A field guide to hoof cracks

When a de­fect ap­pears in the wall of a horse’s hoof, it’s im­por­tant to be able to dis­tin­guish a cos­metic flaw from a se­ri­ous prob­lem.

EQUUS - - Equus - By Heather Smith Thomas

When a de­fect ap­pears in the wall of a horse’s hoof, it’s im­por­tant to be able to dis­tin­guish a cos­metic flaw from a se­ri­ous prob­lem.

First the good news: The vast ma­jor­ity of the time, those cracks, chips and dings you find on your horse’s hoof walls will be harm­less blem­ishes.

Then there’s the bad news: On rare oc­ca­sions, a hoof crack may be a se­ri­ous prob­lem that leads to un­sound­ness. Or a per­sis­tent crack may be a sign of chronic trou­ble. In a worst-case scenario, a deep crack may pro­vide an en­try­way for po­ten­tially life-threat­en­ing in­fec­tions in­side the foot.

The key, of course, is to be able to dis­tin­guish the dif­fer­ence.

“Many of the cracks that we see out on the farm, prob­a­bly at least 90 per­cent, are not go­ing to cause lame­ness,” says Dean Moshier, a far­rier in Delaware, Ohio, whose clients in­clude plea­sure horses as well as top-level ath­letes. “Most are just su­per­fi­cial cracks, where the sur­face of the hoof wall looks rough and lay­ered like shin­gles on a roof.”

Still, it’s a good idea to keep an eye on hoof cracks. Some that are mi­nor to start with may worsen, and if your horse’s hoof cracks seem to be chronic, it’s a good idea to fig­ure out why and take steps to pre­vent them. Here’s what you need to know.

CAUSES OF HOOF CRACKS

Hooves gen­er­ally crack un­der pres­sure from some sort of trauma. The forces con­tribut­ing to the crack can orig­i­nate within the hoof---if there are bal­ance prob­lems from poor or ne­glected far­ri­ery work, for ex­am­ple, or con­for­ma­tion is­sues that place un­usual strains on the hoof wall. And, of course, cracks can be caused by ex­ter­nal trau­mas---any sin­gle se­ri­ous blow to the hoof can cause in­jury, and cracks may also de­velop due to re­peated con­cus­sion, such as the horse who gal­lops on un­for­giv­ing foot­ing or who stomps at flies in­ces­santly on hard ground.

Ge­net­ics also plays a role in the strength and thick­ness of a horse’s hoof walls--some horses are sim­ply more prone to cracks than oth­ers. “A strong foot can with­stand or over­come a lot of ad­verse fac­tors, but a weaker foot may not be able to han­dle it,” says Steve Nor­man, a far­rier from Ge­orge­town, Ken­tucky. “Some horses just have more struc­tural in­tegrity in the feet, and cer­tain breeds have stronger feet than oth­ers.”

Fi­nally, one type of hoof wall de­fect---hor­i­zon­tal cracks that run par­al­lel to the ground---is al­most al­ways caused by an ab­scess that drained through the coro­nary band and tem­po­rar­ily dis­rupted the for­ma­tion of horn, cre­at­ing a gap. Hor­i­zon­tal hoof cracks gen­er­ally are not se­ri­ous and will grow out with­out caus­ing prob­lems. “Hor­i­zon­tal cracks are usu­ally the re­sult of an in­jury or a gravel ab­scess that blew out at the coro­nary band,” says Moshier.

“Hor­i­zon­tal cracks are not nor­mally lame­ness re­lated, even though the ini­tial cause of that crack could have been a lame­ness-caus­ing ab­scess or foot in­jury,” he adds. “The crack it­self is noth­ing to worry about. It will even­tu­ally grow out.”

As the hor­i­zon­tal hoof crack nears the ground, your far­rier may take steps to sta­bi­lize the “loose” piece so it does not break off pre­ma­turely. “Some­times at that point I take out the un­at­tached wall be­low the crack,” says Moshier.

THE MOST COM­MON HOOF CRACKS

You’ll hear many terms for hoof cracks---sand cracks, weather cracks, grass cracks, etc.---but the most ba­sic way to de­scribe these de­fects is ac­cord­ing to their lo­ca­tion and di­rec­tion. These in­di­ca­tors also of­fer clues to the ori­gin and sever­ity of the prob­lem.

