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Yokomori T, Tozaki T, Ohnuma A, Ishimaru M, Sato F, Hori Y, Segawa T, Itou T. Non-Synonymous Substitutions in Cadherin 13, Solute Carrier Family 6 Member 4, and Monoamine Oxidase A Genes are Associated with Personality Traits in Thoroughbred Horses. Behav Genet 2024; 54:333-341. [PMID: 38856811 DOI: 10.1007/s10519-024-10186-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 05/28/2024] [Indexed: 06/11/2024]
Abstract
Retraining retired racehorses for various purposes can help correct behavioral issues. However, ensuring efficiency and preventing accidents present global challenges. Based on the hypothesis that a simple personality assessment could help address these challenges, the present study aimed to identify genetic markers associated with personality. Eight genes were selected from 18 personality-related candidate genes that are orthologs of human personality genes, and their association with personality was verified based on actual behavior. A total of 169 Thoroughbred horses were assessed for their tractability (questionnaire concerning tractability in 14 types of situations and 3 types of impressions) during the training process. Personality factors were extracted from the data using principal component analysis and analyzed for their association with single nucleotide variants as non-synonymous substitutions in the target genes. Three genes, CDH13, SLC6A4, and MAOA, demonstrated significant associations based on simple linear regression, marking the identification of these genes for the first time as contributors to temperament in Thoroughbred horses. All these genes, as well as the previously identified HTR1A, are involved in the serotonin neurotransmitter system, suggesting that the tractability of horses may be correlated with their social personality. Assessing the genotypes of these genes before retraining is expected to prevent problems in the development of a racehorse's second career and shorten the training period through individual customization of training methods, thereby improving racehorse welfare.
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Affiliation(s)
- Tamu Yokomori
- Department of Preventive Veterinary Medicine and Animal Health, Nihon University Veterinary Research Center, Fujisawa, Kanagawa, Japan
| | - Teruaki Tozaki
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan.
| | - Aoi Ohnuma
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan
| | - Mutsuki Ishimaru
- Japan Racing Association, Hidaka Training and Research Center, Urakawa, Hokkaido, Japan
| | - Fumio Sato
- Japan Racing Association, Hidaka Training and Research Center, Urakawa, Hokkaido, Japan
| | - Yusuke Hori
- Graduate School of Arts and Sciences, Department of Life Sciences, The University of Tokyo, Meguro, Tokyo, Japan
| | - Takao Segawa
- Department of Preventive Veterinary Medicine and Animal Health, Nihon University Veterinary Research Center, Fujisawa, Kanagawa, Japan
| | - Takuya Itou
- Department of Preventive Veterinary Medicine and Animal Health, Nihon University Veterinary Research Center, Fujisawa, Kanagawa, Japan.
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Identification of Personality-Related Candidate Genes in Thoroughbred Racehorses Using a Bioinformatics-Based Approach Involving Functionally Annotated Human Genes. Animals (Basel) 2023; 13:ani13040769. [PMID: 36830556 PMCID: PMC9951868 DOI: 10.3390/ani13040769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 02/07/2023] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
Considering the personality traits of racehorses (e.g., flightiness, anxiety, and affability) is considered essential to improve training efficiency and decrease accident frequency, especially when retraining for a second career that may involve contact with inexperienced personnel after retiring from racing. Studies on human personality-related genes are frequently conducted; however, such studies are rare in horses because a consistent methodology for personality evaluation is lacking. Using the recently published whole genome variant database of 101 Thoroughbred horses, we compared horse genes orthologous to human genes related to the Big Five personality traits, and identified 18 personality-related candidate genes in horses. These genes include 55 variants that involve non-synonymous substitutions that highly impact the encoded protein. Moreover, we evaluated the allele frequencies and functional impact on the proteins in terms of the difference in molecular weights and hydrophobicity levels between reference and altered amino acids. We identified 15 newly discovered genes that may affect equine personality, but their associations with personality are still unclear. Although more studies are required to compare genetic and behavioral information to validate this approach, it may be useful under limited conditions for personality evaluation.
