Prevalence of oro-dental pathology in a working horse population in Egypt and its relation to equine health

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1 Equine Veterinry Journl ISSN DOI: /evj Prevlence of oro-dentl pthology in working horse popultion in Egypt nd its reltion to equine helth S. E. SALEM*, N. B. TOWNSEND, W. REFAAI, M. GOMAA nd D. C. ARCHER Institute of Infection nd Globl Helth nd School of Veterinry Sciences, University of Liverpool, Neston, Cheshire, UK Deprtment of Surgery, Fculty of Veterinry Medicine, Zgzig University, Zkzik, Egypt. *Correspondence emil: Received: ; Accepted: Summry Resons for performing study: Oro-dentl disese cn hve significnt impct on equine welfre. Objectives: To determine the prevlence of oro-dentl disese nd to identify risk fctors for oro-dentl disorders nd poor body condition scores (BCS) in working horse popultion in Egypt. Study design: Cross-sectionl survey. Methods: Oro-dentl exmintion ws performed on 450 working horses in 2 Egyptin provinces. Horse nd mngement historicl dt were collected nd horses were ssigned to no/mild, moderte nd severe dentl disese ctegories bsed on findings on exmintion. Multivrible logistic regression nd generlised dditive models were used to identify risk fctors for orl mucosl injuries nd very poor/poor BCS, nd to explore the reltionship between ge nd different oro-dentl disorders. Results: Oro-dentl disese ws common, with 45.3% nd 8.4% of horses considered to hve moderte nd severe oro-dentl disese, respectively. None of these horses hd previously undergone ny form of proper dentl exmintion nd tretment by trined personnel. Orl mucosl injuries (64.2%) nd shrp enmel points (79.8%) were most common. Orl mucosl injuries were significntly ssocited with incresing ge (odds rtio (OR) 1.1, 95% confidence intervl (CI) , P = 0.03), focl dentl overgrowths (OR 2.4, 95% CI , P = 0.002) nd shrp enmel points (OR 6.3, 95% CI , P<0.001). Very poor nd poor BCS were significntly ssocited with severe dentl disese (OR 2.6, 95% CI , P = 0.02), horses ged yers (OR 3.5, 95% CI , P = 0.001), height (OR 0.9, 95% CI , P = 0.001) nd pcked cell volume (OR 0.9, 95% CI , P<0.001). Conclusions: There is need for eduction of working horse-owners in Egypt bout the importnce of oro-dentl disese nd for greter vilbility of veterinrins with suitble trining nd equipment to perform dentl prophylxis nd tretment. Even simple dentl prophylxis could hve significnt impct on the helth nd welfre of this popultion of working horses. Keywords: horse; Egypt; dentl disese; working equids; horse welfre Introduction Oro-dentl disese is common in equids prticulrly when routine dentl cre is not undertken [1,2] nd hs been ssocited with poor body condition, weight loss [3] nd incresed risk of colic [4,5]. Compred with more visully obvious welfre issues such s lmeness nd wounds, equine oro-dentl disese is neglected welfre issue [6] nd hs received little mention in the welfre ssessment schemes of working equids [7,8]. Lck of vilbility of trined personnel, pproprite dentl equipment nd the time nd effort required to perform dentl exmintion nd tretment re the min constrints to delivering routine dentl cre to working horses in developing countries [9]. Most published equine dentl studies hve been conducted on clinicl csesinhospitlsettings[10 12]orusingcdvermteril[13 16], nd these hve furthered our understnding of the pthophysiology of vrious dentl disorders. Field surveys hve key role in determining the prevlence of oro-dentl disorders nd providing evidence tht will ssist veterinry surgeons nd owners understnding of the impct tht dentl disese hs on equine helth nd welfre. A limited number of these studies hve been performed in working equids. Fernndo-Mrtınez et l. [17] nd du Toit et l. [18] conducted surveys of dentl disorders in working equids in Mexico nd reported high prevlence (13 18%) of severe dentl disese. Other studies hve lso reported the types of orodentl disorders found in working equids in Ethiopi [19], Indi [20], Morocco [21] nd Egypt [22]. However, the ltter studies performed limited sttisticl nlyses of the dt nd the reltionship between dentl disorders nd systemic helth ws not reported. Sttistics from the Food nd Agriculture Orgniztion (FAO) hve shown tht the totl number of horses in Egypt hs doubled from 35,000 to 74,050 between 1993 nd 2013 [23]. The proportion of working horses is difficult to estimte due to lck of officil records. However, there hs been noticeble increse in the number of working horses in Egypt, replcing donkeys for griculturl work nd for rice frming processes in prticulr (observtions of primry uthor). There re few published dt bout the prevlence nd types of oro-dentl disorders in working horses in generl, nd within Egypt in prticulr, which limits the mount of evidence-bsed informtion vilble. Such informtion is key to the design of eductionl progrmmes for horse-owners nd veterinry surgeons bout equine