Speed Up Shedding

Wouldn’t it be great if horses just slipped out of their winter coat like a snake shedding its skin?  Unfortunately, at best it’s not even close but there are factors that can slow it down which you should be aware of.

hair

There are some health conditions associated with delayed shedding including parasitism, pituitary pars intermedia dysfunction (Cushing’s) and an underfunctioning thyroid.  Definitely get diagnostics done if the horse has any other indicators he may be suffering from one of these.

Exercise is your friend. It increases blood flow to the skin as well as production of sweat and sebum which help shepherd out those old hairs.  Turning the horse out in an area where he can get a good roll will also reduce the level of sheer labor you have to put into getting rid of that hair.

If you find the horse starting to lag behind in shedding and the coat turning a burnt orange color, especially if there are also issues with dry, flaking skin, consider nutritional support. Several key nutrients for skin and coat health have been identified.

Hay begins to lose vitamin A activity 6 months after baling.  By 1 year it is often too low to meet requirements.  This typically coincides with late winter/early spring, before the grass has come in well or that year’s hay has been baled.  The more faded from bright green the hay has become, the more A loss there has been.  Target supplementation until the horse goes on pasture or that year’s hay is available is 20,000 to 40,000 IU/day.  If the horse is not already getting this much from supplements or grains, add it separately.

The amount of fat a horse requires in the diet to support life is considerably less than what will give you optimal skin and coat health.  A shiny smooth coat, supple moist skin and good local immune defenses result from supplementation of as little as 4 to 6 oz/day.

Biotin is also extremely important for skin health and skin cell division.  Dry, flaking skin can signal suboptimal biotin intake.  No specific daily requirement has been established but research into the effects of biotin on hoof quality have repeatedly demonstrated an intake of 20 to 30 mg/day provides best results. [Note: The hoof wall, sole and frog are specialized forms of skin.]

Finally, inadequate intake of protein in general or specific amino acids will adversely affect hair growth.  If your hay is of poor quality or a very late growth stage cutting you may need more protein from high quality sources like soy and whey. Otherwise it may only be lysine and methionine you need to supplement.  Give 10 g/day of lysine and 5 of methionine.

Whether you have a horse  hanging onto a horrible looking old coat or you just want to support skin and coat to make the process as smooth and quick as possible, plugging the nutritional gaps in your horse’s hay should do the trick.

Eleanor Kellon, VMD

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Sneaky Small Strongyles

Currently the most popular management strategy for the control of intestinal parasites is to deworm based upon fecal egg count results.  This developed because of concerns that the prior approach of routinely deworming at regular intervals was increasing the number of parasites with drug resistance.

The rationale is that if you decrease exposure to deworming drugs you will slow the appearance of resistance.  An integral part of the new approach is to not deworm horses with only low fecal egg counts, to keep unexposed parasites in the population.  Theoretically this will slow the spread of resistance but there may be a price to pay.

cyathostome

from University of Pennsylvania

For one thing, there are reports that large strongyles are making a come back.  These parasites, aka “bloodworms”, were a very significant scourge in the days before ready availability of paste dewormers.  Their immature forms migrate extensively for months in the gut wall and the blood vessels, often causing damage that results in chronic colic for the life of the horse, acute colic from obstructed blood flow or crippling clots in arteries feeding the hind legs.  Now that many horses are only being dewormed once or twice a year, they have a better chance to do damage in that untreated interval.

A more immediate concern is the small strongyles (cyathostomes); recognized as the major intestinal parasite of today’s horses. Infective larvae hatch from the eggs. Inside the horse, the larvae may mature immediately or enter the wall of the intestine to go into a dormant state.

We assume the fecal egg counts are an accurate reflection of parasite burden but that is just not the case with small strongyles.  The encapsulated dormant forms do not lay eggs. Even the adults have highly variable egg laying activity.  Research has shown that egg laying picks up shortly in advance of the time of year when larvae will have the best survival chances on pasture and drops off or stops when environmental conditions are either very cold or hot and dry.

Dormant larvae also seem to adjust the timing of their emergence and maturation to coincide with favorable conditions for the larvae.  Cyathostomiasis is a condition of colic, loss of appetite, weight loss, intestinal ulceration and loss of blood proteins into the intestinal tract.  It is caused by a mass emergence of small strongyle larvae and can actually be fatal.  This is typically observed in late winter in areas that have freezing temperatures over the winter.

Your horse probably doesn’t have enough larvae for a full blown cyathostomiasis episode but could very easily be harboring enough to cause a puzzling colic episode.  Parasite burdens can also delay shedding.

To avoid these issues have a talk with your veterinarian about the timing of fecal exams and drugs used to deworm.  Only moxidectin will reliably remove the dormant forms since there is currently widespread resistance to the five day, double dose fenbendazole (Panacur).  Adults can be killed by moxidectin or ivermectin but if your fecal is taken at a time of year when egg laying could be low you may see a deceptively low egg count.

Don’t be outfoxed by a worm!

Eleanor Kellon, VMD

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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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