Balanced diet for horses? When there are no nutrient deficiences and balanced ratios so that no one mineral causes another mineral to be deficient for the whole intake. Balanced Equine can provide an optimal, balanced diet for horses based on data, and take into account breed, age, workload, reproductive and health status. Or learn how to do this yourself by enrolling in NRCPlus, the 10 week online course provided by Dr Eleanor Kellon VMD. NRCPlus is accredited for further education for American vets. You don't need to be a vet to benefit enormously from Dr Kellon's courses. Horse owners from all around the world enrol in NRCPlus. A balanced diet for horses is an intake that has more than adequate nutrient levels with all the minerals in the right proportions. A balanced diet for horses can solve a lot of problems you may be dealing with. All the following can be symptoms of a nutrient deficient or imbalanced diet: Dull or sunbleached coats or a rust look in dark manes. Poor immune system unable to deal well with infections like greasy heel/mud fever, rain scald, weeping eyes Poor hoof quality, slow growth rate, hoof cracks 'Big head' if your horse is on Kikuyu or Setaria or other oxalate grasses Topline and general muscle building issues Muscle and nerve issues/twitching/overly sensitive behaviours Your horse may fatigue easily when asked to perform That feeling that your horse is simply 'not right' A horse with too much energy, easily over excited Diarrhoea issues or grass/hay bellies Fertility issues in stallions and mares Joint/limb issues in a developing foetus or foal Osteochondritis Dissecans (OCD) The basic nutritional management for horses should be the same, whether you have a much loved member of the family in the back paddock or are feeding a horse to win an endurance ride, a competitive trail ride, or the Melbourne Cup. The ultimate goal in feeding should be to have a healthy horse able to perform at the best of their ability at their level of fitness and conditioning with a robust immune system. A balanced diet includes all the essential nutrients in the proper proportion and sufficient amounts. Dr. Eleanor Kellon VMD, says "Healthy young to middle-aged adult horses will tolerate a wide range of minimal imbalances with no obvious outward signs, but many of the things we take for granted as 'usual' in horses, such as sun-bleaching, tendon/ligament/joint issues, immune system imbalances, poor fertility, muscle and nerve problems, bone problems can all have a nutritional component. All problems are a combination of genetics and outside influences. The list of outside influences is huge, but worth investigating since it's in our control. Horses on pasture, not under any stress, may show no outward signs at all of mineral deficiencies - until their immune system is stressed, they become ill or have an injury." Feeding horses properly is an art and a science. Working out the best diet for your horse or horses from the enormous and confusing array of commercial feeds and supplements, or from more than 100 basic feed ingredients listed in the 2007 'Nutrient Requirements of Horses' from the National Research Council (NRC) can be overwhelming. There are so many products on the market for a huge spectrum of issues that you could easily over supplement, especially performance horses by concerned horse owners. This is not in the best interests of your horses. Burt Staniar, PhD, assistant professor of equine nutrition at the Pennsylvannia State University USA, says "Not only must we supply proper amounts of certain minerals and protein a certain horse requires, but also be aware of energy in the diet and how it affects the horse's metabolism. We must understand how the way we feed horses affects growth, maintenance and performance." The easiest and best way to know what your horse's intake is deficient in, or what is excessive and out of balance to achieve true balance, is to test the forage, what your horses eat. It's not an exact science but the best approach we have in terms of accuracy. Other methods have been suggested as viable for working out what is deficient in the intake, what is in excess and what needs to be supplemented. The following are not designed for this, the following links will take you to more information: Hair testing Blood testing Soil testing
The art and science of feeding horses can be a big learning curve. A growing number of horse owners are looking for an evidence based feeding approach, rather than blind guessing.Data is the key. A science trained, evidence based independent equine nutritionist can help or consider enrolling in the online NRCPlus course provided by Dr Eleanor Kellon VMD. The basic nutritional management for horses should be the same, whether you have a much loved member of the family in the back paddock or are feeding a horse to win an eventing competition, an endurance ride or the Melbourne Cup. The foundation of any diet should be high fibre forage; pasture and/or hay. The ultimate goal in feeding should be to have a healthy horse able to perform at the best of their ability at their level of fitness and conditioning with a robust immune system. All horses, regardless of the level of work or whether they are breeding will benefit from a diet which meets their nutrient requirements and balanced minerals. Above photo is of Twilight Spirit, known as Ebony, STB owned by Belinda Martin. Ebony is glowing with the addition of mineral supplementation. Working out the best diet for your horse or horses from the enormous and confusing array of commercial feeds and supplements, or from more than 100 basic feed ingredients can be overwhelming. There are so many products on the market for a huge spectrum of issues that you could easily over supplement, especially performance horses. This is not in the horse’s best interests or for that matter, the horse owner’s wallet! In this case, an independent equine nutritionist may be a worthwhile investment in the health and well being of the horse. Equine nutritionists have the education and experience to know what the best combination of feeds is for each individual horse’s situation whether a high performance horse or a high needs mare with a foal or your ‘best buddy’ in the paddock. The advantage an independent equine nutritionist offers is that their choice of feeds and supplements is not restricted to the product line sold by an employer. Instead the independent nutritionist can recommend a diet that is best suited for the horse, whether in work or not or breeding. Would you like to learn more or prefer a video? Back in 2017 I put together an 18 minute video to try and cover some of the key points. I edited out all my intakes of breath so try and keep up :) Mineral Balance Dr. Eleanor Kellon VMD, a leader in the field of applications of nutraceuticals for horses in the US, says "Healthy young to middle-aged adult horses will tolerate a wide range of minimal imbalances with no obvious outward signs, but many of the things we take for granted as 'usual' in horses, such as sun-bleaching, tendon/ligament/joint issues, immune system imbalances, poor fertility, muscle and nerve problems, bone problems can all have a nutritional component. All problems are a combination of genetics and outside influences. The list of outside influences is huge, but worth investigating since it's in our control. Horses on pasture, not under any stress, may show no outward signs at all of mineral deficiencies - until their immune system is stressed, they become ill or have an injury." Although the foundation of any diet should be high fibre forage; pasture and/or hay, it is important that the mineral balance is also taken into consideration. An equine nutritionist can help ensure that the mineral ratios are at their optimum, to lessen the likelihood of a mineral imbalance when too much of one mineral is interfering or blocking the absorption of another. For example, a high calcium intake compared to phosphorus has been shown to depress the digestibility of phosphorus. Low calcium compared to phosphorus can depress calcium uptake. This can lead to ‘big head’ disease called Osteodystrophia fibrosa, a deformity of the facial bones. Trace minerals like copper, zinc, iron and manganese are required in very small amounts but that doesn't take away their importance in the running of cellular processes in the body. On the other hand, more is definitely not better when it comes to some nutrients as the horse has to get rid of the excess. Excessive zinc will interfere with the absorption of copper causing a. secondary copper deficiency. This occurs despite adequate copper in the diet. In a study on growing foals zinc intakes between 1000 and 2000 mg/kg without also increasing copper intake caused copper deficiency symptoms of joint swelling, lameness, joint effusions and cartilage defects. A low copper intake compared to high zinc has also been implicated with Osteochondritis Dissecans (OCD) in growing horses, a type of Developmental Orthopaedic Disease (DOD) that includes symptoms like limb deformities and vertebral malformations. What to look for in an equine nutritionist? Ensure they can help with designing a feeding plan based on the whole diet, not just the hard feeds and supplements that may be fed, if any, but also the foundation of the diet; the grass and/or hay. They will assist you with the best procedure for collecting a sample of pasture for analysis at a laboratory set up for analysing feed for horses, not just ruminants like cows. A pasture test that includes the main nutrients and minerals can cost as little as $35USD. If hay is the main forage then the best option is to get it tested for nutrient levels. This is the best option for people who can store large quantities of hay or able to source the hay from the same farmer but for a lot of people the hay can come from different areas so the next best option it to use average figures for the different types and grades of hay. Testing pasture or hay is the easiest and most accurate method for working out how much of those nutrients are being eaten by a horse. Lastly, ensure that the chosen equine nutritionist can devise a feeding plan with the minerals optimally balanced for the whole diet. With the introduction of a mineral balanced diet niggling problems like muscle soreness, coat bleaching, greasy heel and skin conditions like rain scald are more likely to become a thing of the past, because a mineral balanced diet with sufficient nutrient intake equals a strong immune system. Carol Layton B.Sc M.Ed, an independent equine nutritionist can help with a feeding plan based on the NRC 2007 Nutrient Requirements for Horses and Dr Eleanor Kellon's recommendations. Article originally published in the October - November 2009 issue of Hoofbeats magazine (Vol 31 No 3), updated since.
