Equine diseases encompass a wide range of health conditions that can affect horses, including infectious diseases, metabolic disorders, and genetic conditions. These diseases can impact the overall health, performance, and well-being of horses. Common equine diseases include equine influenza, equine herpesvirus, laminitis, and equine metabolic syndrome. Diagnosis and management of these diseases often require a combination of clinical evaluation, laboratory testing, and appropriate treatment strategies. This page gathers peer-reviewed research studies and scholarly articles that explore the etiology, pathophysiology, diagnosis, and treatment options for various equine diseases, providing valuable insights for veterinarians and researchers in the field.
Noble P, Lumay G, Coninx M, Collin B, Magnée A, Lecomte-Beckers J, Denoix JM, Serteyn D.An equine fetlock joint pendulum test was studied and the influence of post mortem time and intra-articular lipid solvent on the viscous frictional response examined. Fresh equine digits (group 1, n=6 controls; group 2, n=6 lipid solvent) were mounted on a pendulum tribometer. Assuming that pendular joint damping could be modelled by a harmonic oscillator fluid damping (HOFD), damping time (τ), viscous damping coefficient (c) and friction coefficient (μ) were monitored for 5h under experimental conditions (400N; 20°C). In all experiments, pendular joint damping was found to follow an expone...
Olive J, D'Anjou MA, Girard C, Laverty S, Theoret C.The purpose was to evaluate the capacity of 1.5 T magnetic resonance (MR) imaging to assess articular cartilage in racehorses with naturally occurring metacarpophalangeal joint osteoarthritis. A sagittal, three-dimensional spoiled gradient-recalled echo (SPGR) with fat saturation (FS) sequence was acquired ex vivo on 20 joints. Following joint dissection, specific areas on the third metacarpal condyle were designated for subsequent sampling for histologic cartilage thickness measurement and modified Mankin scoring. Cartilage thickness was measured and cartilage signal intensity was also graded...
Kodaira K, Muranaka M, Naito H, Ode H, Oku K, Nukada T, Katayama Y.A 1-year-old male thoroughbred racehorse experienced swelling of the left upper lip. The swelling was attributable to enlargement around the incisive bone of the interdental space posterior to the third incisor in the left maxilla. Even after two operations to reduce the bulk of the mass, it continued to increase in size. Dyspnea caused by stenosis of the nasal cavity forced us to perform euthanasia, and a pathological examination was conducted. Macroscopic examination of a section of the mass revealed the formation of multiple areas of solid fibrous tissue, and trabeculae within the incisive ...
Kannegieter NJ, Schaaf KL, Lovell DK, Simon CD, Stone BM.We describe a fibrosarcoma in a 12-year-old Quarterhorse x Arabian gelding as a sequela to equine influenza vaccination. Shortly after the second vaccination, swelling at the site was noticed by the owner and it continued to increase in size over the following 6 months. Biopsy of the mass indicated a fibrosarcoma had developed at the vaccination site. It was approximately 20 cm in diameter and elevated well above the level of the skin. There was no clinical evidence of metastases to the lungs or local lymph nodes. Surgical resection of the mass was performed and the wound healed by first and s...
Hampson BA, Ramsey G, Macintosh AM, Mills PC, de Laat MA, Pollitt CC.The present study investigated the foot health of the Kaimanawa feral horse population and tested the hypotheses that horses would have a large range of foot morphology and that the incidence of foot abnormality would be significantly high. Methods: Abnormality was defined as a variation from what the two veterinarian assessors considered as optimal morphology and which was considered to impact negatively on the structure and/or function of the foot. Fifteen morphometric variables were measured on four calibrated photographic views of all four feet of 20 adult Kaimanawa feral horses. Four morp...
Thomas CM, Whittles CE, Fuller CJ, Sharif M.To investigate whether there are any variations in chondrocyte susceptibility to an apoptotic stimulus between cells of articular cartilage (AC) from equine joints that differ in prevalence of osteoarthritis (OA). Methods: Cartilage from macroscopically normal equine metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints was used. Prior to culture, chondrocyte viability was assessed using the fluorescein diacetate (FDA) and propidium iodide paravital staining method. AC explants were subsequently treated with tumour necrosis factor-α (TNF-α) in comb...
