Equinevet February 2015

Vol 5 Issue 2 2015www.modernequinevet.comEquine Vet

The Modern

Field tips For FindinglamenessRope tricks: Managing dummy foal syndromeSaddle fit: At rest and in motion

2 Issue 2/2015 | ModernEquineVet.com

TAble of ConTenTS

sporTs MedIcInesaddle fit: At rest and in motion ........................................................................................8

neonATAl cArerope trick helps reverse dummy foal syndrome .......................................................12

cArdIologyclydesdale's big heart skips more than a beat ...........................................................16

TechnIcIAn UpdATedo zebras need hoof trims? ...........................................................................................18

newsnew cT scanner tailor made for the horse ....................................................3why do zebras have stripes? .........................................................................11Best foot forward with new hoof book ....................................................15Video: dummy fold syndrome technique ...................................................14

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Field tips for finding lameness

coVer sTory: 6

Cover Photo: [email protected]

SaleS: robin geller • [email protected]

editor: Marie rosenthal • [email protected]

art director: Jennifer Barlow • [email protected]

contributing writerS: paul Basillo • Kathleen ogle

coPY editor: patty wall

Published by

p E r c y b omedia publishing

Equine VetThe Modern

advertiSerSshank's Veterinary equipment ................................ 3Avalon Medical ............................................................ 5

ceVA Animal health ................................................... 7AAeVT ...........................................................................17

PO Box 935 • Morrisville, PA 19067Marie Rosenthal and Jennifer Barlow, Publishers

ModernEquineVet.com | Issue 2/2015 3

www.shanksvet.com • [email protected]

Lifting Large Animals Since 1957

new ct scanner tailor made for the horseEpica Medical Innovations recently released pega-

so, a new computed tomography (cT) scanner specifi-cally designed for equine medicine.

The multi-modality pegaso unit features a resolu-tion that is 1,481 times higher than standard cT. The vastly superior image quality will help practitioners to provide more accurate diagnoses and treatment plans. And they can show these 3D views of the horse’s in-juries or problems to owners so they can make better decisions regarding their animals’ care.

“The pegaso provides unmatched cT image qual-ity for both soft and hard tissues. It will change our imaging paradigm for the horse,” said Chris Kawcak DVM, phD, DAcVS, DAcVSMr, professor, Equine orthopedic research center, college of Veterinary Medicine and biomedical Sciences, colorado State University.

The new diagnostic, interventional and intraop-erative scanner will fulfill the unmet imaging needs of equine veterinarians, who have struggled with getting good equine cT images because of the horse’s size. The average thoroughbred weighs more than 1 ton and stands between 62 and 68 inches tall. With The 1.2 meter diameter of the variable geometry, tilting gan-try, equine veterinarians can perform a cT scan of a standing horse’s head and neck up to the c7 vertebrae.

pegaso can scan any anatomy, including distal limbs, of an anesthetized horse and provides high quality images.

The fully robotic, high-definition cT scanner also includes large field, high resolution flyoroscopy and digital radiography. because it is mobile, it can easily be moved around the practice.

newS

“When we designed the pegaso, our sole focus was to design an imaging device that solved the frustra-tions experienced by equine veterinarians making due with machines that were made for humans and trying to squeeze horses into them. Not only were we able to design such a device, we reduced radiation by 60-90% less than standard cT making pegaso significantly safer for horses and the clinicians who use it.

"We believe this will change the face of veterinary medicine,” said Greg Stoutenburgh, president of Epica Medical Innovations. The drastic reduction of radia-tion enables the practitioner to use the device safely interventionally, or intra-operatively; which opens up a world of new opportunities equine veterinarians can diagnose and treat horses, ultimately improving prog-noses and outcomes.

For a product demonstration, video’ and more in-formation: epicamed.com/products/pegaso. MeV

Pegaso provides scans that are 1,481 times higher resolution than other scans and are built to accommodate a horse's size.

4 Issue 2 /2015 | ModernEquineVet.com

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During the past decade, magnetic resonance imaging (MrI) has become the gold stan-dard for identifying much of the pathology associated with lame-ness of the equine foot, according to tracy a. turner, DVM, MS, DAcVS, DAcVSMr, a veterinar-ian with Anoka Equine Veteri-nary Services in Elk river, Minn.

However, sometimes MrI is almost “too good” at detecting pa-thology, he added, because it can reveal more than one problem area, and a veterinarian still has

Low tech options:

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lameness pathologyField tips for finding

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to depend on his or her diagnos-tic acumen to determine which lesions on the MrI are actually causing the lameness pain.

“How often do you get an MrI report [for a lame horse] and there’s a list of pathologies?” He asked here at the 60th Annual AAEp convention in Salt Lake city. “At that point you start tear-ing out your hair,” he joked.

This scenario highlights the need for a thorough clinical ex-amination—and the use of ma-nipulative tests in particular—to determine the significance of le-sions found in the hoof and guide treatment options.

hoof Tester“Traditionally, the application

of hoof testers has been the biggest manipulative test that we’ve done,” Dr. Turner said. “but we have to

look at how the hoof fits with the rest of the leg, and how stress af-fects different structures and pain inside the foot. There are other manipulative tests that we can do.”

distal limb FlexionFor distal limb flexion, the

horse’s leg is held in flexion for a certain amount of time. A test is considered positive if lameness is exacerbated afterward. Dr. Turner noted that there may be more than one way to flex a horse’s leg, but he is not convinced that there is a sig-nificant difference.