Mineral interactions matter. Why does it matter if zinc is excessive in the diet or too little compared to copper? Or if there isn't enough calcium relative to phosphorus? Trace minerals like copper, zinc, iron and manganese are required in very small amounts but that doesn't take away their importance in the running of cellular processes in the body. On the other hand, more is definitely not better when it comes to nutrients as excessive amounts of some minerals will create problems by interfering with other minerals. For example, the 2007 Nutrient Requirements of Horses from the National Research Council (NRC) has set the requirements per day for a 500 kg mature horse in light work at 100 mg for copper and 400 mg for zinc. That is per day, many pastures and mixed feeds provide far less than this in copper and usually zinc. However, it is not just the total amount per day that counts, the ratio of copper to zinc counts just as much if not more. The recommendation is to feed copper to zinc ideally at the ratio of 1:3. So if your horse is getting 600 mg of zinc per day in his diet then the copper amount ideally should be boosted to 200 mg. Why is this necessary? Because in many cases minerals compete with each other. Some examples - Too much zinc can interfere with copper, causing copper deficiency symptoms and too much copper can cause zinc deficiency Too much copper can interfere with selenium absorption; this has been shown in studies with other animals Sulfur can prevent copper absorption; shown in cattle studies Molybdenum can prevent copper absorption High iron intake is known to reduce zinc levels Too much phosphorus will inhibit calcium absorption Too much calcium will inhibit phosphorus absorption Too much manganese interferes with phosphorus absorption Too much manganese has been suggested to cause intestinal mineral competition in other species In other animals, it has been shown that excessive levels of nutrients can interfere with selenium absorption. Furthermore, adverse mineral interactions can lead to: Too little calcium will cause a horse to get 'big head disease' called Osteodystrophia fibrosa, a deformity of the facial bones caused by calcium loss. Other signs before the 'big head' symptom may show up include intermittent lameness, loose teeth, stunted growth in youngsters, ruptured tendons and increased chances of fractures. If the horse has the swollen facial bones then he may well have trouble swallowing and chewing and obstruction of the nasal passages. Not a happy camper. When there is too little calcium in the diet the parathyroid gland releases parathyroid hormone. Since the blood calcium level is tightly regulated, this hormone dissolves the calcium in the bones so it can go into the blood to keep blood calcium levels at the correct level for heart and muscle function. The facial bones are replaced with fibrous tissue which appears swollen compared to bone. High phosphorus intakes significantly depress calcium absorption. Insufficient amounts of magnesium can cause irritability, twitching, spasm and hypersensitivity. Many calming supplements contain magnesium which explains why they can help. However, they are often expensive and contain other ingredients you don't always need. Magnesium can be supplemented in a more cost effective way than this. Excessive calcium will also cause irritability, twitching, spasm and hypersensitivity. That is because the calcium:magnesium ratio is too high and extra magnesium will help. But if your horse is already getting too much calcium in his diet it may be better to change his feed to reduce the calcium. This will effectively lower the calcium:magnesium ratio. Inadequate copper can cause anaemia. This condition is often misdiagnosed as a iron deficiency, iron metabolism requires copper containing enzymes so if there is a lack of copper then one of the results is less haemoglobin in the blood. Inadequate copper and/or zinc will produce faded coats on horses, known as 'sunbleaching'. If your horse has a dull or washed out coat then insufficient copper in the case of buckskins and chestnuts is most likely the reason and in the case of black, brown and grey horses, copper and zinc is needed for pigment production. A lot of people will rug their horses to stop the 'sunbleaching' but I prefer to see what mineral deficiencies are present and correct them in the right proportions. To provide an optimised diet to your horse all the major minerals (calcium, phosphorus and magnesium) and trace minerals (iron, copper, zinc and manganese) need to be in balance. And it is easier than you may think. Balanced Equine provides a balanced diet and the 'recipe' for making your own custom mineral supplement. Easy to make and the ingredients are not expensive. You can learn how to balance your horse's intake by enrolling in NRCPlus with Dr Eleanor Kellon VMD. Frequently Asked Questions (FAQ) Q. Why can't I just put out a mineral block and let the horses eat what they need?A. I wish it could be that simple. For a start, many horse owners believe that horses 'self medicate' to mean that a horse will eat what he needs, when he needs it and in the right amount. If that was the case then horses would never eat tasty poisonous plants like Croften Weed and dietary laminitis wouldn't exist unless the horse had no choice but to eat high sugar + starch feed. Horses love tasty feed just like us, wild horses get chronic laminitis too if they have access to high sugar + starch grasses in spring. If it appeals at the time they will eat what you offer. The problem with mineral blocks is that horses will only take what appeals to them, not the amount they would need and some horses won't touch them at all. Mineral blocks usually contain molasses or similar to make them palatable so some horses will over do it. However, it is better than not providing any minerals at all but it won't be an optimal balanced diet. Q. I like to feed 'Product X' mineral supplement, my horse has improved on this supplementation. Can I continue feeding it?A. If you would like to continue feeding a commercial supplement then that is fine as I can devise a custom mineral mix that will balance all the the pasture/hay + supplement to ensure that your horse is not deficient in any nutrient and the nutrients are in the right proportions to each other to avoid adverse mineral interactions. A lot of people stop buying the commercial supplement once they have learnt to mix and feed their own custom mineral mix. Commercial mineral mixes are usually very expensive and contain nutrients that your horse doesn't need, all of which has to be excreted. Pasture or hay is always an excellent source for most of the nutrients so it is only the ones that are deficient and need balancing that would be in your custom mineral mix. What I like to do in this case is to provide the recipe for the custom mineral mix with the commercial supplement and a recipe without the commercial supplement in case you decide later to stop buying the supplement. Top of the page is a set of photos sent to me by Melinda Windle who was delighted to see the change in her liver chestnut Chester. Further reading Links may change over time. If a link doesn’t work, search the title in your search engine. Dr Eleanor Kellon VMD offers equine nutrition courses, start with NRCPlushttp://drkellon.com Dr Eleanor Kellon Balancers Can't Balancehttps://drkhorsesense.wordpress.com/2014/10/03/balancers-cant-balance/
Minerals and coat bleaching have a direct link. If you want your horse to look his best you don't need to rug to stop bleaching or fading. A dull and faded coat isn’t a good look for any horse, especially in the show ring or a competitive performance horse. Other suggestions are to keep the horse indoors during the day, paint the horse with products or use a high fat ingredient in the diet to give the horse a shiny sheen but none of these suggestions deal with the actual cause. A diet containing the correct balance of minerals can remedy a dull faded or sunbleached coat and achieve the horse's optimum colour, according to its genes. A sun bleached or dull coat is a classic sign of mineral deficiency and the way to correct this is to put the horse on a more than adequate nutrient and mineral balanced diet. All horses have a requirement for carbohydrates, protein, a small amount of fat, vitamins and minerals and water to stay healthy. Equine nutritionists use the ‘Nutrient Requirements of Horses’, published in 2007 by the National Research Council (NRC) to calculate needs for horses. Lactating mares have the highest needs. Growing horses require less total feed but a higher concentration of minerals compared to mature horses. The greater the body weight or workload, the greater the requirements for protein and minerals. This is why the same diet (pasture and supplementary feed) can appear to support one horse but not another if one is heavier or is on a higher workload despite both horses having a good body condition score. The same can apply to a horse that has his workload increase. The diet may appear to support the horse quite well at the lower workload but signs of mineral deficiency may be expressed at the higher workload. Coat colour Horses most affected by sun bleaching are the darker colours like black and bays but it also affects chestnuts, buckskins and to a lesser extent greys. Some breeds are more affected than others; Friesians for example don’t bleach as much. They may be less prone to it because they genetically produce higher concentrations of very dark, protective melanin. Even if they are producing less than normal it's still more than most other horses. It must be said that horses are individuals so two bay horses of the same weight and breed on the same diet and workload may have one exhibiting a more bleached coat. Both will still have the same mineral deficiency. Melanin Coat pigmentation is determined by the presence, absence or relative proportions of the melanin pigments eumelanin (brown and black) and phaeomelanin (a reddish or yellowish brown). The melanins are relatively large, light absorbing biopolymers that occur in various similar forms. Eumelanin is either brown or black in colour, but is thought to always be black in horses. Melanins are raw materials which include chemicals called indoles along with other products derived from the oxidation of an amino acid called L-tyrosine – which occurs in plants and animals including micro organisms and humans. The resulting copper dependent enzyme, tyrosinase, is then involved in melanin production. Interestingly, the lack of tyrosinase is responsible for albinism in various mammals including humans, and is related to grey hair in humans. True albinism, however, has not been identified in horses. Copper and zinc A copper dependent enzyme called tyrosinase is responsible for the production of melanin, brownish black pigments synthesised from the amino acid tyrosine. This occurs in plants and animals including micro organisms and us. The lack of tyrosinase activity is responsible for albinism and is related to grey hair in us. Sufficient copper is needed to produce the pigment in buckskins and chestnuts and both copper and zinc are needed for black/brown/grey coats. The purpose of the pigments is to act as a shield against light. The fading is caused by ultraviolet light oxidising the pigments. If there are less than optimal levels in the diet, the hair will be more prone to bleaching but will look normal until enough pigment has been damaged to cause the colour change. That’s why a newly grown winter coat will appear darker but then lightens over time if the horse is copper and zinc deficient. If your horse is on a more than adequate nutrient and mineral balanced diet, there is no need for rugging or worse, being kept indoors. Copper deficiency in other species influences coat quality and produces ‘rusting’ of dark coats, this is especially noticeable in the manes of bays and black horses. This effect in horses has not been formally proven, but horses showing red tips on dark manes of dark coats respond well to copper and zinc supplementation. It’s not enough to simply ensure sufficient levels of copper and zinc in the diet, the balance between the two must also be considered as