Rashid A, Mubarak A, Hussain A.Equine babesiosis is a tick-borne haematological disease of equidae that can affect acutely, subacutely and chronically. The disease is manifested by intermittent fever, anaemia, icterus and haemoglobinuria. The authors describe the clinical, haematological and therapeutic aspects of babesiosis in equines at two units in Kotley and at two units in Jehlum of the Remount Veterinary and Farms Corps (RVFC). Animals on these units showed the signs of illness. On clinical examination, intermittent temperature, increased respiratory rate, anaemia, lacrimation, conjunctivitis and pale mucous membranes...
Olstad K, Ytrehus B, Ekman S, Carlson CS, Dolvik NI.It is presently unknown whether cartilage ischaemia plays any part in the pathogenesis of osteochondral fragmentation within the equine metatarsophalangeal joint, as no detailed studies on microcirculation in the area have been reported. Objective: To describe the developmental pattern of the blood supply to the epiphyseal growth cartilage in the metatarsophalangeal joint of foals. Methods: Eight Standardbred foals were sacrificed between birth and age 7 weeks to undergo a barium perfusion procedure to demonstrate vessels within growth cartilage canals of one hindlimb. The metatarso-phalangeal...
Ousey JC, Palmer L, Cash RS, Grimes KJ, Fletcher AP, Barrelet A, Foote AK, Manning FM, Ricketts SW.Standard bacteriological methods for identifying Taylorella equigenitalis in cervical smears are time consuming. Therefore, a more rapid real-time PCR assay was evaluated for its suitability in screening swabs. Objective: To compare the results of a commercially available real-time PCR assay with routine microbiological culture for the identification of T. equigenitalis, the causative organism of contagious equine metritis, in equine genital swab samples, under 'field trial' conditions. Methods: Routine prebreeding genital swabs (n=2072) collected from Thoroughbred mares and stallions during 2...
Wilsher S, Ousey J, Allen WR.Abnormal cord attachment can be a manifestation of an inappropriate fixation position of the conceptus in the uterus, or it may result from disorientation of the conceptus post fixation. The potential for this resulting in fetal and neonatal compromise is reviewed in the light of previous reports and to which 3 cases within the authors' experience are added.
Veraa S, Voorhout G, Klein WR.Infundibular changes are frequently encountered computed tomographic studies of the equine maxillary cheek teeth but the possible importance of this finding is not known. Infundibular caries is a possible cause for pulpitis and apical infection in some horses. Objective: To study the relationship between the 2 pathologies and the frequency of changes. Methods: The maxillary cheek teeth 108-208, 109-209 and 110-210 of 25 horses were evaluated using computed tomography and both the prevalence of infundibular and apical infection changes as the possible link with apical infection evaluated statis...
Tóth F, Frank N, Chameroy KA, Bostont RC.Insulin resistance (IR) is a risk factor for pasture-associated laminitis in equids and alimentary carbohydrate overload may trigger laminitis. Whether glucose metabolism responses to carbohydrate overload are more pronounced in insulin-resistant horses requires further study. Objective: Horses pretreated with endotoxin to alter insulin sensitivity differ significantly in their glucose and insulin responses to carbohydrate overload. Methods: Horses (n=24) were divided into 3 groups. A lipopolysaccharide (LPS; n=8) group that received endotoxin as an 8 h 7.5 ng/kg bwt/h i.v. continuous rate inf...
Whittaker AG, Love S, Parkin TD, Duz M, Hughes KJ.Regulation of pH homeostasis in the equine lung is poorly understood. Measurement of exhaled breath condensate (EBC) pH provided a simple, highly repeatable and noninvasive method for the longitudinal investigation of changes in airway pH in response to environmental changes. Stabling of horses was found to lead to a small (approximately 100-200 parts/billion) but significant (P < 0.001) increase in ambient ammonia concentration when compared to pasture. This increase in exposure to ambient ammonia concentration was associated with significant (P = 0.002) increases in EBC pH and exhaled amm...
