EQUINE SCIENCE UPDATEReports from the world of equine science

Winter 2016

The University of PennsylvaniaSchool of Veterinary Medicine(Penn Vet) has completedinstallation of a revolutionaryrobotics-controlled imagingsystem for use in the standing andmoving horse, and have startedexploring limited diagnosticimaging on patients.

Penn Vet is the first veterinaryteaching hospital in the world touse the EQUIMAGINE™ system,which has clinical and researchapplications for both animal andhuman medicine.

The system can capture equineanatomy in a way not previouslypossible, while the horse is awakeand load-bearing. Existingcomputed tomography (CT)systems usually require the horseto be anesthetized, and arelimited to the parts of the animalthat fit into the cylindricalmachines.

“The robots can easily move allaround the horse in anyorientation while the horse isstanding, so we can see manyparts of the anatomy we’ve neverseen before, and do it in a patientthat is awake,” said Dr. BarbaraDallap Schaer, Medical Director ofNew Bolton Center, the large-animal hospital of the Universityof Pennsylvania School ofVeterinary Medicine.

“We think the system is not onlybeneficial to horses, but also willhave translational benefits forpeople” she added.

The robot-powered imagingsystem can collect typical, two-dimensional CT images; createthree-dimensional images;produce 360-degree digitalradiographic studies; and capturefluoroscopic images at up to16,000 frames per second.Eventually, researchers,clinicians, and engineers hope toprogram the robots to captureimages of a horse running on atreadmill.

According to the experts fromPenn Vet, the quality andresolution of the real-time imagescreated with the EQUIMAGINE™system far exceeds existingtechnology. And the systemmakes imaging much moreefficient and effective. The three-dimensional scans take less thana minute, a fraction of the time ittakes to produce multiple static

images that have limiteddiagnostic value.

Most specialists at New BoltonCenter will be able to takeadvantage of the technology,including those in surgery, sportsmedicine, neurology,cardiovascular medicine, andinternal medicine.

“The possibilities are almostunlimited in terms of theconditions that can be addressedwith this system,” Dallap Schaersaid.

Penn Vet researchers andclinicians are in discussions withcolleagues at Penn Medicine,Nemours Children’s HealthSystem, and other humanmedical centers about possibleapplications of the new imagingsystem.

Robot-driven Imaging System

Continued…

Penn Vet’s New Bolton Center has installed a revolutionary robotics-controlledimaging system for use in the standing and moving horse. © New Bolton Center

Equine Science Update2 Equine Science Update2

Another report of anthelminticresistance

The worrying trend of reports ofanthelmintic resistance continues.In a short communication in theVeterinary Journal, SimonDaniels, Lecturer in EquineNutrition and Parasitology at TheRoyal Agricultural University,Cirencester, and Prof ChrisProudman, of the University ofSurrey School of VeterinaryMedicine, document early signsthat ivermectin and moxidectinare not as effective as they oncewere.

When these anthelmintics werefirst available, the time taken forworm eggs to reappear in thefaeces after treatment (the eggreappearance period - ERP), wasreported to be 8–10 weeks forivermectin and more than 13weeks for moxidectin.

In this retrospective study, datafrom January 1, 2008 and August29, 2011 were reviewed todetermine the ERP afterivermectin or moxidectintreatment under field conditions,in United Kingdom pleasurehorses with persistently positivefaecal egg counts (FEC) followinganthelmintic treatment.

Their findings suggest that ERPfor ivermectin was from 5 weekspost-treatment. For moxidectinthe ERP study was 11–13 weeks.Indeed, in some individualanimals, egg reappearance aftermoxidectin treatment was as lowas 5 weeks.

The authors recognize that thestudy has limitations. However,they suggest that these dataprovide an insight into ivermectinand moxidectin efficacy in thefield. They suggest that furtherexperimental study is required todefine current ERP for these drugs.

The ability to obtain high-qualityimages of a joint in motion, or thespine, or the head, could openvast possibilities of discovery inthe areas of diagnosis, treatment,and medical productdevelopment. In pediatricpatients, it would allow imagingof a child while awake andmoving, rather than undergeneral anesthesia or whilerestrained.

Four-Dimensional DigitalImaging (4DDI), the companybehind the EQUIMAGINE™system, chose the New BoltonCenter to field test the systembecause the veterinary expertsare willing to collaborate todevelop the protocols for use withlarge animals, said Nicholas Hunt,Chief Technology Officer for 4DDI.

“At 4DDI we are excited thatNew Bolton has chosenEQUIMAGINE™ to develop thesenew technologies,” said Hunt, whohas led the team doing theinstallation.

The horse is probably “the mostsophisticated and difficult patientwe will ever encounter,” becauseof the size and complexity of theanimal, as well as the need tocorrect for motion, said YiorgosPapaioannou, 4DDI ChiefExecutive Officer.

“If we are able to tackle andsolve the challenges with thehorse, the technology could beeasily transferred to otherdomains of imaging, in humans,or small animals,” he said. “It’s agreat opportunity for us tovalidate our work with renownedacademics, surgeons, radiologists,and radiographic technicians.”

