Transitioning onto Pasture

Spring grass is mother nature’s panacea for winter’s nutritional hardships and the huge demands of pregnancy and lactation.  However, rangelands utilized by feral horses usually bear little resemblance to the fields of domesticated horses and even in the spring their diets also include high fiber items like shrubs. Unlimited access to powerhouse grasses can cause some problems.

Young grasses are low fiber, very high protein and higher in rapidly fermentable carbohydrate fractions than more mature growths.  This can lead to a variety of hind gut digestive upsets including bloating, varying degrees of manure softening/diarrhea and in some cases colic.  This can be avoided by careful introduction to the new grass.

Given the option, every horse will gorge on the succulent young grasses and largely ignore anything else you try to get them to eat – including grains in many cases!  When their large intestine is packed full of the rapidly fermenting grasses it produces conditions that do not favor proliferation of fiber fermenting organisms.  To balance this out, keep the horses off the grass for 12 to 18 hours per day with access to good hay. When the pasture is particularly dense it may need to be longer than this.  Gradually allow longer grazing periods always keeping a close eye on manure.

Supplementing with live yeast cultures is also beneficial. Yeast have been documented to help avoid the large changes in the colonic environment that have a negative impact on fiber fermentation.  It is also useful to feed a source of easily fermented soluble fiber to further support the fiber fermenting organisms.  Psyllium and beet pulp are particularly good sources.

Spring grasses can also be low in magnesium and sometimes other major minerals such as calcium as well.  Sodium levels are typically quite low.  Combinations of these factors may interfere with digestion or intestinal motility and can even result in electrolyte disruptions such as thumps.  Magnesium sensitive horses can also show increased nervousness and muscular twitching. EPSM horses often have noticeable increase in symptoms which could be from low magnesium intake and/or high sugar and starch in the grass.

Speaking of sugar and starch levels, insulin resistant horses are at extremely high risk of developing laminitis. It may not be a full blown laminitis every year but there will always be damage to some degree. There is no way to prevent this, no supplement or management approach that makes spring pastures safe for IR horses.

If reaction to low magnesium is suspected, supplement with 5 to 10 grams/day.  All horses should also receive a minimum of 1 oz of table salt/day in their feed.  If  free choicing salt, use a coarse granular rather than salt blocks, fed in a covered feeder.  Daily formal exercise is particularly important for EPSM horses on lush spring pastures. If worsening symptoms persist, pull them off pasture until it has matured.

There can definitely be too much of a good thing with high quality spring pastures. Controlled intake and a few intelligently selected supplements will help your horse get maximum benefit without the drawbacks.

Eleanor Kellon, VMD

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The Genetics of Insulin Resistance

Insulin resistance [IR], which is a failure of insulin responsive cells to take up glucose under normal levels of circulating insulin, affects an estimated 12 to 15% of horses. Insulin resistance is typically (but not always) associated with easy weight gain.  Abnormal fat deposits are usually evident. The most important consequence, however, is a risk of developing laminitis.

In a well-intentioned effort to protect horses from laminitis caused by uncontrolled IR, many things have been proposed as causing IR.  These include feeding grain, improved strains of pasture grasses, insufficient exercise, obesity and a host of proposed environmental factors including pesticide and herbicide exposure.

Arguing against the idea there are external causes is the observation that there are very clear breed risk factors for IR, with it being extremely rare to nonexistent in some, like Thoroughbreds, but very common in others, such as Arabians.  Furthermore, the Virginia Polytechnic large long term study of IR in a herd of mixed breed ponies also found strong evidence of a genetic component when they did pedigree analysis.

Most recently, a study just released in the Journal of Animal Science searched the genome of the Arabian horse and identified a genetic risk locus where markers correlated with laminitis, high blood insulin, abnormal indirect measures of glucose metabolism and potential obesity.  The findings were strong and confirm that IR has a genetic cause.

It is also true that feeding an inappropriate diet, no exercise and letting the horse get obese will indeed worsen IR.  So, if these are factors that need to be watched closely what difference does it make whether they actually cause it or not?  It makes a big difference.

If someone has a life-threatening strawberry or peanut allergy, they must avoid those things at all costs but can otherwise live a perfectly normal life if they accept and respect that restriction. The allergy does not go away, it simply is managed by avoiding the dangerous trigger. The same is true for an insulin resistant horse.

On the individual level, if a horse diagnosed as insulin resistant is put on an appropriate diet, exercised and loses weight, eventually resulting in blood insulin levels returning to a normal range, that horse is not cured of insulin resistance.  The underlying genetics are still there.  Failure to appreciate that leads people to do things like turn the horse out on unsafe pastures that put them at risk of deteriorating and developing laminitis.

