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.
Van Cauter R, Caudron I, Lejeune JP, Rousset A, Serteyn D.Osteochondral fragments within equine joints are commonly encountered and may predispose to lameness and limitation to sport purposes. Factors leading to this condition include genetic, nutritional and environmental conditions. However, few studies have evaluated the impact of conformation traits and their correlation with osteochondrosis. This study, based on the radiographic screenings of young horses born in Wallonia (266 individuals, 532 forelimbs), evaluated the correlation between foot, fetlock conformations of the front limb, height at the withers and presence of osteochondral fragments...
Johansson L, Ringmark S, Bergquist J, Skiöldebrand E, Widgren A, Jansson A.The human plasma proteome is rather well studied, but not that of other species, including horses. The aims of this study were to (1), explore differences in plasma proteomic profile of young elite harness trotters kept under standardised conditions and subjected to two different training programmes for 2 years and (2) explore changes in proteomic profile over time during the training period. From September at age 1.5 year to March at age 2 years, 16 Standardbred horses were exposed to the same training programme. In March, high-intensity training was introduced and the horses were divided int...
Duderstadt S, Distl O.The objectives of the present study were to analyze the influence of the stallions employed in the Dülmen wild horses on the genetic diversity and population substructure using Bayesian cluster analysis. The Dülmen wild horse is maintained as a unique horse population exposed to the natural conditions all year round in the Merfelder Bruch near Dülmen in Westphalia, Germany. Stallions selected for breeding have to prove their abilities to survive under this harsh environment. We used multilocus genotypic information from a set of 29 autosomal microsatellites to determine the paternity of 185...
Hoey S, Fogarty U, McAllister H, Puggioni A, Cloak B, Richard H, Skelly C, Laverty S.Articular cartilage can be directly imaged using ultrasonography. The fetlock is a common site of osteochondrosis, with the sagittal ridge of the third metacarpal bone most commonly affected. In osteochondrosis, cartilage thickening may be an initial finding. This postmortem study investigated the ability of ultrasonography to accurately measure the dorsodistal articular cartilage of the third metacarpal bone in young horses, compared to computed tomographic arthrography (CTA) and histological measurements. A total of 33 metacarpophalangeal joints from 18 horses between the ages of 12 days and...
Lashkari S, Beblein C, Christensen JW, Jensen SK.High-starch diets may affect equine hindgut microbiota and increase blood glucose levels, which may cause unwanted physiological changes, but may also elicit behavioural changes such as increased fear reactions. The purpose of the current study was to feed a high starch (300) and low fat (43; HS_LF) or a low starch (60) and high fat (85; LS_HF, g/kg of DM) concentrate within the available commercial range and investigate how muscle endurance and fear reactions of horses respond to different diets. Twenty Danish Warmblood stallions (4 years) were randomly allocated to two treatments: LS_HF (n...
Leng J, Moller-Levet C, Mansergh RI, O'Flaherty R, Cooke R, Sells P, Pinkham C, Pynn O, Smith C, Wise Z, Ellis R, Couto Alves A, La Ragione R....Gut bacterial communities have a profound influence on the health of humans and animals. Early-life gut microbial community structure influences the development of immunological competence and susceptibility to disease. For the Thoroughbred racehorse, the significance of early-life microbial colonisation events on subsequent health and athletic performance is unknown. Here we present data from a three-year cohort study of horses bred for racing designed to explore interactions between early-life gut bacterial community structure, health events in later life and athletic performance on the race...
Okudaira M, Cresswell EN, Wollman CW, McDonough SP, Engiles JB, Reesink HL.To describe the development and maturation of equine proximal sesamoid bones (PSBs) in fetuses and young horses using radiography, microcomputed (micro)-CT, and histology. Methods: A descriptive study. Forelimb PSBs from 12 equids ranging in age from 105 days of gestation to 540 days postgestation were evaluated. Radiography was used for preliminary assessment of metacarpophalangeal joint and PSB mineralization, and micro-CT imaging was performed to assess mineralized PSBs. Tissue volume, bone volume fraction, height, width, depth, trabecular thickness, and anisotropy were quantified from midp...