dentl helth in developing countries. The ims of the current study were to investigte the prevlence of different oro-dentl disorders in working horse popultion in Egypt nd to explore the reltionship between dentl disese nd systemic helth. In ddition, we sought to determine how owners of these horses recognise dentl relted clinicl signs nd the frequency with which they seek dentl tretment for their horses. Mterils nd methods Dt collection The study ws conducted on working horses in the Al Shrquiy nd Al Dkhliy provinces in Egypt between 27 September nd 8 November The timing of dentl exmintion ws specificlly trgeted to void the onset of the green seson in Egypt (November My) when horses re predominntly fed on Egyptin clover Berseem. This diet results in green/ blck stining of the orl mucos mking it difficult to identify oro-dentl disorders. A mobile clinic ws used to visit horse-owners t their villges. Announcements bout the study were mde t locl community gtherings nd vi locl veterinry surgeons. Horses of ll ges, regrdless of ny history of dentl exmintion nd regrdless of ny concurrent medicl conditions were eligible to be included in the study 26 Equine Veterinry Journl 49 (2017) EVJ Ltd

2 S.E. Slem et l. Dentl disorders in working horses in Egypt Horses were exmined unsedted using full mouth speculum, lvge syringe, dentl mirror, dentl probe nd hedlight. The primry uthor performed ll dentl exmintions nd ws ppropritely trined in performing dentl exmintion nd recognising vrious oro-dentl disorders. Where orl exmintion could not be performed without sedtion, horses were excluded from the study. A predesigned dentl exmintion sheet including checklist of dentl disorders [2,24,25] ws completed for ech niml (Supplementry Item 1). Imges were obtined for identified oro-dentl disorders using digitl cmer for review by one of the co-uthors. Lesions clssified s orl mucosl injuries comprised ulcertions nd/or buccl clluses (defined s loss of superficil epithelium with evidence of necrosis or res of mucosl epithelil hyperplsi) nd lcertions (defined s ters in the orl mucos). Lingul scrring ws defined s evidence of old lcertions nd other heled tongue injuries with resultnt scr tissue formtion, e.g. due to inpproprite bits or use of tongue twitches. Oro-dentl disorders were ssigned into one of 3 ctegories. No/mild dentl disese ws defined s horses tht hd norml dentl rcdes; or hd shrp enmel points but the orl mucos ws norml nd there ws no pin response to plption of the cheek; or hd cheek teeth frctures tht did not involve pulpr exposure; or hd distem(t) with no evidence of ssocited soft tissue inflmmtion. Moderte dentl disese ws defined s horses tht hd wer bnormlities such s focl dentl overgrowths nd shrp enmel points tht cused buccl clluses nd/or mild ulcertion; or horses tht hd distem(t) ssocited with periodontl disese. Severe dentl disese ws defined s horses tht hd severe soft tissue dmge likely to result in orl pin due to wer bnormlities, cheek teeth frctures or displced cheek teeth; or horses tht hd evidence of peripicl infection such s drining trct nd/or swelling on the mndible or mxill. Horses ges were estimted by exmintion of incisor morphology together with informtion provided by the owner. Height nd weight were estimted using mesuring tpe (Esy-Mesure â ) nd body condition score ws evluted on 6-point scle of 0 5 [26]. Informtion bout signlment, use, diet nd history of ny clinicl signs tht might be ssocited with dentl disese ws lso recorded. Blood smples (5 ml) were collected from the jugulr vein into Vcutiner tubes b contining EDTA nd were used for lbortory estimtion of pcked cell volume (PCV) nd totl plsm protein (TP). Following centrifugtion of smples in microhemtocrit tubes, PCV ws determined nd TP ws mesured using refrctometer. All the dt were inputted into dtbse (Epi Info TM 7). c Dt nlyses One-wy nlysis of vrince (one-wy ANOVA) ws used to compre ge, height, weight, PCV nd plsm TP between horses ssigned to ech of the dentl disese ctegories. Welch correction for violtion of homogeneity of vrinces (Welch s ANOVA) ws used only for the vrible ge. Kruskl Wllis equlity-of-popultions rnk test ws used to compre the ordinl vrible body condition scores (BCS) between the sme ctegories. Post hoc pirwise comprisons were performed using the Tukey Krmer test following one-wy ANOVA, Dunnett s modified Tukey Krmer test [27] following Welch s ANOVA nd Dunn s test [28] with Bonferroni djustment following the Kruskl Wllis test. The frequencies of dentl clinicl signs tht were reported by horse-owners were compred between the dentl disese ctegories using Chi-squre test. The effect of horses ge on the log-odds of oro-dentl disorders nd dentl disese ctegories ws investigted using generlised dditive models (GAMs) [29] nd univrible logistic regression. Generlised dditive models fit nonprmetric functions such s cubic smoothing splines to the dt nd produce Chi-squre P vlues for nonprmetric