Ver­ti­cal cracks, which run per­pen­dic­u­lar to the ground, are the most com­mon. The rea­son has to do with the anatomy of the hoof wall it­self. Like hu­man fin­ger­nails, hoof wall is com­posed mainly of a pro­tein called ker­atin, which forms tubules---struc­tures that look like densely packed drink­ing straws. These tubules run ver­ti­cally down the hoof, from the coro­nary band to the ground, and give the hoof much of its struc­tural strength, like the re­bar in con­crete. Weak­nesses that al­low cracks to form are much more likely to de­velop be­tween the par­al­lel tubules than across them.

Lo­ca­tion de­ter­mines how se­ri­ous these cracks are likely to be. Those that orig­i­nate at the bot­tom edge of the hoof wall and climb up­ward are typ­i­cally just a cos­metic con­cern that is likely to be elim­i­nated at the next trim­ming. Ver­ti­cal cracks that orig­i­nate at the coro­nary band and grow down­ward are more wor­ri­some, es­pe­cially if they’re deep, be­cause dis­rup­tion at the coro­nary band af­fects the pro­duc­tion of new, healthy horn.

Ver­ti­cal cracks are fur­ther de­fined by where they ap­pear on the hoof wall:

• Toe cracks oc­cur in the front third of the hoof. Be­cause the hoof wall is thick­est and strong­est at the front of the hoof, se­ri­ous cracks at the toe are less likely to be caused by ex­ter­nal in­juries. How­ever, ab­scesses, bruises and other in­ter­nal is­sues that loosen the bond be­tween the hoof wall and the un­der­ly­ing con­nec­tive tis­sues can cre­ate weak­ness in the struc­ture that may re­sult in a deep crack.

Chronic toe cracks can also oc­cur in horses with con­for­ma­tion is­sues that in­crease stresses on the front of the hoof. “Ab­nor­mally high or low cof­fin bone an­gles cause toe cracks,” says Steve Kraus, BS, CJF, head far­rier of the Cor­nell Uni­ver­sity Col­lege of Vet­eri­nary Medicine. “Often, long pasterns and low-an­gled heels cause the front of the hoof to ex­tend too far ahead of the leg.” As the horse walks, the breakover places ex­treme lever­age on the in­side of the hoof wall, which can bend the wall in­ward and cause cracks.

“When a hoof has an

ab­nor­mally high cof­fin bone an­gle, the hoof will land toe first, which also puts ex­ces­sive force on the in­ner hoof wall, cre­at­ing the crack,” says Kraus.

• Quar­ter cracks de­velop along the side of the hoof; these tend to cause more trou­ble than toe cracks be­cause the wall is thin­ner and must flex as the hoof bears weight. Any cracks in the side of the hoof will be less sta­ble and are more likely to lead to lame­ness.

Quar­ter cracks are often caused by con­for­ma­tion de­fects in the legs, such as legs that toe out. “When the hoof is out of bal­ance it cre­ates too much pres­sure on one side of the cap­sule,” says Tommy Boudreau, a far­rier in Min­eral Wells, Texas. “This will push into the coro­nary band and cause it to jam up. With all the ex­tra pres­sure in one spot on that side of the foot it can make it break out and crack.”

These con­for­ma­tion faults tend to cre­ate chronic cracks in a pred­i­ca­ble lo­ca­tion, says Kraus: “If you drop a plumb line down from the front of the horse’s shoul­der, it will point to the crack.”

An un­der­run heel and long toe also places stresses on the quar­ters with each step. The pry­ing forces will sep­a­rate the hoof wall at the bot­tom first, and the crack will grow up­ward. Its edges will spread apart as the horse bears weight.

• Heel cracks oc­cur at the rear of the hoof, be­low the heel bulbs. Like quar­ter cracks, these, too, are likely to cause lame­ness. A shoe that shifts to the side or is too small to sup­port the en­tire heel to be­gin with is a com­mon cause of a heel crack. The por­tion of the heel that over­hangs the end of the shoe may split ver­ti­cally; the edges of the crack will slide up and down past each other with each step.