“Our results provide evidence forreduced strongyle ERPs followingivermectin and moxidectintreatment in UK pleasure horsesin the field. This work agrees withother recent reports of reducedefficacy of these drugs in the UK.”

For more details, see:

Shortened egg reappearanceafter ivermectin or moxidectinuse in horses in the UKS.P. Daniels, C.J. ProudmanThe Veterinary Journal (2016)Volume 218, pp 36–39

doi:10.1016/j.tvjl.2016.11.003

http://dx.doi.org/10.1016/j.tvjl.2016.11.003

Equine Science Update 3Equine Science Update 3

The identification of markers for prefracture change, that can be detectedusing MRI, suggests that reliablescreening methods for fracture riskmay be developed. The routine use ofsuch screening programmes wouldenable the introduction ofinterventions, such as alterations totraining regimens based on knownrisk factors for lateral condylarfracture that may reduce thelikelihood of fracture in susceptiblehorses.

Sarah Plevin of Florida EquineVeterinary Associates, Ocala, Floridacontinues the podcast with adiscussion on “Association betweensesamoiditis, subclinicalultrasonographic suspensory ligamentbranch change and subsequentclinical injury in yearlingThoroughbreds.”2

Sesamoiditis is a commonradiological finding in yearlingThoroughbreds. The condition isbelieved to be associated withsuspensory ligament branch injury(SLBI), which is known to affectracing performance. Theobservational study evaluated 50

If injuries in racehorses can bepredicted there is a far greater chancethey can be prevented suggests thelatest podcast from the EquineVeterinary Journal (EVJ)

In the 45 minute orthopaedic-themed broadcast Dr Tim Parkindiscusses the advantages of early MRIdetection of bone changes, whichoccur prior to catastrophic limbfracture and Dr Sarah Plevin talksabout the possible relationshipbetween sesamoiditis, subclinicalsuspensory ligament branch changeand suspensory ligament branchinjury in yearling Thoroughbreds.

Fracture of the lateral condyle of thethird metacarpus (MC3) is a commonreason for euthanasia on theracecourse, while suspensory branchligament injury is a frequentstumbling block in yearlingthoroughbreds in the initial months oftraining.

In the podcast Dr Parkin and DrPlevin both explain the potentialadvantages of early intervention toprevent injury and maintain racingperformance.

Dr Tim Parkin of Glasgow UniversityVeterinary School explores thequestion “Can we use subchondralbone thickness on high-field magneticresonance images to identifyThoroughbred racehorses at risk ofcatastrophic lateral condylarfracture?”1

The study, which assessed the bone-level risk factors for fracture inracehorses, is part of long-standingprogramme of research to preventracehorse injury, funded by theHorserace Betting Levy Board (HBLB).

A total of 191 MC3s from 96 horseswith (47) and without (49) lateralcondylar fracture, were subjected toMR imaging. Greater depth of densesubchondral/trabecular bone in thepalmar half of the lateral parasagittalgroove of distal MC3 was associatedwith an increased likelihood of beingfrom a horse that had sustained afracture.

Science of prediction to prevent racehorse injuries

Increases in subchondral bone thickness measured from MRI images were associatedwith increased fracture risk. Image © Tim Parkin / EVJ

untrained yearling Thoroughbreds ata training centre.

The results identified a significantrelationship between significantgrades of sesamoiditis, subclinicalsuspensory ligament branch change(SSLBC) and subsequent suspensoryligament branch injury (SLBI). Theassociations highlight the importanceof ultrasonographic examination ofsuspensory ligament branches inhorses with significant grades ofsesamoiditis. Ultimately the findingscould allow more accurate prognosesto be made regarding thedevelopment of SLBI and provideopportunity for intervention andprevention of such injury.

The EVJ podcast archive is availablefree at: http://apple.co/1KnWqX7 .

The papers are available at

http://onlinelibrary.wiley.com/doi/10.1111/evj.12574/fullandhttp://onlinelibrary.wiley.com/doi/10.1111/evj.12497/full

http://apple.co/1KnWqX7http://onlinelibrary.wiley.com/doi/10.1111/evj.12574/fullhttp://onlinelibrary.wiley.com/doi/10.1111/evj.12574/fullhttp://onlinelibrary.wiley.com/doi/10.1111/evj.12497/fullhttp://onlinelibrary.wiley.com/doi/10.1111/evj.12497/fullhttp://onlinelibrary.wiley.com/doi/10.1111/evj.12497/full

Equine Science Update4

Przewalski’s horses went extinctin the wild in 1968. Successfulbreeding programmes at zoosaround the world helped toreintroduce the animals in theGreat Gobi B protected area insouthwestern Mongolia since1992. The wild horses share theextreme habitat of the GobiDesert with two other equidspecies: the Asiatic wild ass, alsocalled khulan, and the free-ranging domestic horses of localnomads. For the preservation ofthe wild Przewalski’s horse, it isimportant to understand if andhow the three related speciescompete for food in the protectedarea.