“A colleague of mine swears that if you have the foot placed underneath the body then that will test more for the fetlock, and if you place the limb forward then that will test more for the hoof,” he said. “I haven’t seen much of a difference. However, I prefer to

pull the leg forward each time for consistency of pressure. I will hold the end of the toe, pull the leg for-ward, and the horse does all the flexion. I’ll hold the horse in that position for 30 seconds.”

Some studies have shown that distal limb flexion will exacerbate foot lameness in 90% of affected horses. “However, this test has a low specificity,” Dr. Turner said. “In my experience, a strong posi-tive test suggests joint issues, such as osteoarthritis or synovitis.”

wedge TestsIf a flexion test exacerbates

pain inside the foot, Dr. Turner will place the horse on a wedge or a block to further identify the source of the pain.

“by placing it underneath a part of the hoof, the wedge is go-ing to apply pressure to the wall,”

CoVeR SToRy


CoVeR SToRy

Dr. Turner explained. “That is going to compress one side and stretch the other. I find that this test is going to be much more spe-cific for collateral ligament pain.”

A toe wedge test will put pres-sure on the deep flexor tendon, but it also includes compression of the distal aspect of the navicular bone against the deep flexor tendon.

This is an area where remodeling is known to occur in the navicular bone.

“When I see a positive toe wedge test, the response suggests deep flexor pain,” Dr. Turner said. “you could argue that it is an ab-scess, but you’re really stretching the back part of this leg.”

Following a positive toe wedge test, Dr. Turner will perform ul-trasonography of the deep digital flexor tendon, including the pas-tern and across the frog.

A frog wedge test has been shown to have an 85% predictive value for navicular pain, Dr. Turner said. The test compresses the hoof through the frog and the digital cushion and puts pressure on the navicular bursa.

“A positive frog wedge test al-most invariably leads me to do a bursagram on the horse,” he said. “It’s going to give me more infor-mation about the pathology.”

A positive test will also pinpoint the need for deep compression with hoof testers and therapy with intra-articular injections, accord-ing to Dr. Turner.

decision tree“It is imperative to rely on a

thorough clinical examination to

help determine the importance of each lesion,” Dr. Turner said. “This is how you can make a hierarchy of the lesions.”

If the wedge tests are negative, then the focus shifts to intra-artic-ular or peripheral analgesia to look for joint pain, additional imaging and possible need for a farrier. A positive test leads to ultrasonog-raphy of the collateral ligaments. If the ultrasound is positive, the horse will need rest because it has a serious injury.

“A positive frog wedge test means deep pain inside the foot,” Dr. Turner explained. “It also tells me the frog pressure tolerance the horse has, and this specifical-ly can have implications toward shoeing."

often, the frog wedge test can lead a veterinarian to perform an-algesic injection of the navicular bursa or peripheral analgesia for a specific area, he said.

"If I have a positive frog wedge test, I am going to want to do a toe wedge test, which will lead me to look at increased pressure be-tween the deep flexor tendon and the navicular bone or deep flexor pain. That is going to lead me to perform peripheral analgesia,” Dr. Turner explained. MeV

clockwise: toe wedge; frog wedge test; wall wedge

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Now FDA approved for use in the U.S. and available from your veterinary distributor, Tildren® (tiludronate disodium) controls clinical signs associated with navicular syndrome in horses. Tildren works at the areas of active bone resorption, restoring balance to the process of bone remodeling.

NOW AVAILABLE IN THE U.S. Over 250,000 doses administered worldwide in the last 12 years.

©2015 Ceva Animal Health, LLC. Lenexa, KS 66215 TILDREN is a registered trademark of Ceva Santé Animale, France.

Do not use in horses with impaired renal function or with a history of renal disease. NSAIDs should not be used concurrently with TILDREN. Concurrent use of NSAIDs with TILDREN may increase the risk of renal toxicity and acute renal failure. Horses should be observed closely for 4 hours post-infusion for the development of clinical signs consistent with colic or other adverse reactions. Caution should be used when administering TILDREN to horses with conditions affecting mineral or electrolyte homeostasis (e.g. HYPP, hypocalcemia) and conditions which may be exacerbated by hypocalcemia (e.g. cardiac disease). The safe use of TILDREN has not been evaluated in horses less than 4 years of age, in pregnant or lactating mares, or in breeding horses.

Contact your local distributor or Ceva Animal Health representative for more information.

TILDREN.COM/US

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Bisphosphonate drug for intravenous infusion. For use in horses only.

Brief Summary: See package insert for full prescribing information.

Caution: Federal law restricts this drug to use by or on the order of a licensed veterinarian.

Description

TILDREN is a sterile powder. Each vial of TILDREN contains 500 mg of tiludronic acid (as tiludronate disodium) and 250 mg mannitol USP (excipient).

IndicationTILDREN is indicated for the control of clinical signs associated with navicular syndrome in horses.

Contraindications

Do not use in horses with known hypersensitivity to tiludronate disodium or to mannitol. Do not use in horses with impaired renal function or with a history of renal disease. Bisphosphonates are excreted by the kidney; therefore, conditions causing renal impairment may increase plasma bisphosphonate concentrations resulting in an increased risk for adverse reactions.

