Tuesday, December 31, 2024

Welcome to The Equinist

Welcome to "The Equinist", the blog of equine journalist, photographer and horse trainer, Susan Kauffmann. Susan's many articles have been featured in such publications as EQUUS, Trail Blazer, HorseCare, and Western Horse Review, for whom she has also served as Health Editor. In addition, Susan has written content for equine-related courses for Michigan State University's MSU Global program, she presents educational seminars for horse owners, and her reference guide to the equine hoof, The Essential Hoof Book, is scheduled for publication in September of 2017. If you would like to see some of Susan's equine photography, please visit: EquineShots.blogspot.com and WildOnesMustangs.blogspot.com.

I love writing for horse magazines and feel extremely privileged to do so. However, it has always frustrated me that once an issue is off the shelf, people no longer have easy access to the information in the articles. It is also frustrating at times to be unable to express my own opinion in the articles I write, especially on subjects I care very deeply about. I therefore decided to create this blog as an antidote to those frustrations -- a place where I can make my work permanently available in hopes that it might benefit horse owners seeking information, and a place where I can speak my mind freely on horse related issues and products.

I would also like to invite readers to post their questions and comments here (try my "Ask The Equinist" column!), and I will do my best to answer you if I am able. Thank you for visiting "The Equinist", and happy trails to you all!

To contact me, click on the link that says "THE EQUINIST" under where it says "About Me" on the lower left side of the main page, and you will find another link that says "email me".

Addendum: For those of you who have asked, the image above is a digitally enhanced photo of my morgan, Gryphon. Yes, he really is that pretty, but no, he doesn't have calligraphic markings -- wouldn't that be something?

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Thursday, June 8, 2017

"The Essential Hoof Book" to be released in September, 2017!

NOW AVAILABLE FOR PRE-ORDER from Trafalgar Square Books, Amazon, Barnes & Noble, etc. Scheduled for release in September of 2017!

The equine hoof is a complex marvel of natural engineering, built to withstand tremendous forces and able to adapt to an astonishing range of environmental conditions. It also changes daily–for better or for worse–in response to external and internal factors. Few horse owners have the opportunity to acquire a deep understanding of the hoof, which limits their ability to advocate on their horses’ behalf and make informed decisions about hoof care and management. This book is the first resource of its kind to combine the most current and useful information available, gleaned from the research and wisdom of top hoof experts around the world, with a unique “hands-on” approach. Authors Susan Kauffmann and Christina Cline provide basic terms and anatomy, clearly illustrate the differences between healthy and unhealthy feet, discuss biomechanics and management concerns, and cover the causes, treatments, and prevention of commonly encountered problems, including laminitis, white line disease, and thrush. Along the way, readers are given activities to help them better analyze and understand the most important aspects of equine hoof health, such as hoof balance, depth of sole, and point of breakover. Easy–to–follow language, over 400 full–color photographs, and do–it–yourself exercises promise to empower horse owners and caretakers of all experience levels with the tools they need to accurately assess hoof health and keep their horses as sound and happy as possible. Read more!

