• Asian-Australasian Journal of Animal Sciences
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• v.19 no.6
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• pp.784-788
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• 2006

Microsatellite polymorphism and the genetic relationship were estimated using genotype information of 305 horses from 11 microsatellite loci. The breeds include the indigenous Korean breeds, Korean native horse (102) and Jeju racing horse (56) together with Japan Hokkaido horse (5), Mongolian horse (19), Thoroughbred horse (108), Quarter horse (11) and Przewalskii horse (4). Allelic frequencies, the number of alleles per locus were estimated by direct counting from observed genotype, and genetic variability was computed using the CERVUX software and DISPAN. The number of alleles per locus varied from 6 (HMS6) to 18 (ASB17) with an average value of 10.45 in horse breeds. The expected total heterozygosity ($H_T$) and coefficient of gene differentiation ($G_{ST}$) ranged 0.764-0.921 (the average value was 0.830) and 0.102-0.266 (the average value was 0.180) in horse breeds, respectively. Four populations (Przewalskii horse, Japan Hokkaido horse, Quarter horse, Thoroughbred horse) showed lower heterozygosity than the average value (the average value was 0.710). The expected heterozygosity within breed ($H_S$) and mean no. of observed alleles ranged from $0.636{\pm}0.064$ (Japan Hokkaido horse) to $0.809{\pm}0.019$ (Mongolian horse), and from 2.73 (Przewalskii horse) to 8.27 (Korean native horse), respectively. The polymorphic information content (PIC) ranged from 0.490 (Przewalskii horse) to 0.761 (Mongolian horse) with an average value of 0.637 in horse breeds. The results showed three distinct clusters with high bootstrap support: the Korean native horse cluster (Korean native horse, Mongolian horse), the European cluster (Przewalskii horse, Thoroughbred horse), and other horse cluster (Jeju racing horse, Japan Hokkaido horse, and Quarter horse). A relatively high bootstrap value was observed for the Korean native horse cluster and European cluster (87%), and the Korean native horse and Mongolian horse (82%). Microsatellite polymorphism data were shown to be useful for estimating the genetic relationship between Korean native horse and other horse breeds, and also be applied for parentage testing in those horse breeds.

• Korean Journal of Veterinary Research
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• v.40 no.4
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• pp.683-689
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• 2000

The present study was carried out to investigate the blood markers of Thoroughbred horses (TB) The blood red cell types and blood protein types (biochemical polymorphisms) were tested from 1,125 Thoroughbred horses by serological and electrophoretic procedures, and their phenotypes, gene frequencies, heterozygosity, polymorphic information content values and exclusion probability were estimated. The blood group and biochemical polymorphism phenotypes observed with high frequency were Aaf(91.7%), Ca(94.7%), K-(94.5%), Ua(75.9%), P-(50.6%), Qabc(82.6%), ALB-BB(67.7%), GC-FF(92.7%), AIB-KK(99.6%), ES-II(77.9%), TF-DF1(23.6%), PI-LL(23.2%), HB-B2B2(73.6%), PGD-FS(45.4%) and genotypes Dcgm/dk(16.9%), Dbcm/cgm(13.6%), Dbcm/dk(11.9%), Dcegmn/cegmn(10.0%), Dcgm/cgm(8.7%) in TB. Alleles observed with high frequency were Aaf(0.796), Ca(0.769), Ddk(0.266), Dcgm(0.261), Dbcm(0.211), K-(0.972), P-(0.710), Qabc(0.565), Q-(0.368), Ua(0.509), $HB^{B2}$(0.858), $PGD^F$(0.634), $ALB^B$(0.825), $GC^F$(0.927), $AIB^K$(0.998), $ES^I$(0.881), $TF^{F1}$(0.346), $TF^D$(0.319), $TF^{F2}$(0.184), $PI^L$(0.479), $PI^N$(0.214), $PI^U$(0.116) in TB. The heterozygosity, polymorphic information content (PIC) and exclusion probability (PE) were calculated. The mean heterozygosity and PIC value were 0.3899 and 0.3375, respectively. The highest heterozygosity and PIC were estimated 0.7834 and 0.7492 in blood group D locus, respectively. The cumulated PE obtained by blood groups and biochemical polymorphisms was 0.9813.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1110-1118
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• 2018

Objective: This study was intended to identify genes positively selected in Thoroughbred horses (THBs) that potentially contribute to their running performances. Methods: The genomes of THB and Jeju horses (JH, Korean native horse) were compared to identify genes positively selected in THB. We performed cross-population extended haplotype homozygosity (XP-EHH) and cross-population composite likelihood ratio test (XP-CLR) statistical methods for our analysis using whole genome resequencing data of 14 THB and 6 JH. Results: We identified 98 (XP-EHH) and 200 (XP-CLR) genes that are under positive selection in THB. Gene enrichment analysis identified 72 gene ontology biological process (GO BP) terms. The genes and GO BP terms explained some of THB's characteristics such as immunity, energy metabolism and eye size and function related to running performances. GO BP terms that play key roles in several cell signaling mechanisms, which affected ocular size and visual functions were identified. GO BP term Eye photoreceptor cell differentiation is among the terms annotated presumed to affect eye size. Conclusion: Our analysis revealed some positively selected candidate genes in THB related to their racing performances. The genes detected are related to the immunity, ocular size and function, and energy metabolism.