effects. The results were displyed grphiclly to visulise these reltionships ( the smooth ). Multivrible logistic regression models were built for 2 outcomes: orl mucosl injuries (Model 1) ndbcsctegory0 1 (very poor/poor, Model 2). Preliminry screening of ll vribles ws performed using univrible logistic regression (Supplementry Item 2). The functionl forms of the reltionships between continuous predictor vribles nd outcome vribles were exmined using GAMs nd vribles tht demonstrted significnt nonlinerity were ctegorised. Vribles with univrible P vlue of <0.25 were considered for inclusion into multivrible logistic regression models. The models were built using forwrd stepwise selection procedures nd vribles were retined if their inclusion resulted in likelihood rtio test sttistic of P<0.05. Eliminted vribles were then forced bck into the relevnt model to ssess for confounding, nd biologiclly plusible interction terms between vribles remining in the finl models were evluted for sttisticl significnce. Model fit ws evluted by the Hosmer Lemeshow goodness of fit test sttistic nd model stbility ws ssessed by exmintion of the stndrdised deltbets. Sttisticl nlyses were performed using Epi Info TM 7 c nd Stt TABLE 1: Multivrible logistic regression models of risk fctors for orl mucosl injuries (Model 1) nd very poor/poor body condition scores (BCS 0 1) (Model 2) Vrible Coefficient Stndrd error Odds rtio Lower 95% CI of odds rtio Upper 95% CI of odds rtio Likelihood rtio test P vlue Model 1: Orl mucosl injuries Age (yers) Focl overgrowth No Ref. Yes Shrp enmel points No Ref. Yes <0.001 Feeding rice brn No Ref. Yes Model 2: Very poor/poor BCS Height (cm) Pcked cell volume (%) <0.001 Age yers Ref yers Severe dentl disese No Ref. Yes CI = confidence intervl, Ref. = reference ctegory. The Hosmer Lemeshow test sttistic: Model 1, P = 0.75; Model 2, P = Number of observtions: Model 1, 354; Model 2, 397. Equine Veterinry Journl 49 (2017) EVJ Ltd 27

3 Dentl disorders in working horses in Egypt S.E. Slem et l. softwre (SttCorp Stt Sttisticl Softwre: Relese 9). d The sttisticl pckges gm (version 1.12) nd mgcv (version 1.8-6) on R softwre environment version [30] were used to fit GAMs. Sttisticl significnce ws set t P = Results Study popultion In totl, 460 horses from 41 villges nd 2 cities (Supplementry Item 3) were presented to the clinic. Full dentl exmintion ws performed in 450 horses; 10 horses were excluded becuse they were either too ggressive to be exmined unsedted or their owners were unwilling to hve the horses mouths exmined. Horses hd medin ge of 6 yers (rnge yers) nd medin durtion of current ownership of 2 yers (rnge 1 month to 20 yers). The horses included 270 (63.1%) femles, 156 (36.5%) stllions nd 2 (0.5%) geldings (dt not recorded for sex of 22 horses) nd hd medin body condition score of 2 (rnge 0 4). None of the horses recruited to the study hd previously hd dentl exmintion performed by qulified veterinrin or dentl technicin under current ownership. Nine horses were reported to hve some previous dentl procedures in the form of cutting of cnine teeth nd/or teeth rsping performed by frrier in 5 horses, by friend in one horse nd by the owner in 3 horses. This ws undertken following observtion of quidding (n = 5), poor ppetite (n = 1) nd excessive slivtion (n = 3). Of this group of horses, when full orl exmintion ws performed, one hd evidence of severe orodentl disese (severl cheek teeth frctures, orl ulcertion nd periodontl disese), 5 horses hd moderte oro-dentl disese (shrp TABLE 2: Prevlence of different cheek teeth disorders, their Tridn loctions nd numbers of ffected cheek teeth (CT) Dentl pthology %Prevlence (n) No. of CT ffected Mxillry Tridn loctions (n) Mndibulr Tridn loctions (n) Shrp enmel points 79.8 (359) NA NA NA Overgrowth (hooks included) 30.2 (136) (117), 10 (2), 11 (9) 06 (81), 07 (1), 08 (2), 10 (1), 11 (1) Hooks 16.4 (74) (115) 11 (10) Wve mouth 4 (18) NA NA NA Smooth mouth 0.2 (1) NA NA NA Elevted trnsverse ridges 1.3 (6) NA NA NA Worn tooth 4.2 (19) (10), 07 (1), 08 (3), 09 (5), 10 (1), 11 (4) 06 (1), 07 (1), 10 (2) Bucclly displced tooth 1.1 (5) 5 05 (1), 06 (1) 07 (2), 08 (1) Lingully/pltlly displced 1.1 (5) 5 07 (1) 06 (1), 07 (1), 08 (2) tooth Missing tooth 0.8 (4) 4-06 (2), 11 (1) Deciduous cps 2.5 (11) (3), 07 (7), 08 (2) 07 (4) Distem(t) 9.1 (41) /07 (10), 07/08 (15), 08/09 (3), 09/10 (1) 06/07 (22), 07/08 (3), 08/09 (1), 09/10 (2) Periodontl disese 6.7 (30) NA NA NA Pulpr exposure 1.6 (7) 7 09 (3), 06 (1), 08 (1) 11 (1), 08 (1) Infundibulr cries 4 (18) (1), 07 (1), 08 (1), 09 (18), 10 (8) - Dentl frcture 5.3 (24) (1), 08 (4), 09 (3), 10 (2) 06 (1), 07 (1), 08 (6), 09 (3), 10 (7), 11 (1) NA = not pplicble. TABLE 3: The effect of horses ge on the log-odds of identified oro-dentl disorders nd dentl disese ctegories Dentl pthology Functionl form of the reltionship v 2 P vlue P vlue of smooth term Coefficient Stndrd error Odds rtio Lower 95% CI