Over­strikes, when a horse hits the coro­nary band of a front foot while over­reach­ing from be­hind, are an­other com­mon cause of both heel and quar­ter cracks. “A blow to the coro­nary band causes a bruise and dam­age to those tis­sues,” says Boudreau. “If there’s not enough blood sup­ply in the dam­aged area that took the blow, this can cause a quar­ter crack. If the horse over­reaches and hits the coro­nary band, it is usu­ally some­where in the area be­tween the re­gion of the heel nail and the but­tress--the back part of the foot.”

TRIAGE FOR CRACKED HOOVES

When you no­tice a crack you’d never seen be­fore, you need to make a de­ci­sion: Do I need to call a far­rier right away? Or can this wait un­til our next sched­uled visit? You’ll need to get a close look at it.

In gen­eral, the sever­ity of a crack de­pends upon its depth. Even if they’re long, cracks that are lim­ited to the outer lay­ers of the hoof wall are usu­ally not se­ri­ous. Most will grow out with the wall and even­tu­ally be trimmed off with no harm to the horse. It is, how­ever, a good idea to keep an eye on these blem­ishes to make sure they do not de­velop into more sig­nif­i­cant in­juries.

The cracks to worry about ex­tend deeper into the hoof wall---enough to weaken it. Call your far­rier right away if you dis­cover a hoof crack with any of these signs:

• In­sta­bil­ity of the hoof wall. Watch as a friend walks your horse a few steps on hard, level ground. Does the hoof wall shift as the horse places his weight on it? If you pick up the hoof and han­dle it gen­tly, you may be able to feel the in­sta­bil­ity on each side of the crack.

• Drain­ing flu­ids. Any blood or pus that ap­pears around the edges of the crack may in­di­cate that the fis­sure has pen­e­trated all the way to

the in­te­rior of the hoof.

• Pain or lame­ness. Any sore­ness or un­sound­ness, how­ever mi­nor, is worth in­ves­ti­gat­ing.

• In­volve­ment of the coro­nary band. Any in­jury at the coro­nary band can af­fect the growth of fu­ture hoof wall.

Moshier says he runs into many peo­ple who are un­sure whether to call the far­rier be­tween reg­u­lar vis­its to look at a crack. “My an­swer is that they should call the far­rier when the horse is lame as a re­sult of the crack,” he says. If they’re still in doubt, he adds, “I ask my own­ers to take pic­tures of the feet with their phone, so they can send a photo to me to ask if it’s some­thing they need to worry about.”

TREAT­MENT OP­TIONS

The ba­sic ap­proach to man­ag­ing any hoof crack, no mat­ter how se­ri­ous, is to sta­bi­lize the hoof and keep the horse com­fort­able while new horn grows in and the dam­aged sec­tion is trimmed away---this can take up to a year for cracks that started at the top of the hoof. “Trauma to the hoof, such as an ab­scess, sel­dom re­quires more than good reg­u­lar trim­ming and in some cases a prop­erly fit­ted shoe,” says Heather O’Brien, a far­rier from Bri­tish Columbia.

Bar shoes are often used to help sup­port cracked hooves. “In most cases the far­rier will put clips on the shoe---on each side of the crack---to help pre­vent move­ment,” says Moshier. “It de­pends on the case.” Not all cracks spread apart when weighted---some toe cracks roll in­ward and “over­lap” when the horse puts weight on the foot. “While peo­ple tend to think that we need to sta­bi­lize that crack by keep­ing it to­gether, some types of crack re­pair in­volve keep­ing the edges of the crack apart, so they don’t roll in­ward,” he adds. “Clips, in this case, won’t do much good.”

More ex­ten­sive mea­sures may be needed to man­age cracks that are un­sta­ble. “Lac­ing,” for ex­am­ple, in­volves bind­ing the two sides of the crack to­gether us­ing var­i­ous ma­te­ri­als and tech­niques, in­clud­ing metal plates or steel wires. “If there is a lot of move­ment in the crack, we might have to lace it to­gether,” says Moshier. “This can be done by putting horse­shoe nails across the crack to hold it to­gether or lac­ing with stain­less steel threads.”

