Young horses are generally defined as those under five years of age, transitioning from foals to adults. Research in this area examines the study of equine development, behavior, and health across different life stages. This includes the physiological and anatomical changes that occur as horses mature from foals into adults. Additionally, understanding behavioral aspects such as socialization, learning, and adaptation to training is key to this field. This page gathers peer-reviewed research studies and scholarly articles that explore the developmental processes, health considerations, and management practices relevant to young horses and their transition into adulthood.
Robert C, Valette JP, Jacquet S, Denoix JM.The relationship between osteoarticular status and future athletic capacity is commonly accepted in equine practice, but there is little to support this belief in Thoroughbreds. The objective of this study was to assess the prevalence of juvenile osteochondral conditions (JOCC) in Thoroughbred yearlings and to investigate the significance of these with regard to subsequent racing performance. The radiographic files from 328 Thoroughbred yearlings born in Normandy were assessed in a consistent manner and entered into a database together with racing records. Logistic regression models were used ...
van Weeren PR, Denoix JM.Juvenile osteochondral conditions (JOCC) have a major impact on the equine industry and include many musculoskeletal disorders of the young horse, of which osteochondrosis (OC) is the most prominent. The Breeding, Osteochondral Status and Athletic Career (BOSAC) project is the first large, comprehensive, longitudinal field study on the subject conducted in three breeds of performance horses (Thoroughbreds, Standardbred Trotters and Warmbloods) that were monitored in their natural environment where they were reared under common field conditions. The BOSAC study used a radiographic protocol desi...
Jönsson L, Roepstorff L, Egenvall A, Näsholm A, Dalin G, Philipsson J.Soundness of an individual horse is important for animal welfare and owner economy. However, knowledge of health status in normal horse populations is limited due to lack of systematic health recordings. The aim of the investigation was to study the prevalence of veterinary clinical findings in 4-5-year-old Swedish warmblood riding horses, and their influence on overall health scores, where associations to future longevity has been indicated. Results: The prevalence of clinical findings in 8,281 horses examined during 1983-2005 was studied according to a standardised protocol and related to ov...
Tallmadge RL, Tseng CT, King RA, Felippe MJ.Humoral immunity is a critical component of the immune system that is established during fetal life and expands upon exposure to pathogens. The extensive humoral immune response repertoire is generated in large part via immunoglobulin (Ig) heavy chain variable region diversity. The horse is a useful model to study the development of humoral diversity because the placenta does not transfer maternal antibodies; therefore, Igs detected in the fetus and pre-suckle neonate were generated in utero. The goal of this study was to compare the equine fetal Ig VDJ repertoire to that of neonatal, foal, an...
Kim W, McArdle BH, Kawcak CE, McIlwraith CW, Firth EC, Broom ND.To investigate histomorphometric changes in the cartilage and subchondral bone of the third carpal bone associated with conditioning exercise in young Thoroughbreds. Methods: Nine 18-month-old Thoroughbreds. Procedures-Both third carpal bones of 9 horses (4 exercised spontaneously at pasture only and 5 given additional conditioning exercise beginning at a mean age of 3 weeks) were evaluated. Histomorphometric variables (hyaline and calcified cartilage thickness and collagen orientation; vascular channel area, number, and orientation; and osteochondral junction rugosity) of the third carpal bon...
Lucia JL, Coverdale JA, Arnold CE, Winsco KN.Nineteen weanling Quarter Horses (225 to 380 kg) were used in a randomized complete block design to investigate the effects of intra-articular lipopolysaccharide (LPS) to induce acute joint inflammation in young horses. Horses were blocked by age, BW, and sex and were randomly assigned to 1 of 3 treatments for a 35-d experiment. Treatments included intra-articular injection of 0.25 ng (n = 7) or 0.50 ng (n = 6) of LPS obtained from Escherichia coli O55:B5 or sterile lactated Ringer's solution (n = 6; control) into the radial carpal joint. Synovial fluid was obtained at preinjection h 0 and 2, ...
