FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
New Zealand veterinary journal2005; 53(2); 123-132; doi: 10.1080/00480169.2005.36489

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 8. Quantitative back-scattered electron scanning electron microscopy and confocal fluorescence microscopy of the epiphysis of the third metacarpal bone.

Abstract: To characterise and explain the increase in density evident by computerised tomography (CT) and radiography in companion studies as a response to training, in bone in the palmar and dorsal regions of the condyles of the third metacarpal bone (Mc3) of 2-year-old Thoroughbred horses. Methods: Compositional back-scattered electron (BSE) imaging in scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM) were conducted on polymethyl methacrylate (PMMA)-embedded mediolateral slices of the right distal Mc3 from seven 2-year-old Thoroughbred horses trained on a racetrack and seven untrained horses kept at pasture. One left Mc3 from each group was studied in transverse section planes. This study focussed on regions of Mc3 found to differ in density between the trained and untrained horses in companion studies using CT and radiography. Results: The increase of bone density in the condyles of Mc3 in trained horses compared with untrained horses occurred, without prior osteoclastic resorption, via the deposition of new bone on pre-existing internal surfaces. Within prior marrow spaces of cancellous bone, there was also rapid formation of immature strands and fronds of bone which were more cellular and mineralised, and more lamellar bone tissue was deposited on these new scaffolding elements in the trained horses. Both resulted in increased bone volume fraction (BVF). The microscopic mineralisation density of the bulk of the new tissue was lower than in pre-existing bone, and CT and radiography underestimated the increase in BVF. The new tissue was thus probably less stiff at the microscopic scale than pre-existing bone, though its addition would stiffen the global structure. Conclusions: In Mc3 of all the trained horses, there were obvious differences in microscopic structure compared with those from the untrained horses. Moderate, industry-standard levels of exercise used to prepare young horses for racing induced the formation of new bone in non-bone spaces in bone tissue, such that the bone organ should better withstand later increased levels of exercise.
Get Full Text
Publication Date: 2005-04-23 PubMed ID: 15846396DOI: 10.1080/00480169.2005.36489Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Comparative Study
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research sought to understand the reasons behind increased bone density in Thoroughbred horses’ third metacarpal bone (Mc3) after training, observed through previous CT and radiography studies. Methods used included back-scattered electron (BSE) imaging in scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM) performed on bone samples collected from both trained and untrained 2-year-old Thoroughbred horses. The study found that training without prior osteoclastic resorption resulted in increased bone density via new bone deposition on existing internal surfaces.

Methodology

  • The researchers utilized compositional back-scattered electron (BSE) imaging in scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM) to analyze bone samples.
  • The samples were taken from the condyles of the third metacarpal bone (Mc3) of seven trained and seven untrained 2-year-old Thoroughbred horses.
  • These samples were embedded in polymethyl methacrylate (PMMA) and studied in mediolateral and transverse section planes.

Results

  • The training led to increased bone density in the Mc3 bone in trained horses, when compared with untrained ones. This occurred without prior osteoclastic resorption and was instead achieved through the deposition of new bone on pre-existing internal surfaces.
  • New bone rapidly formed in previous marrow spaces of cancellous bone, resulting in immature strands and fronds of bone that were more cellular and mineralized, plus increased lamellar bone tissue deposition.
  • This formation led to an increase in the bone volume fraction (BVF) – the new tissue, though less stiff at the microscopic level than pre-existing bone, would stiffen the overall bone structure.
  • However, CT and radiography underestimated this BVF increase: the microscopic mineralization density of the new bone was lower than in pre-existing bone.

Conclusions

  • The microscopic structure of the Mc3 bone in trained horses significantly differed from that of untrained horses.
  • Training, even at moderate levels, induced the formation of new bone material in the bone tissue, thereby enhancing the bone’s structural strength to withstand increased levels of exercise in the future.