Warnings

Do not use in horses intended for human consumption. NSAIDs should not be used concurrently with TILDREN. Concurrent use of NSAIDs with TILDREN may increase the risk of renal toxicity and acute renal failure. Appropriate wash-out periods should be observed between NSAID and TILDREN administration, and BUN and creatinine should be monitored. If treatment for discomfort is required after TILDREN administration, a non-NSAID treatment should be used.

Human Warnings

Not for human use. Keep this and all drugs out of the reach of children. Consult a physician in case of accidental human exposure.

Precautions

Approximately 30-45% of horses administered TILDREN will demonstrate transient signs consistent with abdominal pain (colic). Hand-walking the horse may improve or resolve the colic signs in many cases. If a horse requires medical therapy, non-NSAID treatments should be administered due to the risk for renal toxicity. Avoid NSAID use.

TILDREN should be administered slowly and evenly over 90 minutes to minimize the risk of adverse reactions.

Horses should be well hydrated prior to administration of TILDREN due to the potential nephrotoxic effects of TILDREN.

Concurrent administration of other potentially nephrotoxic drugs should be approached with caution, and if administered, renal function should be monitored.

Caution should be used when administering TILDREN to horses with conditions affecting mineral or electrolyte homeostasis (e.g. hyperkalemic periodic paralysis (HYPP), hypocalcemia, etc.) and conditions which may be exacerbated by hypocalcemia (e.g. cardiac disease). TILDREN should be used with caution in horses receiving concurrent administration of other drugs that may reduce serum calcium (such as tetracyclines) or whose toxicity may exacerbate a reduction in serum calcium (such as aminoglycosides).

Horses with HYPP (heterozygous or homozygous) may be at an increased risk for adverse reactions, including colic signs, hyperkalemic episodes, and death.

The safe use of TILDREN has not been evaluated in horses less than 4 years of age. The effect of bisphosphonates on the skeleton of growing horses has not been studied; however, bisphosphonates inhibit osteoclast activity which impacts bone turnover and may affect bone growth.

Bisphosphonates should not be used in pregnant or lactating mares, or mares intended for breeding. The safe use of TILDREN has not been evaluated in pregnant or lactating mares, or in breeding horses.

Increased bone fragility has been observed in laboratory animals treated with bisphosphonates at high doses or for long periods of time. Bisphosphonates inhibit bone resorption and decrease bone turnover which may lead to an inability to repair microdamage within the bone. In humans, atypical femur fractures have been reported in patients on long term bisphosphonate therapy; however, a causal relationship has not been established.

Adverse Reactions: The most common adverse reactions reported in the field efficacy and safety studies were clinical signs consistent with abdominal discomfort or colic. Other reported signs were frequent urination, muscle fasciculations, polyuria with or without polydipsia, and inappetance/anorexia.

For technical assistance or to report suspected adverse reactions, call 1-800-999-0297.

Marketed by: Ceva Animal Health, LLC Lenexa, KS 66215

Tildren® is a registered trademark of Ceva Santé Animale, France

NADA 141-420, approved by the FDA

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B y p a u l B a s i l i o

Current recommendations for proper saddle fit are largely empirical. It is understood that the saddle needs to fit the rider and the horse at rest and in motion to avoid pain and impairment of perfor-mance, but the science behind the fitting often is neglected.

sue dyson, MA, VetMb, phD, DEo, FrcVS, of the centre for Equine Studies at the Animal Health Trust in New Market, UK, and her colleagues recently investigated the factors involved in exercise-induced changes in muscle dimensions and the effects those changes can have on a horse’s performance and overall well being.

“In humans, exercise induces an acute change in cross-sectional ar-eas of muscle that vary depending on the exercise type and intensity of the muscles used, and whether blood supply is limited,” Dr. Dyson said here at the 60th Annual AAEp convention in Salt Lake city.

“However, we have little knowl-edge of the changes in muscle di-mensions associated with work in horses.”

Dr. Dyson’s study investigated changes in back dimension in horses of various ages and work. The study was designed to quantify changes in back dimension that oc-cur subsequent to ridden exercise, and to determine the influence of work quality, saddle fit and rider skill level.

“We hypothesized that the changes immediately after exercise would be quantifiable,” she said. “Horses working on the bit would have larger changes than horses not working on the bit, and an ill-fitting saddle before work would diminish any transient increase in back di-mensions after work.”

The prospective study involved 63 horses who were ridden by their usual rider in normal tack. back dimensions were measured before and immediately after exercise at the 18th, 13th and 8th thoracic ver-tebrae (T18, T13, and T8), as well as a point one-third of the distance from the point of the elbow to the point of the shoulder. A flexible curve ruler was contoured around the horse’s back and then the out-

line was traced on graph paper. The width of the horse’s back was mea-sured at 3 cm and 15 cm ventral to the dorsal midline, and ratios for these distances were determined.

The fit of the saddle and numina were assessed objectively. All horses were ridden for 30 minutes on the flat by their normal rider. Video footage was obtained near the end of the session in both straight lines and circles.

results“At all measurement sites, we

detected differences in back dimen-sions when comparing the horse before and after exercise,” Dr. Dy-son explained. “There were greater changes at 15 cm ventral to the dorsal midline at the shoulder, T8 and T13. The biggest changes in di-mension were seen at T13 and T18, especially at 3 cm ventral to the midline at T18, which are the areas underneath the middle and back of the saddle.”