Readford PK, Lester GD, Secombe CJ.Two cases of temporohyoid osteoarthropathy (THO) in young Australian horses are described. The pathogenesis of THO is yet to be fully elucidated, but current theories include extension of infection from otitis media or interna to the temporohyoid joint or a primary but non-infectious degenerative condition within the temporohyoid joint. The young age of the horses and the unilateral distribution suggested an infectious aetiology. Both horses partially responded to treatment with broad-spectrum antimicrobial and anti-inflammatory drugs with concurrent management of ulcerative keratitis. The man...
Hoffman CJ, Clark CK.Cervical vertebral malformation (CVM) is seen in young, rapidly growing horses, and is commonly associated with a poor prognosis for racing. Objective: To examine the records of a population of Thoroughbreds with a presumptive diagnosis of CVM and to determine which radiographic findings and neurologic exam findings have an effect on these horses achieving athletic function when managed conservatively. Methods: One hundred and three thoroughbreds presumptively diagnosed with CVM and treated conservatively between 2002 and 2010. Methods: Racing records were reviewed in this retrospective study ...
Jönsson L, Näsholm A, Roepstorff L, Egenvall A, Dalin G, Philipsson J.Soundness is important for welfare and utility of the riding horse. Musculoskeletal disorders are the most common causes of interruption in training and of culling. Despite great importance, heritability of a majority of health traits in horses has previously not been estimated. The objective was to perform genetic analyses of medical and orthopaedic health traits in young riding horses, including estimates of heritability and genetic correlations between health traits, and to reveal possibilities for genetic evaluation of stallions for progeny health. Results: The heritability of health trait...
Earing JE, Lawrence LM, Hayes SH, Brummer M, Vanzant E.The ability of young and mature horses to digest DM, OM, and NDF was compared using 6 weanling colts and 6 mature (13.2 ± 3.0 yr) geldings. Each colt was paired with a gelding, and the pair was adapted to a diet containing 67% alfalfa cubes and 33% concentrate for 21 d. During the adaptation period, horses were accustomed to housing and all handling procedures. The adaptation period was also used to adjust the amount of feed offered to minimize orts and to maintain similar rates of intake within a pair. After the adaptation period, a 5-d fecal collection period using fecal collection harnesse...
Gray SM, Bartell PA, Staniar WB.Growth hormone is a key component of the somatotropic axis and is critical for the interplay between nutrition, regulation of metabolic functions, and subsequent processes of growth. The objective of this study was to investigate potential relations between meal feeding concentrates differing in the glycemic responses they elicit and GH secretory patterns in young growing horses. Twelve Quarter Horse weanlings (5.4 ± 0.4 mo of age) were used in a crossover design, consisting of two 21-d periods and two treatments, a high-glycemic (HG) or low-glycemic (LG) concentrate meal, fed twice daily. Ho...
Greene DA, Naughton GA, Jander CB, Cullen SJ.Our aim was to use Peripheral Quantitative Computed Tomography (pQCT) to assess the bone health of male and female apprentice jockeys and age- and sex-matched peers. 2 groups of 25 young adults (n=50) (age range 15-38 years) were comprised of male and female apprentice jockeys, and male and female controls. We used pQCT to measure the distal tibia and distal radius. After covarying for weight and limb length, apprentice jockeys displayed less tibial cortical area and lower strength strain index at 14% distal shaft, 38% mid shaft and 66% proximal sites measured distally than controls (p=0.001)....
Reed SR, Jackson BF, Wood JL, Price JS, Verheyen KL.The aim of this study was to identify exercise-related risk factors for carpal and metacarpo- and metatarso-phalangeal (MCP/MTP) joint injury occurrence in young Thoroughbreds in flat race training. In a 2-year prospective cohort study, daily exercise and joint injury data were collected from horses in 13 training yards in England. Four injury categories were defined: (1) localised to a carpal or MCP/MTP joint based on clinical examination and/or use of diagnostic analgesia with no diagnostic imaging performed; (2) localised to a carpal or MCP/MTP joint with no abnormalities detected on diagno...
