Monday, September 19, 2011

Raising a Healthy Hoof

We’ve all heard the old adage, ‘No hoof, no horse’, and few would argue with it. Yet many of us are all too familiar with what it’s like to battle bad feet, a problem that is widespread in the stock horse world.  Quarter cracks, thin and brittle walls, white line disease and navicular syndrome are just some of the problems that can at very least put a crimp in your training, and at worst lead to a treasured horse’s early demise. When trying to figure out why this is happening, some people are quick to blame breeders, while others point the finger at the whims of the show world, which at one time favored big horses with tiny feet – a look which is thankfully falling out of fashion. However, an in-depth examination of the problem of bad feet reveals that there are a number of factors that can contribute to the formation of poor quality hooves. Therefore, if we want our horses to have good, strong, healthy feet, we need to look at all of these factors in order to maximize their hoof health throughout their lives.

NATURE vs. NURTURE?

            When we look at certain breeds of horses such as Morgans and Arabians, we see that most individuals in these breeds have strong, solid feet.  Conversely, when we look at Thoroughbreds and Quarter Horses, we see large numbers of individuals with problem feet. This would seem to indicate that genetics is an extremely important factor in the creation of good hooves.  However, current research and a wealth of anecdotal evidence suggest that in most cases, what happens to a horse’s hooves after it is born has far more influence than any genetic contribution. In fact, it may be mostly the management and training practices commonly used with horses of a given breed that lead to the differences we see among breeds.  Still, there is undoubtedly genetic variability in hoof size, conformation and quality, and it only makes sense to give horses the best start possible by breeding for good feet. 
Conscientious breeders like Tom Sword, owner of the AQHA stallion Smart and Lucky Lena, take hoof quality into serious consideration when making breeding decisions. “I won't breed horses just for bloodlines to cross if they have real foot problems,” says Sword. “I'm not going to tell people what they can and can't breed, but as far as mine goes, I won't own a horse that has real bad feet, and if the mare throws babies with real bad feet, I won't keep breeding her. We’re very particular about the feet of our own stock, but I've seen people breeding horses with things like club feet, and you end up with every third or fourth baby having a club foot.  If you breed any of the inferiorities into them, you just make our Quarter Horses worse, not better.”
Sword, who also owned the now deceased halter champion Western Cabernet, would particularly like to see the halter horse industry pay more attention to the feet of the horses they are breeding. As he explains, “I have a little problem with the halter industry because, just being straight now, those horses should be able to be ridden and used. But if you had to take a halter horse out and ride him, and he's got those little tiny feet, you're not going to be able to do it.  If you go back into the legends, the older horses, those horses won halter classes and then went out and won performance classes. As far as I'm concerned, that's what we should be shooting for with our horses -- and they can't do it if they don't have good feet.”
Mark Scott, DVM, MVSc, Dipl. ACVS, of Moore & Company Veterinary Services in Calgary, would also like to see breeders place more emphasis on hoof health and durability when selecting breeding stock.  He states, “I believe that breeding is of paramount importance in relation to horses having healthy hooves. There are specific, well recognized patterns of foot related lameness that I see every day that are a direct result of the horse’s genetics.” Scott believes that a big part of the problem is that we are not necessarily looking at the right factors when making breeding decisions.  “We select which horses to breed to based on paper,” he says, “—paper pedigree, advertising, and money won in competition.  The selection criteria that we tend to use do not emphasize durability, and in some cases may select for horses with small, weak feet.”
Hoof care professionals, like Christina Cline of Sumas, WA, also generally place at least some of the responsibility for the quality of a horse’s feet on the breeder. Says Cline, “Common sense should tell us that breeding horses with weak feet is unwise, and it should be pretty obvious by now that breeding horses with unusually small feet for their size is just an all around bad idea. I also see things like mares that have long, sloping pastern conformation that causes a tendency towards underrun heels and long toes, and you’ll see that same tendency in their babies.” Cline believes that good feet should be a big criteria for any breeding program and points out that breeders who ignore this crucial aspect of horse health are doing both their breed and their own reputation a disservice. “If the horses are constantly plagued with foot problems and break down at a young age, that is going to reflect back on the breeder in the long run.”
Cline, however, also points out that there is usually more going on than just poor genetics when a horse has bad feet. As she explains, “Genetics do play a part, but the whole genetics issue gets a bit muddled, too, because in many cases, the people who are breeding without paying attention to hoof quality may also have management strategies that do not promote optimum hoof development.  Take Thoroughbreds, for example, which are known for having weak feet. People are certainly breeding them without paying attention to hoof quality at all, but at the same time, they coop them up, load them with grain and shoe them at an early age, all of which can seriously compromise even a very healthy hoof. So, sometimes it’s rather fuzzy as to what is actually due to genetics vs. what is due to the environment that the horse was raised in.