Bertuglia A, Pallante M, Pagliara E, Valle D, Bergamini L, Bollo E, Bullone M, Riccio B.Tarsocrural osteochondrosis (OCD) is a developmental orthopedic disease commonly affecting young Standardbreds, with different fragment localization and size. Clinically, it is characterized by variable synovial effusion in the absence of lameness, whose determinants are ill-defined. We hypothesized that localization and physical characteristics of the osteochondral fragments like dimensions, multifragmentation, and instability influence joint effusion and correlate with synovial markers of cartilage degradation and inflammation. Clinical data, synovial fluid and intact osteochondral fragments...
Peat FJ, Kawcak CE, McIlwraith CW, Berk JT, Keenan DP.Changes in the proximal sesamoid bones (sesamoids) and the insertional region of the adjacent suspensory ligament branch (branch) are of particular importance in young Thoroughbreds sold at public auction. Little is known about the prevalence of concurrent ultrasonographical branch change, relative to the various grades of radiological sesamoid appearance. Objective: To examine the existence of concurrent radiological and ultrasonographical findings in individual sesamoid-branch units in sales horses; to determine whether there are any radiological findings that are consistently accompanied by...
Peat FJ, Kawcak CE, McIlwraith CW, Berk JT, Keenan DP, Selberg KT, Ojeda A.Equine suspensory ligament branch (branch) ultrasonography is becoming increasingly commonplace presale. No ultrasonographical branch reference data exists for Thoroughbred sales horses. Objective: To define the prevalence of ultrasonographical findings in the forelimb suspensory branches of yearling and 2-year-old sales Thoroughbreds and to analyse associations with racing performance. To track changes in branch findings between 1 and 2 years of age in horses that present for sale at both ages. Methods: Prospective cohort study using an enrolled sample. Methods: Horses were enrolled from a ...
Kearney MT, Kamm JL.To describe the treatment of subcutaneous lipomas in the horse. Methods: 3 horses. Methods: The horses were aged 1 to 2 years old, with lipoma of the abdomen, prepuce, and tarsus. Results: Recurrence of an invasive thoracic lipoma occurred in case 1 at the exit site of a passive drain. The recurrence was treated unsuccessfully with injectable cisplatin, and a second revision surgery with the use of an active drain resulted in resolution. In case 2, complete resection of an encapsulated lipoma of the lateral prepuce was successful with no recurrence. In case 3, incomplete resection of a tarsal ...
Rapezzano G, Foote A, Petrini F, Pereira R, Marcatili M.A newborn Thoroughbred filly presented with a large mass located on the ventro-rostral aspect of the mandible. The mass was surgically removed under general anaesthesia. Upon gross examination, the mass was well circumscribed with a heterogeneous lobulated appearance. The results of histopathology and immunohistochemistry were consistent with a diagnosis of congenital fetal rhabdomyoma. On follow-up at six months post-surgical excision, no abnormalities were noted on clinical examination.
Ramos GV, Santos MM, Gava FN, de Lacerda-Neto JC.The effects of conditioning on cardiac function in young horses is still unknown. For this reason, this study evaluated the left ventricular (LV) function of young horses by echocardiography after six weeks of conditioning. Fourteen untrained young purebred Arabian horses were evaluated at rest and after a stress test (ST) before and after a six-week conditioning program. There was an increase in V4 (p < 0.001) after conditioning, as well as a reduction in both heart rate (HR) at rest and peak HR during the ST (p < 0.001). There was also a reduction in internal diameter, along with an in...
Bugno-Poniewierska M, Jankowska M, Raudsepp T, Kowalska K, Pawlina-Tyszko K, Szmatola T.Chromosomal abnormalities occur in the equine population at a rate of approximately 2%. The use of molecular cytogenetic techniques allows a more accurate identification of chromosomal abnormalities, especially those with a low rate of abnormal metaphases, demonstrating that the actual incidence in equine populations is higher. Objective: Estimation of the number of carriers of karyotypic abnormalities in a sample from a population of young horses of various breeds, using molecular cytogenetic techniques. Methods: Cross-sectional. Methods: Venous blood samples were collected from 500 young hor...