too much zinc in the diet has been shown to interfere with copper uptake. This is known as a secondary copper deficiency. Too much copper in the diet is believed to interfere with zinc uptake. Some people add copper sulfate to a feed; this is not good practice without taking into account the copper and zinc intake for the whole diet (pasture plus any additional feeds). The ideal ratio for copper to zinc is 1:3. A secondary copper deficiency can be caused by other factors. High molybdenum and sulphates from grazing on affected pasture is known to interfere with copper intake. Some horse owners add inorganic yellow sulphur to their horses’ feeds. There is a very small requirement for sulphur in a horse’s diet that is easily satisfied by grass or hay, the yellow sulfur obtained from stockfeed suppliers should never be fed to a horse, it can be toxic. A copper deficiency may be obvious with coat colour changes but can be more subtle in other parts of the body. Copper is part of many enzymes responsible for chemical reactions throughout the body. A deficiency can lead to abnormalities in bone, cartilage, tendons and ligaments and has been linked to uterine artery rupture in mares, a fatal complication of labour and with zinc, developmental bone disease in foals. Studies have shown that a high iron intake can interfere with zinc levels causing a secondary zinc deficiency. Since pasture and hay generally have excessive levels of iron, avoid supplements that add more iron to your horse’s diet unless an iron deficiency is confirmed by your vet. A zinc deficiency can cause a raft of issues from skin flaking and poor coat quality to poor fertility, poor hoof quality and ridging, mouth ulcers, mild anaemia (oxidative damage), suboptimal immunity and predisposition to skin infections. It’s worth noting that anaemia due to iron deficiency is extremely rare, more likely caused by a copper deficiency as the production of the oxygen carrying haemoglobin for red blood cells requires a number of crucial copper dependent enzymes. Other nutrients Of course, it’s not just copper and zinc but protein, vitamins and other minerals also need to be part of the balanced diet. Fortunately, the good news is that if your horse is on a high intake forage diet, most of the vitamins will be supplied and won’t need supplementing. An exception is vitamin E if your horse is in work. The motto to remember is that ‘more is not better’. If there is more than adequate protein in your horse’s pasture, supplementing more is not helping your horse at all as it has to be excreted. Keratin Keratin is an extremely strong protein and is the major component in skin, mane and tail, hooves, and teeth as is the case for us with our skin, hair and nails. Keratin is made up of a chain of amino acids with unique properties depending on the sequence; it can be inflexible and hard like hooves or soft as is the case with skin depending on the levels of the various amino acids. Many of the amino acids that are needed for keratin are never deficient; horses can manufacture them from other amino acids. One that has to come from the diet is methionine as it cannot be manufactured by the horse. Methionine has a sulphur bond which has confused some people into thinking that sulphur should be supplemented in the diet. Feeding sulphur doesn’t create more methionine but fortunately methionine is in grass and hay and is unlikely to be deficient unless the horse is on a high grain diet with little forage. Fats in the diet The last consideration should be given to fat in the diet. Many people supplement vegetable oils like canola to add a shine to their horse’s coat. Without taking into account the whole diet, rectifying any deficiencies and balancing the minerals, this simply results in a shiny, mineral deficient horse. Since horses evolved on a low fat intake, less than 6%, is this in the best interests of the horse? Fat is never deficient in the diet if grass is the predominant forage, there is no necessity to supplement more fat unless the horse is on little pasture and hay instead. Grass contains the anti inflammatory omega-3 and pro inflammatory omega-6 fatty acids in a ratio of roughly 4:1. Both are necessary for the immune system. Unfortunately all vegetable oils with the exception of linseed contains very little to no omega-3 and an abundance of omega-6 fatty acids. If your horse is mainly fed hay, he should be supplemented with linseed oil or the ground linseeds as the curing of hay destroys the fragile omega-3 fatty acids. To learn more about linseeds go to this page: Linseed, is it safe? The next time you visit your stockfeed supplier or saddlery, have a look at all the coat, mineral and hoof supplements, the two minerals they will all have in common is copper and zinc. Ask an independent nutritionist to help you have your pasture and/or hay tested and a mineral supplement formulated to correct any nutritional deficiencies and balance the minerals. Let your horse be the colour his genes designed him to be. Article originally published in the August - September 2010 (Vol 32 No 2) issue of Hoofbeats magazine with the title of 'Minerals and Coat Colour', updated since. Further reading: Links may change over time. If a link doesn’t work, search the title in your search engine. Dr Eleanor Kellon VMD offers equine nutrition courses, start with NRCPlushttp://drkellon.com Dr Kellon (2014) Copper and Zinchttps://drkhorsesense.wordpress.com/2014/01/20/copper-and-zinc/ NRC Nutrient Requirements of Horses (2007)https://www.nap.edu/read/11653/chapter/1
Iron overload by Dr Eleanor Kellon VMD Iron is absolutely essential for life. The high affinity of iron for oxygen is what makes it so useful in trapping oxygen in haemoglobin for delivery to the body tissues. Iron is also incorporated in some very reactive enzyme systems. However, iron’s high affinity for oxygen and high reactivity also makes it dangerous. Free, ionised iron will react with peroxide or water in the body, ending in the creation of OH*, hydroxy radicals. OH* damages lipids/fats in cell structures and membranes, in the process generating more radicals to produce a chain reaction of destruction. Iron is absorbed by binding to specific metal transporters in the small intestine, and also passively via the junctions between cells. Work in other species has shown that the volatile fatty acids produced from fibre fermentation enhance iron absorption in the colon. Because the horse is a hind gut fermenter, this likely is a significant source of iron. Iron bound to metal transporters is taken inside the intestinal cells. From there, it may be bound to blood proteins and released, or continue to accumulate and eventually be lost into the manure when the cell dies. By regulating how much iron gets released into the blood, the body has some control. However, the other pathways for absorption cannot be regulated. If you ask any veterinary pathologist they will tell you that finding black, iron loaded livers at necropsy is common in horses. The colour comes from iron deposits called hemosiderin. This is so common it is considered 'normal'. There are reports of iron causing liver disease, even death in foals, but chronic conditions related to iron overload were not recognised in horses. Iron overload in humans is usually caused genetic disorders resulting in over absorption, or diseases that require frequent transfusions. However, overload related to diet is also possible. Liver damage or liver failure does occur, but is a late stage. Earlier symptoms include fatigue, joint pain/arthritis and often metabolic syndrome/insulin resistance. The same syndrome and consequences has been recognised in a variety of animal species, including several birds, black rhinoceros, tapir, lemur, and dolphin. It may also be linked to IR in other old world primates but iron overload has not been studied in them. Iron overload symptoms in horses include coat changes of bleaching and red ends on dark manes and tails, often hoof issues such as laminitis and abscessing. This study linked iron status to insulin resistance (IR) in horses. Other areas for exploration to determine if there is a link with iron status include arthritis, raised liver enzymes and other issues, even Cushing’s disease because the changes seen in the brains of horses with Cushing’s are virtually identical to those seen in human brains with iron overload. There is a discussion of this and suggestions for further research in my Equine Congress paper here. Diagnosis and treatment of iron overload in horses The only way to accurately diagnose iron overload is with the correct blood work. Serum iron alone is not accurate. It reflects iron in the diet but not how much is stored. Transferrin is the protein that carries iron in the blood. When transferrin and iron are both measured, the percent transferrin saturation can be calculated by dividing serum iron by transferrin and multiplying by 100. That % is useful in interpreting the third test that is needed, ferritin. Ferritin is a measure of the body's total iron content. High ferritin can mean iron overload but chronic disease involving inflammation or infection may also elevate ferritin. With true iron overload, transferrin saturation is high normal or elevated. There is currently only one laboratory in the world that can measure equine ferritin, the comparative hematology laboratory at Kansas State Veterinary Diagnostic Laboratory. [Note: The only lab in the world calibrated for horses is in America: Kansas State University. No lab in Australia is calibrated for horses.] Iron overload in humans is treated by phlebotomy – blood draws. Blood letting sounds positively medieval but is a very effective way to reduce the body’s iron level because of how much iron is in red blood cells. Stored iron is then used to replace the lost red cells. It works in horses too and can have dramatic effects on IR. A case in point was a gelding with PPID (also known as Cushings) and IR that needed to have surgery to break up and remove a very large bladder stone. Despite diet and pergolide control, his insulins were always running around 120 and he was iron overloaded. The surgery took several hours and blood loss was substantial. His insulin dropped to 20 after surgery, despite a postop diet of senior feed. Dr Kellon VMD You can read more about iron and the role of copper and zinc supplementation to deal with iron overload in my article on Minerals and Coat Bleaching. Further reading: Links may change over time. If a link doesn’t work, search the title in your search engine. AZA Prosimian Taxon Advisory Group (PTAG) (2003) Iron storage disease in lemurs. Working paper, PTAG meeting on iron storage disease, 29 March, St. Louis Zoo, St. Louis, Missouri.http://forageplustalk.co.uk/wp-content/uploads/2015/08/Iron-Storage-Disease-in-Leamurs.pdf Clause M and Paglia DE (2012) Iron storage disorders in captive wild mammals: The comparative evidence J. Zoo Wildl Med. 43(3):S6-18https://www.researchgate.net/publication/233534108_Iron_storage_disorders_in_captive_wild_mammals_The_comparative_evidence Kellon E Iron status of hyperinsulinemic/insulin resistant horseshttp://forageplustalk.co.uk/wp-content/uploads/2015/08/IRON-STATUS-OF-HYPERINSULINEMICINSULIN-RESISTANT-HORSES.pdf Molenaar F (2005) Assessing iron storage disease in eastern black rhinoceroses (Diceros bicornis michaeli), reference ranges for iron levels and biochemistryhttp://www.rhinoresourcecenter.com/pdf_files/117/1175862663.pdf Nielsen B (2012) A potential link between insulin resistance and iron overload disorder in browsing rhinoceroses investigated through the use of an equine model J. Zoo Wildl Med. 43(3):S61-65https://www.ncbi.nlm.nih.gov/pubmed/23156707 Venn-Watson et al (2012) Hemochromatosis and Fatty Liver Disease: Building Evidence for Insulin Resistance in Bottlenose Dolphins (Tursiops Truncatus) J. Zoo Wildl Med. 43(3):S35-47https://www.researchgate.net/publication/233534111_Hemochromatosis_and_fatty_liver_disease_Building_evidence_for_insulin_resistance_in_bottlenose_dolphins_Tursiops_Truncatus Kansas State Veterinary Diagnositic Laboratoryhttp://www.ksvdl.org/laboratories/comparative-hematology/ Anatomical drawing above of the equine liver, visceral surface sourced from here.