Upper 95% CI LRT P vlue Incisor pthology Liner 0.18 < <0.001 Shrp enmel points Liner Focl dentl overgrowth Nonliner 0.01 <0.001 Hooks only Liner Wve mouth Liner 0.27 < <0.001 Worn tooth Liner 0.75 < <0.001 Distem(t) (cheek teeth nd Nonliner <0.001 <0.001 incisor) Periodontl disese (cheek Nonliner < teeth, incisor) Infundibulr cries Liner 0.08 < <0.001 Frcture (cheek teeth, incisor) Liner <0.001 Wolf tooth Nonliner <0.001 <0.001 No/mild dentl disese Liner <0.001 Severe dentl disese Nonliner <0.001 Moderte dentl disese vs. Nonliner no/mild ctegory Moderte dentl disese vs. severe ctegory Nonliner <0.001 <0.001 No/mild nd severe dentl disese ctegories were compred with the whole cohort while the moderte dentl disese ctegory ws compred with no/mild nd severe dentl disese ctegories seprtely. A Chi-squre (v 2 ) test P vlue <0.05 indictes the vrible hs nonliner reltionship with the log-odds of the outcome vrible, smooth term of P vlue <0.05 indictes significnt effect on the log-odds of the outcome vrible. Vribles tht showed liner reltionships were further exmined using univrible logistic regression. LRT = likelihood rtio test, CI = confidence intervl. 28 Equine Veterinry Journl 49 (2017) EVJ Ltd

4 S.E. Slem et l. Dentl disorders in working horses in Egypt Log-odds of no/mild vs. other disese ctegories Log-odds of severe vs. other disese ctegories Log-odds of moderte vs. no/mild disese ctegory Log-odds of moderte vs. severe disese ctegory Log-odds of periodontl disese Log-odds of distem(t) Log-odds of focl dentl overgrowth Fig 1: Grphicl illustrtions of the estimted reltionships ( the smooth ) between horse ge (yers) nd the log-odds of the 3 dentl disese ctegories nd 3 oro-dentl disorders. The plots show fitted curves with 95% confidence intervls (dshed lines) nd the rug plots long the x-xes represent the number of dt points. The dotted horizontl lines re t log-odds = 0. enmel points ssocited with mild orl ulcertion) nd 3 horses hd no oro-dentl disese. Signs of dentl disese Clinicl signs consistent with possible oro-dentl disese prior to exmintion were reported for 36.7% (165/450) of the horses. These included quidding (n = 127), weight loss (n = 58), poor ppetite (n = 45), excessive slivtion (n = 5) nd nsl dischrge (n = 4). These signs were reported in 21%, 44.6% nd 79% of horses tht were ssigned to no/mild, moderte nd severe dentl disese ctegories, respectively. This ws significntly different between groups (P<0.001). Of the horses tht were reported by the owner to hve clinicl dentl signs, 73% were found to hve moderte or severe dentl disese on exmintion. Clinicl signs identified during exmintion were fcil swelling (n = 4), buccl food impction (n = 40), drining trct on the mndible (n = 2), hlitosis (n = 4), enlrgement of mndibulr lymph nodes (n = 2), nsl dischrge (n = 2), evidence of poorly digested ingest (long fibres) in feces (n = 2) nd quidding (n = 1). The ltter signs were identified in 49 (10.9%) horses. Orl mucosl injuries Orl mucosl injuries were identified in 289 horses (64.2%). Ulcertions nd/ or buccl clluses were evident in 287 (63.7%) horses. The primry cuses ofthesewereconsideredtobeenmelovergrowths(85.9%),focldentl overgrowths (5%), displced cheek teeth (0.7%), bit relted injuries (0.7%), retention of deciduous cps (0.7%), nd frctured cheek teeth (0.7%). Lcertions of the orl mucos were identified in 11 horses (2.4%) nd were Equine Veterinry Journl 49 (2017) EVJ Ltd 29

5 Dentl disorders in working horses in Egypt S.E. Slem et l. considered secondry to focl dentl overgrowth(n = 4), shrp enmel points (n = 1) nd bit relted injuries (n = 1). Awns from poor qulity whet strw were found lodged in some of these lesions (n = 29); however, it ws not cler whether these were the primry cuse. Other less frequent soft tissue disorders included lingul scrring (n = 5), fcil swellings (n = 4) nd orl msses (n = 2). In multivrible model built with orl mucosl injuries s the outcome of interest, incresing ge, focl dentl overgrowth nd presence of shrp enmel points were significntly ssocited with this type of oro-dentl disorder (Tble 1). Feeding rice brn ws retined in the finl model s it significntly improved model fit. Incisor disorders Disorders of the incisors were identified in 23.6% (106/450) of the horses. These included mlocclusions: brchygnthism (7.8%, n = 35), bnorml wer (4.6%, n = 21), ventrl curvture (1.1%, n = 5), digonl bite (0.9%, n = 4) nd prognthi (0.7%, n = 3); eruption nd teeth lignment disorders: distem(t) (6.9%, n = 31), missing incisor teeth (0.4%, n = 2), deciduous cps (1.8%, n = 8), rotted teeth (0.4%, n = 2) nd loose teeth (0.4%, n = 2); periodontl disese (3.1%, n = 14); nd cries (2.7%, n = 12). These disorders were considered of clinicl significnce in 19 (18%) horses. Cheek teeth disorders The prevlence of different cheek teeth disorders, their Tridn loctions nd number of bnorml teeth re summrised in Tble 2. First premolr teeth (05s) were identified