Martina Burnik Šturm and PetraKaczensky from the ResearchInstitute of Wildlife Ecology atVetmeduni Vienna, in cooperationwith the Leibnitz Institute for Zooand Wildlife Research in Berlin,used a special method based onthe chemical analysis of tail hairsto investigate the dietary habitsof the animals. The analysisallowed them to determine thecomposition of the diet of each of

Equine Science Update4

Przewalski’s horse, a species ofwild horse that has beensuccessfully reintroduced to theGobi Desert, shares its pasturegrounds with wild asses andfree-roaming domestic horses. Ascarce supply of food could leadto food competition among thedifferent species, especially ifthey make the same dietarychoices. A team led byresearchers from VetmeduniVienna therefore chemicallyanalysed the tail hairs of theanimals to determine theseasonal dietary habits of thethree species.

They found that while the wildass switches from being a grazerin the summer to also browse inthe winter, the wild and domestichorses eat exclusively grass allyear round. In the lean wintermonths, this leads to increasedfood competition between wildand domestic horses. Thisunderstanding could help improvewildlife management measuresfor the Przewalski’s horse in thefuture. The study was publishedin the Journal of Applied Ecology.

Tail hairs tell of diet of Gobi desert horses

the three species, which led to thediscovery of increased dietarycompetition in the winter months.

The chemical analysis of the tailhairs revealed that Przewalski’shorses and domestic horses areyear-round grazers. Khulan, onthe other hand, switch fromgrazing in the summer to a highproportion of shrubs in the winter.“When food becomes scarce in thelong winter months, competitioncan be expected especiallybetween the two species ofhorse,” explains Martina BurnikŠturm.

In the summer, the food supplyis relatively high. At the sametime, the local nomads leave theGobi and take their horses to thehigh pastures of the surroundingmountains. “In the hot season,Przewalski’s horses mainly grazenear sources of water. Khulan, onthe other hand, also graze onpastures far from water sourcesas they are better able to conservewater. The potential for pasturecompetition in the summer istherefore relatively low among thethree species in the Great Gobi Bprotected area,” adds PetraKaczensky.

The chemical analysis used byBurnik Šturm and Kaczenskymeasures so-called stableisotopes in the tail hairs. “Stableisotopes are atoms of the samechemical element with the samenumber of protons but differentnumber of neutrons and thus withdifferent masses. The isotopevalues in the body tissue of livingorganisms are the result of theisotope values in the environmentand of the animal’s metabolism,”explains Burnik Šturm. Grassesand shrubs in the Gobi Desertexhibit different values of carbonisotopes, which make it possible

Grazing Przewalski᾽s horses in the Dzungarian Gobi, Mongolia(Photo: Martina Burnik Šturm/Vetmeduni Vienna)

Equine Science Update 5Equine Science Update 5

Mule or hinny. Can you tell the difference?

Mules (male donkey x female horse)and hinnies (male horse x femaledonkey) have been used throughoutthe world for thousands of years tocarry loads and people, and to workthe land.

Despite their importance, it isdifficult to separate mules fromhinnies by appearance alone. Thedifferences between them are subtleand not sufficient to confidentlydifferentiate one hybrid from theother.

Now researchers in Brazil havedeveloped a new technique to identifythe maternal origin of mules andhinnies, by looking for mitochondrialDNA (mtDNA), which is inherited fromthe mother.

In a report published in Genetics andMolecular Research, Mauricio MFranco and others describe amultiplex-polymerase chain reactionmethod, which targets the hyper-

to differentiate between grazersand browsers.

Because the tail hairs of horsesgrow at a regular rate, they act asan archive storing the isotopevalues at each growth stage. Thelonger the hair, the farther backinto the past the researchers canlook. “If you know how fast thehairs grow, you can date specifichair segments and clearly assignthem to a certain season.Consecutive hair segmentstherefore provide valuableinformation about the diet andwater balance of an individualanimal,” explains Burnik Šturm.

International research teams,under the direction of VetmeduniVienna and in close cooperationwith the Great Gobi B protectedarea, have for years beencommitted to the reintroductionprogramme in the Gobi Desert.The long-term goal is to establisha self-sustaining and viablepopulation of Przewalski’s horses,but also to protect other keyspecies such as the khulan.

An exact understanding of thedietary behaviour of thePrzewalski’s horse and the khulanis important for improving theconditions in the protected area.The high potential for pasturecompetition between domesticand wild horses highlights theneed for stricter regulation and arestriction on the grazing ofdomestic horses. Theestablishment of artificial watersources should be well consideredto avoid infringing on the khulan’sareas of retreat.

For more details, see:

Sequential stable isotopeanalysis reveals differences indietary history of threesympatric equid species in theMongolian GobiM Burnik Šturm, O Ganbaatar, CC. Voigt, P Kaczensky

Pictures of representative equids. A. Donkey (Pêga); B. horse (MangalargaMarchador); C. mule; D.hinny.Photo: copyright MM Franco et al (CC BY-SA)

variable mitochondrial DNA D-loopregion.