RAISING A HEALTHY HOOF:  MOVEMENT

            The work of Michigan State University researcher Robert Bowker, one of the world’s foremost experts on hoof development and biomechanics, has shown us that a healthy hoof has certain characteristics that allow it to function properly over a lifetime of hard use.  These include thick, tough walls and soles; strong, well-developed lateral cartilages; dense, fibrous digital cushions; broad, strong frogs that makes contact with the ground; short toes; and heels that are wide and low but not underrun. Whether or not a horse’s feet develops these characteristics will depend to a very large extent on how the horse is raised. 
How it works is as follows:  When a horse is born, the internal and external structures of the hoof are relatively soft and unformed – perfect to support the weight of a newborn foal, but only the weight of a newborn foal. In a free-roaming environment, the foal is up and moving within hours, often over hard, harsh terrain, so its feet immediately start working and adapting to this work load.  Every step the young horse takes helps transform its feet, stimulating the soft, fatty digital cushions to become thick and fibrous to protect the coffin bone, helping the tube-shaped baby hoof to spread into a stronger conical shape, strengthening the lateral cartilages and toughening the other structures of the hoof.  As the horse grows and becomes heavier, its feet adapt to be able to support the increased stress put on them by a heavier body.  As long as the horse is allowed to move in a natural manner on firm terrain, the feet will continue to develop in size and strength well into the fifth or sixth year of life.  This is probably the single most important factor in the development of healthy hooves.
It follows, therefore, that management practices that restrict a young horse’s movement will retard hoof development, especially if the horse is kept on soft footing.  Explains Dr. Scott, “Exercise is imperative for normal musculoskeletal development and maintenance.   While the horse is growing, the development of its skeleton and soft tissues (both of which are present in the hooves) is influenced by the stresses placed upon them.   If the tissues are not stressed appropriately, they will not develop appropriately.   If this development does not occur optimally in the young growing horse, permanent impairment of musculoskeletal development is possible.   It has been shown that as little as three weeks of stall confinement in a young horse can have measurable negative effects on skeletal development.” 
Dr. Bowker also believes that movement is key to healthy hoof development.  “The environment is the major determinant of a healthy foot rather than genetics,” he says. He also points out that we may see bad feet in some of our best horses because the more expensive horses often have more confinement early in their lives. “In fact,” he says, “there seems to be an inverse relationship between expense and movement!”  Bowker emphasizes that a horse deprived of appropriate movement is going to be far more likely to suffer from lameness issues down the line, regardless of breed or breeding.
Some people try to compensate for a lack of turnout by longing a young horse, especially if they are trying to condition the horse for show.  Unfortunately, this is far more likely to do harm than good.  Says Scott, “Attempting to exercise the young horse through methods such as longing risk injury, as they involve repetitive movements which may overload developing tissues.  In order for tissues (bone, muscle, tendon, ligament, or hoof) to develop strength, they need to be stressed by exercise and then have time to heal and strengthen in response to that stress.   It has been shown that bone can have an adaptive modeling response to specific stress with as little as 30 cycles of a given stress – this means that as little as 30 strides of galloping exercise will stimulate a young horse bone to adapt specifically to galloping.   If the young horse was galloped 300 strides every day, however, this would overload the musculoskeletal system and allow insufficient time for tissue recovery, which is likely to result in injury.  Rather than longing, the type of exercise that is needed is that which is typical of young horses at play – short bursts of galloping, romping around, running up and down hills, etc.  It is difficult to mimic the varied influences of play exercise with a training program.”
           Cline also believes that natural exercise is best for young horses, adding, “I know of one vet who says that longing a young horse should be a crime, and I must say I agree. I would also like to see people wait longer to start riding these horses, as this is a huge factor in the early breakdowns we see so often these days. A big part of my job is rehabilitating horses that have broken down, and when you see horses that are three, four and five years old with all these problems, you can’t help but wish people would just give them more time to grow up before subjecting them to activities that we know are damaging to growing joints.  Call me crazy, but I just don’t like seeing three year olds with radiographically confirmed arthritis. 
            Asked what we can and should do to make sure our young horses get enough of the right kind of exercise, Cline says, “The more space they can be turned out in, the better. If you can avoid keeping them in stalls completely, that is definitely a plus. 24-7 turnout with lots of room to run and play, and in as firm of an environment as possible, as opposed to soft, spongy, muddy terrain, will really go a long way towards building healthy feet . Ideally, they should be turned out with other youngsters, because they stimulate so much play and movement amongst themselves that they'll get more exercise than if they're just standing around alone or with their mom.  Ponying a foal off the mare from a young age is a great thing to do. Not exercising them to death, but starting to pony them for 15 minutes here, 20 minutes there, then gradually increasing the time as they get older is a great way to exercise a youngster if you don't have a lot of space, plus it gives mom the exercise she needs.  However, if you don't have an appropriate amount of space or the right kind of footing to let young horses really move and develop optimally, you might want to consider boarding the horse somewhere that has that kind of environment while the horse is still growing. This is not only in the best interest of the horse, but also in the best interest of the rider/owner in the long run, as you are far more likely to end up with a strong, healthy horse overall.”

