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The aim of the research was to monitor current trends in international show jumping and assess how the proportion of Thoroughbred blood in the pedigree of horses, age, breed, sex and sport season influenced the competition results of show-jumping horses at the world level. The research was based on the databases of jumping rankings for the years 2010, 2014 and 2018 published by the International Federation for Equestrian Sports (FEI). All horses from the FEI rankings were included in the database with the exception of ponies and also horses lacking basic data. This yielded a total of 14,980 horses. The rankings of horses were calculated according to FEI methodology on the basis of the best 30 results every year in international show-jumping competitions with a minimum fence height of 1.45 m. The most represented breed was the Dutch Warmblood (19.26%) and the most common sex was gelding (43.98%). Since 2010 the standard proportion of Thoroughbred blood in the pedigrees of show-jumping horses has decreased and in 2018 the average proportion of Thoroughbred in the pedigree was 41.61%. The analysis of the statistics in the whole database established a significant (p ˂ 0.01) influence of all observed factors. The horses achieved a statistically higher ranking in 2018 (117.57) than in 2010 (98.33) and 2014 (105.93). The groups with a proportion of Thoroughbred between 30.10 and 70.00% achieved a significantly higher ranking than horses with a zero proportion of Thoroughbred in the pedigree. Stallions achieved a significantly higher ranking (117.84 points) compared to geldings (105.76 points) and mares (104.66 points). The horses aged 10–13 years old achieved better results (124.71 points) than the younger group of horses (76.66 points) and older group of horses (109.29 points, p= 0.0033). Statistically conclusive differences were found between AES horses (162.81 points) and the group of non-sport horse breeds (68.26 points) and also between AES horses and horses of unknown pedigree (38.61 points). There were no significant differences between the principal warmblood sport breeds produced in Europe.

The aim of this study was to investigate the effects of maternal, hormonal, and fetal factors on early fetal volume (FV) measurements in mares obtained by three-dimensional (3D) ultrasound. Furthermore, postpartum parameters were explored in regard to their association with early FV. For this purpose, 149 German warmblood mares that were artificially inseminated and confirmed to be pregnant between days 14–16 of gestation, were examined transrectally at day 45 ± 1 of gestation with the portable 3D ultrasound device Voluson® i (GE, Zipf, Austria). FV was calculated by using the extension software Virtual Organ Computer-aided AnaLysis (VOCAL™). Two different mixed linear models were used to analyze associations between the investigated maternal and fetal factors and the FV. Explanatory variables investigated in the first model were: maternal age, parity, maternal weight, and body condition score, type of pregnancy (recipient or biological mother), barren status (lactating or non-lactating), fetal sex, progesterone (P4) and equine chorionic gonadotropin (eCG) concentrations; and in the second model outcome variables such as gestational length, birth weight, placental weight, fetal sex, and abortion were included in the analysis. The final models revealed a significant relation between FV and eCG (b = 0.011, P = 0.030), as well as with P4 (b = −0.053, P = 0.016), but interestingly P4 was negatively related to FV. Fetal sex showed the most prominent effect on FV (b = −0.256, P = 0.039), with female fetuses being smaller than male fetuses. In the second model none of the investigated parameters were related to early FV except for fetal sex (b = -0.328, P = 0.047), again with female fetuses being smaller. In summary, it was found that FV is related with eCG, P4 and fetal sex, but was no suitable predicting factor for the investigated outcome parameters. Furthermore, the findings suggest that sex specific growth differences exist already in early gestation. The detailed biological mechanism by which P4 and eCG affect fetal size has to be investigated in prospective studies.

OBJECTIVE: To evaluate the antinociceptive effect of a bolus of intravenous levomethadone administered to horses during romifidine constant rate infusion (CRI).STUDY DESIGN: Prospective, randomized, masked, crossover experimental study.ANIMALS: A group of eight adult Warmblood horses (seven geldings, one mare) aged 6.6 ± 4.4 years, weighing 548 ± 52 kg [mean ± standard deviation (SD)].METHODS: Levomethadone 0.1 mg kg-1 or an equivalent volume of saline (control) was administered intravenously to standing horses 60 minutes after starting a romifidine CRI. Blood samples to quantify romifidine and levomethadone plasma concentrations by capillary electrophoresis were collected up to 150 minutes after levomethadone administration. The nociceptive withdrawal reflex threshold (NWRT) was determined continuously using an automated threshold tracking device. Sedation and cardiopulmonary variables were assessed at regular intervals. A pharmacokinetic-pharmacodynamic (PK-PD) model was elaborated. Data are presented as mean ± SD or median (interquartile range, 25%-75%) where appropriate. Differences between groups were considered statistically significant for p < 0.05.RESULTS: Horses exhibited higher NWRTs after levomethadone administration than after saline (123 ± 9% versus 101 ± 9% relative to baseline, p < 0.05). The PK-PD model identified a contribution of levomethadone to the NWRT increase. Effect size was variable among individuals. No adverse reactions to levomethadone administration were observed. A slight effect of levomethadone on sedation scores was evident for the 60 minutes following its administration.CONCLUSIONS AND CLINICAL RELEVANCE: A single injection of levomethadone has the potential to increase the NWRT during romifidine CRI in horses and can be administered in combination with α2-adrencoceptor agonists to enhance antinociception in horses. However, individual variation is marked.

