Belgian Horses Research Articles

Alleviating lesions of chronic progressive lymphedema in Belgian draft horses by successfully treating Chorioptes bovis infestation with moxidectin 0.5% pour-on

The aim of this prospective, randomized, single-blinded, and placebo-controlled clinical trial was to investigate the efficacy of a moxidectin pour-on solution for the treatment of Chorioptes bovis infestation in Belgian draft horses, and in addition, to evaluate the effect of this treatment on the clinical signs and lesions associated with chronic progressive lymphedema (CPL). Nineteen privately owned Belgian draft horses were randomly assigned to either a treatment group (moxidectin pour-on formulation, n = 10) or a placebo group (phosphate-buffered saline (PBS), n = 9). On Day 0, all 19 horses tested positive for the presence of C. bovis in superficial skin scrapings. Prior to treatment, all feathering on the distal limbs of the horses was clipped. Treatment was applied twice (Day 0 and 7). Pour-on moxidectin (Cydectin 0.5% Pour-On; Zoetis) was evenly distributed over the distal legs of the horses at a dose of 1.5 mg moxidectin/kg body weight. Animals in the placebo group were treated with PBS. Pretreatment and follow-up examinations consisted of counting living mites in superficial skin scrapings, scoring pruritus, and scoring mange-associated and CPL-associated lesions (skinfold score and skin lesion score). Horses in the placebo group and moxidectin group were followed up to 8 weeks and 24 weeks after the first treatment, respectively. On Day 14, no living mites were found in any of the horses in the moxidectin group (p = 0.013). These horses continued to remain free of mites, until the final sampling conducted at 24 weeks following the initial application of moxidectin, when three horses again showed living mites in skin scrapings. Treatment with moxidectin resulted in a significant reduction of both CPL-associated skin lesion scores (p = 0.003) and pruritus scores (p = 0.001) after only seven days. By Day 56, still no signs of pruritus (p < 0.0001) were detected, with significant improvement of mange-associated lesions (p < 0.0001). Although the skinfold score did not show a significant reduction by Day 56, the score for skin lesions associated with CPL had significantly improved (p < 0.0001). In conclusion, the results of this study demonstrate that pour-on moxidectin, at a high dose and applied directly to the mite predilection site, was an effective treatment for C. bovis infestation in feathered draft horses, providing positive effects on CPL lesions, pruritus and mange-associated lesions. Furthermore, these findings emphasize the therapeutic significance of addressing mange in the management of CPL-affected draft horses.

Chronic Progressive Lymphedema in Belgian Draft Horses: Understanding and Managing a Challenging Disease.

Chronic progressive lymphedema (CPL) in draft horses is characterized by increased dermal thickness and fibrosis, with the development of skinfolds and nodules, hyperkeratosis, and ulcerations on the distal limbs of affected horses. Secondary bacterial, fungal, or parasitic infections frequently complicate and aggravate the lesions, as well as the progression of this disease. CPL has a particularly high prevalence of up to 85.86% in the Belgian draft horse breed. Due to the disease's progressive and incurable nature, affected horses are often euthanized prematurely. The treatment options are solely symptomatic, aimed at improving the horse's quality of life. Despite the severity of this condition, many uncertainties about its etiology and pathogenesis still remain to date. The established scientific research on CPL is rather limited, although there is an urgent need for strategies to tackle this disease. This review summarizes the available knowledge, serving as a guideline for practitioners, and provides perspectives for future research programs.

Risk of anesthesia-related complications in draft horses: a retrospective, single-center analysis

ObjectiveTo report anesthetic-related complications and determine risks associated with anesthesia in draft horses. Study designRetrospective study. AnimalsA total of 401 anesthetic records for draft horse breeds that underwent general anesthesia from January 2010 through December 2020 were reviewed; horses euthanized during general anesthesia were excluded. MethodsDemographics, perioperative drugs used, procedure type and duration, time to extubation, number of attempts to stand, use of sling in recovery and perioperative morbidity and mortality were investigated. Morbidity and mortality statistical evaluation included univariable logistic regression analysis and ordinal regression analysis. ResultsAmerican Society of Anesthesiologists (ASA) status I–II, ASA III–V and total mortality rate for all cases was 0.69% (2/288), 6.19% (7/113) and 2.24% (9/401), respectively, with Belgian horses being overrepresented (6/9). Cardiac arrest occurred in six out of nine horses that died without euthanasia, and five out of six of these horses underwent colic surgery. Factors associated with increased mortality risk included ASA status of III–V, increased body weight, emergency status and horses presenting for colic. Hypotension, hypercarbia and hypoxemia occurred in 56% (224/401), 46% (186/401) and 14% (58/401) of horses, respectively. During recovery from anesthesia, lighter horses and horses undergoing shorter anesthetic procedures were more likely to be successful on the first or second attempt to stand and were less likely to require a sling in recovery. Conclusions and clinical relevanceDraft horses undergoing general anesthesia had a higher mortality rate than previously reported for all types and breeds of horses.