in 209 (46.4%) horses nd were unerupted in 2 horses. Shrp enmel points were identified in 359 (79.8%) horses. These were locted t the buccl spect of mxillry cheek teeth rcdes only in 104 (29%) horses, t the lingul spect of mndibulr cheek teeth rcdes only in 13 (3.6%) horses nd concurrently in both dentl rcdes in 242 (67%) horses. Bsed on evidence of concurrent orl mucosl injuries nd pinful response exhibited by horses when the cheeks were plpted, shrp enmel points were considered cliniclly significnt in 241 (67%) horses. Cheek teeth distemt were evident in 41 (9.1%) horses; these were open distemt in 20 horses (48.8%) nd vlve distemt in 21 (51.2%) horses. Distemt were considered cliniclly significnt in 12 horses (29.3%) bsed on the extent of ssocited periodontl disese. Periodontl disese ws dignosed in 30 horses where the perceived cuses were distemt (n = 14), deciduous cps (n = 5), food pocketing between the dentl rcdes nd buccl mucos (n = 3), cheek teeth frctures (n = 3) nd picl infection confirmed by the presence of drining trct on the mndible (n = 1). Cheek teeth frcture types tht were identified included mxillry buccl slb frcture (n = 4), mndibulr buccl slb frcture (n = 5), infundibulr sgittl frcture (n = 2), miscellneous mxillry (n = 4) nd mndibulr (n = 11) frcture ptterns. Reltionship between ge nd oro-dentl disese The effects of ge on the log-odds of identified oro-dentl disorders nd dentl disese ctegories together with the functionl form of these reltionships re summrised in Tble 3. The grphicl illustrtions of the estimted reltionships ( the smooth ) between ge nd log-odds of the dentl disese ctegories nd 3 oro-dentl disorders re shown in Figure 1. The grphicl illustrtions of these reltionships for other orodentl disorders re provided in Supplementry Item 4. The estimted smooth of the horses ge (Fig 1) showed tht the likelihood of no/mild dentl disese is greter in younger horses nd the likelihood of severe dentl disese incresed shrply fter 18 yers of ge. Reltionship between oro-dentl disese nd systemic helth Of the horses exmined, 46.2% (208/450) hd no/mild dentl disese, 45.3% (204/450) hd moderte dentl disese nd 8.4% (38/450) hd severe dentl disese. Figure 2 shows some of the typicl lesions tht were identified on dentl exmintion of 4 horses. There were significnt differences in BCS (P = 0.002), ge (P = 0.001) nd body weight (P = 0.007) between the dentl disese ctegories, wheres the men height, PCV nd TP did not differ significntly. Post hoc pirwise comprisons showed significnt differences between severe dentl disese nd no/mild (P = 0.001) or moderte (P = 0.001) dentl disese ctegories for BCS. Significnt differences in ge were found between no/mild nd moderte or severe ) b) c) d) Fig 2: Oro-dentl disorders tht were identified on exmintion of 4 horses; Horses c were ssigned to the severe dentl disese ctegory while Horse d ws ssigned to the moderte dentl disese ctegory. ) A 25-yer-old mre tht hd deep ulcertion of the orl mucos nd shrp enmel points on the mxillry cheek teeth rcde. b) A 1.5-yer-old colt tht hd lcertions of the ventrum of the tongue with some wns lodged in the lesion. c) A 17-yer-old mre dignosed with severe overgrowth of tooth 206 tht resulted in deep ulcertion of the orl mucos. d) A 2.5-yer-old filly tht hd food pocketing in the periodontl spce nd retined deciduous cp. 30 Equine Veterinry Journl 49 (2017) EVJ Ltd

6 S.E. Slem et l. Dentl disorders in working horses in Egypt BCS (0 5 scle) Horse weight (kg) dentl disese ctegories. The men body weight differed significntly between moderte nd no/mild (P = 0.04) or severe (P = 0.02) dentl disese ctegories (Fig 3). In multivrible model, the likelihood of horse being identified s hving very poor/poor BCS ws significntly nd positively ssocited with incresing ge nd being ssigned to the severe dentl disese ctegory, while it ws negtively nd significntly ssocited with height nd PCV (Tble 1). Discussion n = 194 n = 202 n = 36 b No/mild Moderte Severe n = 208 n = 204 b n = 38 b No/mild Moderte Severe n = 208 n = 204 b n = 38 No/mild Moderte Severe Dentl disese ctegories Fig 3: Boxplots showing distribution of body condition score (n = 432), ge (n = 437) nd body weight (n = 440) in horses ssigned to no/mild, moderte nd severe dentl disese ctegories. Box represents the 25th nd 75th percentiles of the dt, the horizontl line cross the middle of the box represents the medin, nd the dot is the men. Whiskers represent the minimum nd mximum vlues. Disese ctegories with different letters re significntly different t P<0.05. BCS = body condition score. This is the first study tht hs investigted the prevlence of nd risk fctors for oro-dentl disorders nd their effect on systemic helth in working horse popultion in Egypt. The results provide evidence of high prevlence of oro-dentl disese, significnt effect of oro-dentl disese on systemic helth nd totl lck of routine dentl cre of horses in the study re. This