Buying into the idea that IR can be caused by diet has also led to an epidemic of concerned owners becoming positively paranoid about feeding any starch and the simple carbohydrate levels in pastures. While it is certainly true that many horses do not need supplemental grain (or fat calories), it is not a metabolic poison that must always be avoided. Similarly, the vast majority of horses are not at risk of laminitis from pasture levels of simple carbohydrates.  Despite this, grass “sugar” tends to be blamed for a host of hoof quality issues, hoof tenderness and even thrush when the real cause(s) has nothing to do with sugar.

It is important to be diligent about correctly identifying and managing horses with IR as early as possible for the best outcomes.  It is equally important to realize this is a lifetime commitment.  At the same time, remember that the vast majority of horses do not have this issue and there is no reason to be unduly restrictive with their turnout or diet and certainly no need to buy into a long list of supplements to treat or prevent a condition they do not have.

Eleanor Kellon, VMD

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The Foundation for Strong Immunity

There are many herbs, plant or bacterial extracts and probiotics that can stimulate the immune system but they won’t help if the horse’s body does not have the basic raw material it needs to respond. That comes from the diet.

Macrophage Engulfing Bacteria (the ovals)

You may not think of them this way, but basic vitamins and minerals play a crucial role in your horse’s immune system.

Magnesium: Magnesium maintains function of T lymphocytes. Magnesium also participates in the regulation of inflammatory cytokines.

Copper: Forms the active center of the antioxidant superoxide dismutase. Copper maintains the structural integrity of skin, mucus membranes and lymph nodes. Required for normal production of the neutrophils, a type of white blood cell.

Zinc: Like copper, zinc can form the active center of antioxidant superoxide dismutase. Zinc is important at multiple steps in the production of immune system cells and their function including direct cellular killing of organisms as well as antibody production.

Selenium: A selenium enzyme keeps the antioxidant glutathione functioning. Selenium is involved in antibody production.

Iodine: Iodine forms the core of thyroid hormones. Thyroid hormones influence T lymphocyte numbers and activity.

B Vitamins: The B vitamins are essential for all rapidly dividing tissues, including white blood cells in the bone marrow and lymph nodes.

Vitamin A: Vitamin A deficiency depresses immune system functions across the board, including antibody production.

Vitamin E: Vitamin E is an antioxidant and has far-reaching effects in the immune system including increasing immunoglobulin (antibody) levels in mare’s colostrum and in their foals.

Vitamin C: When fighting a disease the immune system generates huge amounts of oxygen free radicals. Vitamin C is the antioxidant that protects structures inside the cells from also being damaged and protects the lungs from environmental free radicals.

These are the major players with roles possible for other nutrients as well such as chromium and vitamin D.

There is a place for immune stimulating products but before considering one it’s vital to put the foundation into your horse’s immune system with a good vitamin/mineral supplement. It may be all you need.

Eleanor Kellon, VMD

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These Are Not True Symptoms

There has been an insidiously growing trend to label certain observations as indicators of a disease/disorder when actually they are really almost universal aspects of normal equine behavior. If you are trying to convince an owner to buy a product or service based on these observations you are set to make a killing.  If you are the owner being targeted, you could be wasting a lot of worrying – and money – for nothing.

Sensitivity to touch is too nonspecific for a diagnosis

Girthiness:  Resistance to having the girth tightened, or even reaction to pressure along the midline of the lower abdomen, is typically blamed on gastric ulcers.  This makes no sense anatomically since the stomach sits high in the midline of the abdomen with colon between stomach and lower abdominal wall.  Higher up it is flanked on either side by the spleen and the liver.

Furthermore, you have to search far and wide to find any horse that does not react in some way to having the girth tightened. Some just pin their ears. Some take a deep breath and hold it.  Others actually kick or snap.  In short, horses don’t like having the girth tightened.

Flank sensitivity to touch:  Sensitivity to touch in the flank is similarly blamed on a gut problem, typically hind gut “ulcers” or “leaky gut”, sometimes ovarian issues, but once again this is a very common reaction even in normal horses.  The flanks are a vulnerable area.  They lack the thick skin and dense fat layer that protects the hind quarters and without the ribs are a direct portal to internal organs for a predator.  All  horses are protective of their flanks and reactive to touch here, especially if they do not know it is coming.

Weak going to the right:  Weakness traveling to the right or trouble holding the right canter lead, falling to the inside on the right lead have been blamed on a problem with the cecum (usually acidity) or even neurological disorder.  Horses, like people, have a strong and a weak side.  The vast majority of horses are stronger going to the left and similarly most riders are better going to the left.