Orzołek A, Rafalska KT, Domosławska-Wyderska A, Rafalska AM, Dziekońska A, Jastrzębska E, Dobbek D.The aim of the study was to assess the impact of solarium light therapy on selected biological and biochemical parameters of peripheral blood in recreational horses. The study involved 10 horses divided into two groups of young (aged 5 to 7 years) and old (aged 14 to 19 years) individuals. All animals participated in light therapy sessions every other day. Blood was sampled three times during the study: before the treatment, after five light sessions, and after ten light sessions. Morphological parameters, the activity of antioxidant enzymes, TAS values, and the levels of glutathione (GSH), vi...
Nielsen MK, Finnerty CA, Ripley NE, Page AE, McClendon ME, Adams AA.Anthelmintic performance against equine cyathostomins can be evaluated by two different non-terminal measures; the Fecal Egg Count Reduction Test (FECRT) and the Egg Reappearance Period (ERP). Most available FECRT and ERP data have been determined in populations of young horses, and very little information is available from mature and senior horses. Furthermore, it is unknown how commonly occurring equine endocrine disorders such as Insulin dysregulation (ID) and Pituitary pars intermedia dysfunction (PPID) may interfere with these measurements, but it has been suggested that horses with these...
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...
Pereira-Figueiredo I, Rosa I, Sancho Sanchez C.Horses are often still exposed to stressful or inadequate conditions and difficult relationships with humans, despite growing concerns about animal welfare. In the present study, we investigated the impact of different approaches of short-term handling sessions on young Lusitanian horses raised on a high-breed farm, specifically on their later adaptability to humans and stressful environments. Thirty-one foals (3 months old ± 15 days), from both sexes, were separated into three groups, one submitted to 3 consecutive days of handling sessions (Int-H), another to one handling session each month...
Álvarez Narváez S, Beaudry MS, Norris CG, Bartlett PB, Glenn TC, Sanchez S.GITDs are among the most common causes of death in adult and young horses in the United States (US). Previous studies have indicated a connection between GITDs and the equine gut microbiome. However, the low taxonomic resolution of the current microbiome sequencing methods has hampered the identification of specific bacterial changes associated with GITDs in horses. Here, we have compared TEHC, a new approach for 16S rRNA gene selection and sequencing, with conventional 16S rRNA gene amplicon sequencing for the characterization of the equine fecal microbiome. Both sequencing approaches were us...
Helmerich P, Bachmann I, Gygax L.Horses must lie down to go into vital rapid-eye movement (REM) sleep. If they are not lying down for sufficiently long periods they can become so sleep-deprived that they collapse uncontrollably, which results in a risk of injuries. Objective: To investigate how recumbency as a prerequisite to REM sleep on the experimental days and the following nights was influenced by changes in social and spatial environment throughout the day. Methods: Cross-over design in which subjects experienced each experimental condition twice. Methods: Observations were conducted on a horse farm. Ten young horses in...
Sawesi OK, Elbaz AK, Mahmoud AS, Duro EM, Alteab AA, Milad KK, Bennuor EM.Hematological evaluation is an important step for health assessment in equine medicine. Besides biochemical tests, that evaluation could be pivotal for diagnosis, prognosis, and treatment monitoring. In Libya, the horse population has drastically increased in the last years, and hitherto, no report addressed the reference hematological values for the existing equine breeds. Unassigned: This study aimed to establish the reference for hematological indices of traditional equestrian and stud-farm equine breeds in Western Libya in regard to some variables such as individual characteristics, manage...
Schneider C, James K, Craig BW, Chappell DE, Vaala W, van Harreveld PD, Wright CA, Barnum S, Pusterla N.Equine rhinitis B virus is a lesser-known equine respiratory pathogen that is being detected with increasing frequency via a voluntary upper respiratory biosurveillance program in the United States. This program received 8684 nasal swab submissions during the years 2012-2023. The nasal swabs were submitted for qPCR testing for six common upper respiratory pathogens: Streptococcus equi subspecies equi (S. equi), equine influenza virus (EIV), equine herpesvirus type 1 (EHV-1), equine herpesvirus type 4 (EHV-4), equine rhinitis A virus (ERAV), and equine rhinitis B virus (ERBV). The overall ERBV ...