Sound horses had greater mean changes in back width 15 cm ven-tral to the midline at T8 and 3 cm

SpoRTS MediCine


at rest andsaddle Fit:

In Motion


SpoRTS MediCine

ventral to the midline at T13 when compared with lame horses. In-terestingly, 22 horses that were thought to be sound by the owners had gait abnormalities.

Twenty-eight riders were evalu-ated. Four were categorized as hav-

ing a poor skill level, six were cat-egorized as moderate, and 18 were categorized as good. The mean changes in back dimensions at each site were greater in horses ridden by good riders compared with moder-ate and poorly skilled riders.

“The mean changes at T8 were actually greatest for the moderately skilled riders, but all of those horses had a well fitting saddle,” Dr. Dyson noted.

The saddle was balanced in 39 horses and fitted with even contact without bridging in 35 horses. In 24 horses, the saddle was unbal-anced. Saddles tipped backward in 9 horses and forward in 15. Saddles consistently slipped to one side in 4 horses, and oscillated from left to right in 5 horses. In 2 horses, the saddle consistently slipped forward.

“We can see that the changes in the back ratios are consider-ably greater in horses with fitting saddles compared with ill-fitting

instant gratificationOne horse involved in the study had padding under the saddle, a gel pad and a very thick, fluffy numnah. After exercise, dry spots were noted under the saddle, which is an indication of an improper fit.

“This horse worked in a very uncomfortable manner with its head in front of the vertical (i.e., ‘above the bit’),” Dr. Dyson said. “There was little change in back dimension in this horse.”

When the pads were removed and the exercise was repeated, the horse showed a markedly improved increase in back dimensions at all measured sites.

“The horse worked phenomenally better in quality after the pads were removed,” she explained.

the back of a horse ridden with the fluffy numnah

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saddles,” Dr. Dyson said. “In fact, some horses with ill-fitting saddles had negative changes after exercise.”

Age was associated negatively with ratio changes. older horses showed less change in back dimen-sion than younger horses did. In ad-dition, the more convex the shape of the back before exercise, the less change in ratio was noted following exercise.

“This demonstrates there are quantifiable changes in back di-mensions with exercise, and horses working correctly on the bit in a well-fitted saddle are likely to have greater changes than those in ill-fitting saddles who are ridden in-correctly,” she said. “Failure to work correctly will result in lack of long-term muscle development, and the horses may have poor muscle tone.”

Saddles that tip forward or back-ward are also likely to result in a fo-cal increase in pressure. cumula-tive pressure over days and months may result in back pain and altered movement of the back, which can contribute to failure of the develop-ment of back muscles or the induc-tion of muscle atrophy.

“A saddle that fits a horse at rest may not fit the horse when it is in a correct posture and working prop-erly with increased tightness of the panels, especially in the region of the stirrup bars,” Dr. Dyson said. “This has potentially important implications for movement of the back, the scapulae and the thoracic girdle. It seems likely that back mus-cle development is in part related to these transient exercise-induced in-creases in back dimensions.”

The high proportion of incor-rectly fitted saddles in the study may be an indication that better owner education about saddle fit is needed. “Saddle fit should be checked before and after exercise,” she said. “Lack of clearance of the spinous processes by the saddle or by an overtight numnah may com-promise back movement.” MeV

One of nature's fascinating questions is how zebras got their stripes. A team of life scientists led by UCLA's brenda larison, PhD, has found at least part of the answer: The amount

and intensity of striping can be best predicted by the temperature of the zebra's environment.In the January cover story of the Royal Society's online journal, Open Science, the researchers make the case that

the association between striping and temperature likely points to multiple benefits, including controlling zebras' body temperature and protecting them from diseases carried by biting flies.

"While past studies have typically focused their search for single mechanisms, we illustrate in this study how the cause of this extraordinary phenomenon is actually likely much more complex than previously appreciated, with temperature playing an important role," said thomas b. Smith, PhD, professor of ecology and evolutionary biology in the UCLA College and senior author of the research.

Dr. Larison, a researcher in UCLA's department of ecology and evolutionary biology and the study's lead researcher, and her colleagues examined the plains zebra, which is the most common of three zebra species and has a wide variety of stripe patterns. On zebras in warmer climes, the stripes are bold and cover the entire body. On others—particularly those in regions with colder winters, such as South Africa and Namibia—the stripes are fewer and are lighter and narrower. In some cases, the legs or other body parts have virtually no striping.

Zebras evolved from horses more than 2 million years ago, biologists have found. Scientists have previously hypothesized that zebras' stripes evolved for one, or a combination of, four main reasons:

1. Confusing predators, 2. Protecting against disease-carrying

insects, 3. Controlling body temperature and 4. Social cohesion. And while numerous previous studies

of the phenomenon focused on a single hypothesis, Dr. Larison’s team were the first to fully test a large set of hypotheses against one another.

Analyzing zebras at 16 locations in Africa and considering more than two dozen environmental factors, the re-searchers found that temperature was the strongest predictor of zebras' striping. The finding provides the first evi-dence that thermoregulation is the main reason for the stripes and the patterns they form.

Separate research by daniel rubenstein, PhD, a Princeton University professor of ecology and evolutionary biology and a co-author of the Open Science paper, and Princeton undergraduate damaris iriondo strongly suggests that boldly striped zebras have external body temperatures about 5° F cooler than other animals of the same size, such as antelopes, which do not have stripes but live in the same areas. The Rubenstein study is not yet published, but it is cited in the Open Science paper.