Cite This Article

APA
Boyde A, Firth EC. (2005). Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 8. Quantitative back-scattered electron scanning electron microscopy and confocal fluorescence microscopy of the epiphysis of the third metacarpal bone. N Z Vet J, 53(2), 123-132. https://doi.org/10.1080/00480169.2005.36489

Publication

New Zealand veterinary journal
ISSN: 0048-0169
NlmUniqueID: 0021406
Country: England
Language: English
Volume: 53
Issue: 2
Pages: 123-132

Researcher Affiliations

Boyde, A
  • Biophysics, Centre for Oral Growth and Development, St Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Whitechapel, London E11BB, England.
Firth, E C

    MeSH Terms

    • Animals
    • Bone Density / physiology
    • Epiphyses / anatomy & histology
    • Epiphyses / diagnostic imaging
    • Epiphyses / physiology
    • Epiphyses / ultrastructure
    • Female
    • Horses / anatomy & histology
    • Horses / physiology
    • Metacarpus / anatomy & histology
    • Metacarpus / diagnostic imaging
    • Metacarpus / physiology
    • Metacarpus / ultrastructure
    • Microscopy, Confocal / veterinary
    • Microscopy, Electron, Scanning / veterinary
    • Microscopy, Fluorescence
    • Physical Conditioning, Animal / physiology
    • Reference Values
    • Tomography, X-Ray Computed / veterinary