ZusammenfassungEin 15-jähriger Warmblutwallach wurde wegen multipler großflächiger, ulzerativer und krustiger Hautveränderungen vorgestellt, die seit 4 Jahren bestanden. Anhand der histologischen Untersuchung von Hautbioptaten wurde eine subepidermale Spaltbildung unterhalb der Basalzellen und oberhalb der Basalmembran festgestellt und ein bullöses Pemphigoid diagnostiziert. Durch eine immunsuppressive Therapie mit Dexamethason und Azathioprin konnte nach 14 Wochen eine vollständige Remission der Hautläsionen erreicht werden, wobei die betroffenen Hautareale durch Narbengewebe ersetzt wurden. Die Dauertherapie wurde nach schrittweiser Dosisreduktion über 5 Monate mit einer Erhaltungsdosis von 0,5 mg/kg Azathioprin täglich fortgesetzt. Nach 63 Wochen erfolgreicher Stabilisierung kam es zu einem Rezidiv sowie zusätzlich zu unerwünschten Arzneimittelnebenwirkungen (akute Hufrehe und erhöhte Infektanfälligkeit), sodass der Wallach aus Tierschutzgründen euthanasiert wurde.

The equine graying with age causative mutation in the syntaxin-17 gene (STX17) has been known for over a decade, but proper genotyping of this variant remains challenging due to its molecular character (4.6-kb tandem duplication). Precise information on gray mutation status is important for horse breeders and veterinarians, since gray homozygous horses are more prone to developing aggressive melanoma tumors than heterozygotes. Since recent studies have confirmed that droplet digital PCR is a valuable technique for copy number analysis, we decided to investigate whether this method can be used for accurate genotyping of the horse graying-related variant and established the copy numbers of the 4.6-kb fragment in the available cohort (n = 75) of gray and nongray horses of various breeds. Surprisingly, we found that our STX17 genotype results varied from what has been previously published, suggesting that gray phenotype is associated with the presence of six (GG) or four (Gg) copies of studied region. All the examined nongray horses (gg) have the two copies of these fragments. This new pattern and its inheritance were also confirmed by an analysis conducted for the Polish Warmblood horse family. We noted no further copy number variation in the entire tested samples set. Our study confirmed the usefulness and accuracy of droplet digital PCR for genotyping STX17 gene variant. Further studies on a broader range of materials are needed to fully understand the origin and molecular structure of the graying causative mutation in the horse STX17.

Article Details: Received: 2020-10-20 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.1-4 Abstract The aim of the study was to observe the salivary concentrations of cortisol in horses during daily routine over the course of four weeks lasting experiment in three different stages of day to monitor the changing values of cortisol in horse saliva during the day. Saliva was obtained from 12 Slovak warmblood horses – 1 stallion, 6 mares and 5 geldings. In the experiment we focused purely on changes of salivary cortisol concentrations over the course of the daily routine.The results shown us multiple significant changes between individual sample collections and thus, we can state that according to our results the highest concentration of cortisol in horse saliva is in the morning and it decreases throughout the day with lowest measured concentrations being in the final sample collection of the day (at 22:00). These changes had no visible effect on horses´ organism throughout entirety of the experiment and were caused due to horses daily rhythm. Keywords: horse, cortisol, saliva, rest, daily routine References Bohak, Zs, Szabo, F, Beckers, J-F, Melo de Sousa, N, Kutasi, O., Nagy, K, Szenci, O. 2013. Monitoring the circadian rhythm of serum and salivary cortisol concentrations in the horse . Domest. Anim. Endocrinol. 45:38-42. https://doi.org/10.1016/j.domaniend.2013.04.001 Contreras-Aguilar, MD, Lamy, E, Escribano, D, Ceron, JJ, Tecles, F, Quiles, AJ, Hevia, ML. 2020. Changes in salivary analytes of horses due to circadian rhythm and season: A Pilot Study. Animals. 10(9):1486. https://doi.org/10.3390/ani10091486 Halo, M, Hollý, A, Mlynekova, E, Polyakova, L, Horný, M, Kovalcik, E. 2009. Influence feeding and training on the metabolic profil sport horses . J Cent. Eur. Agric. 10(4):411-416. Halo, M, Strapak, P, Mlynekova, E, Kovalcik, E, Horný, M. 2008. Influence stres on the training process of the horses. J. Cent. Eur. Agric. 9(1):217-224. Ille, N, von Lewinski, M, Erber, M, Wulf, M, Aurich, J, Mostl, E, Aurich, C. 2013. Effects of the level of experience of horses and their riders on cortisol release, heart rate and heart rate variability during a jumping course. Anim. Welf. 22:457-465. 10.7120/09627286.22.4.457 Irvine, CHG, Alexander, SL. 1994. Factors affecting the circadian rhythm in plasma cortisol concentrations in the horse. Domest. Anim. Endocrinol. 11(2):227-238. https://doi.org/10.1016/0739-7240(94)90030-2 Kang, O-D, Lee W-S. 2016. Changes in salivary cortisol concentration in horses during different types of exercise . Asian-Australas J Anim Sci. 29(5):747-752. 10.5713/ajas.16.0009 Kang, O-D, Yun Y-M. 2016. Influence of Horse and Rider on Stress during Horse-riding Lesson Program. Asian Australas J Anim Sci. 29(6):895-900. 10.5713/ajas.15.1068 Leal, BB, Alves, GES, Douglas, RH, Bringel, B, Young, RJ, Haddad, JPA, Viana, WS, Faleiros, RR. 2011. Cortisol circadian rhythm ratio: A simple method to detect stressed horses at higher risk of colic? Equine Vet. J. 31:188-190. https://doi.org/10.1016/j.jevs.2011.02.005 Massanyi, P, Stawarz, R, Halo, M, Formicki, G, Lukac, N, Cupka, P, Schwarcz, P, Kovacik, A, Tusimova, E, Kovacik, J. 2014. Blood concentration of copper, cadmium, zinc and lead in the horses and its relation to hematological and biochemical parameters. J. Environ. Sci. Health A. 49:973-979. 10.1080/10934529.2014.894322 Peeters, M, Sulon J, Beckers J-F, Ledoux D, Vandenheede M. 2011. Comparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge . Equine Vet J. 43(4):487-493. 10.1111/j.2042-3306.2010.00294.x Schmidt, A, Mostl, E, Wehnert, Ch, Aurich, J, Muller, J, Aurich, Ch. 2010. Corisol release and heart rate variability in horses during road transport . Hormones Behaviour. 57: 209-215. 10.1016/j.yhbeh.2009.11.003 Strzelec, K, Kankofer, M, Piertzak, S. 2011. Cortisol concentration in the saliva of horses subjected to different kinds of exercise. Act Vet. Brno. 80:101-105. 10.2754/avb201180010101 Stull, CL, Morrow, J, Aldridge, BA, Stott, JL, McGlone, JJ. 2008. Immunophysiological responses of horses to 12-hour rest during 24 hours of road transport. Vet. Rec. 162:609-614. 10.1136/vr.162.19.609 Van der Kolk, JH, Nachreiner, RF, Schott HC, Refsal KR, Zanella AJ. 2001. Salivary and plasma concentration of cortisol in normal horses and horses with Cushing´s disease. Equine Vet J. 33(2):211-213. 10.1111/j.2042-3306.2001.tb00604.x