Rogers CW, Bolwell CF, Gee EK.Across many equestrian disciplines the median competition career of a horse is relatively short. One of the major reasons for short career length is musculoskeletal injury and a consistent variable is the trainer effect. There are significant opportunities within equestrian sport for a holistic approach to horse health to attenuate musculoskeletal injury. Proactive integration of care by health professionals could provide a mechanism to attenuate injury risk and the trainer effect. However, the limited data available on current exercise regimens for sport horses restricts interpretation of how...
Lucidi P, Bacco G, Sticco M, Mazzoleni G, Benvenuti M, Bernabò N, Trentini R.The conflicting results regarding the study of motor laterality in horses may indicate that there does not exist a proper method to assess the degree and the direction of motor bias in these animals. Unfortunately, even less is known about the development of laterality in horses, and to what extent early manipulations can still exert their effects in adulthood. We propose a new method that can be easily applied at a very early age thus avoiding testing adult horses eventually biased by human handling and/or training. Forty-six horses (29 nine-month-old foals and 17 two-year old horses) were ha...
Preston SA, Brown MP, Chmielewski TL, Trumble TN, Zimmel DN, Hernandez JA.To determine the effects of yearling sale purchase price, exercise history, lameness, and athletic performance (speed) on purchase price of 2-year-old in-training Thoroughbreds and to compare the distance exercised within 60 days prior to 2-year-old in-training sales between horses with high yearling sale purchase prices versus those with low yearling sale purchase prices and between horses with lameness during training and those without lameness during training. Methods: Prospective study. Methods: 51 Thoroughbreds. Methods: Thoroughbreds purchased at a yearling sale were trained prior to res...
Preston SA, Brown MP, Trumble TN, Chmielewski TL, Zimmel DN, Hernandez JA.To determine the effects of various presale radiographic findings for Thoroughbreds sold at a yearling sale on 2-year-old racing performance of those horses. Methods: 397 Thoroughbreds. Methods: Cohort study. Methods: Thoroughbreds offered for sale at a Thoroughbred sales facility in Kentucky were selected via a randomization procedure. Effects of various presale radiographic findings on the following measures of 2-year-old racing performance were determined: having started a race and having placed (ie, finished in first, second, or third place) in a race at least once, total amount of money e...
Finno CJ, Famula T, Aleman M, Higgins RJ, Madigan JE, Bannasch DL.Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (NAD/EDM) is a neurodegenerative disorder affecting young horses of various breeds that resembles ataxia with vitamin E deficiency in humans, an inherited disorder caused by mutations in the alpha-tocopherol transfer protein gene (TTPA). To evaluate variants found upon sequencing TTPA in the horse, the mode of inheritance for NAD/EDM had to be established. Objective: NAD/EDM in the American Quarter Horse (QH) is caused by a mutation in TTPA. Methods: 88 clinically phenotyped (35 affected [ataxia score ≥2], 53 unaffected) QH...
Vander Heyden L, Lejeune JP, Caudron I, Detilleux J, Sandersen C, Chavatte P, Paris J, Deliège B, Serteyn D.Osteochondrosis (OC) is the most common developmental orthopaedic disease in horses and represents a major problem to the horse industry. The complete mechanism of this multifactorial disease is not yet elucidated, but it is accepted that OC lesions are the result of intrinsic genetic and external factors. The aim of the present work was to evaluate the relationship between breeding management and OC. Breeding conditions were recorded, and a radiological examination was performed in 223 foals. Feeding practice and housing management were analysed in a multivariate model to determine risk facto...
Hauspie S, Forsyth R, Vanderperren K, Declercq J, Martens A, Saunders JH.The objective of this study is to describe the normal histological appearance of the dorsoproximal aspect of the sagittal ridge of the third metacarpal/metatarsal bone in young Warmblood horses, and to compare it to the different radiographic variations (irregular, indentation, lucency, notch) described at this level. A total of 25 metacarpo/metatarsophalangeal joints of 12 Warmblood horses were used. Five samples of each radiographically described group were selected for histological processing. Each category was compared with the normal control group. Each group showed a bone cortex, covered...