Feed your horse salt for your horse's well being and prevent fatigue. There are many body processes that require electrolytes plus a lot is lost in sweat. The reason why it is so important to feed salt is that salt is made up of sodium and chloride (NaCl). These key electrolytes are often too low in horses' intakes. This is true for cold climates and even more likely in a hot climate or use rugs or do a lot of floating (transporting) of horses; horses need salt supplementation as so much can be lost in sweat. The key electrolytes include sodium, chloride and potassium. Grass/hay and other feeds are relatively high in potassium for horses which is fantastic as it means you generally don't need to supplement potassium, unless the horse has no access to feed for a period of time and is sweating. Horses need electrolytes for daily body maintenance jobs (staying alive) and to replace what is lost in sweat. Some of the important jobs include: The production and secretion of sweat, saliva, intestinal tract fluids, urine and mucus Skeletal muscle contraction Heart contraction Nerve function Intestinal movement (and other involuntary smooth muscle contraction, such as the uterus) Absorption of nutrients across the intestinal wall and into the body cells Maintenance of normal acid-base balance (pH) Maintenance of normal hydration (the body contains roughly 70% water) Preventing tying up Preventing fatigue How to supplement salt Providing a salt lick or better, a bucket of loose salt is an excellent strategy in addition to feeding salt, but on it's own, can’t be relied on to cover maintenance and sweat requirements. Despite salt being the only documented craving horses have, some horses won’t touch a salt lick or not access it enough. Don't rely on free choice salt intake unless you can accurately measure what each horse is taking in. Adding salt to a feed will go a long way to ensure a horse will have the sodium and chloride needs covered with forage and feeds as the potassium source. For an untested situation, Dr Kellon recommends around 2 metric tablespoons of salt in a feed, and more per day for horses in hot climates. If you plan to introduce feeding salt, start with a very small amount and build up gradually to allow time for the horse to adjust to the change in flavour. If possible, mix the salt in with the soak water in your choice of bagged feed/chaff you put in the feed bucket. Ideally your chosen feed is a high fibre feed (beet pulp, soybean hulls and/or lupin hulls) rather than low fibre/high starch/grain feed. This video shows one approach for adding salt (and minerals). The salt will become sodium and chloride ions in the soak water. Whatever your choice of feed, it should be fed wet to prevent choke and reduce dust. Which salt? Best salt to use is plain salt or iodised salt if your horse needs more iodine. If the salt is pink or what is known by many nutritionists as 'dirty salt' then you are probably paying a premium for a salt product that contains microscopic traces of minerals and heavy metals. The amount of minerals in these products are so tiny it's not worth counting towards satisfying daily requirements. Salt can be purchased cheaply in bulk in 20 or 25 kg bags from many stockfeed suppliers. Quirky behaviours One horse owner who contacted me wondered why his horse always licked the ground in the same spot when out on a trail ride. On adding 2 tablespoons of salt to his horse’s feed (per day) he found his horse no longer wanted to lick the ground. He observed his horse drinking more water and looking more hydrated. Over the years I've been asked about this with similar stories. There may be a particular spot in the paddock or out on the trail or a propensity for eating dirt or manure. Whilst a salt craving may not be the only possible answer, it's easy to experiment to see if the behaviour continues after feeding salt. One theory that explains why horses have such a relatively high need for salt is that they evolved in a region of North America with very saline soils. What about potassium? Is potassium harmful in excess - NO unless in exceptional circumstances due to say poor choices with fertilising pasture results in >4% DM on the pasture test OR the horse has a veterinary issue such as Hyperkalemic Periodic Paralysis (HYPP), an inherited condition. All forages; grass and hay are a rich source of potassium so it doesn’t need to be supplemented for a horse that is not in work. Access to food means the horse will be getting a lot of potassium. Any electrolyte excess is easily and efficiently excreted from the kidneys in the urine. Of course, drinking water should always be provided. This is normal for horses, does no harm. The excess can be removed as quickly as within an hour. Timing of feeding salt If you feed more than once per day, spread out the daily amount among those feeds since horses can't 'stockpile' electrolytes. Can sodium or chloride deficiency be harmful - Yes. Electrolytes in the body If your horse often seems tired or flat/ little energy, one possible reason is a lack of salt in the intake as insufficient sodium is related to dehydration. Precise electrolyte concentrations are maintained in and out of cells and in certain parts of cells. The movement of electrolytes in and out of cells is what enables nutrients to move from one place to another. Electrolytes are vital for the function of the nervous system and skeletal muscle and to prevent tying up. Electrolyte supplementation even enhances muscle glycogen repletion which means your horse is more likely to have energy stores replenished for the next workout. Dr Eleanor Kellon VMD, a leader in equine nutrition reports that as little as 2 to 3% dehydration can lead to a 10% drop in performance. Electrolyte levels in the blood are tightly regulated by hormones. This is of paramount importance so other areas of the body will go without to ensure the bloodstream maintains a narrow range of concentration. If sodium is low, the body will draw the sodium ions from the extracellular spaces (between cells) and results in the horse’s skin getting that dehydrated, tented look. When a vet pinches the skin near the shoulder they are getting a measure of skin elasticity, an indication of sodium deficiency. There is some evidence that the sodium in sodium chloride can increase absorption of other ionised minerals. Sodium appears to increase permeability of the lining. For example, in the case of phosphorus (and glucose) there is a cotransporter that absorbs them together. Sodium is also the major controller of water balance in tissues. Sodium levels in the brain are read by cells called osmoreceptors, short for osmolality. In addition to ‘holding’ water in the tissues, sodium is what the brain ‘reads’ in determining when to trigger thirst and when to regulate the amount of sodium and water the body excretes in the urine. Chloride is involved in a host of reactions that include maintaining normal pH, fluid volume and electrical conductivity of cells. All forages; grass and hay are a rich source of potassium so it doesn’t need to be supplemented for a horse that is not in work. Sodium though is rarely in sufficient quantities to satisfy maintenance needs unless the soil the pasture is grown on is quite saline. Adding 2 metric tablespoons of salt (sodium chloride) per feed to a horse’s feed is a reasonable amount to cover maintenance electrolyte requirements, especially for a horse that sweats on a hot day standing around in a paddock or on a short trail ride. Any excess is easily and efficiently excreted from the kidneys. Of course, drinking water should always be provided. Potassium is the major electrolyte inside a cell; the difference in sodium and potassium concentrations outside and inside cells is responsible for excitability of muscle and nerve tissue. If potassium is deficient symptoms can include fatigue, heart rhythm irregularities, muscle weakness or tying up (Rhabdomyolysis) and nerve irritability, also known as ‘Thumps’. For example, the National Research Council (NRC), in the current 6th revised edition of Nutrient Requirements of Horses (2007) gives the following calculations to determine maintenance requirements based on body weight (BW). For sodium it is 0.02 x BW and chloride, 0.08 x BW. A 450 kg horse requires 9 grams of sodium and 36 grams chloride per day. These are minimum levels; it doesn’t take into account sweat losses on a hot day or exercise. A level tablespoon of salt contains approximately 9 grams of sodium and 14 grams of chloride. If a horse is exercised for more than 2 hours then an electrolyte mix with potassium is necessary to replace heavy losses in sweat. Electrolytes can be added directly to a feed or syringed. If syringing, mix with a little sugar, preferably glucose. Sodium, chloride and potassium move through the intestinal wall into the bloodstream via passive transport; the ions fit through the small holes or pores. However, a small amount of sugar or amino acids (protein) will enable active transport of sodium, a quicker process than passive transport. This applies only to sodium, not chloride or potassium. You might see your foaming if heavily sweating during exercise. Read about latherin in foam. Article originally published in the November - December 2009 issue of Equine Excellence magazine with the title of 'The importance of electrolytes', updated since. Further reading: Some examples of research.Links may change over time. If a link doesn't work, search the title in your search engine. Jansson A, Dahlborn K (1999) Effects of feeding frequency and voluntary salt intake on fluid and electrolyte regulation in athletic horses J. Appl. Physiol. 86(5):1610-1616https://www.physiology.org/doi/pdf/10.1152/jappl.1922.214.171.1240 Dr Eleanor Kellon offers equine nutrition courses including electrolyteshttp://drkellon.com Dr Eleanor Kellon Dirty Salthttps://drkhorsesense.wordpress.com/2013/11/22/dirty-salt/ Dr Eleanor Kellon Designer Salthttps://drkhorsesense.wordpress.com/2017/03/16/designer-salt/ Matsui A et al (2002) Estimation of total sweating rate and mineral loss through sweat during exercise in 2 year old horses at cool ambient temperature J.Equine Sci. 13(4):109-112https://www.jstage.jst.go.jp/article/jes/13/4/13_4_109/_pdf Schott H Electrolytes for sport horses - are they needed?https://newcms.eventkaddy.net/event_data/60/session_files/EQ017_Conference_Note_jjacobs_cvma.net_EQ017_SCHOTT_Electrolytes_for_Sport_Horses_Are_They_Needed_20150511175547.pdf Zeynar A et al (2017) Effects of different oral doses of sodium chloride on the basal acid-base and mineral status of exercising horses fed low amounts of hay PLoS One. Jan 3;12(1)https://www.ncbi.nlm.nih.gov/pubmed/28045916 NRC Nutrient Requirements of Horses (2007)https://www.nap.edu/read/11653/chapter/1 Hyperkalemic Periodic Paralysis (HYPP)https://www.vgl.ucdavis.edu/services/hypp.php Thumbnail image sourced from here.