Catheter‐associated air embolism of the brain in a hospitalised horse

AbstractAn 8‐year‐old, approximately 590 kg Belgian draft cross gelding was anaesthetised for tenoscopy and repair of a tendon sheath laceration. The horse remained hospitalised for several days. During post‐operative hospitalisation, the jugular catheter accidentally became disconnected from the extension set. The next day, the horse was blind bilaterally and circling to the left. Elevated cardiac troponin with mild tachycardia was also noted. The horse was treated supportively, but neurologic signs persisted, and after 3 weeks of no improvement humane euthanasia was elected. The most significant finding on gross postmortem examination was generalised cerebral oedema and gross malacia and haemorrhage of the left occipital cortex. Histopathology revealed regionally extensive grey and white matter necrosis in the left and right occipital cortices, consistent with an infarctive pathogenesis. The history and postmortem examination findings are compatible with air emboli in the brain. This is a rare but serious complication of intravenous catheter use in horses.

How to Behave Like a Good Banker?

In April 2015, as a means for improving the integrity of the banking sector, The Netherlands adopted a Disciplinary Law for bankers. In this article, the authors discuss the Banker’s Oath by which bank employees are bound to the disciplinary law, the disciplinary procedures and sanctions that can be imposed, which acts of bankers do and do not fall within the scope of the disciplinary law, conflicts of interest that may exist between bank employee and the bank that employs, the question whether banks that notify an employee must or must not anonimise files that they provide to the disciplinary committee, the limited transparency of decisions of the Disciplinary Committee, whether accused bank employees have a right to a fair trial, and the independence and impartiality of the Disciplinary Committee. We also discuss a selection of cases that have been brought before the Disciplinary Committee.The Dutch example of a banker’s disciplinary law will be followed by Belgium. The authors compare the Belgian draft bill for a banker’s disciplinary law with the Dutch system.

DDB2 Genetic Risk Factor for Ocular Squamous Cell Carcinoma Identified in Three Additional Horse Breeds.

Squamous cell carcinoma (SCC) is the most common cancer affecting the equine eye. A missense variant within the gene damage-specific DNA binding protein 2 (DDB2 c.1013C>T, p.Thr338Met) was previously identified as a causal recessive genetic risk factor for the development of ocular SCC within Haflingers, Belgian Draft horses, and Rocky Mountain Horses, but not in the Appaloosa or Arabian breeds. This study aimed to evaluate three cases of ocular SCC in additional breeds and determine if DNA testing for the DDB2 variant in warmblood horses and Connemara ponies is warranted. Histopathology confirmed ocular SCC in all three cases and DNA testing confirmed each horse was homozygous for the DDB2 risk factor. The DDB2 risk allele frequency was estimated to be 0.0043 for Holsteiners (N = 115), 0.014 for Belgian Warmbloods (N = 71), and 0.22 for Connemara Ponies (N = 86). Taken together these data support using DNA testing for DDB2 in Connemara Ponies to assist in mate selection and clinical management. Given the low observed allele frequencies in both the Holsteiner and Belgian Warmblood breeds and that the case under investigation was a warmblood cross-bred, evaluating additional SCC affected warmbloods is warranted to fully determine the importance of DDB2 genotyping as a risk factor in warmblood breeds.