Haberland AM, König von Borstel U, Simianer H, König S.Reliable selection criteria are required for young riding horses to increase genetic gain by increasing accuracy of selection and decreasing generation intervals. In this study, selection strategies incorporating genomic breeding values (GEBVs) were evaluated. Relevant stages of selection in sport horse breeding programs were analyzed by applying selection index theory. Results in terms of accuracies of indices (r(TI) ) and relative selection response indicated that information on single nucleotide polymorphism (SNP) genotypes considerably increases the accuracy of breeding values estimated fo...
Christensen JW.The ability of horses to habituate to novel objects influences safety in the horse-human relationship. However, the effectiveness of different habituation techniques has not been investigated in detail. Objective: 1) To investigate whether horses show increased stress responses when negatively reinforced to approach novel objects, compared with horses allowed to voluntarily explore the objects and 2) whether a negatively reinforced approach facilitates object habituation. Methods: Twenty-two 2-3-year-old Danish Warmblood geldings were included. Half of the horses (NR group) were negatively rei...
Laurent R, Uhring J, Bentahar M, Constantinou B, de Billy B, Langlais J.Children increasingly participate in horseback riding, especially young girls, with more and more accidents during this activity. The severity of the injuries caused by horses seems to be higher than in other sports. Methods: In a retrospective study, we reviewed 303 accidents of children younger than 15 years of age during the past 13 years. Our study only investigated children who were hospitalized after their accident. Results: Eighty-two percent of the injured children were girls, but there was no difference between girls and boys in terms of severity. In most cases, children were hurt by ...
Walker VA, Walters JM, Griffith L, Murray RC.A recent epidemiological study indicated that various factors may be related to injury in dressage horses, but the mechanism by which these injuries occur has yet to be determined. The suspensory ligament (SL) is a frequent site of injury, and it is assumed that greatest strain is placed on this structure in collected trot; this has yet to be proved conclusively. The study aimed to investigate the effect of collected and extended trot on the hindlimb movement pattern. Four dressage horses were fitted with markers and inertial motion sensors (IMS). High-speed video was obtained for 2 strides on...
Wagner AL, Urschel KL.To determine whether feeding-induced activation of translation initiation factors, specifically protein kinase B, ribosomal protein S6 kinase (S6K1), ribosomal protein S6 (rpS6), and eukaryotic initiation factor 4E binding protein 1, in horses is affected by age. Methods: 6 yearlings, six 2-year-old horses, and 6 mature horses. Methods: After an 18-hour period of feed withholding, horses consumed a high-protein meal (2 g/kg) at time 0 and 30 minutes (postprandial state) or continued to have feed withheld (postabsorptive state). Blood samples were collected for the duration of the experimental ...
Townsend WM, Wasserman N, Jacobi S.Intraocular lenses (IOLs) have been implanted in adult equine eyes after cataract surgery. Foals and weanlings comprise a large proportion of those horses undergoing cataract surgery. Due to potential differences in the size and corneal curvature of the juvenile eye, it is not currently known whether implantation of adult IOLs is appropriate in foals and weanlings. The objective of the study was to measure the anterior chamber depth (ACD), central lens thickness (CLT), vitreous chamber depth (VCD), axial globe length (AGL) and corneal curvature of horses less than one year of age. The axial di...
Ralston SL.Equine teaching and research programs are popular but expensive components of most land grant universities. External funding for equine research, however, is limited and restricts undergraduate research opportunities that enhance student learning. In 1999, a novel undergraduate teaching and research program was initiated at Rutgers University, New Brunswick, NJ. A unique aspect of this program was the use of young horses generally considered "at risk" and in need of rescue but of relatively low value. The media interest in such horses was utilized to advantage to obtain funding for the program...