Article Details: Received: 2020-10-15 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.145-149 The aim of the study was to determine the effect of training process on changes of quantitative and qualitative indicators of the movement mechanics of sport horses. A load controller was used to evaluate the motion mechanics. The training load was divided into three stages with different lengths, speeds and degrees of load. Tested animals were 14 horses of Slovak Warmblood breed. Our results have shown that gradual increase of load in the tested horses resulted in better spaciousness of movement, which was reflected in the elongation of the horse´s stride, regular movement and significant energy of the pelvic limbs (p

Article Details: Received: 2020-10-21 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.105-108 During their career, horses are affected by a large number of direct and indirect factors. The aim of our study was to determine the effect of indirect factors, such as year of start, sex, breed, number of starts, age and proportion of genes of Slovak Warmblood horse breed. For determination of indirect factors on performance level, results from test efficiency and final placement in showjumping category 4, 5 and 6 years old young horses were used. 540 horses of Slovak Warmblood breed were analysed between 2015 - 2019 and 1155 data samples were collected. Based on the results of the linear model, parameters – the effect of gender and the influence of the gene proportion of Slovak Warmblood horse had statistically significant influence (p

Background Arrhythmias are common in horses, but catheter-based minimally invasive electrophysiological studies and therapeutic interventions have been poorly explored in equine medicine, partly due to the lack of detailed anatomical knowledge of the equine heart. Objectives To describe the dimensions and anatomical features of some electrophysiologically important landmarks of the right atrium in detail and assess their correlation with bodyweight and aortic diameter. Study design Ex vivo cadaveric study. Methods Twenty-one hearts of Warmblood horses, subjected to euthanasia for noncardiovascular reasons, were examined post-mortem. The dimensions and anatomical features of the coronary sinus, the great cardiac vein and the oval fossa were recorded. Spearman's Rho correlation coefficients were calculated for correlations between the quantitative parameters and bodyweight and aortic diameter. Results Median dimensions for coronary sinus, great cardiac vein and oval fossa were obtained. A Thebesian valve, partially covering the ostium of the coronary sinus, was present in 9 of the 21 hearts. A median of 6.5 (range 4-9) valves were present in the great cardiac vein. Several parameters, among which the dimensions of the oval fossa and the length of the great cardiac vein, were significantly positively correlated with bodyweight and aortic diameter. Main limitations Measurements do not consider the dynamic changes during the cardiac cycle as measurements were performed ex vivo. All specimens were retrieved from Warmblood horses, therefore measurements might not apply to other breeds. Conclusions This study delivers a detailed description of important right atrial-related structures, necessary for the development of minimally invasive intracardiac procedures in horses. Adequate imaging techniques will have to be explored in order to guide these procedures.