Hunter JO.Irritable bowel syndrome (IBS) in man is not a single entity but has several causes. One of the most common forms has similarities with colic and laminitis in horses. Undigested food residues may pass from the small intestine into the colon where bacterial fermentation produces chemicals that lead to disease. In horses the consequences may be disastrous, but in healthy humans such malabsorption may not be harmful. After events such as bacterial gastroenteritis or antibiotic treatment, an imbalance of the colonic microflora with overgrowth of facultative anaerobes may arise, leading to malferme...
Nolen-Walston RD, Parente EJ, Madigan JE, David F, Knafo SE, Engiles JB.This clinical report describes 8 cases of branchial remnant cysts (BRC) in the horse. The horses presented with bimodal age distribution, with 5 cases in mature horses (age 8-21 years) and 3 in foals (age 1, 6 and 10 months). Mature cases presented for dysphagia or intermittent oesophageal obstruction (2/5), and retropharyngeal swelling (3/5), whereas respiratory stridor and visible mass were presenting complaints in the foals. Presence of a right-sided (5/8) or dorsally located (2/8) palpable retropharyngeal mass of 3-35 cm diameter was noted clinically; one left-sided mass was identified as ...
Willing B, Vörös A, Roos S, Jones C, Jansson A, Lindberg JE.Diets rich in readily fermentable carbohydrates, fed traditionally to meet the increased energy requirements of the performance horse, are associated with a number of gastrointestinal disorders that involve disturbances in the intestinal microbiota, however, these changes are poorly understood. Objective: With the long-term objective of improving intestinal health and to increase understanding of the relationship between diet and microbiota, the effect of feeding Standardbred horses a high-energy forage-only (F) diet was studied compared to a more traditional forage-concentrate (C) diet on fae...
Meghoufel A, Cloutier G, Crevier-Denoix N, de Guise JA.The hypothesis is that an imaging technique based on decompression and segmentation of B-scan images with morphological operators can provide a measurement of the integrity of equine tendons. Methods: Two complementary approaches were used: (i) Simulation of B-scan images to better understand the relationship between image properties and their underlying biological structural contents and (ii) extraction and quantification from B-scan images of tendon structures identified in step (i) to diagnose the status of the superficial digital flexor tendon (SDFT) by using the proposed imaging technique...
Olive J, D'Anjou MA, Girard C, Laverty S, Theoret CL.Marginal osteophytes represent a well known component of osteoarthritis in man and animals. Conversely, central subchondral osteophytes (COs), which are commonly present in human knees with osteoarthritis, have not been reported in horses. Objective: To describe and compare computed radiography (CR), single-slice computed tomography (CT), 1.5 Tesla magnetic resonance imaging (MRI), and histological features of COs in equine metacarpophalangeal joints with macroscopic evidence of naturally-occurring osteoarthritis. Methods: MRI sequences (sagittal spoiled gradient recalled echo [SPGR] with fat ...
Withers JM, Voûte LC, Hammond G, Lischer CJ.Plain radiography is the standard imaging technique for investigation of diseases associated with the articular process joints (APJ) of the caudal neck; however, the radiographic anatomy of these structures on both lateral and oblique radiographic projections has not previously been described in detail. Objective: To determine the optimal technique for obtaining oblique radiographs of the APJ of the caudal cervical vertebrae (C4-5, C5-6 and C6-7) and to provide a detailed description of their normal radiographic appearance, on both lateral and oblique radiographic projections. Methods: Radiopa...
van Eps AW.Acute laminitis is a serious complication of many primary conditions in the horse. This article summarizes the most appropriate approach to management of the horse with acute laminitis, based on current information.