Abbas G, Stevenson MA, Bauquier J, Beasley A, Jacobson C, El-Hage C, Wilkes EJA, Carrigan P, Cudmore L, Hurley J, Beveridge I, Nielsen MK, Hughes KJ....This study aimed to assess Australian veterinarians' knowledge, perceptions and treatment strategies for worm control in horses with an online questionnaire. The questionnaire comprised 64 questions covering various aspects of: (i) veterinary practice; (ii) the veterinarian's knowledge of gastrointestinal nematodes (GINs) and the importance of parasites in different age groups of horses; (iii) the diagnosis and control of worms; (iv) anthelmintics and anthelmintic resistance (AR); (v) grazing management; and (vi) the means of communication and the discussion between veterinarians and their cli...
Chapard L, Meyermans R, Gorssen W, Hooyberghs K, Meurrens I, De Smet S, Buys N, Janssens S.The main goal of the Belgian Warmblood horse studbook (BWP) is to breed successful competition horses, with emphasis on show jumping. However, competition results are only available later in life and competition traits are lowly heritable. Hence, the use of phenotypes that record performance-related traits at an early life stage could help increase genetic progress. In this study, we evaluated the potential of eleven linear scored early life jumping traits assessed during jumping in freedom (2-5 years old) or under the saddle (4-6 years old) as proxies for later success in show jumping com...
Bennet ED, Parkin TDH.Racehorse training and racing schedules in many parts of the United States and Canada were interrupted or otherwise reduced during the first three to six months of 2020. This was an indirect consequence of mitigations to prevent the spread of the pandemic virus COVID-19. Data from the Equine Injury Database, a census-level survey of all race starts made in the USA and Canada, were used to analyse the incidence of fatalities in 2009-2022 among three age cohorts of racehorses within each year. There was a statistically significant increase in the incidence of musculoskeletal fatalities among 2-y...
Matas Riera M, Cardenas Nadal M, Martínez-Sogues L, Ferrer L.Dermatological clinical signs have been seldom reported in the literature secondary to equine leishmaniasis. This case depicts the clinical signs, treatment, and outcome of a young horse with a pink, elevated lesion on the ventromedial quadrant of the cornea. A corneal cytology was performed and revealed the presence of leishmania amastigotes reaching the diagnosis of keratitis secondary to leishmania. Surgical resection was recommended but the owner declined the procedure, and the lesion was treated with a topical antimonial for 6 weeks. The lesion reduced remarkably during the first weeks ...
Vergara-Hernandez FB, Nielsen BD, Kottwitz JJ, Panek CL, Robison CI, Paris BL, Welsh TH, Bradbery AN, Leatherwood JL, Colbath AC.To determine the single-dose pharmacokinetics of clodronate disodium (CLO) in juvenile sheep and the plasma protein binding (PPB) of CLO in juvenile sheep and horses. Methods: 11 juvenile crossbred sheep (252 ± 6 days) for the pharmacokinetic study. Three juvenile crossbred sheep (281 ± 4 days) and 3 juvenile Quarter Horses (599 ± 25 days) for PPB analysis. Methods: CLO concentrations were determined using liquid chromatography-mass spectrometry. Pharmacokinetic parameters were calculated by noncompartmental analysis from plasma samples obtained at 0, 0.5, 1, 3, 6, 12, 24, 48, and 72 hours ...
Olstad K, Ekman S, Björnsdóttir S, Fjordbakk CT, Hansson K, Sigurdsson SF, Ley CJ.Recently, the central and third tarsal bones of 23 equine fetuses and foals were examined using micro-computed tomography. Radiological changes, including incomplete ossification and focal ossification defects interpreted as osteochondrosis, were detected in 16 of 23 cases. The geometry of the osteochondrosis defects suggested they were the result of vascular failure, but this requires histological confirmation. The study aim was to examine central and third tarsal bones from the 16 cases and to describe the tissues present, cartilage canals, and lesions, including suspected osteochondrosis le...
McCoy AM, Scolman KN.The aim of this study was to identify the radiographic prevalence of periarticular osteophytes of the distal tarsus in nonlame yearling Standardbred horses, and to evaluate its potential impact on race performance. Methods: Cross-sectional cohort study. Methods: Client-owned yearling Standardbred horses (n = 416). Methods: Bilateral tarsal radiographs were available from all horses for review. Osteophytes were measured on radiographs using clinical visualization software and categorized by size. Racing records were obtained from the United States Trotting Association. Regression analysis w...