This study was performed to examine and clarify the cause of hindlimb ataxia and neuropathy seen in the South Korean horse population. Fifty horses diagnosed with hindlimb ataxia and neuropathy were referred for this study. Neurological examination was performed on 47 horses while necropsy was performed in all 50 animals. The occurrence of neurological diseases increased rapidly in the summer and 47 out of 50 horses were referred after the end of July. The incidence of neurological diseases started from the southern part of Korea in July and proceeded northward in August and September. Although there was no correlation with age, Thoroughbred and Warmblood horses showed a higher incidence rate than Halla and Jeju horses. The incidence rate was 5 times higher in geldings than in mares and stallions. Of the 20 cases, 16 were diagnosed with eosinophilic meningoencephalomyelitis in 2015. The most common lesions observed in 2016 were parasitic meningoencephalomyelitis (10 cases, 33%) and eosinophilic meningomyelitis (7 cases, 23%). Histopathological analysis of the brain and spinal cord revealed nematodes of approximately 100-200 µm in diameter, microcavitation and infiltrates of eosinophils, and brown pigmented macrophage infiltrates. The nematodes were identified as Setaria digitata via DNA sequencing, performed subsequent to polymerase chain reaction using DNA isolated from formalin-fixed paraffin-embedded tissue sections of the spinal cord. These results show that aberrant migration of Setaria digitata larva in the brain and spinal cord was a major cause for neurological signs in horses.

This article focuses on interspecies communication between rider and jumper horse (show jumpers), as well as its effect on equine sport performance, on the basis of individual differences of riding style and skill. Its primary goal was to discover the consequences of the possible differences in horse performance due to the number of riders who have changed over the course of the horse performing career. Unfortunately, the data used do not allow to determine whether the change of rider also meant a change in the social environment with all contexts (moving the horse to other stable, among other horses, and the use of other training methods). Nevertheless, the change of rider represents a number of individual deviations in the rider's effect on the horse. Riders communicate in the same language, but each rider has a different “handwriting.” The secondary goal of this study is to identify the age at which a competitive jumping horse reaches its maximum competitive performance. A total of 3,097 horse competitive result histories were used in the study, covering participation in 277,198 jumping competitions. The database was divided into three groups as per the competitive success of horses. The data were collected by the Czech Association of Horse Breeders Warmblood on the basis of all horse starts in horse jumping competitions during the years 1997-2009. Within these groups, horses were compared depending on whether they were ridden by one to two riders, three to four riders, and five or more riders over the course of their careers. The results show that among most horse groups their peak performance, represented by the highest level of competition difficulty, was reached in their tenth year of age. In all groups of horses, divided as per their competitive success rates, the best performance was achieved by those with a maximum of two riders over the course of their career. The results clearly speak in favor of both the social stability of horses and performance success of those horses affected by a less frequent change of the rider. It could be stated in accordance with achieved sports results that fewer riders over the course of a horse's career are for jumping horse’s better variant.

Knowledge on the best timing for horse performance is necessary to ensure horse well-being and longevity. The training plan should take into account seasonal preferences of horses to establish the optimal performance timing. The effect of season/month on horse performance was investigated as the retrospective evaluation of secondary data using a cross-sectional design on the basis of official standardized performance tests for young breeding warmblood horses (2050 mares and 73 stallions) to establish the best performance months. The tests for mares were conducted in all months of the year and for stallions in two different seasons/months. Analysis of variance was performed to evaluate the fixed effects of season/month, year, training center, breed register, random effect of sire, and linear regression on age in days. The influence of month of testing was statistically significant for the traits of “character” (P = 0.0053) and “temperament” (P = 0.0166) evaluated in mares. The trait “rideability” (P = 0.0098) differed between months in mare station tests, but not in field tests. Lower performance results were obtained generally in March and November. These months seem to be suboptimal for young horse performance in temperate climate zones. Behavior-related traits of mare performance demonstrate season-dependent characteristics, which was not the case for mare locomotion traits and stallion characteristics.

Case history: A 9-year-old warmblood gelding with a history of chronic intermittent tachypnoea and dyspnoea was presented for evaluation and removal of a mass on the left side of the neck. A fibrou...

Background Difficulty in detection of silent carriers of Streptococcus equi is a key reason for its continued spread to immunologically naïve groups of horses. Objective To determine whether clinical examination, markers of inflammation, or serology differentiate silent carriers of S. equi in recovered comingled horses. Animals Ninety‐eight warmblood yearlings and 72 unaffected mares on a large breeding farm (outbreak A), 38 mature Icelandic horses at a riding stable (outbreak B), and 27 mixed breed horses at a boarding stable (outbreak C). Methods Prospective observational study 6 months to 2 years after strangles outbreaks. Carriers were defined as any animal positive on culture or qPCR to S. equi from nasopharyngeal lavage or guttural pouch endoscopy and lavage. Most horses had complete physical exams and 1 group included evaluation of white blood cell counts and serum amyloid A. Sera from all horses was tested for antibodies to antigens A and C of S. equi using an enhanced indirect ELISA. Descriptive statistics were calculated. Data were compared using paired t tests, Wilcoxon ranked test, chi square, or the Fishers exact test. Significance was set at P

