Winter Laminitis

Frozen lumpy ground can make any horse look lame but if the horse has insulin resistance there may be more going on.

winter-hoof

Winter laminitis strikes with n0 change in diet or management.  The horse does not necessarily have a prior history of laminitis.  The pain is often severe, but the feet aren’t hot as they are in classical acute laminitis cases. The digital pulses may or may not be elevated. Radiographs tend to remain stable in most cases; without major changes with rotation or sinking. NSAIDs (Non-Steroidal Anti-Inflammatories) like phenylbutazone, which are commonly used any time there is foot pain similar to this, have no positive effect.

The body’s normal response to cold is to constrict blood vessels in the periphery to reduce heat losses but in IR horses the reaction appears to be exaggerated. The role of the potent vasoconstrictor endothelin-1 in IR is well-documented. The first study investigating the role of endothelin-1 in laminitic horses looked at it in starch-induced laminitis. The most recent study confirmed that endothelin-1 is involved with laminitis due to elevated blood insulin.

With normal insulin sensitivity inside a blood vessel, the endothelial cells, when exposed to insulin, produce nitric oxide and dilate. If the cells are insulin resistant, and not responsive to insulin, they constrict under the influence of endothelin-1.  A normal horse, with normal circulation, can adapt to the cold and will open and close vessels to perfuse areas before they reach a critical low oxygen level. IR horses have pre-existing damage, even though it may be micro-damage, to the circulation in the feet and there are higher levels of endothelin-1.  Cold triggers a reduced blood supply severe enough to cause pain.

Protection against the cold is therefore the first step in combating winter related hoof pain. Horses should be protected from high winds, rain and snow.  They should be blanketed, wear leg wraps to warm the lower legs and lined boots. Effective lower leg wraps include standard polos and cottons, leg warmers or even fleece lined shipping boots.

This helps, but for some horses is not enough. If your horse ends up with laminitis, even after blanketing and wrapping, supplements to enhance blood flow may help. Herbal products known as “adaptogens” promote healthy stress responses and may be very beneficial. Jiaogulan (Gynostemma pentaphyllum) is a good one to use because it also strongly supports vascular nitric oxide production, which improves blood delivery to the extremities and feet. Jiaogulan can be given twice daily.

The amino acid arginine, as well as citrulline may also be very beneficial in promoting good blood flow to the hoof.   Arginine is the precursor to nitric oxide, which is a vasodilator. Citrulline is converted to arginine after absorption.   Taurine has been found in a recent study to improve insulin sensitivity. L-glutamine is also useful to support antioxidant glutathione and carnitine derivatives to support horses with neuropathic pain and help with insulin sensitivity.

It can be confusing when the horse looks like a typical laminitis case but without the heat and high pulses.  Inadequate blood supply makes perfect sense.  Relief is rapid if you warm the feet and legs, support circulation.

Eleanor Kellon, VMD

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The Ancient Art of Poulticing

Poultices have been in use as long as horses have been domesticated. In fact, they used to be a very common human remedy as well. Major uses for poultices are:

  • to soothe and cool inflamed or overheated areas
  •  to draw excess moisture (edema water) from the skin
  • to draw oils and organic matter (bacterial or insect toxins, edema/inflammatory proteins) from the skin

poultice

With as long as they have been in use you might expect good research to support their use but this isn’t the case. The medical literature is actually pretty scarce but it does support the ability of clays in poultices to draw out harmful minerals are well as proteins that would accumulate in areas of inflammation.

Poultices are commonly applied to bites, abscesses, wounds (not recommended for this unless extremely pure), areas of fresh musculoskeletal injury and as a prophylactic measure following hard work.

A dream poultice product would:

  • have a high capacity to draw organic material
  • be easy to work with and apply
  • remain moist for at least 12 hours with appropriate bandage
  • have low potential to irritate the skin
  • be easy to remove

All of these features are important when picking a poultice you would keep around the barn for general use. In addition, an all purpose poultice should be gentle to the skin and free of ingredients that would generate an irritant/counterirritant effect since this would be contraindicated with acute inflammation.

Feet can often benefit from the cooling and drawing effects of poultices but to remain in place they need to adhere well and not become overly runny when warm. You also want a product that will not become completely hardened to a concrete like consistency overnight, and one that will not overly dry out the feet.

All poultices are based on clays such as kaolin and silicates. They work by drawing inflammatory proteins out of the tissues and also dissipating heat by drawing it from the inflamed tissues into the wet clay and then off by evaporation. Additives such as menthol, witch hazel and camphor produce a cooling sensation on the skin and help block pain. Glycerin helps hold water in the poultice and makes it easy to apply and remove.