Krueger K, Farmer K, Heinze J.Social learning is said to meet the demands of complex environments in which individuals compete over resources and cooperate to share resources. Horses (Equus caballus) were thought to lack social learning skills because they feed on homogenously distributed resources with few reasons for conflict. However, the horse's social environment is complex, which raises the possibility that its capacity for social transfer of feeding behaviour has been underestimated. We conducted a social learning experiment using 30 socially kept horses of different ages. Five horses, one from each group, were chos...
Fortier G, van Erck E, Pronost S, Lekeux P, Thiry E.Equine gammaherpesviruses (γEHV) have been widely studied over the past 45 years and many isolates have been characterised. Despite this, the diagnosis of γEHV infection remains difficult to establish as its clinical manifestations lack specificity, ranging from mild respiratory signs in a small number of animals to outbreaks in large groups of young horses. This review focuses on the epidemiology, pathogenesis, clinical manifestations and diagnosis of equine herpesvirus (EHV)-2 and -5 infections, as well as on the genetic variation of these viruses. Study of these variations has resulted in...
Patterson-Kane JC, Firth EC, Goodship AE, Parry DA.To measure collagen fibril crimp angles and lengths as well as collagen fibril mass-average diameters in central and peripheral regions of the superficial digital flexor tendon of wild horses, to ascertain any age-related changes in either region in the absence of imposed galloping exercise. Methods: Measurements from a random cull of wild horses. Methods: Superficial digital flexor tendon samples were taken from 23 wild horses ranging in age from two to ten years. Methods: Horses were divided into 'young' (< 5 years, n = 10), 'middle-aged' (5 to < 10 years, n = 9) and 'ol...
Moss PS, Wan A, Whitlock MR.To describe the demographics and nature of injuries occurring on or around horses, to examine the nature of protective clothing in relation to these injuries, and to compare our data with previously published work in this area. Methods: Patients were identified using the term "sports injury-horse riding" from the departmental database for one calendar year from February 2000. Data were collected regarding demographics, injuries, protective clothing, and outcome. The data were then analysed and compared with the previously published literature. Results: 260 patients' records were analysed. The ...
Dyson PK, Jackson BF, Pfeiffer DU, Price JS.The first major epidemiological study of injury incidence in the UK flat racing Thoroughbred (TB), published in 1985, found lameness to be the single largest reason for days when horses failed to train. It was considered advisable to ascertain if progress has been made in reducing the problem of musculoskeletal injuries in the intervening period. Objective: To quantify injury incidence and days lost from training by 2- and 3-year-old TBs in UK training yards during 2002 and 2003. Methods: One-hundred-and-eighty-two yearling TBs were recruited at the end of 2001 and daily training and injury re...
Hussey SB, Clark R, Lunn KF, Breathnach C, Soboll G, Whalley JM, Lunn DP.Equine herpesvirus-1 (EHV-1) infection is common in young horses throughout the world, resulting in respiratory disease, epidemic abortion, sporadic myelitis, or latent infections. To improve on conventional diagnostic tests for EHV-1, a real-time polymerase chain reaction (PCR) technique was developed, using primers and probes specific for the EHV-1 gB gene. Amplification efficiencies of 100% +/- 5% were obtained for DNA isolated from a plasmid, infected peripheral blood mononuclear cells (PBMCs), and nasal secretions from infected ponies. The dynamic range of the assay was 8 log10 dilutions,...
Wood JL, Newton JR, Chanter N, Mumford JA.Respiratory disease is important in young Thoroughbred racehorses, but the variation in the rates of occurrence between different ages and training groups has not been characterised. Objective: To determine the rates of respiratory disease, particularly inflammatory airway disease (IAD), as well as evidence of infection, and their variation between age and group. Methods: Horses were examined monthly in 7 British flat training yards over a 3 year period. IAD was defined as increased mucus in the trachea with increased proportions of neutrophils in tracheal wash samples. Frequencies of disease ...