Background A 20‐year‐old grey Warmblood gelding that had history of dermal melanomatosis. Objective To report surgical treatment of a 6‐cm large malignant metastatic melanoma located in the cutaneous trunci muscle of the left lateral thorax of a horse. Methods A 20‐year‐old grey Warmblood gelding was referred for evaluation of a large, rapidly growing, thoracic mass. Clinical examination revealed an ovoid, firm, non‐painful, movable mass, approximately 6 cm in diameter, located in the cutaneous trunci muscle of the left lateral thorax. Multiple melanocytic nodules were also found at the perianal region and ventral tail. Rectal examination, ultrasonography and endoscopy of the respiratory tract revealed no melanomas internally. Haematological and biochemical values were within normal limits. Surgical excision of both the thoracic mass and perianal nodules was the treatment of choice. Histopathology of the distant thoracic mass confirmed the diagnosis of malignant metastatic melanoma secondary to the perineal lesions that were confirmed as dermal melanomatosis. Results The horse recovered uneventfully. Up until 3 years post surgery there was no tumour regrowth at the excision sites. Conclusion Surgical excision of the metastatic melanoma was performed and considered successful, with no gross evidence of tumour reoccurrence. Despite the fact that surgical excision is considered a treatment option regarding equine dermal melanomatosis, there is no previously published study proposing surgical removal of distant malignant metastatic melanocytic masses. This is the first report of a successful surgical excision of a large (6 cm) metastatic melanocytic tumour from the skeletal muscle of the lateral thorax of a horse., A 20‐year‐old grey Warmblood gelding was referred for evaluation of a large, rapidly growing, thoracic mass. Histopathology of the distant thoracic mass confirmed the diagnosis of malignant metastatic melanoma. Surgical excision of the metastatic melanoma was performed and considered successful, with no gross evidence of tumour reoccurrence.This report proposes surgical excision as a treatment option for distant malignant metastatic melanocytic masses in skeletal muscle.

Clinical and radiographic examination of the cervical spine has been of increasing interest in the prepurchase examination and clinical work‐up conducted for horses. The objective of this study was to describe a grading system useful for evaluating all the cervical articular process joints (cAPJs). Additionally, the findings of the cervical radiographs (occiput, cAPJ and intercentral joint space grading, intra‐ and intervertebral sagittal ratios, and intervertebral disc width measurements) were reported, and their association with clinical complaints in a large group of Dutch Warmblood horses (n = 598) were investigated. Significant associations were found between cAPJ radiographic grades and clinical complaints using the chi‐squared test (C2‐3 [P = 0.01], C5‐6 [P = 0.006], C6‐7 [P < 0.001], and C7‐T1 [P = 0.02]). Higher occiput grades were significantly associated with clinical complaints (chi‐squared test, P = 0.005). A large variability was found for intra‐ and intervertebral ratios and minimum intercentral joint space in the control group, but no significant association between intercentral joint space and clinical complaints was observed using the Kruskal–Wallis test followed by post hoc testing with the Wilcoxon rank sum test with a Bonferroni correction. The main limitations of this study were that only information regarding localisation was used for the statistical analyses, without any other details of the clinical complaints. Furthermore, clinical records were retrospectively reviewed, and a bias towards cervical findings in the clinical data recordings should be considered. It was concluded that knowledge of the distribution of the radiographic findings evaluated in this study and their associated clinical relevance can be useful in reaching a science‐based diagnosis in daily practice.

Background: There is a paucity of research describing the gait pattern of lame horses at the walk. Objectives: To describe the changes in motion pattern and vertical ground reaction forces (GRFz) in horses with induced forelimb lameness at the walk and compare those changes with the changes observed at the trot. Study design: Experimental study. Methods: In 10 clinically sound Warmblood horses, moderate forelimb lameness was induced using a sole pressure model followed by trot and walk on a treadmill. Kinematic data were collected using 3D optical motion capture (OMC), and GRFz by an instrumented treadmill. Mixed models were used to compare sound baseline versus forelimb lameness (significance was set at P

Background Arterial rupture mainly affects older horses. The reason why older horses are more prone to arterial rupture and which underlying vascular changes predispose older horses to aortic rupture is still unclear. Objectives To investigate the effect of ageing on the equine arterial wall and blood pressure. Study design Cohort study. Methods Non-invasive blood pressure measurement using a tail cuff and vascular ultrasound from aorta, common carotid artery and external iliac artery was performed in 50 healthy young (3-7 years) and 50 healthy old Warmblood horses (>18 years). Arterial diameters and cross-sectional areas, and arterial wall thickness were measured offline. Regional arterial wall stiffness of the aorta and common carotid artery were assessed using pulse wave velocity, while lumen area/diameter change, strain, compliance and distensibility were calculated to assess local arterial wall stiffness. Results No difference in blood pressure was found between old and young horses. All arterial dimensions and intima-media thickness of the common carotid artery were significantly larger in old horses. A significantly higher local arterial wall stiffness was found for the aorta and the caudal common carotid artery in older horses. For the external iliac artery, no significant differences in arterial wall stiffness were found. Both aortic and carotid pulse wave velocities were higher in older horses compared with younger horses. Main limitations Blood pressure was measured non-invasively. Conclusions In horses, arteries stiffen with age, in combination with luminal enlargement and arterial wall thickening. This might, at least partially, explain the increased incidence of arterial rupture in older horses.