In short, poultices are used to cool and soothe tissues after hard work or injury, draw proteins and bacterial products out of areas of inflammation or infection. To accomplish this the poultice must be moist. A poultice can be applied with no outer wrapping but these will dry out the quickest. A layer of plastic holds moisture well but also holds heat. A topping of wet paper helps hold moisture without trapping heat. A standard stable wrap and polo are often applied on top of these. If also wet, they will help the poultice do its job of dissipating heat.

Our tendency today is to go to drugs and high tech therapies but old time treatments like poulticing are still very effective. A container of poultice is something you should consider always keeping in your barn, to deal with problems from insect stings/bites to acute injuries or suspected abscesses. There’s no down side.

Eleanor Kellon, VMD

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Three Supplements Every Horse Needs

A universal requirement for horses around the world is salt, primarily for sodium but chloride can also be deficient.  The diet of all horses is deficient.  Wait.  If that’s true, how

SALT BLOCK

All equine feedstuffs are deficient in sodium and the horse has an instinctive                                                               hunger for salt

did horses survive without people to feed them salt?  Feral horses make regular sojourns to areas with natural salt deposits where they stock up.  Bone has a sizeable reservoir of sodium.  In between, homeostatic mechanisms allow them to hold on to electrolytes in short supply. Left to their own devices, feral horses are perfectly content not to move at a pace beyond a walk so do not normally have excessive sweat losses. They are, however, at risk of severe dehydration if anything upsets this fragile balance.

Research has quantified what daily losses of sodium are and we also know how much is lost in sweat.  There is no harm whatsoever in supplementing those losses as they occur to prevent the horse from going into negative balance.  Doing so ensures optimal hydration, enhances digestion and mineral absorption, maintains normal nervous and muscular function.

In times of the year when fresh grass is not available, the horse’s diet goes from one rich in omega-3 fatty acids (about half of their intake) to one with virtually none because these fragile fats do not survive long in cut and baled hay.  Grains, brans, etc. are also low in omega-3s.

Omega-3 fatty acids are typically thought of as important to antiinflammatory balance but two studies have also shown supplementation boosts immune system responses in general.  They are also pivotal in the development and health of the brain and eyes, and may influence behavior in young horses.

Vitamin E, abundant in fresh plant material, suffers the same fate as omega-3 fatty acids in hay.  As outlined in detail in last week’s blog, there are very real consequences to ignoring vitamin E intake.  Nutritional Russian roulette is not a good approach.

Those are the big three.  Even if your horse is on a supplemented feed or a balancer you are probably not meeting requirements.  A strong case can also be made for selenium, iodine, zinc and copper in most areas but they are not quite as universal as omega-3s, vitamin E and salt.

Cheap insurance!

Eleanor Kellon, VMD

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The Case for Vitamin E Supplementation

Nutritional minimalists take the position that supplementation of a “quality”[not defined] diet is virtually always a waste of money. I recently read this opinion about supplementing vitamin E:  “…Vitamin E deficiencies are occasionally seen in horses that don’t have access to fresh forage, or good quality green hay.  But it’s so occasionally that it’s not worth worrying about in most cases, especially if there is green forage or fresh, high-quality hay.”

GRASS

               Green pasture is a good source of vitamin E; hays, not so much.

There are a quite few qualifiers in that statement – occasionally, in most cases, if – and exactly what is meant by “fresh” and “high quality” hay is unclear. Fresh is particularly important here because E is lost as the hay ages.  Published levels vary a bit, likely depending on how old the hay was when sampled.  Alfalfa is higher than grass hays, with the range for all hay about 30 to 100 IU/kg when cut which drops by 53 to 73% in 12 weeks.

If your horse is mature and basically doing nothing, 10 kg of hay will meet the minimum recommended for maintenance of 1 IU/kg body weight if it is at least 50 IU/kg, so some will do when first cut but within 3 months all hays will be deficient.  For growing, pregnant, lactating and exercising horses the current NRC recommended minimum is 2 IU/kg of body weight so a 500 kg horse eating 10 kg of hay may luck out with a hay that was just cut and has the upper level but this won’t last for long.  How many horses eat only hays that are 1 or 2 months old?

If you feed a balancer or supplemented grain you are not protected either. Amounts are typically too small to meet requirements and vitamin E, even in protected forms, is not stable for long in a feed or mineral mix.  In fact, because of its reactivity as an antioxidant it is commonly used as a natural preservative for the feed.