Rucker A.In the chronic-laminitic foot, severe soft-tissue compression and compromised circulation can result in osteitis and sepsis at the margin of the distal phalanx. Resultant inflammation and sepsis may cause the coronary corium to swell, drain, or separate from the hoof capsule, usually within 8 weeks of laminitis onset. Slow-onset cases of soft-tissue impingement can develop secondary to distal phalanx displacement due to lack of wall attachment. With either presentation, partial upper wall resection is required to reverse compression and vascular impingement by the hoof capsule. If the patholog...
Hajialilo E, Ziaali N, Harandi MF, Saraei M, Hajialilo M.In the present study, the prevalence of antibodies to Toxoplasma gondii in sport horses of Qazvin was examined using modified agglutination test (MAT). On 52 horse sera totally examined for anti-Toxoplasma antibodies, 37 horses (71.2%) were seropositive by MAT. Results of the present study showed a high rate of Toxoplasma infection in horses in Qazvin area. More comprehensive study on equine toxoplasmosis is recommended.
Belknap JK.The black walnut extract (BWE) model was developed after the discovery that horses bedded on shavings from black walnut trees commonly developed laminitis. The first investigators that consistently induced laminitis with black walnut shavings established that it was only the heartwood of the tree that induced laminitis. The BWE model of laminitis has allowed investigators to determine many of the early pathologic signaling events likely to occur in the developmental and acute clinical stages of the disease process, and has brought inflammatory injury to the forefront of laminitis research. The...
Pollitt CC, Visser MB.In acute laminitis, the suspensory apparatus of the distal phalanx fails at the lamellar dermal/epidermal interface. A grading system for the histopathology of laminitis is based on the consistent pattern of histologic changes to the secondary epidermal lamellae, basal cells, and basement membrane that occur as carbohydrate-induced laminitis develops. The actual trigger factors of carbohydrate-induced laminitis remain unidentified.
van Eps AW.Digital hypothermia successfully reduces the severity of experimentally induced laminitis. Continuous-distal limb cryotherapy may be a useful technique in clinical cases that are at risk of developing laminitis. This article examines the effects of hypothermia on tissue as well as the rationale, and suggested protocols for the usage of distal limb cryotherapy in the prevention and treatment of laminitis.
Engiles JB.The etiopathogenesis of laminitis is complex and involves multiple tissue types. It may be initiated by biomechanical, traumatic, inflammatory, vascular, toxic, and metabolic factors. Although histopathologic changes occurring within the lamellae of experimental models of laminitis are well described and reported, histopathologic changes occurring in the distal phalanx are not, even though gross and radiographic evidence of disease are often apparent and bony lesions could be considered a significant source of pain. Recent scientific evidence indicates that the microenvironment of bone is an i...
Heymering HW.The causes of laminitis are many-often interrelated, sometimes direct opposites. The history of laminitis has been a search for the cause or causes of laminitis and for effective treatment. Going in and out of fashion, many treatments have lasted for centuries, some for millennia, but very few have been proven.
Heymering HW.For most of history, the causes of laminitis have been based on observations. In the last 30 years or so, however, the number of theories has exploded, with only a few being confirmed by experiments. This article highlights these theories.
Love CC.Ultrasonographic examination of the testis, epididymis, and spermatic cord of the stallion can be used to enhance the routine breeding soundness evaluation of the stallion. Normal ultrasonographic anatomy of the testes and associated structures are presented to aid the clinician in differentiating abnormalities of these structures.
Webbon PM.The normal appearance of the superficial (SFT) and deep (DFT) digital flexor tendons was described and the difference between their histological structures was emphasised. Further differences were recognised between different sites from the same tendon and between tendons in the fore and hind limbs of the same animal. Both of the tendons underwent changes with age but although a number of alterations in the histological appearance were described, a particular change, involving a patchy loss of stainable nuclei, was found at the common site of SFT injuries. While this appearance has been seen i...