Background: Aortic rupture is more common in Friesians compared to Warmbloods, which might be related to differences in arterial wall composition and, as such, arterial wall stiffness (AWS). Currently, nothing is known about differences in AWS between these breeds. Objectives: Comparison of AWS parameters and noninvasive blood pressure between Friesians and Warmbloods. Animals: One hundred one healthy Friesians and 101 age-matched healthy Warmbloods. Methods: Two-dimensional and pulsed-wave Doppler ultrasound examination was performed of the aorta, common carotid artery, and external iliac artery to define local and regional AWS parameters. Regional aortic AWS was estimated using aortic-to-external iliac artery pulse wave velocity (PWVa-e) and carotid-to-external iliac artery pulse wave velocity (PWVc-e). Noninvasive blood pressure and heart rate were recorded simultaneously. Results: Systolic, diastolic, and mean arterial blood pressure and pulse pressure were significantly higher in Friesians compared to Warmbloods. No significant difference in heart rate was found. Most local AWS parameters (diameter change, compliance coefficient, distensibility coefficient) were significantly lower in Friesians compared to Warmbloods, indicating a stiffer aorta in Friesians. This difference could be confirmed by the regional stiffness parameters. A higher PWVa-e and PWVc-e was found in Friesians. For the cranial and caudal common carotid artery and external iliac artery, most local AWS parameters were not significantly different. Conclusions and clinical importance: Results indicate that aortic AWS differs between Friesian and Warmblood horses. Friesians seem to have a stiffer aorta, which might be related to the higher incidence of aortic rupture in Friesians.

Background In Warmblood horses, degenerative joint disease is involved in cervical malformation and malarticulation (CVM). The degree of contribution of articular process joint (APJ) osteochondrosis (OC) is not clear. Objectives (a) To explore the presence of predilection sites for APJ OC in cervical and cranial thoracic vertebral columns of Warmblood foals and (b) to examine the correlation of such a site with the predilection site of CVM. Study design Case series. Methods Seven hundred APJ facets of C2 to T2 of 29 foals (11 months gestation to 12 months [median age 7 days; range 365 days; 95% confidence interval [95% CI] 2-47 days]) were examined for OC and prevalence between joints, and the predilection site for CVM and the cranial cervical vertebral column were evaluated. Results About 20.6% of facets revealed OC. There was no predilection site. Prevalence decreased with age up to 1 year (odds ratio [OR] 0.997; (95% CI 0.975-0.998)) but not up to 5 months. Severity increased with age in all age ranges (up to 1 year OR 1.023; 95% CI 1.005-1.049; >1-5 months, OR 1.203; 95% CI 1.014e+00-1.921; up to 1 month, OR 1.114; 95% CI 1.041-1.228). Highest prevalence was in cranial facets of the cervical and cervical-thoracic joints and in caudal facets of the thoracic joint up to 1 year and up to 1 month (OR 0.364; 95% CI 0.170-0.745, OR 0.434; 95% CI: 0.235-0.782, OR 7.665; 95% CI: 1.615-66.553 and OR 0.400; 95% CI 0.170-0.880, OR 0.351; 95% CI 0.172-0.700, OR 5.317; 95% CI 1.098-44.344 respectively). Main limitations Two-thirds of the foals were less than 1 month of age. Conclusions Articular process joint OC in Warmblood foals is common and is not more prevalent at CVM predilection sites, suggesting that abnormalities of enchondral ossification may not be major contributors to CVM.

Objective This study compares the mechanical stability and surgical usability of 2 locking plate systems (Kyon ALPS-20 and Synthes PIP-LCP system) for arthrodesis of the equine proximal interphalangeal joint (PIJ). Material and methods The experimental ex vivo study included 6 pairs of cadaver distal limbs (n = 12). All specimens were derived from Warmblood horses of various ages that were euthanized for non-orthopedic reasons. Of the 12 limbs collected, 3 left and 3 right distal limb specimens were randomly assigned to each system for implantation. Two abaxial 4.5-mm cortical screws were inserted transarticularly in all cases. Both systems were implanted according to the manufacturer’s instructions with the plates placed centrally between the 2 transarticular screws. The ALPS-20 systems were implanted using Kyon B-6.4-mm monocortical locking screws in all positions. The LCP systems were implanted axially using 2 Synthes 5-mm locking screws in the proximal and distal positions, with a standard 4.5-mm cortical screw inserted in the middle position. All constructs underwent CT-scans after implantation and biomechanical testing to detect implant deformation. Uniaxial mechanical loading was applied via a servo-hydraulic test system at a test speed of 50 mm/s, up to a maximum displacement of 80 mm. The resulting load-displacement curves were used to calculate yield point, stiffness, and maximum force for each construct. The measured values were evaluated for statistical significance (p < 0.05) between the 2 plate systems via one-factor ANOVA (Tukey test). The statistical power was verified for yield force, stiffness, and maximum load. Results No statistically significant differences between the 2 preparation groups were calculated across all of the measured parameters (p > 0.05). The ALPS system implants showed no signs of deformation, either in the plates or the screws. In contrast, the LCP demonstrated visible deformation, which had already occurred at the time of implantation from the tightening of the middle screw, as well as during the subsequent testing of the implants. After biomechanical testing, deformations ranging between 3.1° and 7.0° were measured in 4 LCPs. A total implant failure was observed for 2 LCPs. Conclusion and clinical relevance Both systems demonstrated comparable mechanical properties in the present study’s ex vivo test model for equine PIJ arthrodesis. As such, the Kyon ALPS-20 may be a good alternative to the Synthes LCP for equine PIJ arthrodesis.