Thorpe CT, Riley GP, Birch HL, Clegg PD, Screen HR.Some tendons, such as the human Achilles and equine superficial digital flexor tendon (SDFT), act as energy stores, stretching and recoiling to increase efficiency during locomotion. Our previous observations of rotation in response to applied strain in SDFT fascicles suggest a helical structure, which may provide energy-storing tendons with a greater ability to extend and recoil efficiently. Despite this specialization, energy-storing tendons are prone to age-related tendinopathy. The aim of this study was to assess the effect of cyclic fatigue loading (FL) on the microstructural strain respo...
Kopesky PW, Lee HY, Vanderploeg EJ, Kisiday JD, Frisbie DD, Plaas AH, Ortiz C, Grodzinsky AJ.Our objective was to evaluate the age-dependent mechanical phenotype of bone marrow stromal cell- (BMSC-) and chondrocyte-produced cartilage-like neo-tissue and to elucidate the matrix-associated mechanisms which generate this phenotype. Cells from both immature (2-4 month-old foals) and skeletally-mature (2-5 year-old adults) mixed-breed horses were isolated from animal-matched bone marrow and cartilage tissue, encapsulated in self-assembling-peptide hydrogels, and cultured with and without TGF-beta1 supplementation. BMSCs and chondrocytes from both donor ages were encapsulated with high viab...
Witkowska-Piłaszewicz O, Grzędzicka J, Seń J, Czopowicz M, Żmigrodzka M, Winnicka A, Cywińska A, Carter C.Assuring a high level of animal welfare is a critical aspect of contemporary animal husbandry. Equine athletes begin their careers at a very young age when they are still developing and they are both physically and mentally immature. Lack of scientific knowledge of the stress related to horse racing impedes the development of optimal training programs to attain equilibrium between the best sport results and optimal welfare. This study aimed to determine the influence of the intensity and type of physical activity on peripheral blood cortisol concentration. Thirty untrained Arabians, 9 enduranc...
Newton JR, Townsend HG, Wood JL, Sinclair R, Hannant D, Mumford JA.Field outbreaks of influenza that occurred in vaccinated Thoroughbred racehorses in Newmarket in 1995 and 1996 were investigated by nucleoprotein ELISA and serology. Investigations showed that serum levels of vaccine-induced single radial haemolysis (SRH) antibody correlated closely with protective immunity against equine influenza and were consistent with observations made in previous experimental studies using nebulised aerosol challenge. In the second part of this study, antibody levels stimulated by vaccination were investigated to examine probable protection in high risk groups, such as y...
Verheyen KL, Wood JL.Musculoskeletal injury is the major cause of days lost from training and wastage in Thoroughbred racehorses. Little scientific information is available on the majority of injuries occurring in training. Objective: To estimate the incidence of fractures in British racehorses in training and describe the occurrence of different fracture types and bones involved. Methods: Thirteen UK racehorse trainers participated in a prospective study, providing data on horses in their care for 2 years. Details on horses, their daily exercise and fracture occurrence were recorded. Results: A total of 1178 hors...
Faber M, Johnston C, Schamhardt H, van Weeren R, Roepstorff L, Barneveld A.To determine movements of the vertebral column of horses during normal locomotion. Methods: 5 young Dutch Warmblood horses that did not have signs of back problems or lameness. Methods: Kinematics of 8 vertebrae (T6, T10, T13, T17, L1, L3, L5, and S3) and both tuber coxae were determined, using bone-fixated markers. Measurements were recorded when the horses were trotting on a treadmill at a constant speed of 4.0 m/s. Results: Flexion-extension and axial rotation were characterized by a double sinusoidal pattern of motion during 1 stride cycle, whereas lateral bending was characterized by 1 pe...
Dowling BA, Dart AJ.The in vitro and in vivo mechanical properties of the superficial digital flexor tendon have been described. To date the focus has been on single load to failure testing, however refined in vivo methods may prove useful to evaluate the effects of treatment and exercise on tendons. During maximal exercise, the adult superficial digital flexor tendon operates close to its functional limits with a narrow biomechanical safety margin. This combined with exercise and age associated microdamage, and a limited adaptive ability may increase the risk of fatigue failure. Studies evaluating treatment regi...