evidence cn be used to inform eductionl strtegies for veterinry surgeons nd horse-owners in Egypt nd development of outrech progrmmes. Very few horses (2%) in the current study hd previously undergone ny form of dentl exmintion nd tretment, nd in none of these horses hd this been performed by suitbly trined person. This is in contrst with the UK nd Irelnd where routine dentl prophylxis ws rrnged by 83% of horse-owners [31]. This demonstrtes lck of knowledge bout the importnce of routine dentl cre mongworkinghorse-ownersinthisprt of Egypt. Around third (36.7%) of horses exmined were reported to hve dentl clinicl signs by their owners nd lrge proportion (73%) of these horses were found to hve moderte or severe dentl disese on exmintion. These findings suggest tht horse-owners re ble to identify signs of oro-dentl disese. However, dentl tretment ws not sought which my be in prt due to the lck of trined veterinry surgeons or dentl technicins with the pproprite equipment to perform dentl exmintion nd tretment [6] in this re of Egypt. Shrp enmel points nd focl dentl overgrowth were the most common dentl disorders found in this study, which is consistent with previous dentl surveys in horses [32]. Orl mucosl injuries were lso common (64%) with similr prevlences reported in other studies [33,34]. When djusted for ge nd types of feeds, horses dignosed with shrp enmel points nd focl dentl overgrowths were round 6 nd 2 times more likely to hve orl mucosl injuries, respectively [33]. The findings suggest tht reltively bsic skills in dentl exmintion nd tretment to reduce enmel nd focl dentl overgrowths could hve significnt impct on the helth nd welfre of this working horse popultion. There were positive nd significnt ssocitions between incresing ge nd presence of orl mucosl injuries, incisor disorders, shrp enmel points, hooks, wve mouth, worn teeth, infundibulr cries nd dentl frcture in n pproximtely liner reltionship. The effect of ge on the prevlence of dentl disorders hs previously been reported [1,2,18,33,35]. In previous studies, the ge of the nimls ws ctegorised using different cut-off points where younger ge groups were shown to hve significntly lower prevlence of dentl disorders. Shrp enmel points, however, were found to be significntly higher in donkeys ged 0 10 yers old in one study [2] nd cheek teeth frctures did not differ significntly mong ge groups in nother study [1]. The current study hs lso demonstrted significnt liner effect of ge on the prevlence of no/mild dentl disese where incresing ge ws ssocited with decresing number of horses ssigned to this ctegory [14,18]. In the current study, older horses were more likely to hve severe dentl disese; however, number of younger horses were dignosed with severe dentl disese, nd therefore routine dentl cre should not be preferentilly directed towrd older horses. There ws lso n interesting triphsic reltionship between horse ge nd the prevlence of periodontl disese. The likelihood of periodontl disese incresed between the ges of 2 nd 6 yers nd then decresed stedily until round the ge of 17 yers when the likelihood incresed gin. A similr pttern ws lso evident for distemt, but the second pek strted t round 10 yers of ge. Bker [16,35] reported the sme pttern for periodontl disese prevlence nd proposed tht the period of eruption of permnent dentition is criticl in the pthogenesis of the disese which seems to be reversible during this period of horses life. Wlker et l. [10] hve reported greter prevlence of distemt t ge extremes of 1 5 yers old(39%) nd yers old (87.5%) which would be consistent with the results of the current study. Horses dignosed with severe dentl disese in the current study were more likely to hve lower poor BCS nd to be of significntly lower body weight compred with horses ssigned to other dentl disese ctegories. Assocition between dentl disorders nd low BCS hs been reported for working donkeys [3,17]. Our results re in contrst with other studies [18,19,34] tht reported no ssocition between BCS nd dentl disorders. Incresing height nd ge rnge of yers were ssocited with decresed risk of lower BCS in the present study. It is possible tht height nd ge re cting s proxy mesures for the purchse price of working horses nd tht tller nd younger horses might be owned by more welthy people who cn fford to provide good qulity feed for their nimls. This ge group ws more likely to hve moderte rther thn severe dentl disese, which might lso explin this ssocition. Horses identified with BCS 0 1 (very poor/poor) were lso more likely to hve significntly lower PCV compred with other BCS ctegories. Similr findings hve previously been reported in working horse popultion in Pkistn [36]. The ssocition between higher hemoglobin nd greter BCS vlues in the ltter study ws considered to potentilly reflect horses tht hd better nutrition nd less severe/chronic disese. It is likely tht Equine Veterinry Journl 49 (2017) EVJ Ltd 31