A 10-year-old, 595���kg Irish Warmblood stallion used for showjumping was presented with a marked right forelimb lameness at walk. The horse sustained a dorsal plane fracture of the accessory carpal bone (ACB) when falling with both carpi in flexion. The fracture was repaired by means of computer-assisted orthopaedic surgery (CAOS) using two cortex screws placed in lag fashion. In a second CAOS procedure, a dorsoproximal fragment of the ACB was removed after further proximal displacement had become apparent. Both surgical procedures were facilitated by the application of a fibreglass cast to immobilise the carpus in extension and to allow for the placement of the patient tracker distant from the surgical site. One year after surgery, the horse had returned to full athletic activity. Neither the antebrachiocarpal joint nor the carpal sheath were distended. Control radiographs and standing cone beam computed tomography showed complete osseous union of the fracture and osteophyte formation on the caudal aspect of the radius and the proximal border of the ACB.

OBJECTIVE To quantify the degree of dural compression and assess the association between site and direction of compression and articular process (AP) size and degree of dural compression with CT myelography. ANIMALS 26 client-oriented horses with ataxia. PROCEDURES Spinal cord-to-dura and AP-to-cross-sectional area of the C6 body ratios (APBRs) were calculated for each noncompressive site and site that had > 50% compression of the subarachnoid space. Site of maximum compression had the largest spinal cord-to-dura ratio. Fisher exact test and linear regression analyses were used to assess the association between site and direction of compression and mean or maximum APBR and spinal cord-todura ratio, respectively. RESULTS Mean ± SD spinal cord-to-dura ratio was 0.31 ± 0.044 (range, 0.20 to 0.41) for noncompressive sites and 0.44 ± 0.078 (0.29 to 0.60) for sites of maximum compression. Sites of maximum compression were intervertebral and extra-dural, most frequently at C6 through 7 (n = 10), followed by C3 through 4 (6). Thirteen horses had dorsolateral and lateral compression at the AP joints, secondary to AP (n = 7) or soft tissue proliferation (6). Site significantly affected direction of compression, and directions of compression from occiput through C4 were primarily ventral and lateral, whereas from C6 through T1 were primarily dorsal and dorsolateral. No linear relationship was identified between mean or maximum APBR and spinal cord-to-dura ratio. CONCLUSIONS AND CLINICAL RELEVANCE CT myelography may be useful for examination of horses with suspected cervical compressive myelopathy. Degree of compression can be assessed quantitatively, and site of compression significantly affected direction of compression.

Background Warmblood Fragile Foal Syndrome (WFFS) is an autosomal recessive disorder caused by a mutation in the procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 (PLOD1) gene. Homozygosity for the mutation results in defective collagen synthesis which clinically manifests as the birth of non viable or still born foals with abnormally fragile skin. While the mutation has been identified in non Warmblood breeds including the Thoroughbred, to date all homozygous clinically affected cases reported in the scientific literature are Warmblood foals. The objective of this study was to investigate the carrier frequency of the mutation in the Thoroughbred and sport horse populations in Ireland. Methods A test was developed at the UCD School of Veterinary Medicine using real-time PCR to amplify the PLOD1 gene c.2032G > A variant. A subset of the samples was also submitted to an external laboratory with a licensed commercial WFFS genetic test. Results Warmblood Fragile Foal Syndrome genotyping was performed on hair samples from 469 horses representing 6 different breeds. Six of 303 (1.98%) sport horses tested and three of 109 (2.75%) Thoroughbreds tested were heterozygous for the WFFS polymorphism (N/WFFS). The WFFS polymorphism was not identified in the Standardbred, Cob, Connemara, or other pony breeds. Conclusions The study identified a low frequency of the WFFS causative mutation in sport horses and Thoroughbreds in Ireland, highlighting the importance of WFFS genetic testing in order to identify phenotypically normal heterozygous carriers and to prevent the birth of nonviable foals.