High Seroprevalence Against Lawsonia intracellularis Among Adult Horses in Belgium

Lawsonia intracellularis (LI) is an obligate intracellular gram-negative rod causing equine proliferative enteropathy (EPE). Occasional cases of EPE have been reported in foals living in Belgium, but the seroprevalence of equine LI in this country is unknown. The target population included clinically healthy adult horses, whose blood samples were collected and analyzed for specific IgG antibodies against LI using a blocking enzyme-linked immunosorbent assay test. The results were expressed as percentage of inhibition (PI). Samples that had a PI <20% were judged as negative, those between 20 and 30% as inconclusive, and those >30% were considered positive. A total of 356 blood samples were analyzed with 352 horses (98.8%) testing positive, 2 horses (0.6%) testing negative, and 2 horses (0.6%) showing inconclusive results. The large percentage of seropositive samples obtained in this study confirms a widespread exposure of Belgian horses to LI.

A Genome-Wide Association Analysis in Noriker Horses Identifies a SNP Associated With Roan Coat Color

The roan coat color in horses is characterized by dispersed white hair and dark points. This phenotype segregates in a broad range of horse breeds, while the underlying genetic background is still unknown. Previous studies mapped the roan locus to the KIT gene on equine chromosome 3 (ECA3). However, this association could not be validated across different horse breeds. Performing a genome-wide association analysis (GWAS) in Noriker horses, we identified a single nucleotide polymorphism (SNP) (ECA3:g.79,543.439 A > G) in the intron 17 of the KIT gene. The G -allele of the top associated SNP was present in other roan horses, namely Quarter Horse, Murgese, Slovenian, and Belgian draught horse, while it was absent in a panel of 15 breeds, including 657 non-roan horses. In further 379 gray Lipizzan horses, eight animals exhibited a heterozygous genotype (A/G). Comparative whole-genome sequence analysis of the KIT region revealed two deletions in the downstream region (ECA3:79,533,217_79,533,224delTCGTCTTC; ECA3:79,533,282_79,533,285delTTCT) and a 3 bp deletion combined with 17 bp insertion in intron 20 of KIT (ECA3:79,588,128_79,588,130delinsTTATCTCTATAGTAGTT). Within the Noriker sample, these loci were in complete linkage disequilibrium (LD) with the identified top SNP. Based upon pedigree information and historical records, we were able to trace back the genetic origin of roan coat color to a baroque gene pool. Furthermore, our data suggest allelic heterogeneity and the existence of additional roan alleles in ponies and breeds related to the English Thoroughbred. In order to study the roan phenotype segregating in those breeds, further association and verification studies are required.

Inter- and intra-breed genome-wide copy number diversity in a large cohort of European equine breeds

BackgroundCopy Number Variation (CNV) is a common form of genetic variation underlying animal evolution and phenotypic diversity across a wide range of species. In the mammalian genome, high frequency of CNV differentiation between breeds may be candidates for population-specific selection. However, CNV differentiation, selection and its population genetics have been poorly explored in horses.ResultsWe investigated the patterns, population variation and gene annotation of CNV using the Axiom® Equine Genotyping Array (670,796 SNPs) from a large cohort of individuals (N = 1755) belonging to eight European horse breeds, varying from draught horses to several warmblood populations. After quality control, 152,640 SNP CNVs (individual markers), 18,800 segment CNVs (consecutive SNP CNVs of same gain/loss state or both) and 939 CNV regions (CNVRs; overlapping segment CNVs by at least 1 bp) compared to the average signal of the reference (Belgian draught horse) were identified. Our analyses showed that Equus caballus chromosome 12 (ECA12) was the most enriched in segment CNV gains and losses (~ 3% average proportion of the genome covered), but the highest number of segment CNVs were detected on ECA1 and ECA20 (regardless of size). The Friesian horses showed private SNP CNV gains (> 20% of the samples) on ECA1 and Exmoor ponies displayed private SNP CNV losses on ECA25 (> 20% of the samples). The Warmblood cluster showed private SNP CNV gains located in ECA9 and Draught cluster showed private SNP CNV losses located in ECA7. The length of the CNVRs ranged from 1 kb to 21.3 Mb. A total of 10,612 genes were annotated within the CNVRs. The PANTHER annotation of these genes showed significantly under- and overrepresented gene ontology biological terms related to cellular processes and immunity (Bonferroni P-value < 0.05). We identified 80 CNVRs overlapping with known QTL for fertility, coat colour, conformation and temperament. We also report 67 novel CNVRs.ConclusionsThis work revealed that CNV patterns, in the genome of some European horse breeds, occurred in specific genomic regions. The results provide support to the hypothesis that high frequency private CNVs residing in genes may potentially be responsible for the diverse phenotypes seen between horse breeds.