Dr. Larison has studied many zebras during her field work throughout Africa, including Kenya, South Africa, Tan-zania, Uganda and Zimbabwe. Using the fact that their stripes are as unique as fingerprints, she is able to distinguish one zebra from another.

The research was supported by the National Geographic Society Committee for Research and Exploration.Dr. Larison and her research team have also collected zebra tissue samples and have used cutting-edge technol-

ogy to sequence zebra DNA to try to identify which genes code for striping. The team is continuing to study the benefits stripes provide. MeV

why do zebras have stripes?

newS noTeS

a zebra with a foal in tanzania's tarangire national Park. Credit: Brenda Larison/UCLA

For more information: Larison B, Harrigan RJ, Thomassen HA, et al. How the zebra got its stripes: a problem with too many solutions. Royal Society Open Science, 2015; 2 (1): 140452 DOI:10.1098/rsos.140452


http://rsos.royalsocietypublishing.org/content/2/1/140452


neonATAl CARe

uc davis School of veterinary Medicine professor and researcher John Madigan squeezes a maladjusted foal at victory rose thoroughbreds in vacaville, calif. on Jan. 21, 2015. the squeezing simulates the foal's trip through the birth canal. Madigan's research has found the squeezing to help the foal recover from neonatal Maladjustment Syndrome, sometimes within hours. Photo Courtesy of Joe Proudman / UC Davis

Veterinarians might be able to reduce

maladjustment symptoms in foals by using several loops of

a soft rope to gently squeeze the foal’s upper

torso and mimic the pressure experienced in

the birth canal.

rope ‘trick’ helps reverse

duMMY Foal SYndroMeneonatal maladjustment or dummy foal syndrome has puz-zled horse owners and veterinar-ians for a century.

Foals affected by the disorder seem detached, fail to recognize their mothers and have no inter-est in nursing. New research from the University of california at Davis suggest that abnormal lev-els of naturally occurring neuros-teroids may be the cause, and a low-tech treatment called the Madigan Foal Squeeze procedure may help.

Now the veterinarians have teamed up with their colleagues in human medicine to investigate possible connections to child-

hood autism, because some hu-man infants also have abnormal levels of neurosteroids.

“The behavioral abnormalities in these foals seem to resemble some of the symptoms in children with autism,” said John madigan, DVM, MS, DAcVIM, DAcAW, professor of veterinary medicine at University of california, Davis.

The maladjustment syndrome in foals also caught the attention of isaac pessah, MS, phD, profes-sor of molecular biosciences at the Uc Davis and a faculty member of the Uc Davis MIND institute, who investigates environmental factors that may play a role in the development of autistic spectrum


disorders in children. “There are thousands of po-

tential causes for autism, but the one thing that all autistic children have in common is that they are detached,” Dr. pessah said

Drs. Madigan and pessah and other researchers in veterinary and human medicine recently formed a joint research group and secured funding to investigate links between the two conditions.

Maladjusted foal syndromeIn newborn foals, neona-

tal maladjustment syndrome or dummy foal syndrome, occurs in 3% to 5% of live births. With around-the-clock bottle or tube feeding plus intensive care in a veterinary clinic for up to 10 days, 80% of the foals recover. but for horse owners, that level of care is grueling and costly.

For years, the syndrome has been attributed to hypoxia during the birthing process. Dr. Madigan and Uc Davis veterinary neu-rologist monica aleman, phD,

MVZ, DAcVIM, began sleuthing around for other potential causes, however, noting that hypoxia usually causes serious, permanent damage, while most foals with the maladjustment syndrome survive with no lingering health prob-lems.

one of their prime suspects was a group of naturally occur-ring neurosteroids, which are

key to sustaining pregnancies in horses, especially in keeping the foal “quiet” before birth.

Foals remain quiet in the womb“Foals don’t gallop in utero,”

Dr. Madigan is fond of saying, pointing out the dangers to the mare if a four-legged, hoofed fetus were to suddenly become active in the womb. The prena-

uc davis School of veterinary Medicine professor and researcher John Madigan, inspects a maladjusted foal at victory rose thoroughbreds in vacaville, calif. on Jan. 21, 2015.

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neonATAl CARe

tal calm is made possible, he ex-plains, by neurosteroids that act as sedatives for the unborn foal.

However, immediately after birth, the infant horse must make an equally important transition to consciousness. In nature, an equine neonate would be easy prey for many natural enemies, so the foal must be ready to run just a few hours after it is born.

In short, somewhere between the time a foal enters the birth canal and the moment it emerges from the womb, a biochemical “on switch” must be flicked that

enables the foal to recognize the mare, nurse and become mobile. Drs. Madigan and Aleman sus-pect that the physical pressure of the birthing process may be that important signal.

“We believe that the pressure of the birth canal during the sec-ond stage of labor, which is sup-posed to last 20 to 40 minutes, is an important signal that tells the foal to quit producing the seda-tive neurosteroids and ‘wake up,’” Dr. Madigan said.

neurosteroids persist in the bloodstream

The theory, he said, is support-

ed by the fact that the maladjust-ed foal syndrome appears more frequently in horses that were delivered by cesarean section or experienced unusually rapid births. perhaps those foals do not experience significant physical pressure to trigger the change in neurosteroids, Dr. Madigan said.

Furthermore, the research team has found for the first time that sedative neurosteroids per-sist, and their levels often rise, in the bloodstream of foals born with symptoms of the maladjust-ment syndrome. These neuros-

teroids are known to be able to cross the blood-brain barrier and impact the central nervous sys-tem (cNS), acting on the same receptor as do sedatives and an-esthetics.