Kidney pain:  Sensitivity to pressure along the topline of the back is sometimes said to indicate kidney disease.  However, the kidneys are well protected underneath the ribs/spine and with a layer of encompassing fat.  Kidney disease is extremely rare in horses.  When it does occur, pain on pressure in this area is not a part of the picture.  With back pain look for bone or muscle disorders as the cause.

What if these findings appear suddenly; are a change from the horse’s normal behavior?  Those are valid observations, and important ones, but it’s also important to remember that increased sensitivity to touch/not wanting to be touched is a common and very nonspecific indicator that the horse is in pain or does not feel well.  It doesn’t necessarily tell you anything about why.  Poor concentration and resistance to cues under saddle are also common nonspecific changes.

With any question about how the horse is moving you should start with a good old-fashioned thorough lameness and neurological examination. Always rule out a training or musculoskeletal issue before buying into more esoteric explanations.

Eleanor Kellon, VMD

 

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Spring Grass Laminitis

Spring is the peak time for grass-associated laminitis in most parts of the world. You can effectively treat or, better yet, prevent it but only if you understand the mechanism.

Photo courtesy of Rebecca Scott

A fat pony is the pasture-child for grass-associated laminitis

First, what it’s not.

There is zero evidence to support the idea that naturally occurring spring pasture laminitis is related to fructan and hind gut fermentation.  In fact, all research points to it being caused by high sugar/starch and insulin resistance.  Therefore, products like the antibiotic Founderguard or hind gut buffering agents will not be effective.

Animals at risk are ponies, minis, donkeys, full size horses of breeds prone to insulin resistance and pregnant mares. There may be a history of prior episodes of spring grass laminitis in the individual or their relatives.

Although there is a desperate need for well designed studies to look at this in horses,  a factor in addition to sugar/starch levels in rapidly growing grasses is their magnesium content. In all species studied, low magnesium status worsens insulin resistance while replacing it results in improvement.

Grasses with magnesium less than 0.2% and potassium 3% or higher can cause magnesium-related problems in ruminants.  This is most likely to occur in rapidly growing grasses and made worse by fertilizers containing potassium.  If animals cannot be removed from pasture, supplement with 8 to 10 grams of magnesium/day for an average size horse. However, there is no guarantee this will actually be protective.

Limiting grazing time is not always an effective preventative, at least in part because horses given restricted grazing time have been shown to consume grass at 3 times the normal grazing rate.  As owners of affected animals can tell you, it does not take a long grazing time for susceptible equines to eat enough to cause laminitis.

The best prevention is to avoid access to spring grass completely. You can still turn out for 2 to 4 hour intervals but with a completely sealed muzzle. Feed only hays known to have a combined sugar (ESC) and starch level of less than 10%.  Have minerals analyzed and properly balanced.

If you are dealing with an active case, the above measures still need to be implemented immediately.  The key to stopping the process is eliminating the cause.  If unsure whether your hay is safe, soak it for 1/2 hour before feeding.  A supplement that specifically targets only magnesium, phosphorus, copper, zinc, selenium and iodine will cover the most frequently found mineral deficiencies until a hay analysis can be obtained.  Chromium is useful for hays grown on alkaline soils.

Radiographs and a trim to make sure the hoof wall is tightly aligned to the internal structures is very important in both comfort and preventing any further damage.

Pain control is always understandably a major concern but important to realize you can’t control pain without removing the cause (above). NSAIDs like flunixin, phenylbutazone or firocoxib are reasonable for a few days but actually are not very effective for pain relief because features of other types of laminitis such as inflammation, enzyme activation and endotoxemia do not apply to grass induced laminitis.

Once the correct diet and trim are in place, very good results have been obtained by supporting circulation to the feet with Jiaogulan, L-arginine and L-citrulline to fuel production of the vasodilator, nitric oxide.

Preventing spring grass laminitis is certainly preferable to treating it but effective measures are available if you are faced with this challenge.

Eleanor Kellon, VMD

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Designer Salt

Salt, sodium chloride (NaCl), is arguably the most important mineral.  Animal life is believed to have emerged from the sea. Blood has many similarities to sea water, including a high concentration of sodium and chloride.

                                                             Salts of many colors

Salt is the only mineral for which the horse has an innate taste. Feral horses will make periodic pilgrimages to areas of natural salt deposits. The importance of salt to health, even life, is not debatable.

Without a doubt, your horse needs salt. Does it matter what type of salt? Not to his health.

Concentrated salt deposits are the beds of ancient seas which have dried up. They may be on the surface (salt flats) or underground, including under the ocean floor. Like all natural mineral deposits they are contaminated to varying extents by other minerals.  The table salt you buy in the supermarket has been purified of the contaminating minerals.