Additional Evidence for DDB2 T338M as a Genetic Risk Factor for Ocular Squamous Cell Carcinoma in Horses.

Squamous cell carcinoma (SCC) is the most common periocular cancer in horses and the second most common tumor of the horse overall. A missense mutation in damage-specific DNA-binding protein 2 (DDB2, c.1012 C>T, p.Thr338Met) was previously found to be strongly associated with ocular SCC in Haflinger and Belgian horses, explaining 76% of cases across both breeds. To determine if this same variant in DDB2 contributes to risk for ocular SCC in the Arabian, Appaloosa, and Percheron breeds and to determine if the variant contributes to risk for oral or urogenital SCC, histologically confirmed SCC cases were genotyped for the DDB2 variant and associations were investigated. Horses with urogenital SCC that were heterozygous for the DDB2 risk allele were identified in the Appaloosa breed, but a significant association between the DDB2 variant and SCC occurring at any location in this breed was not detected. The risk allele was not identified in Arabians, and no Percherons were homozygous for the risk allele. High-throughput sequencing data from six Haflingers were analyzed to ascertain if any other variant from the previously associated 483 kb locus on ECA12 was more concordant with the SCC phenotype than the DDB2 variant. Sixty polymorphisms were prioritized for evaluation, and no other variant from this locus explained the genetic risk better than the DDB2 allele (P = 3.39 × 10−17, n = 118). These data provide further support of the DDB2 variant contributing to risk for ocular SCC, specifically in the Haflinger and Belgian breeds.

The Genomic Makeup of Nine Horse Populations Sampled in the Netherlands.

The spectrum of modern horse populations encompasses populations with a long history of development in isolation and relatively recently formed types. To increase our understanding of the evolutionary history and provide information on how to optimally conserve or improve these populations with varying development and background for the future, we analyzed genotype data of 184 horses from 9 Dutch or common horse populations in the Netherlands: The Belgian draft horse, Friesian horse, Shetland pony, Icelandic horse, Gelder horse, Groninger horse, harness horse, KWPN sport horse and the Lipizzaner horse population. Various parameters were estimated (e.g., runs of homozygosity and FST values) to gain insight into genetic diversity and relationships within and among these populations. The identified genomic makeup and quantified relationships did mostly conform to the development of these populations as well as past and current breeding practices. In general, populations that allow gene-flow showed less inbreeding and homozygosity. Also, recent bottlenecks (e.g., related to high selective pressure) caused a larger contribution of long ROHs to inbreeding. Maintaining genetic diversity through tailor-made breeding practices is crucial for a healthy continuation of the investigated, mostly inbred and (effectively) small sized horse populations, of which several already experience inbreeding related issues.

A missense mutation in damage-specific DNA binding protein 2 is a genetic risk factor for ocular squamous cell carcinoma in Belgian horses.

Belgian horses are commonly affected with ocular squamous cell carcinoma (SCC), the most common cancer of the equine eye. A missense mutation in damage-specific DNA binding protein 2 (DDB2 c.1013C>T, p.Thr338Met) has been established as a recessive genetic risk factor for ocular SCC in the Haflinger breed. A sample of Belgian horses with unknown SCC phenotype was shown to possess this variant at a similar frequency to the Haflinger breed. Retrospective studies indicate that chestnut coat colour may predispose to the development of SCC. To determine if DDB2 c.1013C>T is a risk factor for ocular SCC in a strictly phenotyped sample of Belgian horses. To investigate associations between coat colour loci genotypes and ocular SCC. Retrospective and prospective case identification, genetic investigation. Genomic DNA was isolated from blood, hair or formalin-fixed paraffin-embedded tissue from 25 Belgian horses with histologically confirmed ocular SCC and 18 unaffected Belgian horses. Association testing of 34 single nucleotide variants from 11 genomic loci and genotyping for DDB2 c.1013C>T and coat colour alleles were performed. Exons of DDB2 were sequenced in four cases and two controls. Associations were analysed by Chi-square or Fisher's exact tests and relative risk was calculated. Homozygosity for DDB2 c.1013C>T was significantly associated with ocular SCC (P=7.4×10-7 ). Seventy-six per cent of affected horses were homozygous for the variant. Relative risk for homozygous horses developing SCC was 4.0 (P=1.0×10-4 ). Sequencing DDB2 did not identify a variant more concordant with disease phenotype. An association between disease and coat colour loci was not identified. Phenotyping was determined at a single timepoint. Each included horse genotyped as chestnut, so association with this MC1R variant could not be investigated. A missense variant, DDB2 c.1013C>T, p.Thr338Met, is a risk factor for ocular SCC in Belgian horses. A genetic risk test is commercially available.