Adney DR, Brown VR, Porter SM, Bielefeldt-Ohmann H, Hartwig AE, Bowen RA.The Middle East respiratory syndrome coronavirus (MERS-CoV) was first recognized in 2012 and can cause severe disease in infected humans. Dromedary camels are the reservoir for the virus, although, other than nasal discharge, these animals do not display any overt clinical disease. Data from in vitro experiments suggest that other livestock such as sheep, goats, and horses might also contribute to viral transmission, although field data has not identified any seropositive animals. In order to understand if these animals could be infected, we challenged young goats and horses and adult sheep wi...
Aurich J, Wulf M, Ille N, Erber R, von Lewinski M, Palme R, Aurich C.Analysis of salivary cortisol is increasingly used to assess stress responses in horses. Because spontaneous or experimentally induced increases in cortisol concentrations are often relatively small for stress studies, proper controls are needed. This requires an understanding of the factors affecting salivary cortisol over longer times. In this study, we have analyzed salivary cortisol concentration for 6 mo in horses (n = 94) differing in age, sex, reproductive state, and housing. Salivary cortisol followed a diurnal rhythm with the highest concentrations in the morning and a decrease throug...
Birch HL, McLaughlin L, Smith RK, Goodship AE.The equine superficial digital flexor tendon (SDFT) functions as an energy store during high-speed gaits reducing the energetic cost of locomotion. To enable the SDFT to function effectively, the appropriate mechanical properties are essential. We tested the hypothesis that the SDFT does not undergo gross hypertrophy in response to high-intensity exercise whereas tendons not involved in energy storage undergo adaptive hypertrophy. Two groups (n = 6) of Thoroughbred fillies were trained at high-intensity on a high-speed equine treadmill for 5 months (short-term study) or 18 months (long-term st...
Olstad K, Ytrehus B, Ekman S, Carlson CS, Dolvik NI.Material available for research into osteochondrosis (OC) in humans tends to represent chronic lesions. Comparative studies of early lesions in young animals are, therefore, important in clarifying the pathogenesis of OC in humans. Recent studies in pigs provide strong evidence that lesions of articular OC are associated with a focal failure in the cartilage canal vascular supply to epiphyseal growth cartilage (articular-epiphyseal cartilage complex excluding the articular cartilage). The purpose of the present study was to examine histological sections from a specific predilection site for ar...
Firth EC, Rogers CW, Doube M, Jopson NB.To determine the effect of a known training regimen on the size and mineral content of the third metacarpal (Mc3) and third metatarsal (Mt3) bones of 2-year-old Thoroughbred horses trained on racetracks. Methods: Mc3 and Mt3 of seven horses trained on grass and sand tracks were scanned at several sites using conventional quantitative and peripheral computed tomography (CT). Bone dimensions and density in the diaphysis and epiphysis were compared with those from seven untrained horses. Calcein label was injected in two clusters, during Weeks 9 and 12. The extent and rate of diaphyseal modelling...
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...
Cribb NC, Cote NM, Bouré LP, Peregrine AS.To retrospectively evaluate the medical and surgical records of horses with acute small intestinal obstructions associated with Parascaris equorum infection; to describe the gastrointestinal lesions; and to determine the outcome of cases with such lesions. Methods: Records of 25 horses with acute small intestinal obstruction associated with P. equorum between 1985 and 2004 were reviewed to determine signalment, history, physical examination, surgical or post-mortem findings, and outcome. Results: All horses except one were less than 12 months old. Standardbreds were over-represented in the pop...
Buhl R, Ersbøll AK, Eriksen L, Koch J.To evaluate changes over time in echocardiographic measurements in young Standardbred racehorses undergoing training and racing and determine whether there was any relationship between cardiac dimensions and racing performance. Methods: Longitudinal observational study. Methods: 103 horses. Methods: 2-dimensional and M-mode echocardiography was performed 4 times at 6-month intervals. Results: Significant cardiac enlargement took place during the study period as indicated by increases in left ventricular internal diameter in diastole (LVIDd), estimated left ventricular muscle mass (LV mass), an...
Sigurjónsdóttir H, Haraldsson H.We explore how herd composition and management factors correlate with frequencies of social interactions in horse groups. Since the welfare of horses correlates with low aggression levels and social contact opportunities, information of this kind is important. The data are a collection of records of social interactions of 426 Icelandic horses in 20 groups of at least eight horses. The complexities and limitations of the data prohibit useful statistical modelling so the results are presented descriptively. Interesting and informative patterns emerge which can be of use both in management and in...