• Journal of Veterinary Clinics
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• v.31 no.5
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• pp.461-465
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• 2014

A 3-year-old colt Thoroughbred horse was referred with obvious lameness (3/5G) and mild heat and pain on left hoof of forelimb. He was diagnosed with quarter cracks that have a typical conformation of sheared heel, which are a different length and height between medial/lateral heels. Various materials and techniques were carried out to repair quarter cracks by using many different kinds of clips, bar shoes on fifth times for about 10 months. It worked on him without pain and heat on the cracked hoof, and then he could retrain for racing from the 36th weeks beginning of therapeutic shoeing. We suggested that especially fiberglass reinforced plastic (FRP) material and therapeutic shoeing were a great help to treat quarter cracks induced by sheared heel.

• Journal of Veterinary Clinics
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• v.35 no.3
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• pp.107-110
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• 2018

A 5-year-old Thoroughbred race horse was presented to Busan Korea Racing Authority equine hospital with a 3-year history of a slow-growing left rostral maxillary mass. The location and progressive growth of the mass eventually resulted in poor food prehension, quidding and mouth bit placement. The mass was solitary and hard, and covered by normal smooth oral mucosa. Radiographic examination of the maxillae showed a flocculated and mixed radiolucent lesion protruding outward and displacing the 202 and 203 teeth caudally. The 202 tooth was in normal size and the 203 tooth was hypoplastic on radiography. Under general anesthesia, a partial surgical resection of the mass was performed to minimize functional loss and facilitate prompt return to track. After surgery, there was improvement in food intake, mouth bit placement, and cosmetic appearance. Histopathological examination determined the resected maxillay mass to be an ossifying fibroma. However, there was continued growth of remnant mass in the maxilla. Equine ossifying fibroma is a rare condition and primarily affects the rostral mandible, and less commonly, the maxillae. In this case, the lesion was slow-growing, and caused cosmetic and functional impairments, including poor food intake and reduced trainability. Surgical resection was performed, but the effect of treatment was limited due to advanced size / stage of the tumor. Early dental care is suggested for horse owners to prevent belated identification and improve successful treatment of oral disorders like ossifying fibroma.

• Journal of Life Science
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• v.18 no.1
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• pp.69-74
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• 2008

This study carried out to investigate the antimicrobial resistance and biochemical characteristics of Staphylococcus aureus (S. aureus) isolated from reproductive and respiratory tract in Thoroughbred horse. The specimens were collected from equine vaginal mucosa and upper respiratory tract from March to December 2006 using a culture swab in Korea. S. aureus suspected colonies on blood agar plates were selected and identified as standard biochemical tests and PCR (Applied Biosystems, USA). Antimicrobial resistance test of S. aureus isolates was performed with 30 antimicrobial agents (BBL, USA) by using the agar disk diffusion method. S. aureus isolates were isolated 58 (39.2%) strains of 148 samples: wound 64.7% (11/17), genital discharge 37.0% (37/100) and nasal discharge 32.2% (10/31). Almost isolates showed high resistance to spectinomycin, sulfonamides, erythromycin, tetracyelin, ciprofloxacin and penicillin. These results may provide the basic information to establish strategies for treatment and prevention of reproductive and respiratory disease in Thoroughbred horses in Korea.

• Animal Bioscience
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• v.34 no.9
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• pp.1460-1465
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• 2021

Objective: The study aimed to evaluate the diversity of donkey populations by comparing with the diversity of Thoroughbred and Jeju Halla horses; identified breeding backgrounds can contribute to management and conservation of donkeys in South Korea. Methods: A total of 100 horse (50 Thoroughbreds and 50 Jeju Halla horses) and 79 donkeys samples were genotyped with 15 microsatellite markers (AHT4, AHT5, ASB2, ASB17, ASB23, CA425, HMS1, HMS2, HMS3, HMS6, HMS7, HTG4, HTG10, LEX3, and VHL20), to identify genetic diversity and relationships among horses and donkeys. Results: The observed number of alleles per locus ranged from 1 (ASB17, HMS1) to 14 (AHT5), with a mean value of 4.87, 8.00, and 5.87 in Thoroughbreds, Jeju Halla horses, and donkeys, respectively. Of the 15 markers, AHT4, AHT5, ASB23, CA425, HMS2, HMS3, HTG4, HTG10, and LEX3 loci had relatively high polymorphism information content (PIC) values (PIC>0.5) in these three populations. Mean levels of genetic variation were H_E = 0.6721 and H_O = 0.6600 in Thoroughbreds, H_E = 0.7898 and H_O = 0.7100 in Jeju Halla horses, and H_E = 0.5635 and H_O = 0.4861 in donkeys. Of the 15 loci in donkeys, three loci had negative inbreeding coefficients (FIS), with a moderate mean FIS (0.138). The FIS estimate for the HTG4 marker was highest (0.531) and HMS6 marker was lowest (-0.001). The total probability of exclusion value of 15 microsatellite loci was 0.9996 in donkeys. Conclusion: Genetic cluster analysis showed that the genetic relationship among 79 donkeys was generally consistent with pedigree records. Among the three breeds, donkeys and Thoroughbred horses formed clearly different groups, but the group of Jeju Halla horses overlapped with that of Thoroughbred horses, suggesting that the loci would be suitable for donkey parentage testing. Therefore, the results of this study are a valid tool for genetic study and conservation of donkeys.