“Our method only permits us toidentify the maternal origin of thehybrids, differentiating mules fromhinnies” they explain. “However, thephenotypic (visual) differentiation ofmules from horses and hinnies fromdonkeys is not a problem for breedersand ranchers, according to our fieldexperience. Therefore, the pivotalproblem is to distinguish mules fromhinnies and for this the methodpresented in this study is veryeffective.”

They believe that their technique willallow a fast, cheap, and easy way toaccurately differentiate hinnies andmules. “This method can helpbreeders, ranchers, horseassociations, animal scienceprofessionals, and researchers tomanage their equid herds andpedigree registers with moreconfidence and precision.”

For more details see:Quick method for identifying horse (Equus caballus) and donkey (Equusasinus) hybrids.Franco MM, Santos JB, Mendonça AS, Silva TC, Antunes RC, Melo EO.Genet Mol Res. 2016 Sep 23;15(3). doi: 10.4238/gmr.15038895

http://dx.doi.org/10.4238/gmr.15038895

Equine Science Update6

Injecting into joints may benecessary for diagnosis ortreatment of lameness problems,but does carry the risk of jointinfection (sepsis).

Research, by Caroline C Gillespieand co-workers at the PurdueUniversity College of VeterinaryMedicine, West Lafayette,Indiana, looked at the factors thatmight influence of joint infectionsafter intra-articular injections. Thefindings were reported at the2015 ACVS Surgery Summit,Nashville, TN, October 2015, anda full report is published in thejournal Veterinary Surgery.

The study examined the methodsused to prepare sites prior tointra-articular injection, injectionmethods, types of medicationsused for joint injections, andmethods of aftercare.

Over 9000 veterinarians wereinvited to take part. They wereasked to complete a survey thatinquired into how many intra-articular injections they hadperformed and how many jointshad developed septic arthritis.

Two hundred and forty-onecompleted surveys were returned,mostly from clinicians working in100% equine practice. Sixty-fourof the respondents had seen casesof joint sepsis after joint injection.Overall, joint sepsis was reportedin 67 joints out of 319,760 intra-articular injections, (an incidenceof 2.1 septic joints per 10,000.)

The authors point out that thiscompares favourably to thereported infection rate in people(3.7 infections per 10,000 intra-articular injections). However,they do concede that “the numberof septic joints following jointinjection (67 of 319,760) in our

study is likely under-reportedbecause nearly 60% of the surveyrespondents reported treatingseptic joints that occurredfollowing intra-articular injectionby other veterinarians. The datafrom these septic joints were notincluded in our study.”

Three factors were found tosignificantly affect the risk of jointinfection.

Veterinarians than had been inpractice for less than 20 years hada significantly lower reportedinfection rate than those inpractice for 20 years or more. Theauthors suggest that it may bethat younger veterinarians were“more concerned about thecomplications of joint injections,were trained to use gloves andsterile skin preparation inveterinary school, and may havetaken precautions not evaluatedin the survey.”

Veterinarians who prepared theirown injection sites hadsignificantly lower infection rates(OR=0.10; P=.02) that those whoallowed someone else to preparethe site for them.

Although clipping the site priorto disinfection might be expectedto reduce the risk of jointinfection, by allowing for morethorough disinfection, in fact theopposite was found. This agreedwith previous studies that havefound that clipping hair increasedthe number of small hairs and skintransferred into joints by needlesperforating the skin. The authorsalso pointed out that clipping hairmay lead to skin damage over theinjection site, allowing for furtherinfection. Their findings areconsistent with reports thatclipping hair for routine jointinjections is not necessary andmay be detrimental.

Equine Science Update6

Joint injection: risks of infection

Wearing gloves, either sterile ornon sterile, did not have asignificant effect of joint infection,although the results did show atrend towards decreased risk ofinfection when wearing gloves.

The authors conclude “There isa low incidence of septic arthritisfollowing intra-articular injectionand a large number of injectionmethods reported by respondingveterinarians. The low reportedincidence of infection may berelated to the large number ofpractitioners frequently usingcommon methods.”

“Based on the data collectedfrom medical records,veterinarians should consider notclipping the injection site, notusing the same needle to draw upmedications and inject the joint,preparing the injection sitethemselves for 7 minutes or more,and wearing gloves for theinjection when performing jointinjections.”

For more details, see:

Methods and VariablesAssociated with the Risk ofSeptic Arthritis Following Intra-Articular Injections in Horses: ASurvey of Veterinarians.Gillespie CC, Adams SB, MooreGE.Vet Surg. 2016 Oct 1.doi: 10.1111/vsu.12563.

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http://dx.doi.org/10.1111/vsu.12563http://dx.doi.org/10.1371/journal.pone.0137985.g004

Equine Science Update 7Equine Science Update 7

accumulation of polysaccharidethat leads to the clinicalproblems in affected horses. Afull report of the research ispublished in the journalBiochimica et Biophysica Acta.