Saturday, January 3, 2015

Major Minerals: A Balancing Act

By Susan Kauffmann
With special thanks to Dr. Eleanor Kellon

            Most horse owners are aware that minerals are an important part of a horse’s diet.  Some of us try to address this with mineralized salt blocks, supplements or “balanced” feeds, while others believe that a horse will get all the minerals it needs from pasture and/or good quality hay.  Who is right?  Well, like everything else in the horse world, it depends on who you talk to. 
The gold standard for the mineral requirements of horses has long been the National Research Council guidelines, but some researchers and equine nutritionists now feel that these guidelines, published in 1989, are out of date and in need of adjustment.  Some recommend feeding as much as two times the NRC requirements or even more, yet many prefer to stick with the current recommendations, pointing out that there is simply not enough data to support radical changes. 
            Things become even more confusing when you start to look at the interactions of various minerals, the ratios required to keep them all balanced, the bioavailability of different mineral forms, and so on.  Where does this leave the average horse owner?  Should you be supplementing your horse’s diet?  If so, what should you be using, and how much?
            The first step in determining whether or not your horse needs mineral supplementation is figuring out what minerals he is getting in his diet.  The only real way to do this is to have your forage and other feed sources analyzed, then supplement accordingly under the guidance of a well qualified equine nutritionist.  Short of that, there are certain generalizations one can gather about common feeds and forages that are useful when formulating a diet, though far from perfect. 
In addition, it makes sense for all horse owners to try to gain at least a basic understanding of what a horse’s mineral requirements are and how the various minerals affect each other in the horse’s body.  Because a complete examination of these topics would fill a library, this article will focus on the minerals most commonly deficient or out of balance in the average horse’s diet:  calcium, phosphorus, magnesium, copper, zinc and selenium.
            A good place to start is by taking a look at the roles of calcium (Ca) and phosphorus (P) in the horse’s body.  These minerals interact closely with each other and are involved in many important bodily processes, the most significant of which is the development and maintenance of bones.  Another function of calcium is proper contraction of the muscles, including the heart, while phosphorus is needed for kidney function, cell repair and the metabolism of sugars, carbohydrates and fats. 
In order to perform properly, calcium and phosphorus must be present not only in certain amounts, but in a certain ratio to each other – ideally with the Ca:P balance at approximately 2:1.  Most nutritionists agree that healthy adult horses can tolerate a ratio as low as 1:1 and as high as 5:1, but you never want to see the ratio reversed (1:2, for example), as too much phosphorus interferes with the body’s ability to absorb and utilize calcium.  This can cause a serious calcium deficiency, even if the total amount of calcium being consumed is within the NRC guidelines or even higher.  Ultimately, this makes the Ca:P ratio even more important than the total amounts of each mineral.
               Though the importance of the Ca:P ratio has been known for many years, horses are still more likely to suffer from a deficiency or imbalance of calcium and phosphorus than of any other minerals.   In adult horses, this can lead to fractures or mysterious, transient lameness, while growing horses lacking the correct amounts of calcium and phosphorus can suffer from developmental orthopedic diseases such as osteochondrosis and rickets (osteomalacia).  These problems occur because the bones are the body’s storehouse of calcium, so if there isn’t enough of this mineral coming in through the diet, the body will take calcium from the bones to meet other metabolic needs.  This “leeching” of calcium is why horses can end up with weak, brittle bones – or malformed bones and joints in growing horses – if they don’t get adequate amounts of calcium and phosphorus in the right proportion.  The fact that the body will leech calcium from the bones is also why serum testing is a poor indicator of Ca:P status, as there may appear to be plenty of calcium in the blood, but it could have come from the bones, not the diet.
               The most common problem – too much phosphorus in proportion to calcium – can be caused by feeding large amounts of grain or regularly feeding wheat bran or non-calcium balanced rice bran.   Both grains and grain by-products like bran are typically high in phosphorus and low in calcium, which is why it is often better to feed a balanced, commercial grain feed than plain grain.   In the past, it was not uncommon for horses to suffer from “big head” or “bran disease” (nutritional secondary hyperparathyroidism), though this is not frequently seen today.  In this condition, a severely inverted Ca:P ratio causes the concentration of blood calcium to drop, which triggers the release of parathyroid hormone. This hormone then releases calcium from the bone in order to maintain an adequate concentration of blood calcium.   When extensive calcium is removed from the head bones of the horse, the amount of fibrous connective tissue increases, causing the head to actually increase in size.  The head appears puffed or swollen, hence the name "big head disease."  Fortunately, that problem is seen far less often these days, due in part to the awareness modern feed manufacturers have of the importance of the Ca:P ratio. 
                Many horse owners, however, try to do “the balancing act” on their own, and unfortunately,  this can actually make matters worse instead of better.  For example, some owners, convinced that grain is necessary but aware of the high phosphorus levels, try to counter this by feeding large portions of alfalfa, which is known to be high in calcium.  However, it is easy to go overboard with alfalfa, which can skew your Ca:P ratio in the opposite direction.   This can cause a number of problems, particularly for very hard working or endurance horses, as excess calcium affects the body’s production of calcium-regulating hormones, which are then not able to function properly when called upon during extended, strenuous exercise.  The end result for these horses can ironically be insufficient plasma calcium levels, which can lead to metabolic-related disturbances including synchronous diaphragmatic flutter ("thumps").    Excessive calcium can also lead to magnesium deficiency, weakened bones due to changes in the pattern of mineral deposition caused by the secondary magnesium deficiency, and has been indicated in epiphysitis, which is an inflammation of the growth plates. 
            Many nutritionists now recommend that the majority of a horse’s diet should consist of grass hay, which at least usually falls within the range of 5:1 to 1:1 in its Ca:P ratio.  If you do need to increase your horse’s calcium intake (important for pregnant or lactating mares as well as weanlings and growing horses), or you want your horse to have more caloric energy than grass hay provides, you may want to consider adding some beet pulp to the daily rations.  Beet pulp, which is high in calcium, is gaining favor in many corners as the feed of choice to up the calcium and/or energy content in a horse’s diet, as you avoid the possible high protein issues of alfalfa, while at the same time getting approximately the same energy of oats without the glycemic spike of a grain.
               Another mineral that is frequently deficient and must be considered when looking to establish a healthy diet is magnesium (Mg).  Like calcium and phosphorus, magnesium is an important component of bone, but magnesium is also crucial for hundreds of non-bone related functions in the horse.   Magnesium dependent processes include regulation of the insulin response to maintain normal blood sugar levels; proper nerve functioning; protein synthesis for the production and repair of muscle and hoof tissues; normal contracture of cardiac and skeletal muscle, maintaining circulation and preventing blood clots. 
Since magnesium, calcium and phosphorus can interfere with each other’s absorption and utilization, it is important to keep an approximately 2:1:1 ratio of Ca:P:Mg.    
               Magnesium deficiency is thought to be very common in horses, often because of diets too high in calcium and/or phosphorus, but also because magnesium has been consistently depleted in our soils, a situation made worse by the use of potassium and phosphorus laden fertilizers, which alter the ability of plants to uptake magnesium.  Because of this, horses fed only grass or hay without any supplementation are often magnesium deficient, and because magnesium is lost during exercise, hard-working horses can become magnesium deficient if care is not taken.
                 Signs of magnesium deficiency include nervousness, muscle tremors or cramp, poor tolerance for work and in extreme cases, convulsions and even death.   Because of magnesium’s key involvement in nerve function, horses that are commonly described as “high strung” or “spooky” may actually just be suffering from a magnesium deficiency, which is why many products touted as “calming” agents for horses are magnesium based.   Horses that get overly excitable, hyperactive or difficult to handle in the Spring may similarly be magnesium deficient, due to the particularly low levels of magnesium in rapidly growing grasses.  Such horses frequently do calm down when magnesium levels are brought back to normal levels through supplementation.
              Surplus magnesium is excreted in the urine, so excessive magnesium consumption is not generally dangerous in and of itself, although there is some evidence that it may be a factor in the formation of enteroliths (intestinal stones).  The main problem with too much magnesium is its effect on the body’s ability to absorb and use calcium and phosphorus.  Too much magnesium may therefore cause a deficiency of calcium and/or phosphorus, even if the amounts of calcium and phosphorus in the diet are within the recommended levels.  This is why it is so important to consider the ratios of all three of these minerals when attempting to supplement any of them. 
            Yet another ratio that should be considered is that between copper (Cu) and zinc(Z).  Copper is important for the normal development of cartilage, the conversion of cartilage to bone, skin and hair pigmentation, the strength and elasticity of blood vessels, the formation of hemoglobin, nerve conductivity and coordination, prevention of anemia, fertility health and a number of enzymatic functions.  Some of the problems associated with copper deficiency are low fertility in mares, contracted tendons, epiphysitis and other developmental orthopedic disorders in growing horses, anemia, dull and/or “bleached” coats, and a loss of pigment in the skin around the eyes and muzzles.  Some people believe that it can also make horses more vulnerable to bacterial or fungal skin problems like mud fever and rain scald.
            Like copper, zinc is important for many enzymatic functions, acting as both an activator and a co-factor.  There are also more than 200 zinc containing proteins, so it is not surprising that zinc is necessary for healthy skin, bone, connective tissue and hoof growth.  A deficiency of zinc can lead to reproductive problems, a variety of metabolic disorders, as well as bone and cartilage problems, brittle or crumbly hooves, dull coats and dry, flaking skin.
               It is not uncommon for the total amounts of both copper and zinc to be deficient in our horses’ diets, and this can be exacerbated by an imbalance between the two, particularly if there is far more zinc than copper.  It is recommended that the Cu:Z ratio be maintained at a maximum of 1:3, meaning that if your zinc level is more than three times your copper level, you would need to supplement copper.  However, high levels of other minerals such as molybdenum and sulfur can complicate this balance, as these are also known to “tie up” copper, making it unavailable to the body.  In fact, many minerals can influence and interfere with the body’s use of many other minerals, which is one of the reasons why mineral balancing is so complicated.
Minerals are also closely linked to certain vitamins, requiring adequate amounts of those vitamins to be correctly processed and utilized.  One frequently deficient mineral that is well known for its interaction with a particular vitamin is selenium (Se), which works with vitamin-E as part of the cellular antioxidant defense system.  Both nutrients play key roles in the production of enzymes that work to neutralize free radicals that form as byproducts of metabolic activity and as a result of exposure to environmental contaminants. Recent research has also revealed a probable role of selenium in converting thyroxine (T4) to triiodothyronine (T3), which is the tissue active form of thyroid hormone.  It is therefore possible that some of the clinical symptoms often attributed to hypothyroidism in horses are, instead, a result of selenium deficiency. 
               What the horse owner needs to keep in mind about selenium is the fact that while it is deficient enough in many areas to require supplementation, excess selenium is a dangerous poison, and it doesn’t take much to overdose even a big animal like a horse.  Chronic selenium poisoning is an extremely painful condition which can cause separation of the hoof and severe lameness.  In the worst cases, the whole hoof may become deformed and even fall off, requiring that the horse be euthanized.  Acute selenium toxicity, which is sometimes called “blind staggers”, is characterized by apparent blindness, head pressing, abdominal pain, diarrhea, perspiration, increased heart and respiration rates, and lethargy.  Because of the low margin of error in supplementation of selenium, it is particularly important to get professional guidance in regards to this mineral – and to make sure you are not supplementing selenium in an area that already has too much of it, or feeding multiple products that each contain added selenium.
                 If you choose to supplement any individual minerals, be aware that the minerals available at your local feed store are compounds, not pure, elemental minerals, so the amount you need to add must be calculated based on the percentage of elemental mineral in the compound.  For example, calcium carbonate contains 40% calcium, so if you wanted to add five grams of calcium to the diet, you would need to supplement with 12.5 grams of calcium carbonate.  You may also wish to examine the benefits of using organic (chelated) mineral forms as part of your supplementation program, as research suggests that organic minerals have greater bioavailability – meaning that they are more easily absorbed and utilized – than inorganic forms.  Hard working horses in particular seem to benefit from the inclusion of organic minerals in their diets.
                It is also extremely important to keep in mind that adding any individual minerals without taking into account possible toxicity issues, as well as the complex interactions of the entire mineral spectrum, may cause serious harm or potentially dangerous imbalances, and it is therefore recommended that you only supplement individual minerals under the guidance of a qualified equine nutritionist or veterinarian.
                 The table below illustrates the NRC guidelines for the minerals discussed in this article (click on it to bring up all the columns, as they don't all show in this view).  Your nutritionist or veterinarian may very well recommend levels higher than those listed here, particularly for growing horses and pregnant or lactating mares.

            If you are interested in finding out more about minerals and supplementation, we recommend the book Equine Supplements & Neutraceuticals:  A Guide to Peak Health and Performance, by noted veterinarian and equine nutritional expert, Dr. Eleanor Kellon.  A good online source of information is The Equine Cushings Group at:  http://groups.yahoo.com/group/EquineCushings.  Though the site is primarily aimed at owners of horses with metabolic disorders, its files section and archives contain a great deal of excellent information on minerals, mineral balancing, and general nutrition for horses.
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Sunday, June 23, 2013

Hind End Hitch

While there are any number of ailments and injuries that can cause a horse to “go off” behind, some neurological and mechanical problems create specific abnormalities of movement you can learn to distinguish – if you know what to look for. The following guide will help you recognize the abnormalities caused by three ailments often mistaken for one another: upward fixation of the patella (UFP), shivers, and stringhalt. I’ve even included video links so that you can check out the differences for yourself!


