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.
Schuh JC.Bilateral true colobomas with retrobulbar cysts located over the optic nerves are described in an 8-year-old Quarterhorse mare with a history of progressive blindness. Colobomas result from the failure of an embryonic fissure to close and retrobulbar cysts result from eversion of the neuroectoderm through the colobomas. It could not be determined whether the small optic nerves and the scars, rosettes and disorganization of the cell layers in the retina were the result of concurrent dysplasia or were secondary to degeneration.
Moyer W.The foot is the most common source of limb pain. The problems vary from simple to quite complex. An accurate diagnosis is dependent upon a thorough and detailed knowledge of anatomy and of what is available in the way of ancillary examination techniques. The correction of most foot problems requires an appreciation of a multitude of factors and a thorough knowledge of farrier science.
Shadomy HJ, Dixon DM.An unusual fungus, probably traumatically introduced into the eye of a horse while grazing, was studied on various mycological media. Upon examination of colonies the organism produced bulbils and clearly exhibited the characteristics of a new species of Papulaspora, P. equi Shadomy & Dixon.
Cox JH, DeBowes RM, Leipold HW.Two cases of congenital malignant melanomas in horses are described in this report. In each case, wide surgical excision of the mass was performed; no recurrence or metastasis was detected after a minimum of 15 months' follow-up. Melanomas are among the most common neoplasms of horses, but they typically develop in gray horses greater than 6 years old.
Hamir AN.During a routine necropsy examination of a 4-year-old standardbred mare, a well-demarcated dermal mass was seen near the right elbow. Grossly, the mass consisted of multifocal variably sized areas of dark brown, firm material that was separated by thin white septa. Histologically, within the individual compartments, there were numerous multinucleated giant cells, macrophages, and free erythrocytes. A diagnosis of giant cell tumor of soft tissues was made.
Steiss JE, White NA, Bowen JM.Electroacupuncture was used to treat lameness in horses and ponies with chronic laminitis (n = 10) or navicular disease (n = 10). A clinical trial was conducted with random allocation of equal numbers of animals to control and treatment groups. Acupuncture was performed three times per week for four consecutive weeks. The degree of lameness was assessed by 1) a grading scheme, 2) measurement of stride lengths and 3) analysis of weight distribution using a force plate. Although seven out of ten animals with chronic laminitis improved clinically during the trial, there were no statistically sign...
Goetz TE.The structural and vascular anatomy of the healthy equine foot is compared with the pathologic changes in the foot of horses with acute and chronic laminitis. The structural and vascular abnormalities present in the foot of horses with laminitis are demonstrated in order to explain the abnormal manner in which their feet grow. The medical, surgical, dietary, and endocrine management of acute and chronic laminitis is discussed. Various forms of hoof trimming beneficial to the reestablishment of normal digital perfusion, normal hoof growth, and normal spatial orientation among the distal phalanx...
Stashak TS.The causes, clinical signs and various approaches to treatment of injuries involving the foot and pastern regions are reviewed, and the prognosis for each type of injury is discussed.
Hooper RN.Necropsy of a 12-year-old Quarter Horse mare revealed a blind-end segment of intestine originating from the antimesenteric border of the ileum. The blind-end segment had looped around and strangulated the ileum and 3.5 m of the jejunum.
Kainer RA.A review of investigations of the functional anatomy of the equine foot is presented. Emphasis is placed on the relationships of structures involved in the major diseases of the foot.
DeBowes RM, Yovich JV.Foot-associated lamenesses are common diagnostic challenges for the equine practitioner. This article reviews the commonly occurring penetrating and concussive solar injuries of the equine foot. Diagnostic and therapeutic approaches for the management of these conditions are suggested. With proper treatment, many of these serious injuries will show excellent results.
Pool RR, Meagher DM, Stover SM.Navicular syndrome is a degenerative disorder of the distal half of the flexor surface of the proximal sesamoid bone that is predisposed by faulty foot conformation. In horses that become symptomatic, the faulty conformation results in sustained application of nonphysiologic pressure by the deep digital flexor tendon against the flexor cortex of the bone. This force stimulates an intense bone remodeling response in order to attenuate the pressure. An unfortunate sequela of this response is active hyperemia and edema formation in the medullary cavity of the bone. The edema is organized by fibro...