7 Dentl disorders in working horses in Egypt S.E. Slem et l. this lso explins the findings in the present study, i.e. poor qulity nutrition/severe dentl disese my result in lower BCS, nd my be ssocited with subclinicl nemi. Clssifiction of oro-dentl disese into 3 simple ctegories ws bsed on the oro-dentl disorders identified nd their likely impct on individul horses helth. This ws considered prcticl clssifiction tking into ccount tht bnorml dentl disorders such s smll hooks, shrp enmel points nd infundibulr cries my hve miniml impct on oro-dentl pin nd systemic helth [5,11,12]. In the current study, 8.4% of horses were considered to hve severe oro-dentl disese, which is lower thn the severe dentl disese prevlence of % reported in working equids in Mexico [17,18]. The definitions of the term serious dentl disese used in the ltter studies were slightly different. Serious dentl disese ws defined s ny dentl bnormlity ssocited with soft tissue dmge nd interferes with proper chewing, compromising the buccl comfort nd welfre in one study [17] nd the other study defined it s ny dentl disorder excluding focl overgrowth, buccl ulcers nd clluses tht might be ssocited with orl discomfort [18]. Mny horses identified with these disorders might hve been ssigned to the moderte dentl disese ctegory in the current study, which my explin the differences in the reported prevlence between the studies. One limittion of this study ws tht selection of the study res ws not rndom. We initilly imed to systemticlly cover ll big villges in 3 or 4 regions but there ws lck of willingness by some horse-owners or locl veterinry surgeons to prticipte in the study, or communiction ws difficult in other instnces. However, we believe this would hve miniml impct on the study results. It is lso importnt to note tht lmost ll visited villges re not res covered by niml welfre orgnistions in Egypt nd tht the results my hve been different in other regions in which helth progrmmes exist. The current study hs shown tht oro-dentl disese is common in this popultion of horses, is cliniclly significnt in mny nd tht no horses hd undergone ny form of full orl exmintion or pproprite dentl tretment. This provides evidence of the need for n eduction progrmme for horse-owners nd veterinry surgeons in the study re. Simple interventions such s removl of shrp enmel overgrowths could hve significnt impct on the helth nd welfre of this popultion of horses. Authors declrtion of interests No competing interests hve been declred. Ethicl niml reserch This study ws pproved by the University of Liverpool Veterinry Reserch Ethics Committee (reference number VREC247). Owners were informed of the purpose of the study nd the ffilitions of the reserch tem. People were invited to volunteer to tke prt in the study nd verbl informed consent ws obtined. Horse-owners were given detils of the findings on exmintion nd recommendtions for tretment in conjunction with their locl veterinry surgeons. Source of funding Egyptin Ministry of Higher Eduction. Acknowledgements We thnk E. Ezzt, A. Abdell, I. Morsey nd M. Mrzouk from Zgzig University for ssistnce with the dt collection. We lso thnk the veterinry surgeons nd the horse owners who prticipted in the study. Authorship S.E. Slem ws the min resercher nd contributed to ll spects of the study. N.B. Townsend contributed to study design, interprettion of the dt nd preprtion of the mnuscript. W. Refi nd M. Gom contributed to study design nd dt collection. D.C. Archer contributed to study design, dt nlysis nd preprtion of the mnuscript. Mnufcturers ddresses Chndelles Sddlery, UK. b K Vcutest, Hi-lb, Zkzik, Egypt. c Centre for Disese Control (CDC), Atlnt, Georgi, USA. d SttCorp LP, College Sttion, Texs, USA. References 1. Rodrigues, J.B., Dixon, P.M., Bstos, E., Sn Romn, F. nd Viegs, C. (2013) A clinicl survey on the prevlence nd types of cheek teeth disorders present in 400 Zmorno-Leones nd 400 Mirndes donkeys (Equus sinus). Vet. Rec. 173, du Toit, N., Burden, F.A. nd Dixon, P.M. (2009) Clinicl dentl exmintions of 357 donkeys in the UK. Prt 1: prevlence of dentl disorders. Equine Vet. J. 41, du Toit, N., Burden, F.A. nd Dixon, P.M. (2009) Clinicl dentl exmintions of 357 donkeys in the UK. Prt 2: epidemiologicl studies on the potentil reltionships between different dentl disorders, nd between dentl disese nd systemic disorders. Equine Vet. J. 41, Scntlebury, C.E., Archer, D.C., Proudmn, C.J. nd Pinchbeck, G.L. (2011) Recurrent colic in the horse: Incidence nd risk fctors for recurrence in the generl prctice popultion. 