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McBride SD, Roberts K, Hemmings AJ, Ninomiya S, Parker MO. The impulsive horse: comparing genetic, physiological and behavioral indicators to that of human addiction. Physiol Behav 2022; 254:113896. [PMID: 35777460 DOI: 10.1016/j.physbeh.2022.113896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 06/10/2022] [Accepted: 06/27/2022] [Indexed: 11/26/2022]
Abstract
Stress and genotype elicit changes in impulse control in a range of species that are attributable to adaptations in both the central and peripheral nervous system. We examined aspects of this mechanism in the horse by assessing the effect of a dopamine receptor genotype (DRD4) and central dopaminergic tone (measured via spontaneous blink rate [SBR] and behavioral initiation rate [BIR]), on measures of impulsivity, compulsivity (3-choice serial reaction time task) and sympathetic/ parasympathetic system balance (heart rate variability [HRV]). Genotype did not have a significant effect on any of the parameters measured. SBR but not BIR correlated significantly with levels of impulsivity. There was no clear association of HRV parameters with either measures of central dopaminergic activity or impulsivity/compulsivity. Overall, some elements of the data suggest that the horse may be a useful animal model for assessing the genetic and environmental factors that lead to the physiological and behavioral phenotype of human addiction, particularly when considering the relationship between central dopaminergic tone and impulsivity.
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Affiliation(s)
- S D McBride
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3DA
| | - K Roberts
- Royal Agricultural University, Stroud Road, Cirencester, Gloucestershire, GL7 6JS
| | - A J Hemmings
- Royal Agricultural University, Stroud Road, Cirencester, Gloucestershire, GL7 6JS
| | - S Ninomiya
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido Gifu 501-1193, Japan
| | - M O Parker
- School of Pharmacy and Biomedical Science, University of Portsmouth, White Swan Road, Portsmouth, Hampshire, PO1 2DT
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Kis J, Rózsa L, Husvéth F, Zsolnai A, Anton I. Role of genes related to performance and reproduction of Thoroughbreds in training and breeding - A review. Acta Vet Hung 2021; 69:315-323. [PMID: 34739392 DOI: 10.1556/004.2021.00045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 10/01/2021] [Indexed: 11/19/2022]
Abstract
Thoroughbreds have been selected for speed and stamina since the 1700s. This selection resulted in structural and functional system-wide adaptations that enhanced physiological characteristics for outstanding speed of 61-71 kph (38-44 mph) between 1,000 and 3,200 m (5 furlongs - 2 miles). At present, horseracing is still an economically important industrial sector, therefore intensive research is underway to explore genes that allow the utilisation of genetic abilities and are significant in breeding and training. This study aims to provide an overview of genetic research and its applicability related to Thoroughbreds.
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Affiliation(s)
- Judit Kis
- 1Department of Animal Breeding, Institute of Animal Science, Hungarian University of Agriculture and Life Sciences, Kaposvár Campus, Guba Sándor u. 40, H-7400 Kaposvár, Hungary
| | - László Rózsa
- 1Department of Animal Breeding, Institute of Animal Science, Hungarian University of Agriculture and Life Sciences, Kaposvár Campus, Guba Sándor u. 40, H-7400 Kaposvár, Hungary
| | - Ferenc Husvéth
- 2Department of Animal Breeding, Institute of Animal Science, Hungarian University of Agriculture and Life Sciences, Georgikon Campus, Hungary
| | - Attila Zsolnai
- 1Department of Animal Breeding, Institute of Animal Science, Hungarian University of Agriculture and Life Sciences, Kaposvár Campus, Guba Sándor u. 40, H-7400 Kaposvár, Hungary
| | - István Anton
- 1Department of Animal Breeding, Institute of Animal Science, Hungarian University of Agriculture and Life Sciences, Kaposvár Campus, Guba Sándor u. 40, H-7400 Kaposvár, Hungary
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Abstract
Behavior is a valuable quantitative trait in the horse because of its impact on performance, work, recreation, and prerequisite close interactions with humans. This article reviews what is known about the genetics of behavior in horses with an emphasis on the genetic basis for temperament traits, neuroendocrine function, and stereotypic behavior. The importance of using modern molecular genetic techniques to the study of equine behavior and recommendations for future research are also discussed. Ultimately, these studies enhance the understanding of the biology of behavior in the horse, improve handler and rider safety, and benefit horse welfare.