This breakthrough in theunderstanding of PSSM1 mightlead to the development of noveltreatments for this debilitatingdisease. It helps explain whysome forms of treatment mightbe ineffective. RVC researchersare now working towardsimproved treatments andmanagement of this disorder.

Dr Charlotte Maile, PostdoctoralResearch Fellow, said: "PSSM1 isa very common disease,especially in some breeds.Finally, we know the reason whythese horses store excessiveglycogen and polysaccharide intheir muscles. Our goal now is touse this information in designingnew treatments andmanagement strategies.”

Professor Richard Piercy,Professor of ComparativeNeuromuscular Disease, said:“Managing horses that tie-up is

Molecular mechanism behind one form oftying up

The molecular mechanism thatunderpins a common form of“tying up” has been identified byan international team ofresearchers.

Type 1 Polysaccharide StorageMyopathy (PSSM1) particularlyaffects Quarter horses anddraught breeds.

The genetic cause of the diseasewas discovered in 2008 byresearchers at the University ofMinnesota, who found thataffected animals have a mutationof a key enzyme (glycogensynthase) which is involved inenergy metabolism. This leads toincreased storage of glycogenand an abnormal type ofpolysaccharide, a form ofcarbohydrate. The mutation isinherited in dominant fashion –which means that only one copyof the gene needs to be inheritedto cause the disease.

Until now, no-one knew theprecise mechanism by which themutation caused increasedenzyme activity in muscles. DrCharlotte Maile and ProfessorRichard Piercy at the ComparativeNeuromuscular DiseasesLaboratory at the Royal VeterinaryCollege, London, led aninternational team of scientistsfrom the University ofCopenhagen, University ofMinnesota, Indiana UniversitySchool of Medicine and LiverpoolJohn Moore’s University, todiscover the answer.

They found that the mutationleads to a change in the enzyme’sstructure which leaves itpermanently active, so it cannotbe switched off. Thishyperactivity of mutant equineenzyme explains the increasedmuscle glycogen and the

hard, and some recommendedtreatments work poorly in someanimals. By revealing the precisemechanism for this form of tyingup, our work should make a realdifference. Our hope is that bytargeting specific approaches tothe problem, - rather than a ‘onetreatment fits all’ - horse welfarewill be improved allowing themto get back to exercise, whichhas to be good for the horse andtheir owner.”

The work was partly funded bythe Petplan Charitable Trust andthe Morris Animal Foundation.

For more details, see:

A highly prevalent equineglycogen storage disease isexplained by constitutiveactivation of a mutant glycogensynthase.Maile CA, Hingst JR, MahalinganKK, O'Reilly AO, Cleasby ME,Mickelson JR, McCue ME,Anderson SM, Hurley TD,Wojtaszewski JF, Piercy RJ.Biochim Biophys Acta. (2016).doi: 10.1016/j.bbagen.2016.08.021

Dr Charlotte Maile and Professor Richard Piercy at the Royal VeterinaryCollege, London

http://www.vetmed.ucdavis.edu/vmth/diagnostic_imaging/la_imaging/PET.cfmhttp://www.vetmed.ucdavis.edu/vmth/diagnostic_imaging/la_imaging/PET.cfmhttp://www.vetmed.ucdavis.edu/vmth/diagnostic_imaging/la_imaging/PET.cfmhttp://d.doi.org/10.1016/j.bbagen.2016.08.021http://www.vetmed.ucdavis.edu/vmth/diagnostic_imaging/la_imaging/PET.cfm

Equine Science Update8 Equine Science Update8

Effect of shoes on foot biomechanics

An international research teamis working to understand howhorseshoes affect foot skeletonstress in racehorses.

The research team, from theUniversity of Queensland (UQ) inAustralia, the Royal VeterinaryCollege (RVC) in the UK andBrown University in the USA, isharnessing a new approach thatcombines 3D x-ray imagingtechnology with computersimulations and models of theforces exerted on bones.

Dr Olga Panagiotopoulou,research team leader at the UQSchool of Biomedical Sciences,said “This novel combination hasenabled us to study the effect ofa stainless-steel horseshoe onskeletal stresses within theforefoot in a live racehorse.”

“This is the first time thiscombination of techniques hasbeen used in large live animalssuch as horses.

“Future research using moreanimals will enhance ourunderstanding of what regions ofthe horses’ feet are most at riskof damage.”

The method was used effectivelyin a preliminary case study at theRoyal Veterinary College inLondon.

RVC vertebrate biomechanicsand evolutionary anatomyresearcher Professor JohnHutchinson said further researchwas necessary.

“We need to undertake furtherstudies with more horses movingat faster speeds and gaits andwith a similar focus on the hindfeet,” he said.

The research involved walking athoroughbred between threedimensional radiographs, animaging technique developed byProfessor Stephen Gatesy andcolleagues at Brown Universityand used previously to view boneinteraction in small animals suchas fish and birds.

Dr Panagiotopoulou used filmindustry animation techniques totransform the radiographic datainto a life-size three-dimensionalmodel.