SHOEING

            According to the work of Dr. Bowker and others, it is also in the best interest of the horse and owner to delay shoeing a young horse as long as possible, and to only keep shoes on for brief periods, if they are used at all. Bowker has conducted detailed post-mortem studies on thousands of horse feet and discovered that the internal structures of horses shod for a majority of their lifetime often look more like those of immature horses. The digital cushion, for example, will lack the dense growth of fibrous tissue that allows it to properly support the weight of an adult horse.  This lack of development of the key support structures in the back part of the foot often leads to tenderness in that area, which in turn leads to the all too common toe-first landing now thought to be a major factor in the development of navicular disease.
            What this all boils down to is that if you start shoeing a horse when it’s two and don’t give the feet a good part of the year out of shoes, you can essentially “freeze” the internal development of that horse’s feet – and you may also affect the ultimate size and strength of the entire foot. Says Cline, “It would be extremely beneficial to horses if people would delay shoeing until the feet achieved full maturity, at age five or six.  That said, a lot of people are going to shoe earlier and keep the horse shod, which may prevent the hoof from achieving its maximum size. This can lead to problems, because when you have a smaller foot, you have a smaller surface area and less mass to absorb the stress. Every farrier textbook will tell you that shoeing year round is not recommended.  Therefore, if people feel they need to shoe for shows or training, take the shoes off and give the horses a break from shoes for as much of the year as possible, at least until the hoof is fully grown.”
            Another problem that can result from early shoeing – or any shoeing that does not allow for all the support structures of the hoof to work together – is poor wall quality. As Bowker states, “Peripheral loading of the foot usually causes thinner walls.” What this means is that shoeing or trimming a horse so that the walls bear most of the weight without support from the sole, frog and bars not only inhibits the development of the internal structures, but may contribute to the epidemic of thin, brittle walls we are seeing in our horses.  Though conventional shoeing methods are based on peripheral loading, the latest research indicates that all of the structures of the hoof are designed to work together to cope with the tremendous forces placed upon them, and that “hanging the hoof by the walls” interferes with the synergistic relationship of these structures.  Fortunately, there are now farriers like Gene Ovnicek (www.hopeforsoundness.com) and barefoot trimmers like Pete Ramey (www.hoofrehabl.com) who are coming up with viable solutions to this problem, based on what Bowker calls the “physiologic trim” (see http://cvm.msu.edu/news/press/phytrim.htm for details).
Because shoeing can be detrimental in these various ways, Tom Sword believes that young horses are best left unshod as much as possible. “It's true that horses don't quit growing until they're five years old or so -- their whole body keeps growing, so it makes sense that the feet are still growing, too.  I see people shoeing and working these young horses -- some seventeen months or even younger -- and by the time those horses are seven years old, they often have joint problems or hoof problems. The more they shoe them, the worse the frog gets and so on. There are all kinds of problems that develop from continual shoeing on them.  I definitely believe you should pull the shoes and let them be without them as much as possible. Don't shoe them too much, and don’t work them too much or too hard when they're young if you want that horse to last you.”