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Sackman JE, Houpt KA. Equine Personality: Association With Breed, Use, and Husbandry Factors. J Equine Vet Sci 2018; 72:47-55. [PMID: 30929783 DOI: 10.1016/j.jevs.2018.10.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 10/09/2018] [Accepted: 10/13/2018] [Indexed: 01/28/2023]
Abstract
Temperament can be defined as innate properties of the nervous system, whereas personality includes the complex behavioral traits acquired through life. Association between personality and behavior is important for breeding, selection, and training of horses. For the first time, we evaluated if equine personality components previously identified in Japan and Europe were consistent when applied to American horses. We examined the association of personality with breed, age, sex, management, training, stereotypies, and misbehaviors. The owner directed personality survey consisted of 25 questions. An online version of the survey was created. The principal component analysis method was used to associate behavioral traits with personality components. Factor analysis with orthogonal transformation was performed on scores for personality-related questions. A total of 847 survey responses were used. Quarter Horses, "other" breed, and Thoroughbred were the most common breeds. Three principal personality components were extracted as each behavioral trait belonged to one of these three components. Arabians, Thoroughbreds, Saddlebreds, and Walking horses were the most nervous and Quarter Horses, and Paints, Appaloosas, and Drafts were the least nervous. No trained discipline was significantly associated with any personality component. There were no significant associations between stereotypies and misbehaviors and nervous or curious personality. For the first time in predominantly American horses, we have evaluated personality components and their association with breed, age, sex, training discipline, and stereotypies. We refute links between personality and trained discipline and confirm the lack of association between nervous personality and stereotypies and misbehaviors.
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Affiliation(s)
- Jill E Sackman
- Exponent, Farmington Hills, MI; Behavior Medicine Service, Blue Pearl Veterinary Partners, Southfield, MI.
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Hori Y, Tozaki T, Nambo Y, Sato F, Ishimaru M, Inoue-Murayama M, Fujita K. Evidence for the effect of serotonin receptor 1A gene (HTR1A
) polymorphism on tractability in Thoroughbred horses. Anim Genet 2015; 47:62-7. [DOI: 10.1111/age.12384] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2015] [Indexed: 11/27/2022]
Affiliation(s)
- Y. Hori
- Department of Psychology; Graduate School of Letters; Kyoto University; Yoshida-honmachi Sakyo Kyoto 606-8501 Japan
- Japan Society for the Promotion of Science; Kojimachi Business Center Building; 5-3-1 Kojimachi Chiyoda-ku Tokyo 102-0083 Japan
| | - T. Tozaki
- Genetic Analysis Department; Laboratory of Racing Chemistry; 1731-2 Tsurutamachi Utsunomiya Tochigi 320-0851 Japan
| | - Y. Nambo
- Department of Clinical Veterinary Science; Obihiro University of Agriculture and Veterinary Medicine; 2-11 Inada-cho Obihiro Hokkaido 080-8555 Japan
| | - F. Sato
- Hidaka Training and Research Center; Japan Racing Association; 535-13 Nishicha Urakawa Hokkaido 057-0171 Japan
| | - M. Ishimaru
- Hidaka Training and Research Center; Japan Racing Association; 535-13 Nishicha Urakawa Hokkaido 057-0171 Japan
| | - M. Inoue-Murayama
- Wildlife Research Center; Kyoto University; 2-24 Tanaka-Sekiden-cho Sakyo Kyoto 606-8203 Japan
- Wildlife Genome Collaborative Research Group; National Institute for Environmental Studies; 16-2 Onogawa Tsukuba Ibaraki 305-8506 Japan
| | - K. Fujita
- Department of Psychology; Graduate School of Letters; Kyoto University; Yoshida-honmachi Sakyo Kyoto 606-8501 Japan
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Hori Y, Ozaki T, Yamada Y, Tozaki T, Kim HS, Takimoto A, Endo M, Manabe N, Inoue-Murayama M, Fujita K. Breed Differences in Dopamine Receptor D4 Gene (DRD4) in Horses. J Equine Sci 2013; 24:31-6. [PMID: 24833999 PMCID: PMC4013985 DOI: 10.1294/jes.24.31] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2013] [Indexed: 11/21/2022] Open