“By combining the 3D model withother research data, we were ableto measure the force the horse’sfoot bones generated when theyhit the ground and developcomprehensive simulations,” shesaid.

“We believe this work could pavethe way for new directions inresearch which will minimise footinjuries and improve animalhealth and welfare.”

For more details, see:

A preliminary case study of theeffect of shoe-wearing on thebiomechanics of a horse’s foot.Panagiotopoulou O, Rankin JW,Gatesy SM, Hutchinson JR.(2016)A preliminary case study of theeffect of shoe-wearing on thebiomechanics of a horse’s foot.PeerJ 4:e2164https://doi.org/10.7717/peerj.2164

For a video showing an X-rayreconstruction of movingmorphology (XROMM) animationof a horse walking through abi-planar fluoroscopy system, goto:https://vimeo.com/174609162

Equine Science Update e-news is now available.Receive monthly news by e-mail

See: www.equinescienceupdate.com for details.

https://doi.org/10.7717/peerj.2164https://doi.org/10.7717/peerj.2164https://vimeo.com/174609162http://www.equinescienceupdate.com

Equine Science Update 9Equine Science Update 9

cover less common pathologicalconditions.

Practitioners recognise MRI asthe gold standard for neurologicimaging because of the excellentsoft tissue detail but the size ofhorses and the size of scannersmakes it a challenge to use. Anadditional constraint is the longeracquisition time compared to CT.

Notwithstanding theselimitations, three studies in thecollection display the variousbenefits of using MRI for the spineand neck, including the evaluationof 84 equine head disorders, thediagnosis of cervical stenoticmyelopathy, and the assessmentof two foals with closed headtrauma.

Despite the significant advancesin imaging, the horse’s back stilldefies conventional systems,primarily because of its size,concludes a spinal evaluationarticle. New technologies such asrobotic fluoroscopy and cone-beam CT, may provide a cross-sectional method to evaluate theequine spine, but for nowradiographs are still better to helpevaluate findings of spinousprocess impingement seen onscintigraphy. However, physicalexamination still plays a crucialrole in diagnosis of back pain,because of the wide variety ofabnormalities seen onscintigraphy and radiography inhorses with and without back pain.

Imaging the Equine Head andSpine Online Collection can bedownloaded from:

http://bit.ly/2gUxtN8

imaging for dental disease inhorses.

However, a study of horses withdiseased mandibular cheek teethfound that while CT is useful toidentify defects in the bone andtooth it is far less useful for theidentification of inflammation andtissue destruction which is farbetter served by MRI.

The structure of the equine headis complex and subject to greatvariation so several articles focuson practical anatomy andinterpretation of radiographs ofthis region.

Advanced diagnostic techniquesare helping with clinical andsurgical approaches to problemswith the equine head. Forexample, the sphenopalatinesinus is challenging to assessradiographically as it issurrounded by other structures.CT can help overcome thisobstacle. One of the studiesdescribes how CT can help unravelthe pathology of various equinesinonasal tumours. Other articles

An online collection of the latestarticles on imaging the head andspine of the horse have beenmade available thanks tocollaboration between the EquineVeterinary Journal (EVJ), EquineVeterinary Education (EVE) andVeterinary Radiology andUltrasound.

The articles cover theadvantages of cutting-edgemodalities and draw comparisonswith more readily available toolssuch as radiography.

The large size and shape ofhorses has made it difficult to usediagnostic imaging efficiently andaccurately.

Radiographs were the onlyfeasible option until theavailability of ComputedTomography (CT) and MagneticResonance Imaging (MRI).

MRI and CT take detailed, three-dimensional images of organs,soft tissues and bone. Now withthe development and availabilityof bigger, wider and moreadaptable scanners, horses can beexamined in a standing position.This has significantly improveddiagnostic and treatmentstrategies. It also avoids the needfor a general anaesthetic.

Radiation safety is crucial whenusing most forms of diagnosticimaging. Given the increase in useof CT in horses and thecontamination hazards facedparticularly by horse handlers, twopractical articles in the collectiondescribe the role of equine headCT, how to set up standing equineCT and the radiation exposurerisks.

CT is the most revolutionaryrecent advance in diagnostic

Progress in equine head and neck imaging

Transverse CT image at the level of theethmoid turbinates in a horse withepistaxis. ©EVJ

http://bit.ly/2gUxtN8

Equine Science Update1 Equine Science Update10

New information on Equine Grass Sickness

In terms of risk factors, the study‘Equine grass sickness in Scotland: Acase-control study of environmentalgeochemical risk factors’ suggeststhat the high incidence of the diseasein Eastern Scotland may be partlyassociated with the particularcomposition of macro and traceelements in the soil in the fields onwhich horses graze. Further work isrequired to determine whetherinterventions to alter concentrationsof particular elements in soil couldpotentially reduce the risk of EGS.