Shirakawa T, Ide M, Taniyama H, Tobiwatari K, Senba H, Oishi H, Matsui T, Ono T.A 1-month-old male thoroughbred foal, which had difficulty in walking, was killed and examined by histological, histochemical and ultrastructural methods. The muscles of the trunk and upper hind limbs were chiefly affected, and changes in the affected muscles resembled those in muscular dystrophy in man. The type of muscular dystrophy present in this foal and the significance of this disease in thoroughbred horses are discussed. The dystrophy in this foal resembled the limb-girdle type or myotonic dystrophy of muscular dystrophy in man.
Moore JN, Allen D, Clark ES.This article reviews research findings relating to the pathophysiology of acute laminitis in horses. The data presently available suggest that the onset of the condition may be due to constriction of the postcapillary vessels in the digit, leading to increased capillary hydrostatic pressure and movement of fluid into the interstitial space.
Park RD.A complete radiographic examination of the equine foot consists of properly exposed, processed, and positioned radiographs. For radiographic interpretation, in addition to knowing radiographic signs of disease, a knowledge of normal radiographic anatomy and possible insignificant anatomic variations is necessary.
Posnett ES, Ambrosio RE.This report describes DNA probes for the identification of Babesia equi. A genomic library of B. equi was constructed in pUC13. Several clones were identified that hybridized strongly to B. equi DNA. Clone pBE33 hybridized specifically to B. equi DNA and did not hybridize to horse DNA nor to DNA from Babesia caballi, Babesia bovis or Babesia bigemina. Two subclones of pBE33 (pSB20 and pEH21) containing B. equi repetitive sequences, could detect 0.49 ng and 0.97 ng B. equi DNA, respectively.
Turner TA.Navicular syndrome can be treated in a variety of ways. This is related to the fact that it has a variety of causes. Prognostically, most horses will improve with treatment. One can expect about 50 per cent of the horses to become useably sound for 1 year, no matter what treatment is used. The disease is progressive, and affected horses eventually will need to be retired because of lameness. The author's therapeutic approach is to utilize shoeing as the primary therapy. Shoeing is performed to correct structural problems and to ensure that shoeing is physiologically sound. Nonsteroidal anti-in...
Reeves MJ, Yovich JV, Turner AS.The etiology, clinical presentation, radiographic findings, diagnostic criteria, differential diagnoses, treatment, and prognosis are reviewed for several clinically important conditions of the equine foot. These include pedal osteitis, sheared heels, distal sesamoid bone (navicular) fractures, subchondral bone cyst of the distal phalanx, distal interphalangeal joint subluxation, congenital phalangeal hypoplasia, bipartite and tripartite distal sesamoid bones, keratoma, ossification of the cartilages of the distal phalanx (sidebones), necrosis of the cartilages of the distal phalanx (quittor),...
Trotter GW, Yovich JV, McIlwraith CW, Norrdin RW.The effect of intramuscular polysulfated glycosaminoglycan (PSG) on repair of cartilage injury was evaluated in eight horses. In each horse, one middle carpal joint had both a partial-thickness and a full-thickness articular cartilage defect created. In the contralateral middle carpal joint, chemical articular cartilage injury was created by intra-articular injection of 50 mg sodium monoiodoacetate (MIA). Horses were divided into two groups for treatment. Group 1 horses (control) received an intramuscular injection of normal saline every four days for a total of seven injections starting seven...
Engelking LR, Anwer MS, Hofmann AF.The role of bile salt in biliary lipid excretion was studied in 3 healthy ponies with chronic external biliary fistulas. After endogenous bile salt pool depletion, micelle-forming taurocholate or taurochenodeoxycholate was infused to replace excreted bile salt. Enterohepatic circulations were held open (total biliary diversion) throughout each study. Results indicated that biliary lipid excretion in ponies (113 +/- 21 nmol/min/kg of body weight) is approximately 10 times less than that reported in rodents. Although the lipid composition (4.4% cholesterol, 5.6% phospholipid, and 90% bile salt) ...
Baxter GM, Laskey RE, Tackett RL, Moore JN, Allen D.The in vitro reactivity of vasoconstrictive mediators that are implicated in acute laminitis was determined in palmar and plantar digital arteries and veins obtained from healthy horses and in palmar digital vessels of horses with early laminitis (Obel grade I). To obtain baseline reactivity data, 3 experiments were conducted, using healthy horses: (1) the reactivity of palmar and plantar digital arteries and veins to angiotensin II, norepinephrine, and 5-hydroxytryptamine (serotonin) were compared; (2) the direct effects of bacterial endotoxin on vascular reactivity were assessed; and (3) the...