Michelotto PV, Muehlmann LA, Zanatta AL, Bieberbach EW, Fernandes LC, Nishiyama A.Inflammatory airway disease (IAD) is prevalent in young racehorses during training, being the 2nd most commonly diagnosed ailment interrupting training of 2-year-old Thoroughbred racehorses. Objective: That stabling and exercise cause oxidative stress, release of platelet-activating factor (PAF) and inflammation in airways of Thoroughbred colts. Methods: Colts in breeding farms (NC, n = 45), stabled for 30 days (EC, n = 40), and race trained (EX, n = 34). Methods: Cytological profile and parameters of bronchoalveolar lavage fluid (BALF) related to oxidative stress, bioactivity of the proinflam...
Riviere JE, Coppoc GL, Hinsman EJ, Carlton WW, Traver DS.Gentamicin pharmacokinetics and nephrotoxic potential were evaluated in twelve 2 to 3 month-old horses. Whereas recent evidence in our clinic indicated that young horses may be especially susceptible to gentamicin nephrotoxicity, young rabbits and rats are usually resistant. Gentamicin (4.5 mg/kg) was given by rapid intravenous injection. Serum gentamicin concentrations over a 13-hour period were fitted to an open, two-compartment, pharmacokinetic model. Subsequently, the same horses were divided into groups of 3 horses each. Each group received 0, 2.2, 4.4 or 8.8 mg gentamicin/kg, intramuscul...
Lowden S, Heath T.Lymphoid tissues in the ileum of young horses form raised plaques that are macroscopically visible from the mucosal surface. These are termed "ileal lymphoid patches". These patches are variable in size, shape and position within the ileal wall, occasionally lying along the site of mesenteric attachment. Within lymphoid patches, follicles exist in three different morphological forms: follicle/dome structures, proprial follicles, and lymphoglandular complexes (LGCs). In follicle/dome structures, the majority of the follicle lies in the submucosa and merges with a dome in the lamina propria thro...
Assenza A, Tosto F, Casella S, Fazio F, Giannetto C, Piccione G.Prothrombin Time (PT), Activated Partial Prothrombin Time (APTT), Fibrinogen concentration (Fbg) and Platelet number (Plt) were evaluated in 20 young athletic horses during a training program. A standardized exercise test (SET) was performed every month for three months. The V4 variations (the speed, in m/min, reached at the blood lactate concentration of 4 mmol/l) obtained for each test were calculated to assess the effect of training program on athletic performance. Blood samples were collected at 20-day intervals over a period of 80 days from the beginning of the training program. The V4 (P...
Edwards LJ, Goodship AE, Birch HL, Patterson-Kane JC.To determine whether specific treadmill exercise regimens would accelerate age-related changes in collagen fibril diameter distributions in the common digital extensor tendon (CDET) of the forelimbs of young Thoroughbreds. Methods: 24 female Thoroughbreds. Methods: Horses were trained for 18 weeks (6 horses; short term) or 18 months (5 horses; long term) on a high-speed treadmill; 2 age-matched control groups (6 horses/group) performed walking exercise only. Horses were (mean +/- SD) 24 +/- 1 months and 39 +/- 1 months old at termination of the short-term and long-term regimens, respectively. ...
Lin YL, Brama PA, Kiers GH, DeGroot J, van Weeren PR.To quantify and compare biochemical characteristics of the extracellular matrix (ECM) of specimens harvested from tensional and compressive regions of the superficial digital flexor tendon (SDFT) of horses in age classes that include neonates to mature horses. Methods: Tendon specimens were collected on postmortem examination from 40 juvenile horses (0, 5, 12, and 36 months old) without macroscopically visible signs of tendonitis. Methods: Central core specimens of the SDFT were obtained with a 4-mm-diameter biopsy punch from 2 loaded sites, the central part of the mid-metacarpal region and th...
Gross I, Hadar A, Bala M, Hashavya S.Horse riding has become increasingly popular in recent years and is a common activity among children. As a result, pediatric horse-related injuries are frequently encountered in emergency departments. Objective: To examine the characteristics of horse-related injuries in the pediatric population. Methods: We collected and analyzed the data on all pediatric horse-related injuries presented to a tertiary hospital, level one trauma center, during the years 2006-2016. Results: A total of 53 children with horse-related injuries were documented. Forty-two patients were male (79%) and their mean age ...