An­other op­tion is to re­pair cracks and re­place lost hoof wall with prod­ucts that fill in the gaps with ma­te­ri­als such as acrylic or polyuretha­ne. In more se­vere cases, the patches may be re­in­forced with fiber­glass. “These sta­bi­lize the cracks---es­sen­tially glu­ing it to keep the edges sta­ble so they won’t be mov­ing as the crack grows out,” ex­plains Moshier.

The patch ma­te­rial will then be trimmed away as the hoof wall grows out. “If you ap­ply the patch prop­erly, you can just keep trim­ming the patch just like the hoof wall as it grows down,” says Boudreau. “If ev­ery­thing works the way it is sup­posed to, it will grow right on off and then you’ll have a strong, healthy foot again.”

For the most se­ri­ous cases, when a horse is sig­nif­i­cantly lame and his long-term sound­ness is at risk, the far­rier will need to work in con­junc­tion with a vet­eri­nar­ian, who can pre­scribe med­i­ca­tions to re­lieve pain and con­trol in­fec­tions.

In some cases, dead or dy­ing tis­sue may need to be re­moved, and x-rays may be needed to look for the po­si­tion and po­ten­tial in­juries to the cof­fin bone and other struc­tures within the foot.

Even as the work to sta­bi­lize the hoof is un­der­way, it is im­por­tant to ad­just trim­ming and shoe­ing to ad­dress any hoof im­bal­ances or other stres­sors that caused the crack in the first place. “The one thing con­sis­tent in all suc­cess­ful re­cov­er­ies from a crack is the proper bal­anc­ing of the foot to the horse’s con­for­ma­tion,” says O’Brien. “With­out this, the crack will keep re­turn­ing un­til proper bal­ance is re­stored.”

PRE­VEN­TIVE MEA­SURES

Sim­ply keep­ing your horse healthy---with bal­anced nu­tri­tion, not over­weight, and plenty of turnout and ex­er­cise in good foot­ing---will go a long way to­ward keep­ing his hooves strong as well. Be­yond that, you can take ad­di­tional steps to re­duce the risk of hoof cracks:

• Stay on sched­ule with your far­rier. Whether the horse is bare­foot or shod, reg­u­lar vis­its from your far­rier are im­por­tant to keep his feet prop­erly trimmed and bal­anced in ac­cor­dance with his con­for­ma­tion. Flares that form at the bot­tom of over­grown hooves can eas­ily form cracks. “When the hoof wall gets too long it will bend, then crack,” says O’Brien. “De­bris from the en­vi­ron­ment can be­come em­bed­ded in the crack, es­pe­cially if the horse is bare­foot, caus­ing ab­scesses and even white-line dis­ease.”

• Use trac­tion aids only when needed. Calks, rims, bo­rium and other trac­tion de­vices may be in­valu­able if you often ride on slick sur­faces, but they can add stresses to the hooves and legs that can lead to cracks. Your far­rier can ad­vise you on the most ap­pro­pri­ate shoes for the type of rid­ing that you do. • Add a sup­ple­ment, if nec­es­sary. A horse whose diet is de­fi­cient in im­por­tant vi­ta­mins and trace min­er­als is likely to have weak, shelly hooves as well as dull, coarse hair. Bi­otin is the pri­mary in­gre­di­ent in sup­ple­ments in­tended to im­prove hoof health; many also con­tain min­er­als such as cop­per and zinc as well as amino acids and omega-3 and -6 fatty acids. If you sus­pect your horse may ben­e­fit from a hoof sup­ple­ment, con­sult with your vet­eri­nar­ian or an equine nu­tri­tion­ist to as­sess his diet and cre­ate a health­ier over­all ra­tion.

• Stop the stomp­ing. Horses ha­rassed by sta­ble flies in the sum­mer will stomp their feet re­peat­edly--which can lead to hoof cracks if they’re on hard, dry ground. Fly sprays will re­pel sta­ble flies, and a num­ber of man­age­ment strate­gies can help keep in­sect pop­u­la­tions un­der con­trol. These flies breed in de­cay­ing or­ganic mat­ter, so clean up soiled bed­ding and ma­nure from turnout ar­eas daily, and treat ma­nure pile with in­sec­ti­cides or lar­vi­cides. If flies re­main a prob­lem, con­sider out­fit­ting your horse with fly boots, which cover the legs and pre­vent the pests from land­ing on your horse.