    Citations

    This article has been cited 29 times.
    1. Noordwijk KJ, Chen L, Ruspi BD, Schurer S, Papa B, Fasanello DC, McDonough SP, Palmer SE, Porter IR, Basran PS, Donnelly E, Reesink HL. Metacarpophalangeal Joint Pathology and Bone Mineral Density Increase with Exercise but Not with Incidence of Proximal Sesamoid Bone Fracture in Thoroughbred Racehorses. Animals (Basel) 2023 Feb 24;13(5).
      doi: 10.3390/ani13050827pubmed: 36899684google scholar: lookup
    2. Pearce DJ, Hitchens PL, Malekipour F, Ayodele B, Lee PVS, Whitton RC. Biomechanical and Microstructural Properties of Subchondral Bone From Three Metacarpophalangeal Joint Sites in Thoroughbred Racehorses. Front Vet Sci 2022;9:923356.
      doi: 10.3389/fvets.2022.923356pubmed: 35847629google scholar: lookup
    3. Palmer AL, Rogers CW, Stafford KJ, Gal A, Bolwell CF. Risk-Factors for Soft-Tissue Injuries, Lacerations and Fractures During Racing in Greyhounds in New Zealand. Front Vet Sci 2021;8:737146.
      doi: 10.3389/fvets.2021.737146pubmed: 34926634google scholar: lookup
    4. Crawford KL, Finnane A, Greer RM, Barnes TS, Phillips CJC, Woldeyohannes SM, Bishop EL, Perkins NR, Ahern BJ. Survival Analysis of Training Methodologies and Other Risk Factors for Musculoskeletal Injury in 2-Year-Old Thoroughbred Racehorses in Queensland, Australia. Front Vet Sci 2021;8:698298.
      doi: 10.3389/fvets.2021.698298pubmed: 34796223google scholar: lookup
    5. Boyde A. The Bone Cartilage Interface and Osteoarthritis. Calcif Tissue Int 2021 Sep;109(3):303-328.
      doi: 10.1007/s00223-021-00866-9pubmed: 34086084google scholar: lookup
    6. Crawford KL, Finnane A, Greer RM, Phillips CJC, Bishop EL, Woldeyohannes SM, Perkins NR, Ahern BJ. A Prospective Study of Training Methods for Two-Year-Old Thoroughbred Racehorses in Queensland, Australia, and Analysis of the Differences in Training Methods between Trainers of Varying Stable Sizes. Animals (Basel) 2021 Mar 25;11(4).
      doi: 10.3390/ani11040928pubmed: 33805873google scholar: lookup
    7. Crawford KL, Finnane A, Phillips CJC, Greer RM, Woldeyohannes SM, Perkins NR, Kidd LJ, Ahern BJ. The Risk Factors for Musculoskeletal Injuries in Thoroughbred Racehorses in Queensland, Australia: How These Vary for Two-Year-Old and Older Horses and with Type of Injury. Animals (Basel) 2021 Jan 21;11(2).
      doi: 10.3390/ani11020270pubmed: 33494508google scholar: lookup
    8. Crawford KL, Finnane A, Greer RM, Phillips CJC, Woldeyohannes SM, Perkins NR, Ahern BJ. Appraising the Welfare of Thoroughbred Racehorses in Training in Queensland, Australia: The Incidence, Risk Factors and Outcomes for Horses after Retirement from Racing. Animals (Basel) 2021 Jan 11;11(1).
      doi: 10.3390/ani11010142pubmed: 33440666google scholar: lookup
    9. Crawford KL, Finnane A, Greer RM, Phillips CJC, Woldeyohannes SM, Perkins NR, Ahern BJ. Appraising the Welfare of Thoroughbred Racehorses in Training in Queensland, Australia: The Incidence and Type of Musculoskeletal Injuries Vary between Two-Year-Old and Older Thoroughbred Racehorses. Animals (Basel) 2020 Nov 5;10(11).
      doi: 10.3390/ani10112046pubmed: 33167429google scholar: lookup
    10. Martig S, Hitchens PL, Stevenson MA, Whitton RC. Subchondral bone morphology in the metacarpus of racehorses in training changes with distance from the articular surface but not with age. J Anat 2018 Jun;232(6):919-930.
      doi: 10.1111/joa.12794pubmed: 29446086google scholar: lookup
    11. Corsi A, Ippolito E, Robey PG, Riminucci M, Boyde A. Bisphosphonate-induced zebra lines in fibrous dysplasia of bone: histo-radiographic correlation in a case of McCune-Albright syndrome. Skeletal Radiol 2017 Oct;46(10):1435-1439.
      doi: 10.1007/s00256-017-2698-2pubmed: 28660402google scholar: lookup
    12. Leitch VD, Di Cosmo C, Liao XH, O'Boy S, Galliford TM, Evans H, Croucher PI, Boyde A, Dumitrescu A, Weiss RE, Refetoff S, Williams GR, Bassett JHD. An Essential Physiological Role for MCT8 in Bone in Male Mice. Endocrinology 2017 Sep 1;158(9):3055-3066.
      doi: 10.1210/en.2017-00399pubmed: 28637283google scholar: lookup
    13. Shaw KA, Dunoski B, Mardis N, Pacicca D. Knee morphometric risk factors for acute anterior cruciate ligament injury in skeletally immature patients. J Child Orthop 2015 Apr;9(2):161-8.
      doi: 10.1007/s11832-015-0652-1pubmed: 25821086google scholar: lookup
    14. Remoli C, Michienzi S, Sacchetti B, Consiglio AD, Cersosimo S, Spica E, Robey PG, Holmbeck K, Cumano A, Boyde A, Davis G, Saggio I, Riminucci M, Bianco P. Osteoblast-specific expression of the fibrous dysplasia (FD)-causing mutation Gsα(R201C) produces a high bone mass phenotype but does not reproduce FD in the mouse. J Bone Miner Res 2015 Jun;30(6):1030-43.