The researchers also have demonstrated that maladjust-ment symptoms can be brought on temporarily in normal, healthy foals by administering short infusions of a neurosteroid called allopregnanolone. When the neurosteroid levels drop, the foals return to their normal state.

Foals ‘wake up’ with gentle harness pressure

The veterinary researchers have found that they can reduce maladjustment symptoms in foals by using several loops of a soft rope to gently squeeze the foal’s upper torso and mimic the pressure normally experienced in the birth canal (see video). When pressure is applied with the rope, the foal lies down and appears to be asleep.

After 20 minutes—about the same time a foal would spend in the birth canal—the rope is loos-ened and the squeeze pressure released. In initial cases, the foals have responded well to the proce-dure and recovered, some rising to their feet within minutes and then bounding over to join the mare and nurse.

The researchers suspect that the pressure triggers biochemical changes in the cNS that are criti-cal for transitioning the foal from a sleeplike state in the womb to wakefulness at birth.

Dr. Madigan cautions that, in spite of the strong observational effects, a larger, controlled clini-cal trial of national and interna-tional scope is now needed to reproduce those observed results and provide a better understand-ing of the mechanisms at work in the foals.

Foal behaviors resemble autismThe early findings have com-

pelling implications for the health of newborn foals and have caused the researchers to also explore possible links to autism, which in-cludes a group of complex brain-development disorders. While the symptoms vary, these disorders are generally marked by difficul-ties with social interactions, verbal and nonverbal communication, and repetitive behaviors.

“The concept that a disruption in the transition of fetal conscious-ness may be related to children with autism is intriguing,” said Dr. pessah, noting that the behaviors

http://news.ucdavis.edu/search/news_detail.lasso?id=10791


seen in the maladjusted foal syn-drome truly are reminiscent of those in some autistic children.

He noted that some children with autism do outgrow autistic behaviors by the time they reach 13 years. could this be a parallel to the recovery of the foals with the maladjustment syndrome?

Investigating possible linksA new group called the com-

parative Neurology research Group, consisting of veterinar-ians, physicians, epidemiologists and basic-science researchers, has formed to pursue further studies in this area. Dr. Madigan is working with researchers at the Stanford School of Medicine, ex-ploring the mechanisms of post-birth transitions of consciousness related to neonatal care of infants.

Using data from the foal re-search, Drs. pessah and Ma-digan are working with envi-ronmental epidemiologist irva

Hertz-picciotto, phD, MpH, at the Uc Davis MIND Institute to investigate neurosteroids in children with varying degrees of autism, ranging from some de-velopmental delay to full-spec-trum autism.

The researchers are exploring whether abnormal regulation of neurosteroids during the period around childbirth could be one of many factors that might contrib-ute to autistic spectrum disorders and related neurodevelopmental disorders. A recent study has re-ported elevated levels of neuros-teroids in children with autistic spectrum disorder.

Dr. pessah and colleagues will be looking to see whether there are alterations in blood levels of certain neurosteroids that may serve as a marker for the disor-der. They caution, however, that the relationship right now is just a theory that remains to be vali-dated or disproven. MeV

Keeping horses comfortable and sound can be a complicated and often stressful process not only for the owner, but also for hoof care professionals.

Author monique Craig, a hoof researcher and far-rier, started her learning journey out of personal frus-tration with these same issues. Her goal was initially just to find solutions for her own horses. Eventually, her 20+ years of hoof research yielded results applicable to every horse.

A Modern Look At … THE HOOF, published by outskirts press is a new look at the hoof, focusing on a detailed look at its morphology and function, and discussing implications for how the hoof should be trimmed and cared for. Topics addressed include:

• An introduction to hoof anatomy and structure, bones, hoof capsule, sole shape, pedal bone shape, weight bearing, false sole, the exfoliation cycle, toe callus and bevel, weather and soil mechanics, hoof packing, thrush, break over, tendon mechanics, and more.

• Measuring the hoof, including material on the natural asymmetry of the hoof capsule and bones of the lower leg of the horse. The ramifications of

these asymmetries have been rarely dis-cussed in any other equine literature.

• Assessing the hoof, topic materials in-clude annotated color images illustrat-ing what constitutes a “normal” hoof, painstakingly collected by the author over 20 years of hoof trimming.

• The Epona Trim, which is her ap-proach to trimming and assessing the hoof, addressing the natural asymmetry of the hoof and leg, as well as relating the trim to the bony column of the leg.

• Shoeing, including discussion of shoe placement and attachment (gluing, nailing or casting).

Ms. craig, founder of EponaTech and the Epona-Institute, and inventor of the EponaShoe polyure-thane shoe, includes an in-depth discussion of 16 case studies drawn from real-world application of her shoeing approach. MeV

For more information, visit www.EponaBook.com.

Put best foot forward with new hoof care book

neonatal maladjustment

syndrome occurs in 3% to 5% of

live births. with around-the-clock

bottle or tube feeding plus

intensive care in a veterinary clinic for up to 10 days, 80% of the foals

recover.


CARdiology

clYdeSdale'S

Leading a team of majestic clydesdales is Wind-sor, a special member of the eight-horse team that pulls a historic wagon for the Hallamore corp. So when he wasn’t himself, not pulling his weight, backing out of the harness, farm manager ned niemiec worried about Windsor’s heart.