Genetic Variability of Cold-Blooded Horses Participating in Genetic Resources Conservation Programs, Using Pedigree Analysis

Abstract Two types of Polish local cold-blooded horses – Sztumski and Sokólski, covered by genetic resources conservation programs, were analyzed for founder’s contribution, genetic structure and inbreeding. In both populations, created in the early twentieth century, were used the same stallions, mainly Ardennes, Belgians and Bretons. The aim of the study was to analyze the genetic variability of Sztumski and Sokólski cold-blooded horses, using pedigree information. The reference population contained 2359 horses: 1129 Sztumski and 1230 Sokólski included in conservation programs in 2014. The data set consisted of a total of 12,821 ancestor pedigrees. The results showed that in the analyzed population the number of founders was 1139 for Sztumski and 1118 for Sokólski horses; effective population size and effective number of founders were 688.8; 156.9 and 704.5; 111.4, respectively. The mean coefficient of inbreeding was 1.54 for Sztumski and 1.56 for Sokólski horses. In the gene pool the most important contribution was of Ardennes horses (43.67% in Sztumski and 46.82% in Sokólski horses), followed by Belgian horses (18.32% and 9.3%, respectively). The most important ancestors in both populations were Ardennes sires Roll-tan 699 and Gustaw 2807, and German cold-blooded sires Elbgang 1504 and Bär.

Genetic diversity in five Czech native horse breeds assessed using microsatellite markers

Received: 2018-05-07 | Accepted: 2018-05-14 | Available online: 2018-11-26 https://doi.org/10.15414/afz.2018.21.04.190-193 The aim of the present study was to analyse the genetic diversity of the endangered horse breeds kept in the Czech Republic. A set of 13 microsatellites was used for genotyping 349 Silesian Norikers, 397 Norikers, 552 Czech-Moravian Belgian horses, 271 Old Kladrubers (175 greys, 95 blacks) and 241 Hucul horses. The proportion of obtained heterozygosity indicates no major loss of genetic diversity within analyzed breeds. The Wright’s F ST and genetic distances indicated genetic segregation of both colour varieties of the Old Kladruber breed and small genetic distances between draft horse breeds. Moreover, the membership probability outputs showed that the frequencies of alleles varied across the three main regions. First region is represented by draft horse breeds, second region is represented by Old Kladruber horse and the last is represented by Hucul breed. The study provides data and information utilizable in the management of conservation programs in order to reduce inbreeding and to minimize loss of genetic variability. Keywords : admixture, endangered breeds, horse, loss of genetic diversity References Delgado J.F., De Andres N., Valera M., Gutierrez J.P., Cervantes I. (2014) Assessment of population structure depending on breeding objectives in Spanish Arabian horse by genealogical and molecular information. Livestock Science, 168, 9–16. DOI: https://dx.doi.org/10.1016/j.livsci.2014.07.012 Jombart T., Ahmed I. (2011) adegenet 1.3-1: new tools for the analysis of genome-wide SNP data. Bioinformatics, 27, 3070–3071. DOI: https://dx.doi.org/10.1093/bioinformatics/btr521 Jombart T., Collins C. (2015): A tutorial for diskriminant analysis of principal components (DAPC) using adegenet 2.0.0. MRC Centre for Outbreak Analysis and Modelling. [Online] London: Imperial College London. Available at: http://adegenet.rforge. r-project.org/files/tutorial-dapc.pdf [accessed 20 November 2017]. Kasarda R., Vostry L., Moravcikova N., Vostra-Vydrova H., Dovc P., Kadlecik O. (2016) Detailed insight into genetic diversity of the Old Kladruber horse substructure in comparison to the Lipizzan breed. Acta Agriculturae Scandinavica, Section A – Animal Science, 66, 67–74. DOI: https://dx.doi.org/10.1080/09064702.2016.1249400 Peakall, R. and Smouse P.E. (2012) GenAlEx 6.5: genetic analysis in Excel. Population genetic software for taching and research-an update. Bioinformatics 28, 2537-2539. DOI: https://dx.doi.org/10.1093/bioinformatics/bts460 Szwaczkowski T., Gregula-Kania M., Stachurska A., Borowska A., Jaworski Z., Gruszecki T.M. (2016) Interand intra-genetic diversity in the Polish Konik horse: implications for the conservation program. Canadian Journal of Animal Science, 96 (4), 570–580. DOI: https://dx.doi.org/10.1139/cjas-2015-0173