Incidence: Fairly common
Etiology: Mechanical, possibly linked to conformation in some cases
Breeds affected: Any

What it is: When in a standing position, the horse has the ability to temporarily “lock” or fixate its stifle joints, allowing the horse to stand and even sleep standing up with minimal muscular exertion.  The joint locks when the patella (knee cap) slides into the upward position, and the medial patellar ligament  (MPL) shifts slightly to the inside and hooks over a notch in the medial femoral trochlea, a knob-like structure located at the bottom end of the femur.  The patella is then fixed in its upward position, keeping the limb extended. Fixation only becomes a problem when the locking mechanism doesn’t release properly when the limb needs to flex.   
There are a variety of factors that may contribute to UFP, but one of the most common is thought to be a lack of tone or condition in the muscles and ligaments in the stifle area In the most extreme cases of UFP, the horse is completely unable to flex the affected leg without assistance.  In the mildest cases of UFP, there is only a brief delay in flexion, without any actual locking of the limb. Horses with UFP may  fall anywhere in between mild and severe. Locking or less severe “catching” may be intermittent. 
UFP is usually present in both stifles, though symptoms are generally seen only on one side.  Examination most often shows that the other side is strongly predisposed to develop the problem, and it is not unusual for the “good” side to become symptomatic after treatment of the initially affected side. 

             What it looks like: The most severe cases of UFP are easy to distinguish: the “locked” leg will hyperextend (stick out behind the horse), and cannot release forward. In moderate cases where the leg “catches” noticeably at times but releases on its own, the leg will remain extended behind the horse for longer than normal, then “pop” out of the locked position, often with exaggerated flexion of the hock. There may actually be an audible pop or click when this occurs. Very mild cases can easily go undetected, as there may not be any observable abnormality in the gait. What you may notice instead is that the horse is reluctant to perform movements that require it to push off with or increase flexion of the affected limb. Whatever the severity, it is quite common for signs of UFP to come and go.
              Because of its variability, some cases of UFP can be difficult to diagnose. “The most common way UFP is identified is by manually pushing the patella up into the fixed position and then having the horse take a step forward,” says equine surgeon and lameness expert, Dr. Dennis Meagher, DVM, PhD, Dipl. ACVS, Professor Emeritus at UC Davis. “If the horse is normal, the patella will unlock once the horse takes a step forward.  But if they are having problems with it catching intermittently, you can usually make it catch manually.  In some cases, it is also possible to feel sort of a clicking or catching if you keep your hand on the area as the horse is walked forward.”
              Prognosis: The prognosis in most cases of UFP is very good. Mild to moderate cases can often be improved with a program of specific exercises, and if that doesn’t work, success is often achieved with counterirritant injections or acupuncture. Severe cases or those that don’t respond to conservative treatment can usually be corrected with a simple, minimally invasive surgery known as ultrasound guided splitting of the medial patellar ligament. This surgery is a great improvement over the older method of desmotomy, which cuts the ligament entirely and has the potential for serious complications down the line.
              Most often confused with: Moderate cases of UFP are often confused with stringhalt (see below), as the hyperextension of the limb can release into hyperflexion, which looks somewhat similar to the hyperflexion caused by stringhalt.

                      https://www.youtube.com/watch?v=VmEMdcMyGr4 (more severe)


Incidence: Fairly uncommon
Etiology: Unknown, possibly neurological
Breeds affected: Mainly draft horses, but can occur in QHs, warmbloods, TBs

            What it is: There are several theories as to what type of ailment shivers is. While it is generally categorized as a neuromuscular problem, the cause has yet to be determined. Some researchers believe neuropathy is involved, while others are exploring possibilities such as myopathy (muscle disease), genetic and metabolic disorders
What it looks like: According to a 2006 review by the AAEP, “Shivers is characterized by periodic, involuntary spasms of the muscles in the pelvic region, pelvic limbs, and tail. Mildly affected horses show a tenseness or trembling of the hind limbs and sudden jerky extensor movements of the tail that cause it to elevate.  The degree of tail elevation varies considerably in different cases.” In more severe cases, backing up causes the hind limb to raise suddenly upwards and to the side, and the hoof is held in the air for up to several minutes. The raised limb will tremble, and the tail will usually elevate and tremble as well. The horse may exhibit symptoms in one or both legs. More rarely, shivers can affect the front legs, neck, trunk or facial muscles.
             Prognosis: Horses with mild cases of shivers may perform well for years, though the disease is typically progressive, with spasms occurring more often and with greater severity over time. Muscle atrophy and weakness of the hind end is an almost universal consequence as the disease progresses. There is no known treatment or cure, though anecdotal evidence suggests that a low-carb, high fat diet may help some horses.
              Most often confused with: The sudden raising of the limb caused by shivers can resemble stringhalt (see below), but horses with stringhalt do not hold the limb in suspension as horses with shivers do. Stringhalt also does not affect that tail, which is a characteristic sign of shivers.


Incidence: Rare in North America, very rare in Canada
Etiology: Neurological, some cases thought to be caused by ingestion of toxic plants
Breeds affected: Any

            What it is: Explains Andrea Finnen DVM, DES, MSc, Diplomate ACVIM, a specialist in equine neurology at the Caledon Equine Hospital in Ontario, “'Stringhalt' is the lay term for equine reflex hypertonia. There are two forms of the disease; idiopathic and acquired. In idiopathic disease, signs are usually asymmetric with one hind limb affected only whereas in acquired (also known as Australian stringhalt) disease, both hind limbs are affected and a toxic plant etiology is suspected.”
            What it looks like: Stringhalt is characterized by spasmodic, rapid and excessive flexion (lifting) of one or both hind limbs when attempting to move, most often seen at the walk, when turning or when backing. Says Finnen, “The flexion can be so severe that the horse's hoof hits the abdomen.”  In mild cases or in the early stages of disease, symptoms may be hard to spot. Severely affected horses, however, will exhibit obviously abnormal movement, with the legs jerking upwards hard and fast, and possibly a plunging or hopping gait. Hind limb muscle atrophy is present in some cases, and laryngeal paralysis (roaring) is sometimes an accompanying symptom in Australian stringhalt. Symptoms may appear and disappear intermittently.
            Prognosis: Some cases of stringhalt will resolve spontaneously, but others will progress over time. “It is difficult to predict if a horse will respond to treatment and what the prognosis is,” says Finnen. “Some cases will take a long time to recover and may never regain 100% function. There are reports of clinical improvement with conservative treatment such as anti-inflammatory and anti-oxidant medications. In severe cases, myotenectomy can be performed to relieve the tension on the flexor tendon to prevent the mechanical movement of the limb.”
            Most often confused with: The hyperflexion that is the characteristic symptom of stringhalt is most often confused with shivers, but can also be taken for UFP, especially in less severe instances.
 Video link: https://www.youtube.com/watch?v=Cii3DVIxp7w Read more!

Monday, May 13, 2013

Genetic Diseases in Horses: HYPP, HERDA, GBED, SCID, OLWS

Genetic Disease Primer

            The birth of a foal is usually a joyous occasion, carrying with it the hopes, dreams and aspirations of the breeder and the future owner. Reputable breeders therefore put a great deal of effort into matching the right mare to the right stallion, in hopes of creating a foal that will have the qualities most desired in the breed. Unfortunately, that desire to perpetuate certain characteristics, coupled with the tendency to breed as many foals as possible out of horses that have those characteristics, has led to the proliferation of a number of heritable diseases that have very serious consequences. Although the science of genetics has helped us to understand why these diseases occur, and in some cases, provided us with tests to identify carriers, it is up to the horse owning public – especially those involved in breeding – to try to make these devastating diseases a thing of the past.  Here is a run-down of five genetic diseases you need to know about.

The Disease: Hyperkalemic Periodic Paralysis (HYPP)

HYPP is a muscular disease that is caused by a hereditary genetic defect that disrupts a protein called a sodium ion channel, which functions as a gateway in the membrane of muscle cells. The genetic defect disrupts the channel's normal opening and closing, allowing uncontrolled sodium influxes. According to Sharon Spier, DVM, PhD, Associate Professor of the Department of Medicine and Epidemiology at the University of California, Davis, “The sodium influxes change the voltage current of muscle cells, causing uncontrolled muscle twitching or profound muscle weakness. High levels of potassium in the blood usually are present when the disruptions in the ion channel occur.” HYPP is a dominant disease, meaning that a horse only needs to have one copy (from one parent) of a defective gene in order to have the disorder and exhibit symptoms.

Why You Need to Know About it:

HYPP can have profound implications for owners of affected horses, both in terms of care of the horse and breeding considerations. Symptoms of HYPP can range from virtually nothing to unpredictable attacks of paralysis which can lead to collapse and sudden death in severe cases. The cause of death usually is cardiac arrest and/or respiratory failure. Owners of horses with HYPP will most often notice intermittent episodes of muscle tremors that manifest as generalized or localized shaking, trembling, and weakness. “Occasionally,” adds Spier, “episodes are accompanied by respiratory noises resulting from paralysis of the muscles of the upper airway (larynx and pharynx). In cases of mild attacks, muscle tremors may be so subtle as to be detectable only by an experienced clinician performing EMG testing.”
Fortunately, keeping horses with HYPP on a strict dietary and exercise regimen can eliminate or lessen the severity of attacks in many cases. Many HYPP positive horses can lead relatively normal and productive lives if they receive the lifelong management they require.