Pasture laminitis can be a major problem for some horses, from catastrophic life threatening laminitis to lower grade separation. What does 'pasture laminitis' mean? When we gaze out the window at our horses playing and grazing together in spring (or winter) on plenty of grass we may feel pleased to see our horses doing so well. Yet appearances may be deceiving and down the track we may find our horse’s hooves showing clear signs of separation and tenderness. On top of the separation, there may be abscesses and seedy toe. The question comes to mind, why is it more likely in spring (or winter)? Grass is by far the best feed for horses, with the largest range of nutrients. Not one product, in a bag or container can compete. Horses evolved on a fairly continuous intake of low fat and high fibre forage. Fibre is essential for healthy functioning of the digestive tract, it is not surprising to find horses on high grain/low fibre diets with hours between feeds are more likely to suffer from colic, ulcers and digestive upsets. All horses, even those on very heavy workloads need as much fibre in their diet as possible, and grass is an excellent source of protein, minerals and vitamins. All grass species, regardless of the quality of the soil they are grown in contain varying levels of these nutrients, without those nutrients the plants wouldn’t be able to function and survive. Though grass (and hay) is a nutritious feed it can also be a health hazard to some horses, especially pasture improved species of grass developed to maximise growth rates in cattle. In spring, warmer temperatures and cooler nights produce a lot of new growth, timed beautifully for the higher needs of pregnant and lactating mares. This new growth can be very high in easily digestible carbohydrates called sugars and starch which in some horses, will cause insulin to rise. These horses are metabolically insulin resistant (IR), or due to high levels of gut incretins produced, have high insulin. It's the high levels of insulin that can cause laminitis in these horses with theses metabolic conditions. The first sign of a horse not dealing well with a high sugar + starch intake can be low grade laminitis. Dr Eleanor Kellon VMD and the Equine Cushings and Insulin Resistance group, ECIR recommend sugar (ESC) + starch to be under 10%. Low grade laminitis, as the name suggests, is a mild form of laminitis where the horse shows little of the symptoms associated with laminitis and is far more common than many horse owners realise. Often the horse owner is unaware of any episodes of lower grade laminitis yet the typical changes are there in the feet. If the cause is not removed then initially the horse may not show a lot of pain or discomfort in the hooves yet the hooves may undergo the following changes: Horizontal ridges (rings) on the exterior of the hoof Inflammation and eventual separation of the laminae or leaf like folds in which the pedal bone is normally suspended leads to a separation of the hoof wall from the hoof. This is seen as a widening of the laminae particularly at the toe and has the effect of making the horse more susceptible to hoof abscesses. Rather than standing normally the horse will shift his weight from one foot to the other. If the hind limbs are more affected, the horse will stand with its front limbs back underneath to take more weight. Demonstrate a reluctance to step out when ridden. Reluctance to pick up feet. In time the laminitis could develop to tenderness on any surface with a strong ‘bounding’ pulse to the feet indicating increased blood flow and inflammation (heat) of the area. This chronic laminitis may then develop further with pedal bone rotation and solar penetration, known as ‘founder’. Dietary laminitis is a very complex condition, and the likelihood of any particular horse getting it from excessive sugar and starch in the diet is influenced by numerous factors: Seasonal variation, with early spring grass being the big risk. New shoots of grass are higher in sugar + starch. Type of grass – legumes such as clover and lucerne being particularly rich. Grass stressed from drought or frost is higher in sugar and starch. Cold overnight temperatures can mean that the grass is very high in sugar + starch first thing in the morning. Horses that have had previous laminar disease (whether from laminitis, puncture wounds or severe sole abscesses) seem more susceptible to subsequent bouts of laminitis. Overweight IR horses can have a higher predisposition to laminitis. A horse in regular work is less likely to be affected. What actually causes the separation of the laminae that support the pedal bond is under investigation. A RIRDC study showed that high levels of the hormone insulin triggers lamellar separation. Carbohydrates like sugar and starch are broken down into glucose. As glucose rises in the blood, the pancreas secretes insulin in response to the increased glucose. Insulin enables glucose to move from the blood into cells. A large and prolonged influx of sugar and starch will cause a large and prolonged rise in insulin and this has been demonstrated to trigger separation of the lamellae in the hooves though the actual mechanism is still unknown. Sugar and starch are broken down in the stomach and throughout the length of the small intestine but if a significant amount makes it to the large intestine then the delicate balance of bacteria can be upset. The large intestine becomes more acidic, potentially damaging the intestinal wall so that it becomes ‘leaky’. This acidity may cause many of the fibre fermenting bacteria to die and release toxins that pass into the bloodstream through the breaks in the wall. The toxins are thought to alter the blood circulation within the hooves, or trigger the separation of the lamellae. Another theory suggests that when the intestinal environment changes, bacteria that produces laminitis triggering factors may overwhelm others. How to manage horses prone to lower grade laminitis The prevention and rehabilitation of laminitis is all about removing the cause – in this case the source of the excessive sugar and starch in the diet. To minimise the risk, regular exercise is highly effective and can make all the difference between a horse that has to be deprived of pasture and one that can handle the high sugar + starch content. Domesticated horses kept in small paddocks are at far higher risk than non domesticated horses as they would be covering large distances rather than grazing and gorging themselves in a small area with little movement. Ensure your horse isn’t overweight. It isn’t clear as yet whether it’s the obesity that can reduce a horse’s ability to handle a high level of sugar + starch or the high grain and often high fat diets. At an extreme this can develop into insulin resistance where an inability to respond to insulin occurs. A greater than normal amount of insulin has to be secreted to move glucose into cells, triggering laminitis. For managing horses on pasture that are susceptible to low grade laminitis it is useful to know when sugars and starch are at their highest. Generally, the safest time for horses to graze is between 3am and 10am in the morning as this is when sugars and starch are at their lowest though this won't apply if overnight temperatures are very cold. Grass growing in the shade is safer compared to grass in full sunlight and ditto for a cloudy day compared to a day without clouds to obstruct the sun. If you need to prevent horses from grazing later in the day there are two methods that can be adopted. One option depending on your property is the implementation of a paddock paradise arrangement. Jaime Jackson, a hoof care practitioner in America published ‘Paddock Paradise, A Guide to Natural Horse Boarding’. The paddock paradise idea is where a laneway is fenced off around the perimeter of a paddock using electric tape or around the perimeter of the whole property. Depending on the insulin resistance of the horses, either the grass may need to be removed or their grazing may limit the grass sufficiently. Never underestimate how efficient a horse can be at nipping at the new growth, even when very short. Low sugar + starch hay could be distributed in the laneway. This would entail some initial effort and expense but it would mean that the horses could graze in paddock in the morning when sugars and starch are at their lowest and then later placed in the laneway for plenty of movement which a small dirt yard cannot provide. An extra benefit is that time in the laneway means the paddocks can be rested. Another benefit is that horses kept in paddock paradise type laneway are reported to move far more than horses in paddocks. Read more about paddock paradise, an Australian example. Another option is a well fitting and padded grazing muzzle. A muzzle will restrict grass intake late in the day when sugar and starch is highest but still allows drinking and socialising with other horses in the paddock. A little bit of grass can still be eaten in a muzzle. However, ensure the opening is not too small, and isn't going to damage the teeth surface. The worst option that cannot be recommended is locking a horse up without feed. It means the horse is prevented from moving and getting exercise, no food can lead to digestive upsets and separation from the rest of the herd is distressing. Horses tend to gorge on grass when released if locked up for a period of time. Is slashing a paddock a good idea? Slashing a paddock or mowing a paddock for hay and allowing a horse to graze the new growth is asking for trouble. The best growth stage for the lowest sugar and starch is when the grass has flowered and seed is spread. If any of the grass stills has seeds this may not present a problem even though the seeds like grains are high in starch but their proportion of the grass biomass is small and soluble carbohydrates in the above ground portion of the grasses drops dramatically after the seeds are set. Unfortunately though, some horses are so sugar sensitive that even the seeds will cause harm. Many insulin resistant horses cannot tolerate any grass, let alone mature grasses. Ideally, allow the grass to be grazed when mature and once eaten down to about 8 cm move the horses onto another section or paddock of mature grass. If you do need to slash to manage large areas of pasture, larger than what the horses can eat then slash and wait 2 to 3 weeks