      doi: 10.1002/jbmr.2425pubmed: 25487351google scholar: lookup
    15. Whitton RC, Mirams M, Mackie EJ, Anderson GA, Seeman E. Exercise-induced inhibition of remodelling is focally offset with fatigue fracture in racehorses. Osteoporos Int 2013 Jul;24(7):2043-8.
      doi: 10.1007/s00198-013-2291-zpubmed: 23371360google scholar: lookup
    16. Hamann N, Zaucke F, Dayakli M, Brüggemann GP, Niehoff A. Growth-related structural, biochemical, and mechanical properties of the functional bone-cartilage unit. J Anat 2013 Feb;222(2):248-59.
      doi: 10.1111/joa.12003pubmed: 23083449google scholar: lookup
    17. Eidelman N, Boyde A, Bushby AJ, Howell PG, Sun J, Newbury DE, Miller FW, Robey PG, Rider LG. Microstructure and mineral composition of dystrophic calcification associated with the idiopathic inflammatory myopathies. Arthritis Res Ther 2009;11(5):R159.
      doi: 10.1186/ar2841pubmed: 19857267google scholar: lookup
    18. Muir P, Peterson AL, Sample SJ, Scollay MC, Markel MD, Kalscheur VL. Exercise-induced metacarpophalangeal joint adaptation in the Thoroughbred racehorse. J Anat 2008 Dec;213(6):706-17.
      doi: 10.1111/j.1469-7580.2008.00996.xpubmed: 19094186google scholar: lookup
    19. Bassett JH, Williams AJ, Murphy E, Boyde A, Howell PG, Swinhoe R, Archanco M, Flamant F, Samarut J, Costagliola S, Vassart G, Weiss RE, Refetoff S, Williams GR. A lack of thyroid hormones rather than excess thyrotropin causes abnormal skeletal development in hypothyroidism. Mol Endocrinol 2008 Feb;22(2):501-12.
      doi: 10.1210/me.2007-0221pubmed: 17932107google scholar: lookup
    20. Firth EC. The response of bone, articular cartilage and tendon to exercise in the horse. J Anat 2006 Apr;208(4):513-26.
      doi: 10.1111/j.1469-7580.2006.00547.xpubmed: 16637875google scholar: lookup
    21. Boyde A, Firth EC. Articular calcified cartilage canals in the third metacarpal bone of 2-year-old thoroughbred racehorses. J Anat 2004 Dec;205(6):491-500.
      doi: 10.1111/j.0021-8782.2004.00354.xpubmed: 15610396google scholar: lookup
    22. Pan M, Malekipour F, Pivonka P, Morrice-West AV, Flegg JA, Whitton RC, Hitchens PL. A mathematical model of metacarpal subchondral bone adaptation, microdamage and repair in racehorses. J R Soc Interface 2025 Oct;22(231):20250297.
      doi: 10.1098/rsif.2025.0297pubmed: 41027486google scholar: lookup
    23. Ciamillo SA, Bills KW, Gassert TM, Richardson DW, Brown KA, Stefanovski D, Ortved KF. Effect of high-speed exercise on subchondral bone in the metacarpo-/metatarsophalangeal joints of 2-year-old Thoroughbred racehorses in their first year of training. Equine Vet J 2026 Jan;58(1):40-48.
      doi: 10.1111/evj.14524pubmed: 40323137google scholar: lookup
    24. Malekipour F, Whitton RC, Lee PV. Advancements in Subchondral Bone Biomechanics: Insights from Computed Tomography and Micro-Computed Tomography Imaging in Equine Models. Curr Osteoporos Rep 2024 Dec;22(6):544-552.
      doi: 10.1007/s11914-024-00886-ypubmed: 39276168google scholar: lookup
    25. Irandoust S, O'Neil LM, Stevenson CM, Franseen FM, Ramzan PHL, Powell SE, Brounts SH, Loeber SJ, Ergun DL, Whitton RC, Henak CR, Muir P. Comparison of radiography and computed tomography for identification of third metacarpal structural change and associated assessment of condylar stress fracture risk in Thoroughbred racehorses. Equine Vet J 2025 May;57(3):723-736.
      doi: 10.1111/evj.14131pubmed: 39143731google scholar: lookup
    26. Hewitt-Dedman CL, Kershaw LE, Schwarz T, Del-Pozo J, Duncan J, Daniel CR, Cillán-García E, Pressanto MC, Taylor SE. Preliminary study of proton magnetic resonance spectroscopy to assess bone marrow adiposity in the third metacarpus or metatarsus in Thoroughbred racehorses. Equine Vet J 2025 Mar;57(2):471-479.
      doi: 10.1111/evj.14086pubmed: 38699829google scholar: lookup
    27. Bergstrom TC, Spriet M, Carpenter RS, Jacques KL, Stover SM. Condylar fracture location is correlated to exercise history in Thoroughbred racehorses. Equine Vet J 2025 Jan;57(1):76-86.
      doi: 10.1111/evj.14091pubmed: 38584321google scholar: lookup
    28. Costa da Silva RG, Sun TC, Mishra AP, Boyde A, Doube M, Riggs CM. Intracortical remodelling increases in highly loaded bone after exercise cessation. J Anat 2024 Mar;244(3):424-437.
      doi: 10.1111/joa.13969pubmed: 37953410google scholar: lookup
    29. Wong ASM, Morrice-West AV, Hitchens PL, Whitton RC. The association between Thoroughbred racehorse training practices and musculoskeletal injuries in Victoria, Australia. Front Vet Sci 2023;10:1260554.
      doi: 10.3389/fvets.2023.1260554pubmed: 37941814google scholar: lookup
    Subscribe to our newsletter
    Join 99,727 horse owners like you who receive our email updates on horse health and nutrition.