 Research History and Breakthroughs:

Spier’s research, begun in 1989 and funded by the American Quarter Horse Association, led to the discovery that all horses with HYPP can trace their ancestry back to one stallion: Impressive. For this reason, the genetic defect that causes HYPP is sometimes referred to as “the Impressive gene”.
Dr. Spier and her team at UC Davis made history when they were able to identify HYPP with DNA testing in 1992. HYPP was the first genetic disease that could be identified by DNA testing, and testing soon became widespread for Quarter Horses and breeds that carry a heavy percentage of Quarter Horse blood, especially Paints and Appaloosas.
As for why HYPP became so widespread, this can be traced back to Impressive’s success as a halter horse. In fact, there still exists in the industry the idea that in order for a horse to win at halter, it has to carry the Impressive gene. However, the science does not support this.  Explains Dr. Spiers, “We were curious as to what effect the gene would have on muscle mass, which is just one of the qualities that are selected for in halter horses. We studied muscle cell (muscle fiber) diameter and muscle fiber type distribution (slow twitch and fast twitch fibers) in HYPP positive and negative horses. We found no relationship between large muscle diameter and the gene mutation.”

Where We Are Today:

Dr. Spiers emphasizes that decreasing the incidence of HYPP is important for the long-term health of the Quarter Horse breed. To facilitate this decrease, the AQHA has instituted policies specifically focusing on HYPP.  Says La Donna Wilkinson, Senior Director of Registration of the AQHA, “The HYPP rule was first enacted at the 1996 convention in response to concerns raised by the general membership and in the scientific community as to the adverse physical effects associated with HYPP. Effective January 1, 1998, HYPP was to be recognized as a genetic defect and notification was to be placed on the registration certificate of all foals descending from the stallion IMPRESSIVE. However, at that time testing was not mandatory. Effective with foals born on or after January 1, 2007, all descendants of the stallion IMPRESSIVE are required to be parentage verified and HYPP tested. Any foal testing H/H will not be eligible for registration with AQHA.”
According to the AQHA website, the AQHA will accept HYPP test results only if performed through a licensed laboratory. In Canada, these labs include Vita-Tech Canada Inc., Markham, Ontario; and Maxxam Laboratory at Guelph, Ontario.

What the Future Holds:

Dr. Cecilia Penedo, Associate Director of Service of the UC Davis Veterinary Genetics Laboratory, has noticed a trend in the number of horses being tested for HYPP. “Since the test was made available in the late 1990’s,” she says, “there has been somewhat of a decrease in the number of horses being tested, because a lot of the animals and breeding stock have already been tested.” Unfortunately, widespread testing has not resulted in a drop in the numbers of horses diagnosed with HYPP. States Tammy Canida, Director of Registration Operations at the AQHA, “As of our last statistical analysis, we have not noticed a reduction in the number of affected horses. People are testing them, and I think they know about the disease, but still, some of the traits that those horses have they like as far as what they produce in the show ring. I can’t predict what will happen in the future, but right now, it’s not going away.” One can only hope that further information and education of the public will prompt breeders to be more diligent in their attempts to rid the horse world of HYPP.

The Disease: Hereditary Equine Regional Dermal Asthenia (HERDA)

Hereditary equine regional dermal asthenia (HERDA) is a terrible disease that causes a collagen defect in affected areas of the skin, resulting in a lack of adhesion within the deep layer of skin called the dermis. Like HYPP, the disease affects Quarter Horses and breeds that have a strong component of Quarter Horse blood. The ancestry of most horses diagnosed with HERDA traces back to the prolific sire Poco Bueno on both sides of their pedigree. As such, As HERDA is a recessive trait, both the sire and the dam of a horse must be carriers of the genetic defect for a foal to be born with the condition. Carriers of the gene are not affected by HERDA themselves.

Why You Need to Know About it:

HERDA is a devastating disease that often causes the loss of a horse at the most exciting time for the owner – the beginning of training. The disease causes the outer layer of the skin in the affected areas to split, separate, or peel off completely, most often along the back but sometimes in other areas as well. Even relatively minor trauma to affected areas results in wounds that heal slowly and typically leave depressions (atrophic scars) in the skin. New damage appears frequently, even in the absence of apparent trauma. Traction on the skin may elicit a painful response. Areas of affected skin can range from small and well defined (with a depressed surface) to large regions involving most of the back.
Horses are often diagnosed with HERDA at the age of 2, when training begins and they are put under saddle for the first time. Pressure and movement from the saddle causes the skin to tear and separate, making these horses unsuitable for riding. Sunburn is also a problem for these horses. As there is no cure for the disease, affected horses are often euthanized due to quality of life issues and the fact that they cannot be ridden or bred.  Though some individuals have lived longer with careful management and medical care, the average lifespan for a horse with HERDA is 2-4 years.

Breakthroughs/Where We Are Now:

Recently, a genetic test was developed that can identify normal, carrier and affected horses. Says Dr. Penedo, “The mutation that causes HERDA was identified by Dr. Danika Bannasch, here at UC Davis, in 2007.  We now offer a genetic test for the disease, and there are a lot of horses being tested. Owners and breeders, certainly the ones that are in the section of the quarter horse population affected by it where the incidence is higher were certainly aware of it. However, it is obvious that the problem goes beyond the cutting horse segment of the population, so greater awareness is necessary.”

What the Future Holds:

Responsible breeders in all segments of the stock horse world are taking advantage of the test to eliminate HERDA from their breeding programs, and it is hoped that the incidence will soon begin to decrease. Because the disease is so destructive, it would be best if breeders would not continue to breed HERDA carriers. However, because breeding a carrier to a non-carrier prevents the production of affected horses, it is likely that some breeders will find this an acceptable practice, allowing the gene to remain in the breeding pool.

The Disease: Glycogen Branching Enzyme Deficiency (GBED)

GBED is a recessive genetic disorder that results in the lack of a particular enzyme involved in the storage of glycogen, a type of sugar. The foals lack the enzyme necessary to store glycogen in its branched form and therefore cannot store the sugar molecules necessary to support body or brain function. The genetic mutation traces back to Quarter Horse sire King or his sire, Zantanon. It is estimated that up to 8% of Quarter Horses and Paint horses carry the GBED defect. Unfortunately, pedigree analysis is not particularly helpful in identifying GBED carriers because both King and Zantanon are foundation stallions.

Why You Need to Know About it:

GBED affects Quarter Horse or Paint horse foals, causing abortion or high neonatal mortality. This disease is fatal as the heart muscle, brain and skeletal muscles are unable to function. Affected foals are often aborted in late term or are stillborn. If the foal is born alive, it will be weak, slow to stand and nurse, and it will have a low body temperature. It may also have mildly contracted tendons. Medical intervention may allow a GBED foal to survive for a while, and some may even show signs of improvement before deteriorating again. Others might initially experience respiratory distress, collapse from hypoglycemia, seizures, then sudden death. Even with the best care, most GBED foals will not survive longer than eight weeks.
James Mickelson, PhD, Professor of Biochemistry and Genetics, University of Minnesota College of Veterinary Medicine, notes, “The most common result of GBED is mid-late term abortion, and not the weak foals that people note and try to treat. Thus, a large percent of the GBED problem is going unrecognized and unreported.”

Breakthroughs/Where We Are Today:

It was Dr. Mickelson and Dr. Stephanie Valberg, also at the University of Minnesota, who first identified this deficiency and developed a test to detect the defective gene in 2004. However, it is now believed that GBED has been causing significant fetal and neonatal losses among stock horses for decades.  It is therefore recommended that foal owners try to identify a GBED foal as soon as possible to limit the financial and emotional investment involved in trying to save a foal that is terminally ill. Because it can be difficult to diagnose GBED clinically, suspicious foals (alive or stillborn) should be diagnosed through genetic testing, which is available through the Veterinary Genetics Lab at UC Davis using mane or tail hairs with intact roots, or samples of fetal liver tissue.

What the Future Holds:

 Identifying GBED foals will also help breeders make decisions about continuing to breed carriers of the disease. If a GBED foal has been produced and they choose to rebreed the same mare to the same stallion, they have a 1 in 4 chance of producing another doomed foal. A DNA test is also available to determine whether a horse is a carrier of the deadly disease or not.
Unfortunately, the horse community is not availing itself of testing for GBED as much as researchers hoped they would when they first began offering the test. Says Dr. Penedo, “There is less interest in testing horses for GBED than for HERDA,” she says, “and definitely less than for HYPP. It’s difficult to say why there hasn’t been as much interest generated, as there is no treatment and the disease is inevitably fatal, if the foal is even born alive.” If people don’t test their horses, foals will inevitably continue to be lost.