Morris DD, Moore JN.The formation of eicosanoids may be a primary route through which platelet activating factor (PAF) exerts its effects during endotoxemia. Since endotoxemia is a common cause of death in horses, a study was conducted to determine whether PAF could stimulate equine macrophage release of thromboxane A2 (TxA2) and prostacyclin (PGI2) and whether a PAF-receptor antagonist would alter macrophage eicosanoid synthesis. Equine peritoneal macrophages were cultured from clinically normal horses and exposed to various concentrations of PAF, the PAF-receptor antagonist SRI 63-441, endotoxin, or a combinati...
Palmer E, Duchamp G, Cribiu EP, Mahla R, Boyazoglu S, Bézard J.The aim of this study was to test the possibility that ovulation can occur from a preovulatory follicle emptied of its follicular fluid. Transport of the oocyte into the oviduct and fertilisation in 29% of cases demonstrated that ovulation can occur in the absence of follicular fluid but the higher fertility achieved in control mares (62.5%) suggested that follicular fluid does serve a role during ovulation, fertilisation and oviductal transport. Injection of horse oocytes into preovulatory follicles in mules after removal of the follicular fluid, followed by insemination of the mules with hor...
Dirikolu L, Hughes C, Harkins D, Boyles J, Bosken J, Lehner F, Troppmann A, McDowell K, Tobin T, Sebastian MM, Harrison L, Crutchfield J, Baskin SI....The epidemiological association between black cherry trees and mare reproductive loss syndrome has focused attention on cyanide and environmental cyanogens. This article describes the toxicokinetics of cyanide in horses and the relationships between blood cyanide concentrations and potentially adverse responses to cyanide. To identify safe and humane blood concentration limits for cyanide experiments, mares were infused with increasing doses (1-12 mg/min) of sodium cyanide for 1 h. Infusion at 12 mg/min produced clinical signs of cyanide toxicity at 38 min; these signs included increased heart...
Moreno-Irusta A, Dominguez EM, Marín-Briggiler CI, Matamoros-Volante A, Lucchesi O, Tomes CN, Treviño CL, Buffone MG, Lascano R, Losinno L....Sperm chemotaxis may facilitate the finding of the oocyte. Only capacitated spermatozoa can orient their movement by chemotaxis, which as well as capacitation, is regulated in part by the cAMP-PKA pathway. Reactive oxygen species (ROS) are produced during sperm capacitation which is closely related to chemotaxis. Then, the ROS participation in the chemotactic signaling can be expected. Here we studied the role of ROS in the chemotaxis signaling of equine spermatozoa which produce high quantities of ROS because of their energy metabolism. The level of capacitated and chemotactic spermatozoa was...
Sebastian MM, Giles RC.Fibrocartilaginous embolic myelopathy was diagnosed in a 11-year-old, male, Tennessee Walking Horse by histopathological examination of the spinal cord after the horse was killed because of severe neurological dysfunction. Both ventral funiculi of C6 and C7 cervical spinal cord had extensive necrosis with blood vessels containing fibrocartilaginous emboli. A similar fibrocartilaginous embolus was observed in a single large spinal artery adjoining the vertebral leptomeninges.
Miles CA, Wardale RJ, Birch HL, Bailey AJ.Differential scanning calorimetry (DSC) of equine superficial digital flexor tendons revealed the presence of a small exothermic peak at 23 degrees C of unknown origin, and a large endothermic peak at 70 degrees C due to denaturation of cross-linked collagen fibres. In the central degenerated core of damaged tendons the denaturation temperature remained at 70 degrees C but the enthalpy decreased in relation to the extent of degeneration of the tendon. We suggest that this reduction in enthalpy is due to depolymerisation and denaturation of the collagen fibres. This contention is supported by t...
Hance SR, Embertson RM.Colopexies were performed in 44 broodmares requiring abdominal surgery for large colon volvulus or right dorsal displacement of the large colon. Colopexies were performed by suturing the lateral bands of the left and right ventral colon to the ventral abdominal wall. Forty-seven percent of the mares in which a colopexy was performed had previous surgery for a large colon volvulus or right dorsal displacement of the large colon. Postoperative complications considered directly associated with the colopexy procedure were intermittent abdominal pain in 7, reoperation in 5, subcutaneous fistulous t...