A second study identified keydifferences between EGS andbotulism, which questions thecurrently favoured hypothesis thatEGS is caused by neurotoxins fromClostridium botulinum, a bacteriumwhich commonly inhabits soil. Thestudy ‘Equine grass sickness, but notbotulism, causes autonomic andenteric neurodegeneration andincreases soluble N-ethylmaleimide-sensitive factor attachment receptorprotein expression within neuronalperikarya’ suggests that EGS isunlikely to be caused by neurotoxinsfrom this bacterium and concludesthat further investigation of analternative cause for EGS is needed.

While the majority of horses withEGS can be readily diagnosed byexperienced veterinary surgeons,some cases present a diagnosticchallenge. Indeed the only way todefinitively diagnose the disease in alive horse is to demonstrate thecharacteristic degeneration of nerveswithin biopsies of the intestine.Unfortunately these biopsies can onlybe collected by performing abdominalsurgery under general anaesthesia.In the study ‘Neuronal chromatolysisin the subgemmal plexus of gustatorypapillae in horses with grass sickness’characteristic degeneration of nerveswas identified in small biopsiescollected from tongues of EGS horsesduring post mortem examination.Examination of these biopsiesaccurately differentiated controlhorses from EGS cases. While furthervalidation of this technique isrequired, it could potentially providea relatively non-invasive method of

New research on equine grasssickness (EGS) has improved ourunderstanding of this devastatingdisease.

A collection of recent articles is nowavailable at no cost thanks to theEquine Veterinary Journal.

Four separate studies are included,reporting novel risk factors for thedisease, identifying key differencesbetween EGS and botulism(questioning the hypothesis that EGSis caused by neurotoxins fromClostridium botulinum), reporting anovel diagnostic technique andshowing the value of monitoringweight loss to help predict whetherindividual horses with chronic EGS arelikely to survive.

Despite more than 100 years ofresearch, supported predominantly bythe The Moredun Foundation EquineGrass Sickness Fund(www.grasssickness.org.uk), thecause of EGS remains unknown. Sinceit affects, almost exclusively, grazinghorses, a pasture derived neurotoxinis implicated.

EGS causes gut paralysis as a resultof damage to parts of the nervoussystem that control involuntaryfunctions. Acute and sub-acute EGSis invariably fatal while around 55%of chronic cases can survive andreturn to a useful working life. The UKhas the highest incidence of EGS inthe world; indeed it is estimated thatthe disease kills between 1 and 2%of horses in the United Kingdomannually. Cases are more common inspring.

confirming the diagnosis in a livehorse.

While around 55% of horses withchronic EGS survive, objective criteriafor predicting survival of these casesare currently lacking. The study‘Bodyweight change aids prediction ofsurvival in chronic equine grasssickness’ reported that non-survivorshad greater rate and magnitude ofbodyweight loss than survivors.Survival prediction curves werepublished to allow veterinarysurgeons and horse owners to usebody weight data to help determinewhether an individual horse withchronic EGS was likely to survive ordie.

Professor Bruce McGorum, Head ofthe Equine Section at the Royal (Dick)School of Veterinary Studies & RoslinInstitute in Edinburgh, has beenleading much of the research. Hesaid: “Given that our recent researchsuggests that EGS is unlikely to becaused by neurotoxins fromClostridium botulinum we are nowmoving on to determine whether EGSis caused by ingestion of mycotoxinsproduced by pasture fungi. We arevery pleased that The Horse Trust(www.horsetrust.org.uk) hasprovided funding for this three-yearinvestigation."

Professor Celia Marr, Editor of theEquine Veterinary Journal said: “Whilethe cause of equine grass sicknesscontinues to evade us, these paperspresent an optimistic step in the rightdirection for the eventual preventionof this dreadful disease. It is only withthe support of the MoredunFoundation Equine Grass SicknessFund and more recently that of TheHorse Trust that our world-leadingveterinary researchers are able tocontinue to unravel the mystery.”

The EVJ equine grass sicknesscollection can be downloaded athttp://bit.ly/2dC7Drr

http://bit.ly/2dC7Drr

Equine Science Update 1Equine Science Update 11

Horses askhumans to helpsolve problems

Researchers in Japan haveshown that when horses faceproblems they cannot solvethemselves, they use visual andtactile signals to get humanattention and ask for help.

The study, conducted byResearch Fellow MonamieRinghofer and Associate ProfessorShinya Yamamoto of KobeUniversity Graduate School ofIntercultural Studies, alsosuggests that horses alter theircommunicative behaviour basedon humans’ knowledge of thesituation.

Since they were domesticated6000 years ago, horses havecontributed to human society invarious ways, from transport tocompanionship.

The high social cognitive skills ofhorses towards humans mightpartially explain why humans andhorses have a collaborativerelationship today. However, thescientific evidence for this abilityis still scarce.

Ringhofer and Yamamotoinvestigated horses’ socialcognitive skills with humans in aproblem-solving situation wherefood was hidden in a placeaccessible only to humans. Theexperiment was carried out in apaddock belonging to theequestrian club at KobeUniversity, where eight horsesfrom the club participated with thecooperation of their studentcaretakers.