Abstract
Genetic polymorphisms in genes related to neurotransmitters or hormones affect
personality or behavioral traits in many animal species including humans. In domestic
animals, the allele frequency of such genes has been reported to be different among breeds
and it may account for breed differences in behavior. In this study, we investigated breed
differences in horses in the dopamine receptor D4 gene (DRD4), which has been reported to
affect horse personality. We collected samples from seven horse breeds including those
native to Japan and Korea, and compared the sequence of the DRD4 exon3 region among these
breeds. We found that there were two types of polymorphisms (VNTR and SNPs) in the exon3
region, and some of them seemed to be breed-specific. In addition, we found that the
allele frequency of G292A, reported to be associated with horse personality, differed
greatly between native Japanese horses and Thoroughbred horses. The frequency of the A
allele which is associated with low curiosity and high vigilance, was much lower in native
Japanese horses (Hokkaido, 0.03; Taishu, 0.08) than in Thoroughbreds (0.62). This
difference may account for breed differences in personality or behavioral traits. Further
studies of the function of these polymorphisms and their effect on behavior are
indicated.
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Affiliation(s)
- Yusuke Hori
- Department of Psychology, Graduate School of Letters, Kyoto University, Sakyo, Kyoto 606-8501, Japan ; Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Takatoshi Ozaki
- Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan
| | | | - Teruaki Tozaki
- Laboratory of Racing Chemistry, Utsunomiya, Tochigi 320-0851, Japan
| | - Heui-Soo Kim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Pusan 609-735, Korea
| | - Ayaka Takimoto
- Department of Psychology, Graduate School of Letters, Kyoto University, Sakyo, Kyoto 606-8501, Japan ; Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Maiko Endo
- Animal Resource Science Center, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Kasama, Ibaraki 319-0206, Japan
| | - Noboru Manabe
- Animal Resource Science Center, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Kasama, Ibaraki 319-0206, Japan
| | | | - Kazuo Fujita
- Department of Psychology, Graduate School of Letters, Kyoto University, Sakyo, Kyoto 606-8501, Japan
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Yang H, Ma YH, Li B, Dugarjaviin M. [Progress on horse genome project]. YI CHUAN = HEREDITAS 2010; 32:211-8. [PMID: 20233697 DOI: 10.3724/sp.j.1005.2010.00211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
There is unique genetic information belonging to various kinds of living beings. Understanding of the formation process of organisms and a variety of vital movement is associated with the achievements of genome study. As horse has a notable health condition and great record of the genealogy in the world, thus it becomes a valuable model animal for studying life science. Despite of a late start, the map of the horse genome has undergone unprecedented expansion during the last few years. The current progresses of the horse genome, including genetic map, physical map, comparative genomic map, and functional genomics, were reviewed in this paper. The maps are currently used worldwide to discover genes associated with various traits of significance in horse including general health, disease resistance, reproduction, fertility, athletic performance, phenotypic characteristics like coat color, etc. The results are believed to provide new ideas and approaches for prevention, diagnostics, and therapeutic for horses, and also better foundation of breed selection and equine genetic breeding.
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Affiliation(s)
- Hong Yang
- College of Animal Science and Animal Medicine, Inner Mongolia Agricultural University, Hohhot 010018, China.