Lansade L, Neveux C, Levy F.Learning performance is influenced by emotional reactivity, low reactivity being generally beneficial. Previous experiments show that emotional reactivity can be modified after a period of social isolation. We hypothesized that eleven days of isolation would affect yearlings' emotional reactivity and improve their learning abilities. Twenty-five yearlings were divided into two groups: 12 were continuously isolated for 11 days (isolated) and 13 stayed together (control). During the period of isolation, all yearlings underwent two learning tasks: a habituation procedure in which a novel object w...
Andersen UV, Reinemeyer CR, Toft N, Olsen SN, Jacobsen S, Nielsen MK.Migrating Strongylus vulgaris and encysted cyathostomin larvae cause a localized inflammatory response in horses. It is unknown whether these larvae elicit a systemic acute phase response (APR), evidenced by changes in serum amyloid A (SAA), haptoglobin (Hp), iron (Fe), albumin, or albumin/globulin (A/G) ratio. In this study, 28 horses were randomly allocated to receive either pyrantel tartrate or a pelleted placebo formulation in their daily feed. Concurrent with treatment, all the horses were administered 5000 pyrantel-susceptible cyathostomin infective larvae once daily, 5 days a week, for ...
Seeherman HJ, Morris EA.The purpose of this study was to compare exercise measurements in yearling, two-year-old and adult Thoroughbreds using a standardised treadmill incremental exercise test. Peak oxygen consumption (VO2 peak: 128.0 +/- 2.1, 140.0 +/- 2.1, 163.7 +/- 3.4; ml/kg/min +/- se, P less than 0.05), peak packed cell volume (PCV peak: 0.50 +/- 0.01, 0.58 +/- 0.01, 0.64 +/- 0.01 litres/litre +/- se, P less than 0.05) and the maximum number of steps completed in the exercise test (STEPmax: 7.7 +/- 0.1, 8.1 +/- 0.1, 8.6 +/- 0.1; steps +/- se, P less than 0.05) increased with age and degree of physical activity...
Perryman LE, Bjorneby JM.Immunotherapy for persistent infection caused by Cryptosporidium parvum was attempted in two immunodeficient animal models. BALB/c Athymic (nude) mice were infected with two oral doses of 2 x 10(7) C. parvum oocysts, and subsequently treated with monoclonal antibody (MAb) 17.41 that neutralizes sporozoites and merozoites. Persistent infection was established in all exposed mice. Daily oral treatment with MAb 17.41 for 10 days significantly reduced (p less than 0.005) the number of C. parvum organisms observed by microscopic study of intestinal tracts of infected mice. Young horses with severe ...
Walker VA, Tranquille CA, Newton JR, Dyson SJ, Brandham J, Northrop AJ, Murray RC.Dressage horses are often asked to work in lengthened paces during training and competition, but to date there is limited information about the biomechanics of dressage-specific paces. Preliminary work has shown increased fetlock extension in extended compared with collected paces, but further investigation of the kinematic differences between collected, medium and extended trot in dressage horses is warranted. Objective: Investigation of the effect of collected vs. medium/extended trot on limb kinematics of dressage horses. Methods: Prospective kinematic evaluation. Methods: Twenty clinically...
Onoda T, Yamamoto R, Sawamura K, Inoue Y, Murase H, Nambo Y, Tozaki T, Matsui A, Miyake T, Hirai N.Thoroughbred horses are seasonal mating animals, and their foals are born yearly in spring seasons. In northern regions or countries, the foals generally show a typical seasonal compensatory growth pattern, where their growth rate declines in winter and increases in the next spring. In this study, a new empirical approach is proposed to adjust for this compensatory growth when growth curve equations are estimated, by using BW of Japanese Thoroughbred colts and fillies raised in Hidaka, Hokkaido. Based on the traditional Richards growth curve equation, new growth curve equations were developed ...