For the first experiment, anassistant experimenter hid food(carrots) in a bucket which thehorse could not reach. Theresearchers observed whetherand how the horse sent signals to

Findings from a recent studyshow that 70 percent of injuriesrecorded among thoroughbred flatracing horses on race-day wereminor and did not end the horse’scareer.

Using 14 years of data, the studyfound that soft tissue injuries,respiratory conditions and gaitabnormalities were the mostcommonly reported issues.

Soft tissue injures includewounds and lacerations. Thoseclassified as “gait observations”primarily relate to horses reportedas lame, moving poorly or beingstiff, but without a specific causebeing identified. Most horses withrespiratory conditions hadepistaxis, (blood at the nostrils.)

Researchers recently completedthe first large scale study of race-day veterinary reports recordedfor thoroughbred flat racinghorses in Great Britain and thefindings can help prioritize effortsand direct research to identify riskfactors for the most commonand/or severe conditions, with theaim of reducing their occurrencethrough appropriate interventions.

Now that the most importantrace-day veterinary incidentshave been identified, researcherscan begin to determine what riskfactors and strategies can be usedto build on British racing’s alreadystrong track record of equinewelfare and further reduce injuryand fatality rates in British flatracing.

Sarah Rosanowski, PhDPGDipVCS BSc, at the RoyalVeterinary College said: “It wasnot surprising to find that mostveterinary incidents reported onrace-day are relatively minor andnot career-ending. This is ofcourse a good thing.”

“Although the good news is thatthe majority of injuries are notlife-threatening, the fatality ratesin British flat racing haveremained relatively stable ratherthan declining over the pastdecade.”

“The ongoing surveillance by theBritish Horseracing Authority isimportant as it provides a way totrack the occurrence of veterinaryevents over time. Now that wehave a baseline against which tomonitor the effects of futureinterventions, there will beopportunities to further improvehorse welfare and racing safety.”

For more details, see:

Descriptive epidemiology ofveterinary events in flat racingThoroughbreds in Great Britain(2000 to 2013).Rosanowski, S. M., Chang, Y. M.,Stirk, A. J. and Verheyen, K. L.P.Equine Vet J. (2016)Doi:10.1111/evj.12592

Most thoroughbred flat racinginjuries are minor

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. Every effort is taken to ensure the accuracy of these reports, which are for information only. Veterinary Surgeons are advised to refer to theoriginal research if they wish to take action based on the information.

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Equine Science Update12

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Contents

their behaviour towards humansdepending on the humans’knowledge state. This high socialcognitive ability may have beenacquired during the domesticationprocess, the researchers say.

The team plans further researchto identify the trait that allowshorses to form close bonds withhumans, by comparingcommunication between horses,and by looking more closely at thesocial cognitive ability of horsesin their communication withhumans.

“By deepening ourunderstanding of the cognitiveabilities held by species who haveclose relationships with humans,and making comparisons with thecognitive abilities of species suchas primates who are evolutionarilyclose to humans, we caninvestigate the development ofunique communication traits indomesticated animals. This isconnected to the influence ofdomestication on the cognitiveability of animals, and canpotentially provide valuableinformation for realizing strongerbonds between humans andanimals.”

the caretaker when the caretaker(who was unaware of thesituation) arrived. The horsestayed near the caretaker andlooked at, touched and pushedthem. These behaviours occurredover a significantly longer periodcompared to cases when theycarried out the experimentwithout hiding the food.

These findings show that whenhorses cannot solve problems bythemselves they send signals tohumans both visually (looking)and physically (touching andpushing), the researcherssuggest.

In a further experiment, theytested whether the horses’behaviour changed if thecaretakers’ knew where the foodwas hidden. They found that if thecaretaker hadn’t watched the foodbeing hidden, the horses gavemore signals, demonstrating thathorses could change theirbehaviour in response to theknowledge levels of humans.

These two experiments revealedsome behaviours used by horsesto communicate their demands tohumans. The findings also suggestthat horses possess high cognitiveskills that enable them to change

For more details, see:

Ringhofer, M. & YamamotoWhen horses are in trouble theyask humans for helpS. Anim Cogn (2016).doi:10.1007/s10071-016-1056-4

Horse making demands: The horse a) lightly pushes and b) looks at the caretakerstanding outside the paddock. Food is hidden inside one of the two silver bucketsbehind them. When horses cannot obtain this food by themselves, they give humansvisual and tactile signals. © Monamie Ringhofer, Shinya Yamamoto

Robot-driven Imaging System….……….………….……….……..1

Another anthelminticresistance report………………2

Science of prediction toprevent racehorse injuries ..3

Tail hairs tell of diet of Gobidesert horses…………………..4

Mule or hinny. Can you tell thedifference?………………………5

Joint injection: risks ofinfection………………………….6

Molecular mechanism behindone form of tying up ………..7

Effect of shoes on footbiomechanics…………………..8

Progress in equine head andneck imaging ………………….9

New information on EquineGrass Sickness………….……10

Most thoroughbred flat racinginjuries are minor…………..11

Horses ask humans to helpsolve problems……………….11

a b

http://dx.doi.org/10.1007/s10071-016-1056-4