Two other horses in the team had shown these signs in recent years, he said, and the diagnosis had been atrial fibrillation causing an irregular heart rhythm. So when their primary veterinarian suspected the same condition, Mr. Niemiec loaded up Windsor for the seven-hour drive from Lakeville, Mass., to New bolton center in Kenneth Square, pa.

“We’ve enjoyed a strong relationship with New bolton for many years,” said Mr. Niemiec, who manages all aspects of the Hallamore clydesdales. “We believe in the top, top reputation, especially in the cardiac area.”

Virginia reef, DVM, director of Large Ani-mal cardiology and Diagnostic Ultrasonography at New bolton center, is an expert in equine a-fib. “When a horse has a big heart, atrial fibrillation is more likely,” said reef, who is also chief of the Section of Sports Medicine and Imaging.

A horse with heart Windsor, foaled in England, is a 12-year-old gelding

that weighs more than 2,200 lbs and stands more than 18 hands high. “He’s huge,” Dr. reef said.

Distinctive, with a large white blaze on his face, Windsor is one of 17 clydesdales that live on the 40-acre farm of dennis Barry, who for nearly 45 years has indulged his passion for the breed with his eight-horse hitch.

Mr. barry owns Hallamore, a heavy-hauling trans-

B y l o u i s a s h e p a r d

Big heart skipsMore Than a Beat

http://www.vet.upenn.edu/veterinary-hospitals/NBC-hospital


portation and equipment com-pany that started in 1895 hauling loads with horses. To promote the company and foster positive public relations, a team of eight clydesdales pulls an orange wag-on, built in 1899, in parades and at local fairs.

“Windsor is one of the stars of our operation here,” Mr. Niemiec said. “He’s a wonderful horse. He’s one of the favorites in the barn. He’s not only handsome, he works well, too, and he has a great personal-ity. Willing and attentive, alert and easy, he wants to do his job.”

There was no question that the Hallamore team would do every-thing they could to get Windsor the care he needed.

cardiac care at new Bolton center An electrocardiogram (EKG)

confirmed the diagnosis of atrial fibrillation, Dr. reef said. Wind-sor’s heartbeat was more than 80 beats per minute and did not settle down, compared with a usual rate of 50 beats per minute. Dr. reef treated him with sotalol, an anti-ar-rhythmic drug with beta-blocking properties. “We wanted to slow the heart rate,” she said.

An echocardiogram confirmed that Windsor did not have obvious structural heart disease, such as a leaking heart valve.

one of the ways to “convert” atrial fibrillation is to give the horse IV doses of quinidine gluco-nate, Dr. reef said. This drug can be successful if the atrial fibrilla-tion is new, and the horse does not have structural heart disease, like Windsor.

“We gave him small doses for a good part of the day, and the a-fib resolved,” Dr. reef said.

The treatment worked, but the veterinarians had to watch for “pre-mature” heartbeats, extra beats just before the regular beats. Windsor

was on a continuous electrocardio-gram around the clock.

“He did have a few atrial pre-mature heartbeats,” Dr. reef said. “And when he was on the trailer getting ready to go home, we heard a number of them.”

Windsor was sent home on the drug sotalol to suppress the atrial premature heartbeats. Dr. reef also gave him benazepril, a drug that has been proven to help prevent re-occurrence of atrial fibrillation in humans.

In addition, she recommended potassium chloride supplements because the level of potassium ex-creted by Windsor’s kidneys was low. A potassium deficiency can cause the premature beats, and those premature beats can trigger atrial fibrillation, Dr. reef said. “If the body is depleted of potassium, this can make it more likely for a-fib to occur,” she said.

heading home with a heart Monitor

Mr. Niemiec went home with a 24-hour EKG to monitor Wind-sor’s heart. He did the recordings two weeks later, both standing in the stall, and while exercising, and sent the results to Dr. reef.

Ultimately, they weaned him off the drugs and his heart rhythm stayed steady. Windsor’s heart has made it past the critical four-month period, which is when most relapses occur, Dr. reef said.

“He’s past the first marker, which is good,” Dr. reef said. “but he could still experience a recurrence. So they need to make sure his electrolyte status is good, and make sure he gets potassium supplementation, especially if he works very hard.”

“He’s right as rain,” Mr. Niemiec said. “He seems to tolerate the work, whatever we ask him to do.” MeV

clydesdale caption: winsor, the clydesdale, about to undergo an eKg.

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18 Issue 2/2015 | ModernEquineVet.com18 Issue 2/2015 | ModernEquineVet.com

TeChniCiAn updATe

Carrie Cramer, RVT

an important part of caring for a horse includes keeping their hooves trimmed properly since most of these horses are kept in some form of confinement. Their exotic counterparts, such as zebra and przewal-

ski’s wild horse, roam free and are able to wear down their hooves as they cover miles of terrain.

Although zebras in a zoological setting might have large exhibit spaces, these spaces are nothing like roaming over the African savanna. routine hoof trim-ming is necessary for maintaining the health of these species.

Exotic equines are not amenable to manual re-straint, so we must anesthetize them to perform even basic husbandry. At the San Diego Zoo Safari park,

our veterinarians use combinations of opioids and other anesthetic drugs.

We plan these events days or sometimes weeks in advance because multiple departments are involved and the animal may need to be moved or isolated prior to the procedure. A team of veterinarians, technicians

and keepers participate to expedite the procedure.