Objectives: This study aims to evaluate the distribution and severity of bone and soft tissue lesions in the proximal metacarpal region of warmblood horses in lame and control groups. Correlation between lesions and ability to return to work was evaluated in the lame group.Methods: This restrospective analysis evaluated 62 horses with MRI examination of the proximal metacarpal region between Sept 2015 and Feb 2021. There were 36 lame limbs and 26 control limbs. The control group included seven contralateral limbs.Results: Proximal suspensory ligament (PSL) size was not different between the lame and control groups. Hyperintensity seen on T1W/T2*W GRE images within the dorsal collagenous part of the PSL and hyperintense Short-TI Inversion Recovery (STIR) signal within the dorsal collagenous part of the PSL or within the McIII were only present within the lame group. Palmar cortical McIII resorption and dorsal margin irregularity of the PSL and McIII sclerosis were more severe within the lame limbs, but mild gradations were also seen in control limbs. Intermediate gradings for a subset of lesions were commonly seen in the non-lame contralateral to lame limbs. Return to work in the lame group is not statistically different for any measured observation(s), and 19/33 of the lame horses returned to work at similar or higher levels.Conclusion and clinical importance: Fifty-eight percent in this group of warmblood horses returned to work within a variable time frame. The majority (81%) of lame limbs showed bone and soft tissue abnormalities, but no enlargement of the PSL was noted in lame horses, and no correlation was seen between the severity or type of lesions and the ability to return to work. The presence of STIR hyperintensity within the proximal McIII or dorsal collagenous part of the PSL and hyperintensity within the dorsal collagenous part of the PSL on T1W GRE and T2*W GRE images, as well as significant palmar cortical McIII resorption are considered clinically relevant lesions. Contralateral limbs may not truly represent the normal condition, showing nonclinical variations and adaptive remodeling.

This study aimed to validate eye temperature (ET) assessed using infrared thermography (IRT) as an indicator of welfare in horses. Moreover, this study aimed to determine the most accurate position for ET measured using IRT and to validate this approach as a gold-standard measurement method. As the quantitative data obtained by IRT have strongly influenced the ET results depending on the specific location of the measurement area, an accurate definition of the regions of interest (ROI) was established. A total of 176 horses (Thoroughbred, Warmblood, and Halla horses) were used at the racing course of the Korea Racing Authority and public horse-riding clubs in South Korea. The present study also compared temperatures among three ROIs of the eye—lacrimal sac, medial canthus, and lateral canthus—at rest. Correlations between ET, rectal temperature (RT), heart rate (HR), and respiratory rate (RR) were assessed. There were no significant correlations between HR, RR or RT, however, among the three ROIs, the temperature of the medial canthus was positively correlated with RT (p &lt, 0.05). Furthermore, the size of ROI was negatively correlated with accuracy of temperature measurement. These results indicate that the most suitable area for ET measurement using IRT in horses is the medial canthus, and it is recommended to use the average temperature of the smallest ROIs (2 × 2 pixels) for temperature analysis. Therefore, this study offers a validated protocol in which ET measured using IRT in the horses is useful as an indicator of welfare.

In this study, it was aimed to determine the statistical differences between Arabian horses and Thoroughbred horses based on X-ray images of forelimb digital bones. Latero-medial X-ray images of digital bones of thoracic limbs were taken of 25 Arabian horses and 50 Thoroughbred healthy horses. The difference between males and females within the breed was statistically analyzed as well. Nine measurements and three indexes taken from phalanges of thoracic limbs were used. Thoroughbred horses did not differ significantly between sexes, as indicated by the ANOVA. For the Arabian horses, the length of the middle of the proximal phalanx (p &lt, 0.05), the length of the middle of the middle phalanx (p &lt, 0.001), and the length of the dorsal surface of the distal phalanx (p &lt, 0.05) measurement points were found to be differentiated between sexes. In the analysis made between Thoroughbred horses and Arabian horses with no respect to sex, the critical measurement was the depth of the caput of the proximal phalanx. The discriminant analysis enabled the correct classification of 89.33% of the proximal phalanx samples to the exact breed. The correct classification rate was 77.33% in the case of middle phalanx and 54.67% in the case of distal phalanx. Measurement results of the distal phalanx were found to be insignificant between both breeds and sexes. The radiological measurements of digital bones showed that sexual dimorphism was not too expressed and that decisive differences were found between the breeds.

OBJECTIVE To report arthroscopic osteochondral fragment removal from the equine cervical spine articular process joints (APJs) including long-term follow-up. STUDY DESIGN Case series. ANIMALS Three Warmblood horses with forelimb lameness and/or reduced range of motion of the cervical spine with osteochondral fragments between the cervical vertebrae C5 /C6 or C6 /C7 . METHOD Arthroscopy of the APJs of C5 /C6 and C6 /C7 was performed under general anesthesia. Following endoscopic evaluation of the joints, osteochondral fragments were removed using a rongeur. RESULTS All horses recovered from anesthesia with no anesthetic or minor postanesthetic complications. One horse needed a second procedure for fragment removal. Fourteen to 31 months post-surgery the horses were sound for their intended use and neurological examination revealed no abnormalities. CONCLUSION Arthroscopic removal of osteochondral fragments can be performed safely in the equine cervical APJs of C5 /C6 and C6 /C7 resulting in a favorable long-term outcome. CLINICAL SIGNIFICANCE Arthroscopic removal is a valid option for horses showing clinical signs that can be attributed to osteochondral fragments in the APJs of the neck.