APPROPRIATE HOOF CARE

            It may be desirable to leave the shoes off a young horse, but that doesn’t mean their feet don’t need attention.  Early trimming, in fact, can help ensure that the horse’s feet develop optimally. As Dr. Scott explains, “It is appropriate and in some cases necessary to begin trimming the horse’s feet early in life. The hoof is a very plastic structure, with the ability to change shape depending on how it is stressed. If the foal starts to develop some asymmetry or imbalance in its foot, careful observation and early foot maintenance may limit or reverse this problem.”   It is therefore wise to have a foal’s feet and legs assessed soon after birth to determine if corrective trimming is indicated.  However, as Scott points out, “If young horses are allowed to live in a ‘wild’ state where they can move over a large area with rough hard footing, they may not need their feet trimmed at all. In my opinion, this is the ideal situation for developing a strong healthy foot.”  
            Many youngsters will likely fall somewhere in between, requiring some maintenance from a hoofcare professional.  With a foal, the farrier will mainly be looking at two things:  a) that they’re wearing their feet enough so they don’t have excess growth, and b) that they’re wearing their feet in a balanced manner.  “It’s very common, basically normal to some degree, for a foal to wear their feet a little unbalanced,” Says Cline. “This is because they’ve got narrow chests and they tend to stand base wide, so they’ll wear down the insides faster than the outsides. The farrier will help keep the feet in a balanced state.”  Like Dr. Scott, Cline also likes to see foals assessed very early to detect any problems that could be helped through corrective trimming. “If a foal is born with any hoof or limb deformities,” she says, “getting it trimmed by the first or second week is pretty imperative -- even the first or second day.  A lot of deformities such as carpal valgus (knock kneed), carpal varus (bow legged), wind-swept legs, and rotational limb deformities can be corrected or at least improved by good hoof care early on. Club footed horses also need to get care really early on, as well.”

DIET

             Another component of helping a young horse develop healthy hooves involves diet – and in this case, less is often more.  While it may make us feel good to put our horses out on lush pasture, top them up with grain and buy expensive supplements designed to improve hoof quality, all of these things can actually be detrimental to our horses’ hooves and overall health. What we really need to be looking at, in many cases, is how to keep things out of the horse’s diet that weaken the hoof walls – specifically, too many “quick” carbohydrates.  There is a mounting body of evidence that sugars and starches that convert quickly into glucose in the body cause damage to the laminae –  the strong but sensitive structures that attach the outer hoof wall to the foot.  Weakening the attachment of the hoof wall can cause flaring, stretched whitelines, laminitis, and the opportunistic fungal and bacterial infections that often go along with these problems. Obvious sources of quick carbohydrates are grains and anything sugary or coated with molasses.  Less obvious sources are hays high in NSCs (non-structural carbohydrates), and grasses with elevated levels of sugar due to stresses such as overgrazing, frost or drought.  Non-native or “improved” grasses – varieties of grass that have mostly been designed to put weight on cattle – can also be problematic.
This doesn’t  mean that you should cut grain and grass from your young horse’s diet altogether, but it does mean that you should be careful with such feeds and make sure that your youngster is not getting overweight – a very common problem in the horse world today and one that should be of serious concern.  The feet of a horse that is overweight are subject to both metabolic and mechanical stresses, making them much more prone to problems.  Specifically, a recent study by researchers at Virginia Tech stated that overweight horses are vulnerable to chronic inflammation, oxidative stress, insulin/glucose imbalances, heat stress, reduced performance levels, and increased bone, tendon and joint injuries.  They concluded that obesity is a “major health concern” in horses that has been widely under-reported.
Unfortunately, many of us have horses that are overweight and we don’t even know it, due to widespread misconceptions as to what constitutes a healthy weight.  Today’s leading equine nutritionists say that you should be able to see a hint of ribs on a horse until it is two or so, and after that, you want to be able to easily feel, but not see their ribs.  Once again, the preferences of the show ring may be coaxing us up a dangerous path, but ultimately, it is each owner’s responsibility to decide what is best for their horses. 
A good diet for a young horse will consist mainly of grass and/or hay that is moderate in simple sugars and protein, with a balanced vitamin/mineral supplement if needed, access to salt (loose is preferable to blocks), and little if any grain.  As Dr. Scott says, “The main cause of nutritionally related problems tends to be overfeeding rather than deficiency. I have seen many cases of laminitis and horses that simply outgrew their feet from being overfed.”

THE TOTAL PICTURE

            When we look at the number of horses with problem feet in the stock horse world today, it is not hard to understand why Tom Sword calls this a “shameful state”. In the end, if we want to see fewer problems in the feet of our horses, we are going to have to work as individuals and as an industry to promote practices that will give our horses a good start and help them maximize their potential.  As we have seen here, it takes a multi-pronged approach to raise a healthy hoof, starting with our breeding practices and requiring careful evaluation of our management strategies. This may mean that we might have to make some changes to the way we do things, but as another old cowboy once said, “If it ain’t broke, don’t fix it – but if it is broke, well heck, you might want to do something about it.”  The fate of our horses feet – and ultimately our horses themselves – is in our hands.

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