• Keep an eye on foot­ing. Gal­lop­ing over hard ground poses an ob­vi­ous risk of cracks, but trav­el­ing through deep, soft foot­ing also places stresses on the hoof that can cause in­jury to the

hoof wall. Out on the trail, slow to a walk when you en­counter ground that is ei­ther deep and soft or hard and rocky, and drag your arena fre­quently to keep the foot­ing uni­form.

• Avoid the wet/dry cy­cle. When hooves get wet, they soften and swell; when they’re dry, they stiffen and con­tract. Horses can adapt to ei­ther con­di­tion, but al­ter­nat­ing be­tween the two on a daily ba­sis can loosen shoes and cause cracks.

“It’s not just the horse that’s con­stantly stand­ing in mud, or a horse that lives in a dry desert en­vi­ron­ment,” says Moshier. “The big­gest prob­lems oc­cur when horses are al­ways al­ter­nat­ing, such as go­ing from a stall bed­ded in kiln-dried shav­ings to be­ing turned out in the muck or wet pas­tures.” If your turnouts are chron­i­cally muddy, look for ways to im­prove drainage. Lay­ing gravel in high-traf­fic ar­eas may also help.

• In­spect your horse’s hooves daily. Pick­ing out the hooves is an es­sen­tial part of good horse­man­ship, but as you do this chore, take some time to in­spect the over­all health of the hoof: Run your hand over the hoof wall and coro­nary band to feel for de­fects. Look for dark spots on the sole, which could in­di­cate bruis­ing. Wig­gle the shoe to check for loose­ness---if you have a far­ri­ery tool called clinch­ers on hand, you can tighten the clinches. If the shoe is on the verge of fall­ing off, your safest op­tion may be to re­move it en­tirely. “I ad­vise peo­ple, when clean­ing the feet, to pick the white line and clear ev­ery­thing out of it. That’s the area to look at closely,” says Moshier. “Look for any black­ness in the white line be­cause that’s a sign of in­fec­tion.”

Prob­a­bly the best ad­vice of hoof crack preven­tion and man­age­ment is sim­ple: Get to know your horse’s hooves. As you han­dle his feet, give the hoof walls a once-over. Also con­sider tak­ing pho­to­graphs of your horse’s hooves oc­ca­sion­ally; these may help you de­ter­mine if a crack you’ve spot­ted is new or if a pre­ex­ist­ing de­fect is get­ting worse.

“Talk to your far­rier about what is nor­mal for that foot, and what isn’t, and be able to rec­og­nize any new cracks,” Moshier says. “I had a client who be­came very wor­ried about a crack she no­ticed. I got there and looked at it, and it was a scar type crack from a weak­ness in the wall. This crack had al­ways been there, but it was the first time she’d seen it.”

Keep­ing your horse’s hooves healthy and strong re­quires at­ten­tive care. But if you can pre­vent se­ri­ous hoof cracks, you’ll give him a solid foun­da­tion for a life­time.

The ba­sic ap­proach to man­ag­ing any hoof crack is to sta­bi­lize the hoof and keep the horse com­fort­able while new horn grows in and the dam­aged sec­tion is trimmed away. “Lac­ing” in­volves bind­ing the two sides of the crack to­gether us­ing var­i­ous...

A coro­nary band in­jury can tem­po­rar­ily dis­rupt the pro­duc­tion of hoof horn, re­sult­ing in de­fects in the hoof wall. Any hoof crack that is un­sta­ble or causes lame­ness is cause for a call to the far­rier.

Be­cause they af­fect a por­tion of the hoof wall that flexes as the horse bears weight, quar­ter cracks tend to cause more trou­ble than toe cracks. These cracks are more likely to be un­sta­ble and cause lame­ness.

Toe cracks ap­pear on the front third of the hoof. Those that orig­i­nate at the bot­tom edge of the wall are typ­i­cally just a cos­metic con­cern likely to be elim­i­nated at the next trim­ming. Be­cause they can weaken the en­tire hoof, deep ver­ti­cal cracks...

Hor­i­zon­tal cracks that run par­al­lel to the ground are al­most al­ways the re­sult of an ab­scess that drained through the coro­nary band and dis­rupted the for­ma­tion of horn.

As you pick out your horse’s hooves take some time to in­spect the over­all health of each foot.

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