Inadequate vitamin E intake is associated with a longer list of medical conditions than any other vitamin. These include:

  • Neuraxonal dystrophy (genetic predisposition in several breeds)
  • Equine degenerative myeloencephalopathy (possibly a more severe form of neuraxonal dystrophy , genetic predisposition in several breeds)
  • Pigment retinopathy of the eye
  • Vitamin E deficiency myopathy (newly described, symptoms similar to EPSM)

That’s just the more dramatic examples. Vitamin E protects the integrity of every cell with well documented roles in everything from sperm quality to immunity to athletic performance.

Unlike the other fat soluble vitamins, A, D and K, vitamin E is not stored in the liver.  Although horses with abundant fat may store some extra, the horse basically depends on a constant dietary supply. This is not a vitamin the horse can manufacture himself or absorb after organisms in the intestinal tract make it.

How to supplement can get a little confusing. In nutrition, vitamin E generally refers to alpha-tocopherol but the term vitamin E covers a family of 4 tocopherols and 4 tocotrienols. Alpha-tocopherol is the form active in the body as an antioxidant. “Natural” on a supplement may mean it contains all forms of vitamin E or may refer to the structure of alpha-tocopherol, the d-alpha or l-alpha form.  The d-alpha-tocopherol is the natural, active form, l- being a mirror image which is in many supplements.  The recommendation of 1 IU/kg/day for adults at maintenance and 2 IU/kg/day for other ages and classes refers to a mixture of  d- and l- forms, d,l-alpha-tocopherol.  If using pure d-alpha-tocopherol you can cut the amount in half.  Supplements labeled “mixed tocopherols” or “full spectrum vitamin E” contain 8 eight forms. To know how much to give you would have to know how much of the alpha-tocopherol is in it.

Supplementation isn’t expensive. This is one vitamin where dietary levels and requirements are well worked out.  Don’t skip it.

Eleanor Kellon, VMD

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Feeding for Healthy Weatherproof Hooves

There is a reason hoof supplements have a sizeable market.  There is also a reason they tend to have the same ingredients.

poor-hooves

        There is often a strong nutritional component to poor hoof quality

The quality and integrity of the hoof wall, as well as resistance to infections, results from an interplay between genetics, hoof care/trimming and nutrition.  Genetics can’t be changed.  Inadequate hoof care is a huge factor that can result in things like cracks and flaring even in the strongest hooves.  However, nutrition also plays a very important role and the hooves can mirror several common dietary deficiencies.

The hoof wall is over 90% protein. Protein deficiency severe enough to influence hoof growth or quality is unusual, but individual amino acid deficiencies are not – including methionine, needed for the cysteine which forms strengthening sulfur linkages.  Lysine is another often deficient amino acid that is important in hoof protein. 

A healthy hoof has shine and a slick feeling to its surface.  This comes from a network of fats and waxes.  These are easily manufactured by the cells so there cannot be a fat deficiency per se but horses on hay rather than pasture have very low fat intakes and may have dry coats and hooves that respond well to some fat supplementation.

Zinc is required for every step of cell activity in the keratinocytes that form the hoof structure, as well as for forming the structural protein of the hoof wall.  Zinc is also the most commonly deficient mineral in the United States and around the world. Studies have confirmed that low zinc status results in slow hoof growth, weak connections, thin walls and weak horn.

Zinc and copper together also play a key role in protecting the fatty layers of the hoof wall. Hooves, like fingernails, have a shine and slippery feel when healthy. This comes from fats incorporated into their outer structure, which keep environmental moisture out but critical tissue moisture in. Zinc and copper are essential components of the antioxidant enzymes that protect those fats.

Copper is also required for enzymes that form the reinforcing protein cross-linkages in hoof tissue. Hoof issues linked to copper deficiency include cracks, sole hemorrhages, abscesses, thrush and laminitis.

Of the potential nutritional causes of poor hoof quality, trace mineral deficiencies are the most common. To correct this, you need to supplement with good levels of copper and zinc in a supplement with low or zero levels of manganese and iron which can compete for absorption of those minerals. Many horses will also benefit from some supplemental fat and the amino acids methionine and lysine.  The results will speak for themselves.

Eleanor Kellon, VMD

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How To Make Your Own Feed

Feed companies have been around for quite a while (Purina dates back to 1894) but many operations still mix their own feed.  There are pros and cons.

grains

A big plus is cost. Even if you give a formula to a mill to mix and bag for you, cost is likely to be half what you now pay for a bagged feed.  You get to pick only the ingredients you want and can avoid anything you know your horse does not tolerate well.