As the technician team members, we prepare pa-perwork and supplies the day before the procedure. on the morning of, we load equipment into the veteri-nary truck and have a pre-procedural meeting with all involved.

Since these animals have a large flight distance, the veterinarians must use a remote delivery system to administer the anesthetic drugs. At the Safari park, we use carbon dioxide ri-fles with darts. Depending on the drugs used, induc-tion usually lasts from 3 to 10 minutes. However, there can be variables, such as a partial injection, a dart that bounced off of the animal or injection into a fat pad that may delay induction.

In this case, a Hart-mann’s mountain zebra (Equus zebra hartmannae) was darted with carfentanil (Zoo-pharm) detomidine (pfizer), ketamine (Zo-opharm) and butorphanol

(Zoopharm). Her induction lasted 12½ minutes due to a partial injection. Despite this, she achieved a good plane of anesthesia for the procedure.

once the animal is recumbent, the veterinarian and keepers will restrain and position the patient. For hoof trimming we put the horse in lateral recum-bency and position the legs away from any walls or structures to avoid injury if the horse were to rouse. We place a mattress pad under the head to protect the down eye and keep the neck extended for ease

do Zebras need hoof trims?

clockwise: author drawing a blood sampleFarrier in actionPreparing to collect a urine sample

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Carri

e Cra

mer,

R.V.T

.

http://sdzsafaripark.org


of respirations. We flush and moisten the eyes, then drape with a towel to avoid visual stimulation.

Supplemental oxygen is placed by a tube in the nares or an endotracheal tube. Then we place moni-toring equipment on the patient. A pulse oximeter is routinely used to monitor heart rate and oxygen-ation. Stethoscopes are also readily available.

While the farrier begins to work on the hooves, with a different orientation in lateral recumbency, the technicians will collect any biological samples and give injections while the veterinarian is performing a physical examination, including an oral examination.

collecting a blood sample is given the first prior-ity so as to draw a sample that is as close to ‘normal’ as possible. We try to avoid a stress leukogram that could be seen if we prolong the collection time from recumbency. Injections may include an anthelmin-thic, antibiotic, anti-inflammatory and vaccines.

Simultaneously, another technician or veterinari-an is monitoring respiration, heart rate and tempera-ture. In some cases there may only be one technician,

so these tasks are prioritized on a case-by-case basis.Diagnostics included were urine collection and

ultrasound to confirm pregnancy. A foal was con-firmed with ultrasound and rectal palpation.

The final step is to administer antagonists. Na-ltrexone (Zoopharm) is an opioid antagonist and reverses the effects of the carfentanil and butorpha-nol. Atipamezole (pfizer) is an α-2 antagonist and re-verses, in this case, the detomidine. both drugs were given as intramuscular injections. The patient was standing within 3 minutes after reversal agents were given. Her recovery was smooth and uncomplicated.

All of this zebra’s laboratory results were within normal limits. She gave birth to a live foal three months later. MeV

About the authorCarrie Cramer, RVT, is a veterinary technician at the San Diego Zoo Safari Park, 15500 San Pasqual Valley Road, Escondido, CA 92127.

AAEVT Mission Statement: To promote the health and welfare of the horse through the education and professional enrichment of the equine veterinary technician and assistant.

Are you aware the AAEVT is a professional equine association for not only your technicians and assistants but for your entire support staff as well? Membership is open to all veterinary technicians, assistants, practice managers, support staff and those employed or involved in the veterinary health care industry worldwide. We offer student memberships for those enrolled in an AVMA/CVMA accredited VT program.

• Equine specific continuing education opportunities which include members only registration fee discounts at AAEVT hosted regional CE meetings and at the annual AAEP convention, including TEVA and NEAEP. (Savings of $200.00 or more!)

• Networking opportunities to enhance staff member’s training opportunities that can add value to any practice.

• Biannual newsletters and our weekly email newsflash “HoofBeats” on Industry news.

• Full website access, including our Career Center with job opportunity postings.

• On-line access to industry articles, proceedings and webinars.

• Eligibility to participate in the ACT AAEVT On-Line Equine Certification Program.

• Eligibility for credentialed technicians to join the AAEVT Academy, AEVNT (Specialty in Equine Nursing).

• 20% discount on purchase price of the AAEVT Equine Manual for Veterinary Technicians published by Blackwell Publishing.

• NTRA, Platinum Performance and Working Advantage member benefits.

• Scholarships toward AVMA programs, AAEVT online Equine Certificate program and attend ing Regional CE meetings

• Eligibility to be invited to attend the Purina Equine Veterinary Technician Conference in St. Louis as a guest of Purina – all expenses paid!

Member benefits include:

For additional information, to join online, or to obtain a membership application, visit www.aaevt.org.

Encourage and support your staff to join today!

The primary objective of the AAEVT is to provide continuing education opportunities and training avenues, as well as to improve communications and enhance networking. By keeping members updated regarding current skills and issues within the profession, we continue to educate and promote the role of the technician as a profession to the veterinary community and general public. The end result being, to work more effectively and efficiently with veterinarians to continue to add value and provide the best care possible to improve the health and welfare of the horse.

www.aaevt.org

Reach your veterinarians wherever they are, whenever they want.

For AdVerTIsIng rATes And InForMATIon, eMAIlrobin gellar

Equine VetThe Modern

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Documents

Equinevet February 2015