This is no different from calcium, magnesium etc. supplements you buy. They are mined, cleaned of most if not all contaminating minerals then packaged and sold.

Raw salts have different colors depending on their contaminating minerals. Somewhere along the line someone got the bright idea that these basically dirty salts were more desirable, even offered a health benefit because of the myriad contaminating minerals they contain.  Problem is, the mineral profile of raw salts has virtually nothing to do with the mineral requirements of your horse. When beneficial minerals are present it is in miniscule amounts. There are also many other minerals present, even in larger amounts, that are not nutritionally important or are downright toxic.

For example, a typical analysis of one popular “natural” salt’s trace minerals shows silicon (no deficiency ever noted), aluminum (potential toxic) and fluoride (potential toxic) as the three with the highest levels.  It would take 150 kg (330 pounds) of this stuff to meet the average horse’s daily zinc requirement.  Of the nutritionally important trace minerals, iodine level is highest but 2 oz would provide only 17% of the minimum daily requirement, much less than regular iodized salt.

Bottom line is that unrefined salt has zero health advantage over refined table salt. Despite this, you will be paying at least three times more for this raw material than you would for the purified version of exactly the same thing.

The bogus health claims and inflated price are bad enough but some places are turning things up another notch. It is claimed that standard loose salts and salt blocks are almost useless and potentially dangerous. They are also said to be bleached and altered with chemicals, among other things.  There’s simply no truth to this.

Cooks often use different raw salts in their recipes because they have a subtle different taste.  If you are using one because your horse likes the taste better and you don’t mind paying the outrageous price, fine.  Be sure to read the label carefully though. Some of this stuff has other things added (including flavorings) and is only 40% salt.  Otherwise, think hard before buying into the advertising hype. It really is bogus.

Eleanor Kellon, VMD

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Mud Woes

It’s really hard to come up with anything good to say about mud – except that it’s not ice!  I want to focus on two challenging skin issues which are made worse by mud.  Scratches/Mud Fever and Thrush.

mud

Scratches/mud fever is a skin condition of the back of the pastern, sometimes extending higher up the leg.  It is characterized by heavy, tightly adherent scabs over raw, red and inflamed lesions.  While fungi are often blamed, this is almost exclusively a bacterial infection.  Dermatophilus congolensis is often present, the same organism that causes “rain rot” skin disease on the upper body.

Thrush is an infection deep in the recesses on either side of the frog, in its central sulcus and/or in the space between the heel bulbs. Again, fungus is often suspected but this is really a problem with anaerobic bacteria – organisms that thrive in areas of low oxygen tension. Other bacteria can also be cultured and it is believed some of these create conditions that make it easier for the anaerobic organisms to invade.

Physical measures you can take to help prevent or treat these problems include:

  • Clip the hair on the back of the pastern and fetlock to expose the skin to sun and air
  • Keep the frogs trimmed of flaps (moisture and low oxygen thrive under these)
  • Maintain a balanced trim to avoid shearing forces at the heels which can tear the tissue
  • Check the feet and skin daily
  • Do not keep the horse standing in mud 24 hours a day

There are many, many different treatments for these conditions, both off the shelf and homemade formulas.  I prefer to at least start with herbal ingredients because they can be highly effective and have good residual activity for at least 24 hours, adhering well.

There are two general categories of ingredients to look for.  These are antimicrobial, typically essential oils, and those that condition and support healing.  Salves are better than ointments or creams because they seal better.  To get them into deep spaces like between the heels or the depths of the frog sulci, gently heat by placed a few spoonfuls in a small cup then float in hot water until the product thins.

Antimicrobial ingredients include Tea Tree, Oregano, Calendula, Eucalyptus, Thyme and Rosemary.  For healing support look for Golden Seal, Calendula, Aloe, Comfrey, Oregon Grape, Lavender and Plantain.

To treat skin, remove all surface dirt, clean with warm water and if necessary a gentle, nondrying soap like castile or green soap.  If very thick scabs are present allow lather to sit in place for several minutes before rinsing. This can be repeated to loosen scabs. Rub gently with a wash cloth to attempt to loosen scabs.  If scabs persist, apply your salve then bandage the area. Once scabs come off you can leave it open to the air.

For thrush, clean and wash as above.  Salves should be heated to a thinner consistency that can be injected into the cleft between the heel bulbs and soaked up by cotton balls for packing around the frog.  Keep the horse in a clean, dry area until healed.

Worse than mud is the problems it can cause but with diligent treatment your horse will be healed and ready to go in short order.

Eleanor Kellon,  VMD

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