for the regrowth to reach a height of about 25 cm. The regrowth will use up a lot of the sugar and starch for growth and turn it into protein and fibre. Rotational grazing is the best way to manage your paddocks and sugar sensitive horses who can tolerate some grass. The heights given are a guide only, it will depend on the species of grass. What about hay? Hay can also be very high in sugar and starch. Growing conditions, time of day when harvested and stage of growth are most important. Sugars rise through the day on a sunny day, and decrease overnight when nights are warm. Mature stands of grass are safer than young, growing grasses. This means that unstressed mature grass cut early in the morning will be safer than grass harvested late in the day. Drought or nutrient deficient stressed grass will be higher in sugar + starch. Many people who own horses sensitive to high levels of sugar + starch on predominantly hay diets often like to get their hay analysed at a laboratory to find out how safe the hay is to feed. Soaking hay for up to 30 minutes in hot water, 1 hour in cold water can remove a significant amount of soluble sugar but won’t reduce the starch levels. Dr Eleanor Kellon VMD, an equine nutrition specialist in America was one of the first to be concerned about iron overload as a risk factor for insulin resistance in horses as it is in people; hence any feed or supplements with high levels of iron should be avoided. Article originally published in the September - October 2009 issue of Equine Excellence magazine with the title of 'Grass and subclinical laminitis', updated since. Further information: Links may change over time. If a link doesn’t work, search the title in your search engine. ECIR websitehttps://www.ecirhorse.org/ Equine Cushings and Insulin Resistance discussion group. Dr Eleanor Kellon VMD oversees.https://ecir.groups.io/g/main Dr Eleanor Kellon VMDhttp://drkellon.com/ Jaime Jackson (2007) Paddock Paradise, A Guide to Natural Horse Boardinghttps://www.jaimejackson.com/ Professor Chris Pollitthttps://veterinary-science.uq.edu.au/profile/2242/professor-christopher-pollitt L. R Turner, D. J Donaghy, P. A Lane and R. P Rawnsley (2007) Distribution of Water-Soluble Carbohydrate Reserves in the Stubble of Prairie Grass and Orchardgrass Plants Agron. J. 99(2):591-594https://dl.sciencesocieties.org/publications/aj/abstracts/99/2/591 Safergrass.org with Katy Wattshttps://www.safergrass.org/ M Sillence, K Asplin, C Pollitt and C McGowan (2007) What Causes Equine Laminitis? RIRDChttp://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.577.536&rep=rep1&type=pdf
Understanding a hay or pasture test is important for understanding the nutrient levels and mineral ratios that should make up the largest portion of the intake. The best diet for a horse is a balanced diet based on data. Symptoms like a dull coat, poor hoof quality, less than optimal performance and a weak immune system are the more obvious signs. A balanced diet is essential for performance and in preventing health issues. So what is a mineral balanced diet? A balanced diet is one where all the nutrients are more than adequate to avoid deficiencies and the amount of minerals avoid competition with another. One example is copper and zinc, too much zinc in the diet has been found to interfere with the uptake of copper. Another is calcium and phosphorus, too much calcium can interfere with phosphorus and vice versa. There are many other examples. The cheapest, easiest and most accurate way to find out the level of nutrients in your horse's diet is to test the main forage whether that be hay or pasture. To determine whether nutrient levels are sufficient and balanced in a horse’s diet, the amounts consumed from forage, feeds and supplements can be compared with the amounts recommended in the 2007 Nutrient Requirements of Horses, 6th Edition by the National Research Council (NRC), the reference for equine nutritionists. Providing an insurance buffer by using at least 150% of NRC target minimums and keeping mineral ratios in a tight range will protect the horse from suboptimal intakes of trace minerals. Manufacturers of feeds and supplements should supply a nutrient profile of their products when requested. With pasture or hay, the nutrient levels cannot be guessed by simply looking at it or comparing it with similar looking examples. Improved pastures tend to be higher in protein compared to native pastures but the levels of minerals do not fit a pattern. Previous land use, fertiliser history, plant species, soil type and acidity/pH will influence mineral levels. The cheapest, easiest and most accurate way to find out the level of nutrients in your horse's forage is to send a representative sample to a laboratory for testing. To learn more about how to collect a representative pasture sample, see the post on pasture testing - Case study: 3 pasture tests. Following is a short description of how a pasture or hay test can be used, space doesn’t allow for a full analysis. Pasture test results – a paddock of diverse native grasses A representative sample of a grass hay was sent to Equi-Analytical laboratory in the USA as it's very affordable and they can do the highest quality testing. There are a number of excellent laboratories in Australia but unfortunately the cost for the same test is far more expensive, around $180 plus. The ‘Dry Matter’ column is used for pasture and ‘As Fed’ column for hay. Terms explained: % MoistureThis percentage refers to the amount of moisture in the sample when it was received by the lab. All moisture is removed for testing. % Dry MatterThis portion of the sample contains carbohydrates, protein, fat and minerals. Digestible Energy (DE)Digestible energy gives the energy value of the feed, expressed as Mcal/kg. This mixed grass has an energy value of 1.93 Mcal/kg or 8.1 MJ/kg. To give an idea of what this means, a 500 kg horse in no work would need to consume 8.6 kg in dry matter to maintain a good weight, better known as body condition score. A horse in heavy work such as endurance or eventing would need to consume almost 14 kg in dry matter if no other feed was provided. If a test gives Metabolisable Energy (ME) it's for ruminants like cattle and is not applicable for horses. Crude Protein (CP)Rather than protein itself this measures the level of nitrogen and nitrates. Protein contains nitrogen so it's a useful indicator of protein, when the level of CP is considered high by a nutritionist then it's advised to get the sample tested for nitrates as high nitrate levels can cause health issues in horses. A nitrates test is $9USD. This grass hay indicates 88.6 grams per kg. 8.6 kg contains about 762 grams, enough protein to support a 500 kg horse in no work. Estimated LysineLysine is an essential amino acid which means it must come from the diet. It’s often called the limiting amino acid, if there is a lysine deficiency then the proteins that require lysine cannot be manufactured by the cells and the unused protein will be excreted, causing muscle building issues. This hay is estimated to have 3.1 grams per kg which is borderline for meeting the lysine requirement. Supplementation of key essential amino acids including lysine would be recommended to avoid topline and muscle building issues. The fibre fractions; Acid Detergent Fibre (ADF) and Neutral Detergent Fibre (NDF) are very useful for evaluating the quality of hay. Acid Detergent Fibre (ADF)This gives a measure of two of the complex carbohydrates that make up the cell walls lignin and cellulose. Cellulose is broken down by micro organisms (fermented) in the hind gut but lignin is virtually nonfermentable. Lignin is a key component of wood. The lower the number, the more fermentable the fibre and the easier for nutrients to be extracted from the plant material. Neutral Detergent Fibre (NDF)This includes lignin and cellulose but also hemicellulose, another cell wall component. The lower the ADF and the higher the difference between ADF and NDF, the more fermentable the fibre. In this example, ADF is 38.9% and NDF 59.8% indicating it's not the greatest quality of hay for horses. WSC, ESC and starch can only be reliably tested in hay. When researchers test sugars and starch in pasture they immediately freeze the sample in liquid nitrogen to stop the sugars from metabolising further. Grass will continue to metabolise after it has been cut. WSC (Water Soluble Carbohydrates)These carbohydrates will dissolve to some extent in water and includes digestible sugars such as fructose, glucose, sucrose and indigestible plant sugars and some fructan (complex carbohydrate). ESC (Ethanol Soluble Carbohydrates)ESC is a subset of WSC and includes sugars that are soluble in ethanol. ESC is important as this is the component that causes insulin to spike. StarchStarch is a complex carbohydrate made up of glucose sugars, it’s how plants store glucose. In animals glucose is stored as glycogen. For insulin resistant horses, glucose causes insulin to rise that may trigger the chain of steps resulting in laminitis. Dr Eleanor Kellon VMD advises to keep ESC + starch below 10% for the overall diet and individual feed ingredients. In this example, sugar + starch is 6.4%. Non Fibre Carbohydrates (NFC)This is calculated from adding starch to WSC and soluble fibres and plant sugars other than the simple digestible sugars. It includes all the carbohydrates that are not part of the cell wall of plants. Major mineralsCalcium, phosphorus and magnesium are needed in gram amounts in the diet compared to the trace minerals which are only needed in small amount in miligrams. Many nutritionists aim for a calcium to phosphorus ratio between 1.2:1 to 2:1 though a higher ratio is considered to be okay, a ratio of 5:1 or higher is better to be temporary. A calcium to magnesium ratio is recommended to be between 1.5:1 and 2:1. This hay is fine for calcium up to a light workload for a 500 kg horse but phosphorus too low. Supplementation of phosphorus will also improve the calcium to phosphorus ratio. The test indicates that magnesium levels are quite generous and will support a horse up to moderate work. The levels of electrolytes; potassium and sodium are included. Sodium is very low and cannot support a 500 kg horse’s maintenance needs, this is not looking at losses in sweat. It can be supplemented with salt allowing for a generous buffer, especially if the horse is in a hot climate and sweats easily. 