Identification of loci affecting sexually dimorphic patterns for height and recurrent laryngeal neuropathy risk in American Belgian Draft Horses.

Equine recurrent laryngeal neuropathy (RLN) is a bilateral mononeuropathy with an unknown etiology. In Thoroughbreds (TB), we previously demonstrated that the haplotype association for height (LCORL/NCAPG locus on ECA3, which affects body size) and RLN was coincident. In the present study, we performed a genome-wide association scan (GWAS) for RLN in 458 American Belgian Draft Horses, a breed fixed for the LCORL/NCAPG risk alelle. In this breed, RLN risk is associated with sexually dimorphic differences in height, and we identified a novel locus contributing to height in a sex-specific manner: MYPN (ECA1). Yet this specific locus contributes little to RLN risk, suggesting that other growth traits correlated to height may underlie the correlation to this disease. Controlling for height, we identified a locus on ECA15 contributing to RLN risk specifically in males. These results suggest that loci with sex-specific gene expression play an important role in altering growth traits impacting RLN etiology, but not necessarily adult height. These newly identified genes are promising targets for novel preventative and treatment strategies.

Limbal squamous cell carcinoma in a Rocky Mountain Horse: Case report and investigation of genetic contribution

To document a case of limbal squamous cell carcinoma (SCC) in a Rocky Mountain Horse stallion determined to be homozygous for the genetic risk factor (DDB2 c.1013C>T) strongly associated with the disease in Haflinger and Belgian horses, and to determine the frequency of this allele in a larger population of Rocky Mountain Horses. One privately owned Rocky Mountain Horse and 84 Rocky Mountain Horses screened for allelic frequency. A complete ophthalmic examination was performed on a Rocky Mountain Horse stallion for assessment of a mass affecting the right eye. A clinical diagnosis of suspected limbal SCC was made, and routine keratoconjunctivectomy and adjunctive strontium irradiation were performed. Genotyping for the DDB2 c.1013C > T (rs1139682898) risk variant was performed utilizing an allele-specific PCR assay on DNA isolated from whole blood and hair follicles. Histopathology confirmed the limbal mass to be consistent with SCC. The horse was genotyped as homozygous for the DDB2 c.1013C >T risk variant. The frequency of the variant allele among a population of 84 Rocky Mountain Horses was found to be 0.20. The Rocky Mountain Horse breed possesses the DDB2 variant allele determined to be a significant risk factor for ocular SCC in the Haflinger and Belgian breeds. Genotyping additional Rocky Mountain Horses diagnosed with ocular SCC as well as confirmed healthy controls for this variant should be undertaken to determine whether a significant association exists between ocular SCC and the variant in the Rocky Mountain Horse breed.

Genetic diversity and admixture in three native draught horse breeds assessed using microsatellite markers