Norwood MF, Lakhani A, Maujean A, Downes M, Fullagar S, Barber BL, Kendall E. Equine-assisted therapy may promote positive behavior change in young people "at risk." However, it is not always clear what therapeutic content is involved and if a trained therapist is included. The therapeutic effects of the key part of the "therapy," the horse, are not understood. To investigate the impact of an equine program without a therapist on attention and behavioral outcomes of young people "at risk." A within subjects pre-post design. A small sample also completed a control period. A small riding center in a rural area of outer Brisbane, Australia. Twelve- to 17-year olds (â€...
Sanz MG, Sellon DC, Cary JA, Hines MT, Farnsworth KD.To compare the analgesic efficacy of administration of butorphanol tartrate, phenylbutazone, or both drugs in combination in colts undergoing routine castration. Methods: Randomized controlled clinical trial. Methods: 36 client-owned colts. Methods: Horses received treatment with butorphanol alone (0.05 mg/kg [0.023 mg/lb], IM, prior to surgery and then q 4 h for 24 hours), phenylbutazone alone (4.4 mg/kg [2.0 mg/lb], IV, prior to surgery and then 2.2 mg/kg [1.0 mg/lb], PO, q 12 h for 3 days), or butorphanol and phenylbutazone at the aforementioned dosages (12 horses/group). For single-drug-tr...
Foley GL, Valentine BA, Kincaid AL.In a retrospective study, cutaneous melanocytic tumors from 18 horses, less than 2 years old, were examined histopathologically and clinical follow-up requested. Melanocytomas (benign melanomas) occurred in a variety of breeds and in horses of varied coat color. The age of the horses at the time of biopsy ranged from 3 weeks old to 2 years old. Four melanocytomas were congenital, 11 melanocytomas were acquired by 1 year of age, and three were acquired prior to 2 years of age. Of the 18 horses, five were male, and 13 were female. All tumors were solitary and located on the legs or trunk; none w...
Sherman KM, Miller GJ, Wronski TJ, Colahan PT, Brown M, Wilson W.Right third metacarpal bones (n = 24) from Thoroughbreds, 24 to 48 months old and in race training, were tested to failure in 3 point bending. The neutral load axis was estimated and the distance from the axis to the outer dorsal cortical surface measured. Mid-diaphyseal dorsopalmar and lateromedial outer cortical and medullary diameters were measured. Breaking strength, cortical area and area moment of inertia were also calculated. Significant correlations were demonstrated between months in training and dorsopalmar bone diameter, cortical area and area moment of inertia. Significant linear m...
Oliver LJ, Baird DK, Baird AN, Moore GE.To characterise the prevalence and distribution of radiographic changes in the hocks and stifles of Thoroughbred yearling colts and fillies in New Zealand and compare them with other populations of young horses. Methods: Repository radiographs taken in New Zealand for the 2003-2006 Thoroughbred national yearling sales were evaluated by two individual readers. The distribution of radiographic changes was classified as left side only, right side only, or bilateral. Lesions were categorised by type, location, and sex of the yearling. Complete sets of hock and stifle radiographs of 1,505 yearlings...
Davis EW.The purpose of this study was to determine the feasibility of using laparoscopy to remove cryptorchid testes from standing horses. Methods: Prospective clinical study. Methods: Eleven client-owned horses ranging in age from 4 months to 2 years. Methods: Abdominal insufflation was initiated and maintained using a 20 F insufflation tube, attached via a stopcock, to the low pressure regulator on a standard carbon dioxide pressure tank. After trocar and laparoscope placement in the ipsilateral flank the testes were identified. Local anesthesia of the structures to be manipulated was administered t...
Arroyo LG, Hayes MA, Delay J, Rao C, Duncan B, Viel L.Calcification of large arteries has been sporadically reported in horses. The pathogenesis is still unknown, but recent studies in humans suggest that this is a regulated biomineralizing process. This study surveyed the prevalence, distribution, and severity of vascular calcification in Thoroughbred and Standardbred racehorses. Histopathologic, ultrastructural imaging, and energy dispersive X-ray elemental analyses were used to examine the lesions. Calcification of the tunica media, predominantly the pulmonary artery, was found in 82% of horses (83/101). Young adult horses (mean [SD] age in ye...