The Disease: Severe Combined Immunodeficiency (SCID)

SCID is a deadly genetic disease that affects primarily Arabian horses and part-bred Arabians. Like people with the “bubble boy” condition, SCID foals are born without a functioning immune system. The immune system has two major defense systems: the B-lymphocytes which produce antibodies, and the T-lymphocytes which are responsible for cell-mediated immunity. The SCID defect, or mutation, results in an inability to produce either kind of lymphocytes. Foals with this condition therefore have an enhanced susceptibility to infection and generally first show signs of disease between two days and eight weeks of age. Clinical diagnosis of the disease is generally difficult because the symptoms, such as raised temperature, respiratory complications and diarrhea, are typical of new-born foals with a range of infections. Currently, it is estimated that 28% of Arabian horses are carriers of SCID.

Why You Need to Know About it:

The sad reality is that SCID affected foals always die within the first six months of life, regardless of the level of veterinary care provided. Because the foal may not be identified as suffering from SCID, owners often make great emotional and financial investments in trying to save the foal. As this can go on for some time, it is particularly distressing.
Because the gene that causes SCID is recessive, adult horses may be carriers of the gene, but will not be affected by it themselves. Owners of Arabian and part-bred Arabian horses who are considering breeding their animals need to be aware of this disease and the implications of breeding a carrier animal.

Research History and Breakthroughs:

            The Arabian horse community first became aware of SCID in the 1970s, but at that time, it was extremely difficult to definitively identify carriers. Recalls chair of the Arabian Horse Association’s task force on genetic diseases, “When the Arabian horse community was faced with SCID back in the 1970s and 1980s, it responded with the formation of the Fight Off Arabian Lethals (FOAL) Commission to help educate owners and support genetic disease research. Since that time, a test for SCID has been developed, over 8,000 horses have been tested, and the AHA Code of Ethics has addressed SCID disclosure in the Code of Conduct. The lesson to be learned from this is that focused efforts can be very successful.”
            The genetic test for SCID was developed by a private biotechnology company in 1998. It is now licensed to VegGen, a genetics services and research laboratory that was formed in 1995 as a spin-off from the University of Michigan Department of Human Genetics and the Michigan State University College of Veterinary Medicine.

What the Future Holds:

It is hoped that the newly established genetic diseases task force announced earlier this year by the Arabian Horse Association will help reduce the incidence of not only SCID, but other heritable diseases that affect Arabians and other horses. Says AHA President, Lance Walters, “The purpose of the task force is to have a group of AHA members regularly focused on genetic diseases," said Walters. "The end result will be an Arabian horse community that is educated about genetic diseases and knowledgeable about testing and disclosure. The task force will guide the association in developing policies and educational programs to educate the Arabian horse community about genetic diseases associated with the Arabian breed.”
Currently, there are no regulations requiring testing of Arabian horses for SCID, and even those who do test their breeding stock do not always disclose the results for fear of their animals being ‘boycotted’. There is quite a bit of controversy over whether or not outstanding individuals who are also carriers should be allowed to breed, with heated opinions on both sides. Some feel it is necessary to breed them – albeit carefully – in order to preserve desirable characteristics. Others feel that the only way to rid the gene pool of this devastating disease is to avoid breeding carrier animals altogether. For now, it remains an individual decision.

The Disease: Overo Lethal White Syndrome (OLWS)

OLWS is an inevitably fatal recessive disease that affects Paint horses and other breeds that have Paint blood in them. Though the genetic defect is commonly associated with a certain type of overo coat pattern, the defect has in fact been found in overos, tobianos, toveros, solid-colored horses, crop-out Quarter Horses and pintos.  In terms of breeds, it has been found in Paints, Miniature Horses, half-Arabians, Thoroughbreds, and cropout Quarter Horses.
 OLWS foals are born completely white (or occasionally with small black areas) and suffer from an improperly developed intestinal tract caused by a failure of the embryonic cells that form parts of the gastrointestinal system. In most cases, the intestine does not reach the anal opening, making it impossible for food to pass completely through the foal's digestive system. Attempts to surgically bypass the problem have, to date, been unsuccessful.  

Research History and Breakthroughs:

            The genetic defect that causes OLWS was first identified in 1998 by a team led by Elizabeth M. Santschi, DVM, Dipl. ACVS, Clinical Associate Professor at the University of Wisconsin's School of Veterinary Medicine. In 1991, this same team more accurately determined the coat patterns associated with OLWS in newborn foals. Not all overo horses are phenotypically (how they look) or genotypically (what genes they carry) the same.  There are four distinct overo subtypes--frame, calico, sabino, and splashed white—and not all overos produce affected foals, which left questions about which subtypes are affected. The 1991 study found that in heterozygotes (horses with one normal and one defective allele in the responsible gene), the mutation is usually responsible for a frame overo pattern. However, since frame overos' characteristic pattern can be altered through breeding to horses with other patterns, accurate visual inspection of carriers of the defective gene can be difficult due to blending of the patterns.
It was also found that other genes control both overo and tobiano (the other main type of white patterning recognized by the American Paint Horse Association) patterning besides the one that causes OLWS. Therefore, researchers concluded that the DNA-based test is the only way to be certain whether a white-patterned horse can produce a foal affected with OLWS.

Why You Need to Know About it:

            Foals with OLWS die in an agony of colic if they are not euthanized. The foals initially appear normal except for their unusual white coloring and light eyes. The typically stand and nurse normally, but will fail to have a bowel movement after nursing or an enema. Signs of colic or intestinal cramping begin within twelve hours following birth, caused by the foal's inability to pass feces. In most cases, the foal will start to show signs of distress within three to five hours after birth by rolling up on their back repeatedly.  They can survive for up to several days if they are not released humanely from their suffering. This heartbreaking disease appears quite commonly in the yearly foal crop of Paint horses.

What the Future Holds:

            Although the APHA was financially involved in the research that led to the genetic discoveries related to OLWS, they do not currently regulate the breeding of OLWS carriers or require disclosure for registration purposes. Reducing the incidence of this disease or eliminating it altogether is the responsibility of individual breeders. Testing is highly recommended for anyone considering breeding their Paint or related horses, as the gene appears to have a relatively high prevalence.

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Saturday, December 1, 2012

SLOW FEEDING: How getting closer to nature can make your horse -- and your wallet -- happier and healthier

In recent years, many people have started to discover that a diet closer to what horses eat in the wild – mostly forage with little or no grain – can have great health benefits, including a lower incidence of gastric ulcers and colic. However, it turns out that how wild horses eat may be just as important as what they eat. Proponents of “slow feeding” – using feeders that cause the horse to consume their hay more slowly – believe that this practice has many benefits – for both horses and owners.     