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Indi Hbitt Centre, New Delhi, Indi. pp Wlker, H., Chinn, E., Holmes, S., Brwise-Munro, L., Robertson, V., Mould, R., Brdley, S., Shw, D.J. nd Dixon, P.M. (2012) Prevlence nd some clinicl chrcteristics of equine cheek teeth distemt in 471 horses exmined in UK first-opinion equine prctice (2008 to 2009). Vet. Rec. 171, Simhofer, H., Griss, R. nd Zetner, K. (2008) The use of orl endoscopy for detection of cheek teeth bnormlities in 300 horses. Vet. J. 178, Dcre, I., Kempson, S. nd Dixon, P.M. (2008) Pthologicl studies of cheek teeth picl infections in the horse: 5. Aetiopthologicl findings in 57 piclly infected mxillry cheek teeth nd histologicl nd ultrstructurl findings. Vet. J. 178, Du Toit, N., Gllgher, J., Burden, F.A. nd Dixon, P.M. (2008) Post mortem survey of dentl disorders in 349 donkeys from n ged popultion ( ). Prt 1: prevlence of specific dentl disorders. Equine Vet. J. 40, Du Toit, N., Gllgher, J., Burden, F.A. nd Dixon, P.M. (2008) Post mortem survey of dentl disorders in 349 donkeys from n ged popultion ( ). Prt 2: epidemiologicl studies. Equine Vet. J. 40, Gere, I. nd Dixon, P.M. (2010) Post mortem survey of peripherl dentl cries in 510 Swedish horses. Equine Vet. J. 42, Bker, G.J. (1979) A Study of Dentl Disese in the Horse. PhD Thesis, The University of Glsgow, Glsgow. 32 Equine Veterinry Journl 49 (2017) EVJ Ltd

8 S.E. Slem et l. Dentl disorders in working horses in Egypt 17. Fernndo-Mrtınez, J.A., Hernndez-Gil, M., Aluj, A.S.d., Herrer-Leon, A. nd Velzquez-Rmırez, J.L. (2006) Prevlence of dentl disorders in rurl working equines of Mexico. In: Fifth Interntionl Colloquium on Working Equines. The future for working equines, Eds: R.A. Person, C.T. Muir nd M. Frrow. The Donkey Snctury, Addis Abb, Ethiopi. pp du Toit, N., Burden, F.A. nd Dixon, P.M. (2008) Clinicl dentl findings in 203 working donkeys in Mexico. Vet. J. 178, Giorgis, W.W., Boj, E., Asmmw, K. nd Solomon, M. (2013) Age pttern nd teeth bnormlity observed in working donkeys in selected districts of Sidm zone, Southern Ethiopi. Globl Veterinri 11, Shukl, A. (2006) Common diseses of orl cvity nd dignosis of working equines in Indi. In: 5th Interntionl Colloquium on Working Equines. The future for working equines, Eds: R.A. Person, C.T. Muir nd M. Frrow. The Donkey Snctury, Addis Abb, Ethiopi. pp Ousst, M., Crne, M. nd Misri, E.M. (2010) Bucco-dentl pthologies of working equine in Morocco. In: 6th Interntionl Colloquium on Working Equids, Indi Hbitt Centre, New Delhi, Indi. p Mhgoub, M. (2014) Common equine dentl disorders seen t Brook Alexndri. In: 7th Interntionl Colloquium on Working Equids, Ed: J.F. Wde. Royl Hollowy, University of London, Surrey, UK. p FAO Food nd Agriculture Orgniztion of the United Ntions Sttistics Division Dixon, P.M., Du Toit, N. nd Dcre, I. (2011) Equine dentl pthology. In: Equine Dentistry, 3rd edn., Eds: J.T. Esley, P.M. Dixon nd J. Schumcher, Elsevier. pp Dixon, P.M. (2011) Disorders of development nd eruption of the teeth nd developmentl crniofcil bnormlities. In: Equine Dentistry, 3rd edn., Eds: J.T. Esley, P.M. Dixon nd J. Schumcher, Elsevier. pp Crroll, C.L. nd Huntington, P.J. (1988) Body condition scoring nd weight estimtion of horses. Equine Vet. J. 20, Lu, M.K. (2013) DTK: Dunnett-Tukey-Krmer pirwise multiple comprison test djusted for unequl vrinces nd unequl smple sizes. R pckge version Dunn, O.J. (1964) Multiple comprisons using rnk sums. Technometrics 6, Hstie, T.J. nd Tibshirni, R.J. (1990) Generlized Additive Models, Chpmn nd Hll, London. 30. R Core Tem (2014) R: A lnguge nd environment for sttisticl computing. R Foundtion for Sttisticl Computing, Vienn, Austri Dixon, P.M., Andrew, R., Brnnon, H., Burgess, R., Gibson, A., Little, J.C., Ornge, B., Ross, L., Rudolph, T. nd Shw, D.J. (2004) Survey of the provision of prophylctic dentl cre for horses in Gret Britin nd Irelnd between 1999 nd Vet. Rec. 155, Peters, J.W., deboer, B., Broeze-ten Voorde, G., Broeze, J., Wiemer, P., Sterk, T. nd Spoormkers, T. (2006) Survey of common dentl bnormlities in 483 horses in the Netherlnds. In: Americn Assocition of Equine Prctitioners. Focus Meeting, Indinpolis, Indin, USA. 33. Anthony, J., Wldner, C., Grier, C. nd Lycock, A.R. (2010) A survey of equine orl pthology. J. Vet. Dent. 27, Allen, T.E. (2004) Incidence nd severity of brsions on the buccl mucos djcent to the cheek teeth in 199 horses. Am. Ass. Equine Prctnrs. 50, Bker, G.J. (1970) Some spects of equine dentl disese. Equine Vet. J. 2, Pritchrd, J.C., Burn, C.C., Brr, A.R.S. nd Why, H.R. (2009) Hemtologicl nd serum biochemicl reference vlues for pprently helthy working horses in Pkistn. Res. Vet. Sci. 87, Supporting Informtion Additionl Supporting Informtion my be found in the online version of this rticle t the publisher s website: Supplementry Item 1: Dt collection sheet. Supplementry Item 2: Descriptive sttistics nd univrible logistic regression nlyses of vribles investigted for ssocition with orl mucosl injuries nd very poor/poor BCS. Supplementry Item 3: A mp showing loctions of visited villges. Supplementry Item 4: Grphicl illustrtions of the estimted reltionships between ge nd log-odds of oro-dentl disorders, nd between ge nd logodds of the presence of first premolr teeth. Equine Veterinry Journl 49 (2017) EVJ Ltd 33