2 to 4 tablespoons per day is appropriate, the excess is easily and efficiently excreted. Potassium vastly exceeds a horse’s requirements which is the norm for pasture and hay so never needs supplementing for horses in no work unless the horse has been exercised for more than 2 hours (and unable to eat). Trace mineralsSmaller amounts are required but trace minerals are no less important than the major minerals and includes iron, copper, zinc and manganese. Many nutritionists support the ideal ratio of 1:3 for copper to zinc. In this grass sample the ratio of copper to zinc is close to 1:3 but both copper and zinc are highly deficient for no work and requirements rise with increasing workload so must be supplemented. Molybdenum is a trace mineral that needs to be noted, at high levels it can interfere with copper uptake. Both iron and manganese vastly exceed needs, and in this example, the higher manganese than iron can potentially worsen the problems with too much iron. The results from a pasture or hay test can be used to select the best feeds and supplements to correct any deficiencies and optimise the mineral ratios. Article originally published in the April - May 2010 (Vol 31 No 6) issue of Hoofbeats magazine, updated since. Further reading Links may change over time. If a link doesn’t work, search the title in your search engine. Dr Sarah L. Ralston VMD (2004) Diagnosis of Nutritional Problems in Horseshttps://esc.rutgers.edu/fact_sheet/diagnosis-of-nutritional-problems-in-horses/ Dr Eleanor Kellon VMDhttp://drkellon.com/The NRCPlus course goes into more detail discussing the merits of hair, soil, blood and tissue testing. Also explains how to read a hay or pasture test and design a diet based on the test. Equi-Analytical laboratoryhttps://equi-analytical.com/ ECIR websitehttps://www.ecirhorse.org/ Equine Cushings and Insulin Resistance IO group with Dr Eleanor Kellon VMDhttps://ecir.groups.io/g/main University of Minnesota ExtensionUnderstanding Your Hay Analysishttps://extension.umn.edu/horse-nutrition/understanding-your-hay-analysis Sarah Braithwaite Reasons to Test Hay, Haylage and Grass for Your Horsehttps://forageplus.co.uk/test-hay-haylage-and-grass-for-your-horse/
3 pasture tests - for comparison. Both pasture and hay can widely vary in nutrient levels, not just between types of pasture and hay, but also high variability for each type of grass or hay. You can't tell the nutrient profile by looking at photos of paddocks or hay. With the enormous range of different feeds and supplements on the market the choices of what to feed a horse is very challenging. Many horses are over supplemented leaving horse owners faced with expensive feed bills and horses still may not be getting what they need. Everyone wants to ensure that what our horses are being fed is meeting their nutritional requirements, however to do this, it's important to look at the whole diet rather than parts of it in isolation. Feed manufacturers generally offer well balanced feeds but if the bulk of the diet, pasture or hay is out of balance then these bagged feeds or supplements will not correct any imbalances. For example, the ideal ratio for copper and zinc in the overall diet for horses is 1:3, that is, one part copper to 3 parts zinc. some say 1:4 but environmental contaminants like sulphur can prevent uptake of copper. Too much zinc in the diet is known to interfere with the uptake of copper and it is strongly suspected that too much copper will interfere with zinc uptake. The feed given to the horse may have copper at roughly one third the level of zinc but what about the bulk of the diet coming from pasture or hay? Grass has a lower requirement for copper and zinc and species of grasses differ in their uptake of minerals from the soil. To find out if the whole diet is providing the minerals and other nutrients to satisfy a horse’s requirements and that the ratios are optimally balanced then the first step is to look at the bulk of the diet, the forage. Looking at pasture or hay won’t work Unfortunately it is impossible to tell the nutrient levels of pasture by simply looking. Horse owners know when their pasture increases in energy value, especially with the arrival of spring with warmer temperatures and some rain but it's impossible to tell levels of minerals like calcium, phosphorus, magnesium, copper and zinc just by looking. If any feed program, regardless of the level of sophistication, uses photographs or averages for determining nutrient content of pasture, its validity should be questioned. The very best looking pasture can be very mineral deficient, that is, deficient for horses but not for the species of grass. Pasture testing is the simplest and most accurate way to find out the nutrient profile. It doesn’t have to be a costly exercise either. If the main forage is hay, a representative sample can be sent to a laboratory. A pasture test can give results for digestible energy (horse), crude protein, calcium, phosphorus, magnesium, iron, copper, zinc and manganese - sulphur, molybdenum and selenium can also be requested. All these nutrients at the right levels are necessary for optimum health. For hay, testing the sugar and starch levels will help with determining if the hay is suitable for sugar sensitive or insulin resistant horses. Case Studies Highlighting the differences in pasture which may not be visible to the eye, the following are case study examples from NSW and the ACT. They also show how varying levels of nutrients within each pasture may change the rate of mineral supplements needed for horses for whom a significant intake of the diet is made up of pasture. This applies to hay as well. All values in these cases represent dry matter which means the water content was removed for testing. The following assessments are for a 500 kilogram (kg) horse eating 10 kg pasture. Pasture 1 - Predominantly Kikuyu pasture on the mid NSW coast Pasture on this paddock consists of approximately 70% Kikuyu pasture mixed with 30% native species. Test results indicated a high level of protein and very low sodium. Unfortunately being an oxalate grass species any calcium coming from Kikuyu is unavailable to the horse so calcium supplementation is a must. The phosphorus and magnesium were high enough for a horse in little to no work but extra supplementation would be needed for horses in a higher needs group such as growing, breeding or those on a high workload. Copper was deficient for horses at 8 mg/kg but zinc was a surprisingly high 97 mg/kg. This gives a ratio of 1:12 for copper to zinc. Pasture 2 – Predominantly Kikuyu pasture on the mid NSW coast Located less than 500 metres away from Pasture 1, the Pasture 2 looks the same with 70% Kikuyu and the rest a mixture of native species. Again, test results showed a high level of protein so it’s highly unlikely protein would need to be supplemented for horses on these two properties if the diet was mainly pasture. The phosphorus and magnesium levels were a bit higher than Pasture 1, however both do require significant calcium supplementation. Copper (10 mg/kg) was similar but zinc was a lot lower at 53 mg/kg, a ratio of 1:6. Horses on both properties require copper and zinc supplementation to meet requirements and correct the copper to zinc ratio. Why there is such a significant difference in the level of zinc is interesting as the two pastures are similar to look at. Other factors such as soil acidity (pH), moisture, oxygen and nitrogen levels come into play for influencing a plant’s uptake of minerals and Pasture 1 was used as a chook farm in the long distant past, perhaps that’s why the higher than usual levels of zinc. Pasture 3 – Highly diverse native species pasture in the ACT Many horse owners favour highly diverse native species pasture for horses with many people believing that the greater the number of plant species in the paddock, the less chance of nutritional deficiencies for their horses. Test results for this paddock indicated that protein levels were fine but the biggest surprise were the major minerals; calcium was okay although would need supplementation for a higher needs horse but phosphorus was extremely deficient and magnesium was not much better. Regardless of whether a horse was in work or not, he would be significantly phosphorus deficient grazing on this pasture. Copper (7 mg/kg) and zinc (33 mg/kg) were very low and not optimally balanced at 1:5. All three pastures samples were low in sodium so any horses on these properties need additional salt added to their feed, at least a tablespoon for maintenance needs, more if sweating on a hot day. For the long term heath of pasture, periodic soil testing is recommended. On the basis of the soil tests, decisions can be made on which soil treatments should be applied. But if you want to know what your horse is actually eating, testing what he eats is the most accurate way. The information the test provides can then be used to work out the best choice of supplementary feeds, if any are actually needed. In many cases, the highest quality feed in a horse’s diet is the grass portion. The more supplementary feed fed the less need for the horse to eat the pasture and the horse can end up nutrient deficient. And of course, this will depend on the horse and it's workload and any special needs. Horses that are growing, or breeding/lactating or on a demanding workload will have higher protein and mineral needs than a horse in little to no work. Any mineral deficiencies can be corrected and the mineral ratios balanced. There are many variables in managing horses, many of which are out of our control but one aspect we can control is their nutrition for maintaining optimum health - a very good reason to ensure that the feed they eat is of high quality and contains all of the necessary vitamins and minerals. Do it yourself pasture testing Most laboratory's in Australia can do a pasture test, but they are very expensive (approximately $120 plus) and are geared more towards ruminants (sheep and cattle) rather than horses. I prefer to send pasture and hay samples to Equi-analytical in the US as the costs are vastly cheaper. HANDS ON Taking a pasture sample Oberve your horses to see what plants they like to eat and which ones they prefer to ignore. Walk over the paddock and collect 12 to 20 (or more) random samples by using stainless steel scissors to cut at the same height