In this study, we aimed to estimate and compare genetic diversity of two native draught horse breeds and check the possible influence of Noriker breed population on these native breeds. Genetic analyses of relationships and admixture were performed in two native endangered draught horse populations (Silesian Noriker and Czech-Moravian Belgian horses) and one open breed (Noriker). Totally 104 alleles from 13 microsatellite loci were detected in 1298 horses. The average number of alleles per locus was the highest in the Czech-Moravian Belgian horse (7.62) and the lowest in the Silesian Noriker (7.31), the differences were non-significant, whereas the observed and expected heterozygosities per breed ranged from 0.680 (Czech-Moravian Belgian) to 0.719 (Noriker) and from 0.678 (Silesian Noriker) to 0.714 (Noriker). The estimates of Wright’s F&lt;sub&gt;ST&lt;/sub&gt; between each pair of breeds indicated a low level of genetic segregation. At the individual level across the analyzed population, formation of two clusters was observed with respect to historical breed development. Moreover, the membership probability outputs showed that the frequencies of alleles varied across the two main regions represented by the Czech-Moravian Belgian and other analyzed breeds. Our results indicated high genetic variability, low inbreeding, and low genetic differentiation, especially between Silesian Noriker and Noriker, which is caused by the high level of admixture. This high level of admixture was in accordance with geographical location, history, and breeding practices of the analyzed breeds. The Silesian Noriker and Noriker breeds seem to be the most genetically related and the decision to consider them as the same population is thus highly supported. The study provides data and information utilizable in the management of conservation programs planned to reduce inbreeding and to minimize loss of genetic variability.

Genetic monitoring of horses in the Czech Republic: A large-scale study with a focus on the Czech autochthonous breeds.

We propose the first comprehensive in-depth study monitoring horses in the Czech Republic. We scanned 9,289 animals from 44 populations for 17 equine STRs. Other equids analysed involved Equus przewalskii and Equus asinus. The total of 228 different alleles were detected, with the mean number of 13.4 per locus. The highest allelic richness (AR) was found in the Welsh Part Bred (6.01), followed by the Camargue (5.93) and Czech Sport Pony (5.91), whereas the Friesian exhibited the lowest AR (3.06). Interpopulation differences explained approximately nine per cent of the total genetic diversity. Reynold's genetic distance ranged from 0.003 between the Czech Warmblood and the Slovak Warmblood to 0.404 between the Friesian and donkeys. Close genetic proximity between the Silesian Noriker and Noriker was revealed. The Moravian Warmblood was better differentiated and more distant from the Czech Warmblood than the Kinsky Horse and retained the original genes of the old Austro-Hungarian tribes. A high gene flow level and a lack of genetic structure were found in the seven studied populations. Despite the historical bottlenecks and previous inbreeding, the Czech-Moravian Belgian Horse, Hucul, Old Kladruber Horse and Silesian Noriker did not suffer a serious loss of genetic diversity due to genetic drift/low effective population size. A NeighborNet dendrogram revealed breeds not classified in their groups according to the nomenclature (the Friesian, Hafling and Merens).

MICROSATELLITE DIVERSITY OF CROSSBRED HORSES RAISED IN BOSNIA AND HERZEGOVINA

The focus of this study was microsatellite diversity of crossbred horses raised in Bosnia and Herzegovina. Genomic DNA was extracted from blood samples of 20 individuals (KBA group – 7 individuals, crosses between Bosnian and Herzegovinian mountain horse and Arabian horse; KBR group – 9 individuals, crosses between Bosnian and Herzegovinian mountain and Belgian horses, crosses between Bosnian and Herzegovinian mountain horses and Holstein, crosses between Bosnian and Herzegovinian mountain and Lipizzaner horses and KBN group – 4 individuals, crosses between Bosnian and Herzegovinian mountain horse with an unknown origin of the other parent). The samples were profiled using 17 microsatellite markers. This method consisted of multiplex PCR procedure and generated reasonable amplification across all the loci. All samples were genotyped successfully. Considering all the observed parameters, VHL20 locus showed the highest microsatellite diversity. Locus HMS7 was the least variable in KBR group, while HMS1 locus was the least diverse in KBN group. The highest microsatellite diversity in KBA group was found at AHT5 locus while HTG6 locus was the least diverse. Obtained results suggest that the investigated populations of crossbred horses from Bosnia and Herzegovina are not affected by substantial loss of genetic diversity, as indicated by the presence of reasonably high level of genetic variation. An increase in the inbreeding coefficient and sufficient heterogenity in KBN group indicate occurrence of consanguineous mating. The present research contributes to the knowledge of current status of genetic structure of the investigated crossbred horses.

Horse: anaesthetic management for open castration of a Belgian draught horse with interventricular septum defect, aortic regurgitation and ventricular premature depolarisations

A 2 years and 11 months old Belgian draught horse stallion with a membranous ventricular septal defect, severe aortic regurgitation, mild left ventricular enlargement and ventricular premature depolarisations was anaesthetised...