenging finding the most appropriate diet can be.


    I wish I could just lay out, step-by-step, what to feed and why, but with your horse’s history and current issues – some of which have not been definitively diagnosed yet – not only is that impossible but it also might not be the best advice until you really know what is going on.


    To get that diagnosis, I recommend starting with the new recommendations for identifying Cushing’s Disease or PPID (Pituitary Pars Intermedia Dysfunction). The Equine Endocrinology Group chaired by Dr. Nick Franks at Tufts University has recently released updated guidelines:



    Once you know if you are really and truly dealing with Cushing’s or not (and whether pergolide is necessary), then you can move on to diagnosing gastric and/or hindgut ulcers and then treating and managing them, if necessary. This is important because how we feed gastric ulcers is darn near the complete opposite of how we feed hindgut ulcers or right dorsal colitis. That is, we try to keep forage in front of horses with ulcers in their stomachs at all times, while horses with ulcers in their colon need a “rest” from long-stem roughage and may go on a complete pelleted feed temporarily.


    Get that accurate diagnosis then gradually adjust his diet based on the results and soon your warmblood will be on the right track diet-wise! Lydia Gray, DVM, MA, SmartPak Equine