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Delesalle C, van Acker N, Claes P, Deprez P, de Smet I, Dewulf J, Lefebvre RA. Contractile effects of 5-hydroxytryptamine (5-HT) in the equine jejunum circular muscle: functional and immunohistochemical identification of a 5-HT1A-like receptor. Equine Vet J 2008; 40:313-20. [PMID: 18267888 DOI: 10.2746/042516408x278193] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Prokinetic drugs used to treat gastrointestinal ileus in man have equivocal results in horses. In man, prokinetic drugs have 5-hydroxytryptamine4(5-HT4) receptors as their target, but little is known about the 5-HT-receptor subtypes in the equine small intestine. OBJECTIVE Functional and immunohistochemical identification of the serotonin receptor subtype(s) responsible for the 5-HT induced contractile response in the equine circular jejunum. METHODS Isometric organ-bath recordings were carried out to assess spontaneous and drug-evoked contractile activity of equine circular jejunum. Histological investigations by immunofluorescence analyses were performed to check for presence and localisation of this functionally identified 5-HT receptor subtype. RESULTS Tonic contractions were induced by 5-HT in horse jejunal circular muscle. Tetrodotoxin, atropine and NG-nitro L-arginine did not modify this response. A set of 5-HT receptor subtype selective antagonists excluded interaction with 5-HT1B, 1D, 2A, 3, 4 and 7 receptors. The selective 5-HT1A receptor antagonists WAY 100635 and NAN 190 caused a clear rightward shift of the concentration-response curve to 5-HT. The contractile effect of 5-CT, that can interact with 5-HT1A, 1B, 1D, 5 and 7 receptors was also antagonised by WAY 100635, identifying the targeted 5-HT receptor as a 5-HT1A-like receptor. Immunohistology performed with rabbit polyclonal anti-5-HT1A receptor antibodies confirmed the presence of muscular 5-HT1A receptors in the muscularis mucosae, and both longitudinal and circular smooth muscle layers of the equine jejunum. CONCLUSIONS Contractile responses in equine jejunal circular smooth muscle induced by 5-HT involves 5-HT1A-like receptors.
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Affiliation(s)
- C Delesalle
- Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, Belgium
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Chowdhary BP, Raudsepp T. The horse genome derby: racing from map to whole genome sequence. Chromosome Res 2008; 16:109-27. [PMID: 18274866 DOI: 10.1007/s10577-008-1204-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The map of the horse genome has undergone unprecedented expansion during the past six years. Beginning from a modest collection of approximately 300 mapped markers scattered on the 31 pairs of autosomes and the X chromosome in 2001, today the horse genome is among the best-mapped in domestic animals. Presently, high-resolution linearly ordered gene maps are available for all autosomes as well as the X and the Y chromosome. The approximately 4350 mapped markers distributed over the approximately 2.68 Gbp long equine genome provide on average 1 marker every 620 kb. Among the most remarkable developments in equine genome analysis is the availability of the assembled sequence (EquCab2) of the female horse genome and the generation approximately 1.5 million single nucleotide polymorphisms (SNPs) from diverse breeds. This has triggered the creation of new tools and resources like the 60K SNP-chip and whole genome expression microarrays that hold promise to study the equine genome and transcriptome in ways not previously envisaged. As a result of these developments it is anticipated that, during coming years, the genetics underlying important monogenic traits will be analyzed with improved accuracy and speed. Of larger interest will be the prospects of dissecting the genetic component of various complex/multigenic traits that are of vital significance for equine health and welfare. The number of investigations recently initiated to study a multitude of such traits hold promise for improved diagnostics, prevention and therapeutic approaches for horses.
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Affiliation(s)
- Bhanu P Chowdhary
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77843-4458, USA.
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MOMOZAWA Y, TERADA M, SATO F, KIKUSUI T, TAKEUCHI Y, KUSUNOSE R, MORI Y. Assessing Equine Anxiety-Related Parameters Using an Isolation Test in Combination with a Questionnaire Survey. J Vet Med Sci 2007; 69:945-50. [DOI: 10.1292/jvms.69.945] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
| | - Misao TERADA
- Department of Comparative and Behavioral Medicine, Nippon Veterinary and Life Science University
| | - Fumio SATO
- Equine Research Institute, Japan Racing Association
| | | | | | - Ryo KUSUNOSE
- Equine Research Institute, Japan Racing Association
| | - Yuji MORI
- Laboratory of Veterinary Ethology, The University of Tokyo
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