            Studies of horses living in natural environments have revealed that horses generally graze up to 16 hours a day, rarely going without eating for more than a few hours at a time. As native grasses tend to be relatively sparse, free-living horses often get only a few blades of grass before they must walk to the next little mouthful. This type of grazing takes time, providing a small but steady intake of food – which is exactly what the horse’s digestive system is designed to handle. “The horse has a very small stomach relative to its body mass and metabolic needs,” explains Candace Platz, DVM, of Maine Equine Associates in Gloucester, ME, “and as such it is designed to be a continuous or ‘trickle’ feeder, rather than something like a cow that takes in a lot of food at once and then goes off and digests it.”
The ‘trickle feeder’ model is further born out by the fact that the stomach of the horse secretes hydrochloric acid on a continual basis, regardless of the presence or absence of food.  This works well for an animal designed to take in small amounts of food almost non-stop. Unfortunately, the acidity of the stomach can become dangerously high rather quickly in the absence of food, putting the horse at risk for the development of equine gastric ulcer syndrome (EGUS) – an extremely common condition in domestic horses. One 2009 study, performed by Nanna Luthersson and colleagues at the University of Copenhagen, found that a prime risk factor associated with the development of EGUS is when the interval between forage feedings is greater than six hours.
Another factor that can contribute to high acidity is the way horses secrete saliva. States Platz, “The horse does not secrete saliva continuously, as we do, but only in response to the stimulation of chewing. When they chew, they produce bicarbonate saliva that buffers the acid of the stomach, protecting the stomach lining. However, if the horse is not chewing for any significant length of time, the acidity of the stomach is unopposed by any bicarbonate, contributing to excessive acidity. Thus we are starting to hear experts talk about the importance of ‘chew time’ for the horse – the more the better.”
The common practice of feeding horses large meals twice daily, with long gaps in between, may therefore be problematic. This is even more true for horses with metabolic disorders such as insulin resistance and Cushing’s. While it is generally known that such horses should not be given feeds with a high starch or sugar content, it is less well known that even hay can cause significant fluctuations in levels of glucose, insulin and leptin when fed in large meals separated by long periods of time. “Hay is essentially ‘grass jerky’,” says Eleanor Kellon, VMD, an equine nutritional specialist with a particular interest in metabolic disorders. As she explains, “Hay is a much more nutrient dense food than fresh grass because most of the water has been removed. When horses go for a long time without eating and then get fed a big meal of hay, this causes insulin ‘spikes’ – the same phenomenon that has been documented when humans eat breakfast. This is not natural for any horse, but when a horse has a metabolic disorder, you especially want to try to avoid such peaks and valleys, as they may exacerbate the condition.”
Kellon points to the work of Joshua Cartmill, PhD, of Louisiana State University, whose study on leptin levels in horses documented how different feeding regimens can affect not only leptin – a hormone important in regulating hunger and body condition – but glucose and insulin as well. Meal-fed horses demonstrated the greatest fluctuations, while horses given continual access to hay “had low and constant concentrations of glucose, insulin, and leptin, with no apparent fluctuations”.
With these facts in hand, it becomes evident that feeding large meals 2-3 times daily is not ideally suited to the physiology of the horse. However, the reality is that many of us don’t have access to unlimited, year-round pasture, and feeding many small portions of hay spread out over 24 hours is generally impractical. Providing free-choice hay may be a workable option for horses that don’t put on excessive weight, but it is a risky practice for those that do pack on the pounds, and the wastage involved can make it expensive.
Proponents of “slow feeding”– the practice of using restrictive hay feeders designed to extend the amount of time it takes a horse to eat its hay – believe that they have found a solution. Ranging in design from simple, small-mesh hay nets to elaborately constructed feeding boxes, restrictive hay feeders or “slow feeders” are becoming a must-have for some horse owners, who credit them with improving the mental and physical well-being of their horses. Some creative people design and build their own slow feeders, but a growing number of ready-made products are available for sale, as well.
One place to get a good overview of different kinds of slow feeders, both DIY and store bought, is JoAnn Johnson’s “wiki” website: paddockparadise.wetpaint.com. “I first became intrigued with the idea of slow feeding about 15 years ago,” says Johnson, “but it wasn’t until 2006 that we were able to get set up for keeping our own horses at home and really start trying it. By 2008, I thought I had slow feeding mastered, and I started the website as a way to share what was working for me.” Other people started contributing their own ideas for building different kinds of slow feeders, sparking new creativity with input from people in far flung locals.  Says Johnson, “I once thought that further innovation beyond grids or hay bags was impossible and that the wiki had outlasted its raison d'ĂȘtre.  Then, Cheryl posted her hybrid small mesh hay net/barrel slow feeder concept -- it had hard sides AND mesh.  That's when I realized that the ideas bounced around there will continue to help build a better slow feeder.  I've certainly been humbled and constantly inspired by ideas contributed to the wiki from around the globe.”
What all slow feeders have in common, whether home made or store bought, is that they use some kind of netting, grid or holes to restrict the horse’s access to the hay. The openings must be large enough to allow the horse to extract some hay, but small enough so that the horse can only pull out a few strands at a time. The openings in traditional feeders are typically much to large for this purpose. Regular hay nets, for example, have openings that may stretch to 6” or wider when the net is full, while the openings on a small mesh hay net used for slow feeding will generally be 1-2”. The smaller the holes, the greater the level of “challenge” for the horse, and the longer it takes for the horse to eat the hay.
While the benefits of consuming hay more slowly have not been extensively studied, the anecdotal evidence is overwhelmingly positive, and some veterinarians are reporting quantifiable improvements in conditions such as gastric ulcers and in rates of colic among their clients who implement slow feeding. One such vet is Fred Beasom, DVM of Tehachapi, CA, who now recommends slow feeding to all his clients. “This is simply a more natural way of feeding, keeping food in their stomach all the time vs. gorging them 2-3 times a day like so many people do. Not only are the horses calmer, quieter and demonstrating fewer vices, but I’m seeing a marked reduction in the incidence of ulcers – I’d say about 75%. Consuming the hay more slowly also reduces the likelihood of choke, and it lowers the risk of impaction colic, as well.”
Race horse trainer Matthew Chew has observed all of these benefits among the horses in his stable at Santa Anita, CA. Says Chew, “Slow feeding has been great for us. For one thing, ulcers are a very common problem in racing stables, and we have an intensive program to try to reduce the incidence of ulcers in our horses. We had a number of measures in place for years – preventative medications and such – but we still had lots of horses with ulcers. When we decided to try slow feeding, I had every horse scoped to get a baseline, then we went back and scoped them again after six months of using the small mesh hay nets. I was very pleased to find that our incidences were greatly reduced, and with the horses that had had severe ulcers, the inflammation was quite a bit less. I think this is because they are eating more as if they were grazing in a natural process, and the stomach isn’t sitting empty for any significant period of time.”
Chew has also seen his rate of impaction colics drop to zero. “Maybe we’re just on a lucky streak, but since we started using these nets, we haven’t had a single incidence of impaction colic. In a racing stable, it’s a very controlled environment, but you can’t watch and monitor everything. Sometimes, a groom will put a horse away that’s a little bit hot, and that horse goes sucking hay down, taking large bites, and I think that helps to promote colic because the horse’s body can’t process that amount of hay that fast, especially if you have a little bit of a warm belly because they were put in a little soon or something agitated them in their stalls. I don’t think you’re ever going to completely get rid of the twisted gut colics – those just happen. But as far as the impactions, I definitely think slow feeding helps to prevent that.
“Another thing I like is that the horses are chewing and digesting their hay better, so we’re not seeing incidences of choke, and there is also more consistency in their manure. You can see that the bits of hay in it are finer, and the manure is well-formed with a lot less diarrhea. Add to this the fact that we now have almost no wastage, whereas before we were seeing about 10-15% of our hay lost to wastage. I hate to sound like a commercial for the darn things, but this one change has made a big difference.”
What is particularly interesting in Chew’s case is that his race horses always had free-choice access to hay whenever they were in their stalls, so one would think the horses would have been “grazing” whenever they wanted to already, and therefore, there would be no real added benefits from slow feeding. According to Chew, however, free-choice does not have the same results as slow feeding. As he explains, “A lot of times what would happen in the past is that a horse would go into the stall, particularly after training, and they would eat quite rapidly. When they suck down the hay like that, eating large bites of hay, and they would get fuller quicker. Once they got full they would back off, and then they would either sleep or just stand in the back of their stall. With the slow feeders, it forces them to eat at a slower pace, so it takes longer for them to get full and they never really ever do get totally full, so they’re constantly picking at the hay, and that’s really they way they were designed to eat. It even helps with the picky eaters, because it seems to keep them more interested. Of course this is all just my opinion, but I can tell you that my neighbor, racing hall of famer Richard Mandella, has seen the results I’m getting, and he’s now using the nets for a bunch of his horses, too.”
Another population that may benefit from slow feeding is senior horses. Cindy Daigre runs a retirement home for senior horses in TN, and finds that the practice of slow feeding reduces quidding, greatly reduces the incidence of colic and ulcers, and helps the older horses stay in better weight.  As she explains, “The reason that the nets help with quidding is that the horses are taking much smaller mouthfuls at a time – often only a few strands of hay.  That leads to proper chewing and improved digestion and absorption, which in turn reduces so many of the problems often associated with senior horses.”
Slow feeding also appears to help horses that exhibit stereotypic behaviors, commonly known as stable vices. Beasom has observed a reduction or in some cases elimination of stable vices in horses put on a slow feeding program, and other vets concur. States Platz, “We are learning that intermittent feeding may be at least partly responsible for stable vices (a term I don’t like because it tends to blame the victim). Wood chewing, wind-sucking, weaving, and so on – can all be caused or exacerbated by the horse only having food for very short periods during the day. The horse is programmed by nature to exhibit certain behaviors, and one of those major behaviors is chronic eating. You take that away from them, they are going to do something with that mouth – and that’s often something you don’t want and that’s not good for them. Give that back to them, and you’re likely to see a reduction in those negative behaviors.”
Elizabeth Carr, DVM, PhD, Dipl. ACVIM, Dipl. ACVECC, of the College of Veterinary Medicine at Michigan State University, agrees that slow feeding is likely to be beneficial in numerous ways. As she explains, “I like the slow feeding concept because it more closely mimics natural grazing, and it gives the horses something to do for a longer period of time. I think the psychological benefits of that are obvious, because eating is what horses like to do. Another good aspect of using slow feeders is that they may make group feeding easier. If you have to group feed with loose hay, you sometimes get one horse who inhales it all and then the skinny horse doesn’t get enough food. Using slow feeders kind of evens it up, forcing the easy keeper to eat more slowly and giving the other ones more of a chance to have adequate access.”
Carr also recognizes that slow feeders can make life easier for the owners, as well. “I’m just like any other modern horse owner – I try to feed my horses four to five times a day, but there are days when I can’t and I feel bad about that. In that respect it’s a huge benefit, because you can make those two or three meals last 12 hours – that’s awesome. If you are reducing the time gaps between meals, I think that’s a real positive. There doesn’t seem to be a “con” to using slow feeders, other than buying them or making them.”
Still, Carr cautions that some claims made about slow feeding have not been researched and that anecdotal evidence is not definitive. “Hay, in general, takes a long time to be digested,” she says, “so in terms of protecting the horse’s digestive health, I’m not sure it makes a huge difference if an amount of hay is consumed in say, one hour vs. three. When we scope horses’ stomachs, we tell people to take them off food for about 18 hours at least so that our view won’t obstructed by hay. Normally, even after 12 hours of inappetence, I’ll still see a hay ball – small, but there – in the ventral portion of the stomach. By that time it’s not big enough to protect the upper part of the stomach that is more sensitive to acid, but it does show how long it takes for hay to clear the stomach.  In general, I agree that having a horse eat more slowly over a longer period is a good idea, but what I can’t say is whether that would mean there is a significantly larger amount that is available to protect the upper portion of the stomach for a longer period of time.”