Another big plus is uncoupling minerals and vitamins from calories. You can add the supplements you need for your hay to as large or small a serving of “grain” as you choose.  You also know exactly how old the mixture is, can avoid things that can accelerate organism growth (like molasses) and can check the quality of individual ingredients before they are fed.

On the negative side, fungal toxins are a concern. They are in commercial feeds also but most companies do having some screening procedures in place. Best to avoid high risk ingredients like corn, seed meals and brewers’ or distillers’ grains in a homemade mixture.  You also need to make sure your ingredients are at least balanced for calcium and phosphorus; trace minerals as well if feeding more than 1 kg/day.  There is time involved in designing the feed and mixing ingredients daily (or having it done through a mill) compared to reaching into a single commercial feed bag but it’s actually not all that much.

A popular option is to use a vitamin and mineral mix matched to the hay and a fresh mixed feed with a naturally balanced calcium:phosphorus ratio.  You can then adjust the “grain” up or down as needed without changing the amount of minerals fed.  I use a target Ca:P ratio of 2:1 or less in the feed.  Calculating this is relatively easy.  Convert the typical calcium and phosphorus percentages to a whole number by multiplying by 100; e.g. 0.25% phosphorus becomes 25. Using some commonly available US feed ingredients it looks like this:

Feed Ingredient Calcium Equivalents Phosphorus Equivalents Typical Protein (%)
Alfalfa meal or pellets 147 28 15
Beet pulp 94 9 9
Heavy weight oats 1 41 11
Rice bran 7 178 15
Wheat bran 13 118 18
Flaxseed 22.5 57 27
Split dried peas 12 45 25

A simple combination is equal parts of beet pulp and oats = 94 + 1 calcium equivalents and 9 + 41 phosphorus equivalents = 95:50 for a ratio of 1.9:1.  Another is one part alfalfa and two parts oats = 147 + 2(1) calcium and 9 + 2(41) phosphorus = 149:91 for a ratio of 1.64:1.

A good online source for nutrition information on other possible ingredients is http://www.feedipedia.org.

Maximize feed freshness and quality, improve vitamin and mineral nutrition and do it while saving money.

Eleanor Kellon, VMD

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Hay Analysis in Equine Nutrition

If you think a hay analysis is just something else unnecessary to waste your money on, please reconsider.

hay-analysis

The dairy and beef industry has been utilizing hay analyses since the 1800s.  Why? Because it saves them money through maximized milk production, peak reproductive efficiency, best growth rates, fewer infections, less diarrhea, better response to vaccinations, higher meat, hide and milk quality and strong, sound hooves.

Part of the analysis gives information on protein, calories, fiber, fat and simple carbohydrates.  Equally, if not more, important is the mineral information.

Even if you don’t pay much attention to it, you probably wouldn’t feel comfortable buying a bagged feed for your horse that did not have an analysis.  You trust something labeled for horses to be appropriate for horses.  However, for most horses that bagged feed is no more than 25% of their diet.  What about the rest of it?  The hay is introducing a host of potential deficiencies, excesses and imbalances into the major portion of your horse’s diet.

Everyone has heard the precautions to not feed pets table food because it could upset the  careful balance achieved in their pet food.  Why then do you feel comfortable giving your horse a diet that is 75% nutritionally unknown?

Feeding a supplemented feed or using a “balancer” does not mean all problems are solved.  These help bring the totals for individual  minerals closer to their minimal requirements but more often than not are unable to correct significant mineral imbalances.  Because minerals compete for absorption, even a mineral that is at its minimum requirement can be crowded out enough to cause a deficiency.

These widespread deficiencies are a major reason why there is a flourishing market for hoof and coat supplements.  They’re not going to kill the horse but impact every aspect of health including fertility, tendon and ligament, immunity to infections and wound healing.

Throwing a lot of supplements at the horse without knowing what is actually needed for your specific diet won’t fix the problem.  There is a widespread but very mistaken impression that all alfalfa needs one set of minerals and all “grass” hays can be balanced by one supplement formula.  The fact is that while all alfalfa has excessively high calcium, calcium in grass hay is variable and levels of all other minerals varies tremendously between individual hays.  Factors include type and strain of hay, soil type, geographical location, rainfall, organic matter in the soil, stage of growth, type and amount of fertilizer or soil treatments such as liming.

The solution is simple.  Get a hay analysis.  If hay changes too frequently for that, at least research the regional figures for where the hay was grown.  You will save by supplementing only what your horse truly needs and in the correct amount.  The health benefits are tremendous.

Eleanor Kellon, VMD

 

 

 

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