• Journal of Veterinary Science
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• v.23 no.2
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• pp.19.1-19.9
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• 2022

Background: Gastric ulcer is one of the prevalent diseases in racehorses. However, it has not been recognized as important in Korea, and drugs used to treat gastric ulcers are included in the doping test list, so they are not allowed to be administered to racehorses in training. Objectives: This study was performed 1) to investigate the prevalence and the severity of gastric ulcers in Thoroughbred racehorses in Korea, 2) to confirm the therapeutic effect of ranitidine and omeprazole, and 3) to compare the efficacy between ranitidine and omeprazole. Methods: Forty-nine horses were randomly recruited, and gastroscopy was performed within two days after racing. Twelve horses with a sum grade of five or higher were randomly assigned to two treatment groups. Seven horses were administered ranitidine, and five horses were administered omeprazole. Follow-up gastroscopy was scheduled within one to five days after finishing the treatment. Results: The prevalence of gastric ulcer in Korean Thoroughbred racehorses after racing was 100%, and the grade was more severe in the non-glandular region than in the pyloric region. There was no correlation between the severity of gastric ulcer in the two regions. Omeprazole had a greater therapeutic effect than ranitidine. Conclusions: This study shows the importance of recognizing gastric ulcers as an important factor, and omeprazole as a possible treatment option in Korea, as it has been removed from the list of prohibited substances for racehorses. Thus, the use of omeprazole is currently recommended until one day before the race.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.9
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• pp.1345-1354
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• 2014

Copy number variations (CNVs), important genetic factors for study of human diseases, may have as large of an effect on phenotype as do single nucleotide polymorphisms. Indeed, it is widely accepted that CNVs are associated with differential disease susceptibility. However, the relationships between CNVs and gene expression have not been characterized in the horse. In this study, we investigated the effects of copy number deletion in the blood and muscle transcriptomes of Thoroughbred racing horses. We identified a total of 1,246 CNVs of deletion polymorphisms using DNA re-sequencing data from 18 Thoroughbred racing horses. To discover the tendencies between CNV status and gene expression levels, we extracted CNVs of four Thoroughbred racing horses of which RNA sequencing was available. We found that 252 pairs of CNVs and genes were associated in the four horse samples. We did not observe a clear and consistent relationship between the deletion status of CNVs and gene expression levels before and after exercise in blood and muscle. However, we found some pairs of CNVs and associated genes that indicated relationships with gene expression levels: a positive relationship with genes responsible for membrane structure or cytoskeleton and a negative relationship with genes involved in disease. This study will lead to conceptual advances in understanding the relationship between CNVs and global gene expression in the horse.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.763-774
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• 2016

Equine gastric ulcer syndrome is one of the most frequently reported diseases in thoroughbred racehorses. Although several risk factors for the development of gastric ulcers have been widely studied, investigation of microbiological factors has been limited. In this study, the presence of Helicobacter spp. and the gastric microbial communities of thoroughbred racehorses having mild to severe gastric ulcers were investigated. Although Helicobacter spp. were not detected using culture and PCR techniques from 52 gastric biopsies and 52 fecal samples, the genomic sequences of H. pylori and H. ganmani were detected using nextgeneration sequencing techniques from 2 out of 10 representative gastric samples. The gastric microbiota of horses was mainly composed of Firmicutes (50.0%), Proteobacteria (18.7%), Bacteroidetes (14.4%), and Actinobacteria (9.7%), but the proportion of each phylum varied among samples. There was no major difference in microbial composition among samples having mild to severe gastric ulcers. Using phylogenetic analysis, three distinct clusters were observed, and one cluster differed from the other two clusters in the frequency of feeding, amount of water consumption, and type of bedding. To the best of our knowledge, this is the first study to investigate the gastric microbiota of thoroughbred racehorses having gastric ulcer and to evaluate the microbial diversity in relation to the severity of gastric ulcer and management factors. This study is important for further exploration of the gastric microbiota in racehorses and is ultimately applicable to improving animal and human health.