that the horses graze, trying to collect the different plants in the similar proportions to what is in the paddock, representing what they eat. For example, if you have 75% of plant A and 25% of other plants in your pasture use one plastic bag for Plant A and a second plastic bag for the other plants. Keep collecting till you have 200 - 300 grams, you will need a set of kitchen scales to determine this. Mix the plants together in a small clean bucket with the different plants in similar proportions to what is in your paddock. The aim now is to dry the sample as soon as possible as the grass continue to metabolise sugars after being cut. A microwave or food dehydrator is an excellent way to dry the sample. Place a sheet of newspaper and a glass of water on the turntable in the microwave. Use the medium/low or low setting and check the grass every 3 minutes to see how dry it is, turning it over regularly to help dry the sample evenly. Every time you check, refill the glass with cold water but be very careful not to burn yourself when touching the glass as the microwave is very good at heating up glass and glass is very good at retaining heat. When the grass feels dry to touch it has had enough drying. We only want to partially dry the sample. The colour of the grasss will still be green though may look a bit faded. Depending on the size of the microwave, you may choose to do the sample in 2 to 3 batches. If you don't have a big enough microwave you can spread the grass out on newspaper in the sun. Once the sample feels dry, fill a small snap lock bag and squeeze all the excess air out. Now it is ready to send to any laboratory for testing. If in doubt, contact your chosen lab for instructions on how best to prepare a sample. To help with understanding the lab test results, read Understanding a hay or pasture test. Originally published in the December - January 2010 (Vol 31 No 4) issue of Hoofbeats magazine. Further reading Links may change over time. If a link doesn’t work, search the title in your search engine. Dr Sarah L. Ralston VMD (2004) Diagnosis of Nutritional Problems in Horseshttps://esc.rutgers.edu/fact_sheet/diagnosis-of-nutritional-problems-in-horses/ Dr Eleanor Kellon VMDhttp://drkellon.com/ Equi-Analytical laboratoryhttps://www.equi-analytical.com/
Hair testing is considered by many nutritionists/scientists/vets to be very limited for overall nutrient balance. Nutritionists can't use results for balancing a horse's intake or consider hair testing credible in the face of such significant research. Hair can be analysed for a variety of substances, including drugs, but in nutritional terms hair analysis refers to hair mineral levels. Minerals reach hair via the blood so it's going have similar limitations as blood testing since hormones control the levels of many of the minerals giving little indication of the status for the rest of the body. Dr Kellon VMD "Hair mineral is not an accurate way to determine mineral status and is worthless for formulating the diet and supplements." NRCPlus The kidneys will rapidly excrete minerals when they are higher than a tight range, electrolytes like potassium are a good example. The liver can remove minerals before they reach hair. Hair testing can't tell mineral balance even if the totals were credible as it doesn't indicate whether it's due to a deficiency in the first place or competition with another mineral or the body had a high need at that time. Hair can be useful for some heavy metals and selenium but from a nutrition point of view hair testing is not considered overall to be reliable. Even with selenium, though hair testing is considered accurate by some, the result can't tell us:- if the level will reflect an average of intakes over several months - not how the horse is now- how low (or how high) the dietary levels are. Even selenium results via hair testing is debatable. Veterinarian and nutritionist Sarah Ralston has concerns. Ralston, a faculty member at Rutgers University, agrees that hair analysis may be "vaguely useful" for selenium status, but believes values from blood samples are more representative of true levels. Dr Eleanor Kellon VMD recommends a whole blood sample.Equine Hair Analysishttps://ker.com/equinews/equine-hair-analysis/ There's been many studies which have demonstrated that many factors other than diet affect the mineral concentrations in hair. Things that affect the mineral levels in hair testing include the time of year, location on the body (different parts of the body test differently, even if they are the same hair colour), breed, age, hair colour, shampoo residues, airborne contamination, sweat, dust on the horse, soil on the horse (even if the horse looks clean), all make a difference. It's not uncommon for hair mineral analyses can't tell the difference between minerals that are on the surface of the hair and those that are actually inside the hair. One study found higher concentrations of zinc in different colours of hair on the same animal. The same colour hair on different breeds of cattle eating the same food and in the same paddocks produced different mineral levels. Researchers found the age of calves/cows in the same paddock eating the same feed tested for different levels of minerals. Researchers found differences in mineral content of calf hair in calves by different sires - calves were all together and being fed same food. Animals tested all year round showed different mineral level at different times of year, even though they were eating the same thing. There has been more success with hair testing for arsenic and cadmium, but even such things as age, sex, and length of hair, have been demonstrated to affect the testing for arsenic. One vet researcher sent hair from one horse as separate samples and got very different results. Dr Eleanor Kellon discusses the limitations of hair testing in NRCPlus and Dr Ann Nyland researched this in great detail in her book 'Natural Horse Care The Right Way'. There is a huge body of research on hair analysis, and not one scientific paper has found any evidence that it is in any way effective for balancing the intake (that I know of). A 2015 study by A Ghorbani et al compared blood testing vs hair testing which found (not surprisingly) that hair testing was superior to blood testing. Since we know that blood testing is extremely limited it's not saying much about the validity of hair testing. When published it did cause a stir stating "Hair mineral analysis is a suitable tool for evaluating mineral status in horse." Unfortunately the study design didn't compare with liver nutrient status so wasn't able to verify hair levels with body levels of nutrients. The statement that hair testing is a suitable tool is a stretch. The best and most accurate approach is to have the intake tested (pasture/hay and so forth) and the diet balanced. It's not an exact science but the best we have other than a liver biopsy! Soil testing is valuable for long term soil treatment and improving pastures but not useful for determining what is in your horse's intake. Read more about soil testing and pasture or hay testing. Further reading: Links may change over time. If a link doesn't work, search the title in your search engine. Anke M (1965) Major and trace elements in cattle hair as an indicator of Ca, Mg, P, K, Na, Fe, Zn, Mn, Cu, Mo and Co. 2. Relationship to cutting depth, hair type, hair color, hair age, animal age, lactation state and pregnancy Arch. Tierzucht. 15: 469 Anke, M (1966) Major and trace elements in cattle hair as an indicator of Ca, Mg, P, K, Na, Fe, Zn, Mn, Cu, Mo and Co. 3. Effect of additional supplements on mineral composition of cattle hair Arch. Tierzucht. 16: 57 Barrett S (1985) Commercial hair analysis. Science or scam? JAMA. Aug 23-30;254(8):1041-5https://www.ncbi.nlm.nih.gov/pubmed/0004021042 Barrett S (2018) Commercial hair analysis: A Cardinal Sign of Quackeryhttps://www.quackwatch.org/01QuackeryRelatedTopics/hair.html Combs DK, Goodrich RD, Kahion TS and Meiske JC (1979) Effects of nonnutritional sources of variation on concentrations of various minerals in cattle hair Minnesota Cattle Feeders Rep. 54 Combs DK, Goodrich RD and Meiske JC (1982) Mineral Concentrations in hair as indicators of mineral status: a review J.Anim. Sci. 54(2):391-398https://www.researchgate.net/publication/16155714_Mineral_concentrations_in_hair_as_indicators_of_mineral_status_a_review Combs DK (1987) Hair analysis as an indicator of mineral status of livestock J Anim Sci. 1987 Dec;65(6):1753-1758.https://www.ncbi.nlm.nih.gov/pubmed/3327852 Fisher DD, Wilson LL, Leach RM and Scholz RW (1985) Switch hair as an indicator of magnesium and copper status of beef cows Am. J. Vet. Res. 46(11):2235-2240https://www.ncbi.nlm.nih.gov/pubmed/4073632 Ghorbani A, Mohit A and Kuhi HD (2015) Effects of dietary mineral intake on hair and serum mineral contents of horses J. Equine Vet. Sci. 35(4):295-300https://www.sciencedirect.com/science/article/abs/pii/S0737080615000441 Hambidge KM, Franklin ML and Jacobs MA (1972) Hair chromium concentration: effects of sampling, washing and external environment Amer. J. Clin. Nutr. 25(4):384-389https://academic.oup.com/ajcn/article-abstract/25/4/384/4818962 Hambidge KM (1982) Hair analyses: worthless for vitamins, limited for minerals. Am. J. Clin. Nutr. Nov;36(5):943-949https://www.ncbi.nlm.nih.gov/pubmed/7137078 Hammer DI, J. Finklea JF, Hendricks RH, Hinners TA, Riggan WR and Shy CM (1972) Trace metals in human hair as a simple epidemiologic monitor of environmental exposure In: D. 0. Hemphill (Ed.) Trace Substances in Environmental Health, V.A. 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Nutr. 84(3):205-214https://academic.oup.com/jn/article-abstract/84/3/205/4778209 Ralston SL (2015) The Proof Behind Horse Hair AnalysisCan hair analysis determine what supplements a horse needs?https://dressagetoday.com/horse-health-/experts-27293 Reinhold JG, Kfoury GA and Arslanian M (1968) Relation of zinc and calcium concentrations in hair to zinc nutrition in rats Nutr. 96(4):519-524https://academic.oup.com/jn/article-abstract/96/4/519/4778529 Roug A, Swift PK, Gerstenberg G, Woods LW, Kreuder-Johnson C, Torres SG and Puschner B (2015) Comparison of trace mineral concentrations in tail hair, body hair, blood, and liver of mule deer (Odocoileus hemionus) in California J. Vet. Diagn Invest. 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