McCoy AM, Ralston SL, McCue ME.Osteochondrosis (OC) is commonly diagnosed in young Standardbred racehorses but its effect on performance when surgically treated at a young age is still incompletely understood. This is especially true for Standardbred pacers, which are underrepresented in the existing literature. Objective: To characterise the short- (2-year-old) and long-term (through 5-year-old) racing performance in Standardbred pacers and trotters after early surgical intervention (<17 months of age) for tarsal OC. Methods: Retrospective clinical study. Methods: The study population consisted of related, age-matched Stan...
Ellis DR, Simpson DJ, Greenwood RE, Crowhurst JS.A retrospective study of 119 cases of fracture of the proximal phalanx is described. The short incomplete sagittal fracture (split pastern) was most common and carried a good prognosis for a return to racing following conservative treatment. Longer incomplete fractures also had a good prognosis but complete fractures, either through the lateral cortex of the proximal phalanx or through the bone into the proximal interphalangeal joint, required internal fixation. Careful assessment of these and comminuted fractures was essential before surgery was undertaken. Most comminuted fractures were trea...
Leleu C, Cotrel C.Body composition is an essential factor in athletic performance of human sprinters and long distance runners. However, in horses, many questions remain concerning relationships between body composition and performance in the different equine activities. Objective: To determine relationships between body composition, body score, physiological and locomotor variables in a population of young Standardbreds in training. Methods: Twenty-four 2-year-old Standardbreds were studied, body condition on a scale 0-5 and bodyweight recorded, and height at withers measured. Percentage of fat (%F), fat mass ...
Robert C, Valette JP, Denoix JM.There is limited published data on conformational changes in the forelimbs of growing foals. This study was designed to describe the changes in conformation of the carpus and distal forelimb from birth to weaning in foals of three different breeds. Evaluation of the conformation of the carpus, fetlock, pastern and foot was carried out in 134 Thoroughbreds, 162 French Trotters and 98 Selle Français (French Warmblood) within 1 month of age and then at approximately 2 month intervals until weaning at approximately 6 months of age. The prevalence of limb deviations decreased from birth to weaning...
Young DR, Richardson DW, Markel MD, Nunamaker DM.The third carpal bone (C3) was collected from both forelimbs of 27 Thoroughbreds. On the basis of age, training, and history, specimens were assigned to 1 of 5 groups: yearling, untrained horses (group 1, n = 4); 2- to 3-year-old, untrained horses (group 2, n = 7); trained 2-year-old horses (group 3, n = 6); trained 3-year-old horses (group 4, n = 6); and 3-year-old, trained horses with carpal pathologic features (group 5, n = 4). A transverse section of subchondral bone 5-mm thick was cut in a precise fashion 10 mm below the proximal articular surface of all specimens. After high-detail radio...
Gaesser AM, Usimaki AIJ, Barot DA, Linardi RL, Molugu S, Musante L, Ortved KF.Mesenchymal stem cell (MSC) extracellular vesicles (EVs) have emerged as a biotherapeutic for osteoarthritis; however, manufacturing large quantities is not practical using traditional monolayer (2-D) culture. We aimed to examine the effects of 3-D and 2-D culture 2 types of media: Dulbecco modified Eagle medium and a commercially available medium (CM) on EV yield. Methods: Banked bone marrow-derived MSCs (BM-MSCs) from 6 healthy, young horses were used. Methods: 4 microcarriers (collagen-coated polystyrene, uncoated polystyrene, collagen-coated dextran, and uncoated dextran) were tested in st...
Mele M, Gerber V, Straub R, Gaillard C, Jallon L, Burger D.The objective of this study was to investigate clinical signs indicating diseases with known or suspected hereditary components like equine sarcoid, insect bite hypersensitivity, osteochondrosis, allergic airway diseases, podotrochleosis, prognatism and wind-sucking in the franches-montagnes horse. We performed a clinical examination on 702 three-year-old, privately owned franches-montagnes horses, which were shown at the Swiss-Field-Tests in 2004. With the help of the owners a questionnaire on health, environment and feeding habits of the animals was completed. In 11.9% of the horses, sarcoid...