Carlson CS, Cullins LD, Meuten DJ.The objectives of this study were to determine in horses 1) the ages at which viable cartilage canal vessels are present in the articular-epiphyseal cartilage complex of three predilection sites and one nonpredilection site of osteochondrosis (OC), 2) the prevalence of lesions of OC in these sites, and 3) whether there was an association of lesions of OC with necrotic cartilage canal blood vessels. The medial femoral condyle, lateral femoral trochlear ridge, and distal ends of the tibia and proximal phalanx were examined grossly, microradiographically, and histologically in 35 horses 18 months...
Votion DM, Linden A, Saegerman C, Engels P, Erpicum M, Thiry E, Delguste C, Rouxhet S, Demoulin V, Navet R, Sluse F, Serteyn D, van Galen G, Amory H.The emergent nature of atypical myopathy or atypical myoglobinuria (AM) necessitates precise description of its clinical and epidemiologic features. Objective: To define key features of AM to help practitioners recognize the disease and to advise owners to take preventive measures. Methods: Belgian cases of AM confirmed by histology (CC horses; n = 57) from autumn 2000 to spring 2005 were included in the study. Co-grazing horses (Co-G horses; n = 77) that remained free of any abnormal clinical signs constituted a control group. Methods: History, environmental characteristics, clinical signs, a...
Stover SM, Pool RR, Martin RB, Morgan JP.The dorsal cortex of the equine third metacarpal mid-diaphyseal bone was characterised during growth by the histological and microradiographic examination of specimens from 30 horses ranging in age from 2 months to 8 y. Bone from horses aged less than 6 months was characterised by rapid periosteal apposition of circumferential trabeculae of woven bone that were next connected by radial trabeculae to the parent cortex. Deposition of lamellar bone on the inner trabecular surfaces resulted in rows of primary osteons. Replacement of primary bone occurred only after 4 months of age and preferential...
Frazer ML.Lawsonia intracellularis is an emerging equine pathogen that is a cause of equine proliferative enteropathy (EPE). Objective: To describe the signalment, month of presentation, common clinical signs, clinicopathologic values, diagnostic tests used, antimicrobial use, and survival status in horses affected with EPE; to evaluate how affected horses sold at public auction as yearlings; and to determine results of fecal polymerase chain reaction (PCR) and serum immunoperoxidase monolayer assay (IPMA) results in age matched, clinically normal herdmates. Methods: The study group was 57 horses treate...
Cozzi B, Ballarin C, Mantovani R, Rota A.The present article examines over 63,000 medical records belonging to the Veterinary Hospitals of the Universities of Bologna, Torino, and Padova, all in Northern Italy, and relative to dogs (approximately 50,000), cats (approximately 12,000), and companion horses (slightly less than 1,000). The animals of the three species were divided into age classes and categorized per sex into males, females, and neutered individuals. The mean age at visit and the effects of age classes and category (analyzed ANOVA) are presented and discussed. The data indicate that many animals are presented to the hos...
Peachey LE, Castro C, Molena RA, Jenkins TP, Griffin JL, Cantacessi C.A plethora of data points towards a role of the gastrointestinal (GI) microbiota of neonatal and young vertebrates in supporting the development and regulation of the host immune system. However, knowledge of the impact that infections by GI helminths exert on the developing microbiota of juvenile hosts is, thus far, limited. This study investigates, for the first time, the associations between acute infections by GI helminths and the faecal microbial and metabolic profiles of a cohort of equine youngstock, prior to and following treatment with parasiticides (ivermectin). We observed that high...
Buckley SM, Chalmers DJ, Langley JD.This study describes the epidemiology of injuries due to falls from horses in New Zealand. There were 54 fatalities from 1977 to 1986 (0.17 per 100,000 persons per year). There were 773 hospitalisations in 1987 (23.7 per 100,000 persons per year). Head injuries were predominant among both fatal and nonfatal injuries. The incidence of nonfatal head injury in the 10 to 19 age group was significantly higher than the incidence in all older groups (P = 0.003). Young people, particularly females, were the segment of the population most affected by the problem of falls from horses. Reference to data ...