Louise Husted, DVM, PhD, an Assistant Professor at the University of Copenhagen who studies gastric ulcers in horses, believes that any extension of the period a horse spends chewing its hay is likely beneficial. However, she agrees that more work needs to be done in this area. “In summary,” she says, “the time spent chewing roughage is time spent buffering the acidic environment in the stomach. Longer seems intuitively better in order to prevent gastric ulcers, but this is still just theory. What we do know is that when the gastric acid comes into contact with the stomach mucosa near the region where ulcers are most often found (margo plicatus), this predisposes horses to develop ulcers or at least erosions. This has a certain time component to it, as it has been demonstrated in vitro that the mucosa does not become damaged if the time frame is less than a few hours. 

“The logical thing would then be to avoid the gastric acid coming into contact with the mucosa completely. Measuring the pH in the region reveals that when the stomach contains feed material based on roughage (for example hay), then pH during most of the day and evening will be around 7-8. During these circumstances, development of mucosal erosions or ulcers are not favored. Hence, making sure that the equine stomach contains roughage material most of the time would seem like a favorable factor against ulcer development. This could be achieved either by feeding small amounts of roughage feed throughout the day and night. Alternatively, one could look at how the feed could last the longest, as is accomplished with slow feeders.”

If you are interested in trying a slow feeder for your own horses, it is also important to recognize that not all horses have the same nutritional requirements, so you need to take their individual needs into account when selecting a feeder and planning a program. “I can’t let my horse have free access to hay, even in a slow feeder,” says horse owner Jennifer Franklin, from Langley, BC. “My horse is insulin resistant,” she explains, “and even on hay that would make other horses get ribby, he gets fat if he gets too much.
“I tried free-choice feeding from one of those very large, small-hole hay nets, but he started to put on too much weight. I had been told to try it for a few weeks, that he would eventually ‘self-regulate’ once he realized that the food was never going to run out, but that didn’t happen. And, since that particular net only works well if you keep hay in it at all times, my horse ended up chewing big holes in it when I tried putting him back on rationed amounts of hay and it would start to run out.”
The solution for Franklin has been to find another slow feeder that cannot be easily damaged, even when the horse is going after the last few stems of hay. “There are so many slow feeders on the market now, and for me it was a process of trial and error until I found which one worked best for me. I still can’t give my horse free access to hay, but at least the hay he does get now lasts for hours, instead of getting hoovered up in minutes.”
As for people who worry that loading a slow feeder will take more time and effort than simply throwing a couple of flakes on the floor, Franklin says, “Yeah, it probably takes me a whole extra minute or two to load the feeders, but overall it actually saves me a lot of time. I can now do fewer feedings because each feeding lasts so much longer, and I’m also not spending time raking up wasted hay because it’s not getting thrown all over the place and walked on.
“However, I want to say that even if it wasn’t saving me time and hay, I would still do it because the health benefits are enormous and to me, quite obvious. Specifically, before I started using the slow feeders, my horse colicked four times, and he hasn’t colicked once since we started slow feeding. Of course that’s just ‘anecdotal evidence’, but I’m convinced that his gut is functioning better and feeling better because he has food going through it in smaller amounts over a longer period of time. That alone is worth the price of the feeder and any extra time or effort it could take!”
Mike Lane, a horse owner from Redding, CA, doesn’t have horses with metabolic problems, but he is also convinced that slow feeding is the way to go. “I was feeding a well-balanced, properly supplemented diet three times a day,” Lane says, “but my horses were obviously bored and hungry in between. They were chewing wood, chewing trees, and they would practically inhale their food when they got it. It was also difficult for me, because I had to hire someone to do their lunch feed, and I was tied to the other two feedings every single day. Then someone told me about the idea of slow feeding, and a big old light bulb went on in my head.”
Lane discovered Johnson’s wiki website and tried out a couple of home-made designs before deciding to purchase some small mesh hay nets. “I tried a few different kinds of nets,” he states, “but the one I’m using now can hold a huge amount of hay, and it also really slows the horses down. I can now load the nets up once a day, and there is still some left when I go to feed the next day. The horses always have hay in front of them, and you can just see how much more content they are. No more wood or tree chewing, their weight is good, and no more anxiety around feeding time.”
Another benefit Lane has noticed is far less hay wastage. As he says, “Before I started using slow feeders, I was throwing away a significant amount of hay. My guys seemed to trample and mess on as much as they ate – it was like watching dollar bills being ground into the muck. I had tried free feeding, and that was even worse because they would pick through the bales and leave all the stems. Now, with the slow feeders, there is practically zero wastage. The horses can only pull out a small mouthful at a time, which they then chew and swallow. Some fine bits do fall on the ground, but I put a rubber mat under the net and the horses clean that up every few minutes, so I have almost nothing going into the wheelbarrow – it’s all going into the horse!”
One further benefit has been a reduction in the dust being inhaled by Lane’s horses. “One of my horses is sensitive to dust,” says Lane, “and whenever he would break apart a flake or stick his nose in a pile, he would always sneeze or cough a couple of times. I used to water his hay to try to keep the dust down – when I had time. I’ve been very happy to see that when he eats out of the slow feeders, he doesn’t sneeze or cough at all. I think it’s because his nose never gets shoved into the hay, so what dust does get created by pulling the hay out of the net just disperses into the air, away from his nose. I had heard that slow feeders were better for the horse’s gut and could save you money, but this was a bonus I didn’t know would happen.”
Lane recently added another slow-feeding tactic – a feed-dispensing “toy” that helps keep his horses busy and interested while helping to encourage movement. “The only thing that isn’t great about my horses eating from the nets is that they pretty much just stand there, because the food is in one place. I wanted to get them to move around a bit more, so I got a couple of these toy things and I put little hay cubes and treats in there, and the horses push and roll these things all over the place to get the stuff out. I like to see them moving, and I think they actually find the toys fun. Overall, I really think my horses are happier now, and hey, I can head out for dinner and a movie and not worry about getting home in time to feed.  I just don’t see a down side to slow feeding at all.”
Platz agrees. “Between the savings of money from not wasting hay and all the physical and psychological benefits to the horse,” she says, “to me it’s such a no-brainer. I used to go out a lot at night to check my horses and re-feed to make sure they had  food in front of them. And now, we just fill their nets – I have two per horse of the ones I use – and that takes them through until morning and they still have hay left. That amount of hay would not have lasted them before. They would have picked through it, walked on it, made a mess of it and left over the ruined hay – and then they would have stood there hungry. Honestly, unless you have your horses on 24-7 pasture or you’re okay with them wasting a ton of hay with regular free-choice feeding, I can’t see why anyone wouldn’t switch to slow feeding.”
If you would like more information on slow feeding, check out: http://paddockparadise.wetpaint.com/page/Slow+Feeders where you will find discussions, photographs and ideas for many different types of home made slow feeders, as well as links to a variety of commercially available feeders.

Sidebar: One horse owner talks about her DIY slow feeders

B. Bolliger of Brentwood, CA, currently uses a combination of commercially available small mesh hay nets and several slow feeders she built herself.

“In 2008 I received a flyer about a clinic given by Swedish Hoof School owner, Ove Lind, and heard raves about it.  I talked to one woman who had attended the previous year and she mentioned he would cover slow feeders, and she in fact already had built one and would give me more information at the clinic.  I attended, and found out many of the reasons why barefoot feet, slow feeding, low sugar diets, and lots of exercise are so good for horses.  I was so completely sold on the slow feeder concept that I came home and had one built immediately.  It was exactly what I had wanted to do for a long time!
“For the first horizontal feeder I used one of the 85 or 110 gallon water tubs, with a 2”x 2” grid to go on top of the hay, cut to fit the tub/  I  purchased the grid from a local salvage yard.  I contacted a government agency about testing for lead, and was told that I could purchase a test kit at a local hardware store, so I tested any painted metal used in the feeders for lead before using.  I eventually had to put rope and snaps on the grid to hold it in as the youngest horse tipped it up with his feet, and without something to hold the grid in, the hay dumps out, which is what he wants!  Holes are drilled in the tub just above ground level, one on each side, then I use thin rope through the hole to the inside, and one-handed bull snap tied to each rope to fasten to the grid, and then these neat fasteners secured high up on the outside that secure the rope whatever length is needed when it is pulled tight.
“The second and third feeders are also horizontal feeders, and were made of ¾” plywood, in the shape of a box—the first 2’x4’, using one sheet of plywood.  One-inch holes were drilled near the four corners for fines and dust to be swept out.  The grid was easier to fit in something with square corners rather than the curved tub.  Since the horses learned to get their heads beneath the grid to get to the food and eat too fast, I eventually put a piece of 4” ABS at each end, with 2 bolts on each one so they didn’t turn, and so that the bolts stick out to the outside of the box.  One end was bolted , and the other secured with wing nuts and a large area washer to keep in place.  To add hay, I just take off the wing nut, remove the ABS, lift up the grid, and add the hay, and replace the ABS.  Since my creative horses were also dumping these down, I secured them to the rubber water tubs, and that took care of the problem.  I also tie them to the side of the three-sided shelter so they can’t move them all over the place.
“The third feeder was the vertical type, with the grid at the front of the feeder, a hinged lid on the top for filling, and a smooth “slide” at a 45-degree angle inside the box to make the hay slide to the bottom, where the horses eat it.  They love this one, and I have never had a problem with hay getting caught.  It is by far the easiest to fill as well.  The grid for the front came with four edges, as a frame, so the box was made to fit the grid.  The grid openings are a little larger than 2”x2”, but it works fine.  The grid is fastened onto the front of the box by sliding it onto protruding bolts, one on each side, through holes drilled in the frame.  They are fastened with a wing nut on each side.  The frame is notched at the bottom and fits over a round head bolt on the bottom of the box..  It is very easy to get the grid off and on, but that is not necessary very often.  The top is slanted so that rain water would run off toward the back if it is used outside. It was also primed and painted so can be used for outdoor feeding.  The top is closed securely with a gate-type hinge and snap to keep the clever horses from opening the top and eating out of there.  Since the young horse has a Mustang frame of mind, and is very clever, it is also tied to the wall, and even more, has a turnbuckle system and a small piece of 2x4 wood on each side to keep it from being picked up and moved.  One thing about feeders, the horses are very determined, and it is sometimes a laughable challenge to keep one step ahead of them—actually, it is more like letting them get ONLY one step ahead!”


Sidebar: Slow Feeders Put to the Test

Intrigued by the idea of slow feeders, author Susan Kauffmann decided to try a few on her own horses to get a sense of how well they worked, and just how much they slowed the horses down.

            Knowing about the potential detriments of traditional feeding practices but struggling to manage multiple feedings a day, I loved the idea of slow feeders. I tested three, using seven pounds of hay fed loose on a ground mat as a “control”. It took each of my horses about 1 hour, 45 minutes to finish their seven pound control portion on the mat. Here are the results I got with the various feeders, after allowing for a “learning curve” period for the horses:

Feeder: “The Grazer” (www.doublel.com/equinedivision/haygrazer.html)
Description:  Basically a metal box with a spring-loaded tray that lifts the hay up against a metal grate.
Price: As low as $129.99 U.S. online
Time to eat 7 lbs. hay: 2 hours, 30 minutes (+ 45 minutes)
Learning curve: Both of my horses figured out how to eat from this feeder within a few minutes.
Notes: Sturdy construction – held up to my youngster bashing it repeatedly with his enormous hooves…I think he thought it was a drum. We found that hay fines would build up quickly under the unit, so we put our up on blocks to make it easy to reach under and clean them. Took me a while to get the hang of loading them; found it helpful to nail up a bungee to hold the top grate up while pressing the hay down. Very little wastage of hay. Can hold up to about three flakes at a time.

Feeder: “Freedom Feeder” (freedomfeeder.com)

Description: Small mesh hay net made of 250 lb. test woven 3 mm nylon twine.
Price: $40.00 U.S. from manufacturer; has Canadian distributor: Lisa Reid, Edmonton, lisasss1971@yahoo.com
Time to eat 7 lbs. hay: 3 hours, 45 minutes (+ 2 hours)
Learning curve: It was probably a few days before the horses had really figured out how to get the hay out in a comfortable way. Best to follow manufacturer’s instructions when introducing and using these nets.
Notes: Slowest of the three test feeders. Designed to have hay in them at all times. Horses did fine with them like that, but chewed holes in the nets if the hay was allowed to run out. Can hold an entire 100 lb. square bale, if you want them to. Can be hung from a fence, tree, etc. If you want to keep hay in front of your horses at all times, this net is great – but don’t let it run out.

Feeder: “The Nibblenet” (www.thinaircanvas.com)
Description: Webbing hay net, comes in various sizes and styles; custom orders available.
Price: I chose the largest “Double Nibble” (has webbing on both sides), with 1.5” holes. Cost $61.99 U.S. Smaller sizes cost less.
Time to eat 7 lbs. hay: 3 hours, 15 minutes (+ 1.5 hours)
Learning curve: Very little, but my horses had already learned to eat from the Freedom Feeder nets.
Notes: Very durable, easy to load. Must have a wall behind them for the horses to push against or it too difficult for them to get the hay out. I can get up to four flakes off a 100 lb. bale in each. Choose the 1.5” openings (or smaller…they are now coming out with a 1.25” option), as the 2” openings do not slow most horses down enough. The different sizes and styles provide great options for trailering, ponies, etc.



            Features: Many sizes available with choice of hole size, sturdy construction of nylon webbing, can be attached to wall or ground. Square sides allow for ease of loading and larger amount of hay in the net.

2. Freedom Feeder: http://www.freedomfeeder.com/
            Features: small-mesh hay net comes in three sizes – one large enough to hold an entire 100 lb. bale of hay. Really slows hay comsumption very well.
            Comments: If hay is allowed to run out, horses are more likely to chew holes through this net. Made sores on the lips of my horses because of this, as I can’t allow Gryph to free feed, even with a net.

            Features: small-mesh hay net that comes in various sizes – one large enough for use with a round bale.

4. Busy Horse Feeders: http://www.busyhorse.com/
            Features: several sizes available with choice of hole size, sturdy nylon-webbing construction.
            Comments: Flat design (as compared to Nibblenet) would make it harder to load and not hold as much hay as a comparably sized Nibblenet.

5. Swedish Hoof School nets: http://caisasshop.ebutiken.nu/
            Features: several sizes available, tape-sewed edges and poly material may be more durable than nylon nets.


            Features: various size hole plates available, plug for soaking/draining, D-rings for wall and/or pipe panel attachment.
Comment: Plate does not spin – maybe hard for horse to get some of the hay? VERY pricy!

            Features: various size holes in restrictor pan, plug for soaking/draining, optional lid can also hold water (7.5 gallons). Restrictor pan can spin in any direction, possibly making it easier for horse to get at all the hay.
            Comment: Not sure if/how it attaches to wall/fence. Fairly pricy.


            Features: sturdy metal construction, spring-loaded tray to lift hay up to grate.
            Comments: Does not hold much hay (only up to 3 flakes, in my experience), does not slow the horses down all that much. Small bits of hay build up under unit – hard to clean under if you don’t put it up on blocks.

2. The Natural Feeder: http://thenaturalfeeder.com/

3.  The Slow Grazer:  http://www.grazingbox.com/


1. The Nose-It: http://www.nose-it.com/

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