Ducharme NG, Horney FD, Hulland TJ, Partlow GD, Schnurr D, Zutrauen K.The purpose of this project was to attempt restoration of abduction of a recently experimentally denervated left dorsal cricoarytenoid muscle by implanting a transected nerve-end into the paralyzed muscle. In six ponies the cut end of the second cervical nerve was implanted into a slit made in the left dorsal cricoarytenoid muscle. The nerve end was secured in place with one 5-0 polypropylene suture connecting the epineurium to the epimysium. The left recurrent laryngeal nerve was transected during this procedure. All six ponies showed signs of complete left laryngeal hemiplegia immediately af...
Lyons ET, Drudge JH, Tolliver SC, Swerczek TW, Collins SS.A total of 59 equids (54 horses and five Shetland ponies) were treated with pyrantel pamoate once, at the dose rate of approximately 6.6 mg base kg-1, during the period November 1985-January 1988. The drug was administered as a paste formulation (51 equids) intraorally or as a suspension formulation by stomach tube (eight equids). The purpose of treatment was to evaluate the activity of pyrantel pamoate (at the therapeutic dose rate) for removal of the tapeworm, Anoplocephala perfoliata, by a modified (24-h) critical test. The presence or absence of tapeworms was not determined for the equids ...
Waelchli RO, Winder NC.The distribution of histopathological lesions in the equine endometrium was examined to investigate the representativeness of a single biopsy specimen in terms of the whole endometrium. Five sections from each of 110 uteri obtained from slaughtered mares were evaluated microscopically and classified according to a four-category grading system used for endometrial biopsies. Depending on the extent of agreement between the categories of the homologous sections, the uteri were considered to show either good agreement (81 uteri; 73.6 per cent), moderate agreement (26 uteri; 23.6 per cent) or poor ...
Wheeler SJ, Plummer JM.Transverse sections of the lateral palmar nerve from a group of horses free from neuromuscular disease were assessed quantitatively, with emphasis on differences in the fibre population related to age. Morphometric analysis of the population of myelinated and unmyelinated fibres was performed. Changes were identified, there being a loss of larger myelinated fibres in older horses. The relationship of myelin thickness to axon diameter and the unmyelinated fibre population did not alter with age. The lateral palmar nerve is suitable for biopsy and electrophysiological study in the horse, but age...
Moorman VJ, Jann HW.A 2-day-old Thoroughbred intact female was presented for a large subcutaneous swelling in the right inguinal region. Surgical repair was performed using a double layer polypropylene mesh. To the authors' knowledge, there have been no previous reports of surgical repair of congenital body wall hernias with polypropylene mesh in foals. Une femelle pur sang intacte âgée de deux jours est présentée pour de l’enflure sous-cutanée importante dans la région inguinale droite. Une réparation chirurgicale est réalisée en utilisant une double couche de maille de polypropylène. À la connaiss...
Perryman LE, Mason PH.Monoclonal antibodies (MAbs) have been successfully used to evaluate immune responses in horses, and to target important antigens of equine infectious agents to which protective immune responses may be directed (1–5). Most of these studies are performed with murine MAb produced by fusing spleen cells from immunized mice with an appropriate myeloma cell line, as described in Chapter 3. However, there are experimental questions for which murine MAb are not adequate. These include:
1.Definition of microbial epitopes recognized by the infected host;
2.Identification of immunodominant epito...
Kruger K, Saulez MN, Neser JA, Solberg K.Lead (Pb) intoxication in horses is usually a chronic phenomenon with clinical signs associated with central nervous dysfunction. This report gives details of a case of acute Pb intoxication in a 9-year-old American Saddlebred mare with severe, progressive and ultimately fatal neurological deterioration. During the 4 days of hospitalisation, clinical signs progressed from intermittent headshaking and depression to severe, continuous, uncontrollable manic behaviour. At autopsy, three grey-coloured, hard metal particles were present in the gastrointestinal tract and subsequently found to contain...
Klomkleaw W, Kasashima Y, Kobayashi A, Fuller GA, Morimoto M, Nakade T, Muto M, Oba T, Hamlin RL, Yamaguchi M.Tubular aggregates (TAs) originate from the sarcoplasmic reticulum (SR) and form polymorphic double (or single) -walled structures in cross section. TAs are involved in various human skeletal muscle disorders including periodic paralysis, congenital myasthenic syndromes, inflammatory myopathies, and malignant hyperthermias. Horse lumbrical muscle (LM) is a slender fusiform muscle that shows varying degrees of regression due to its limited activity in the limb. Double-walled TAs were found in degenerating spindle fibers and with a range of 80-116 nm (average 92 nm, n=135) for outer layer and 50...
Eberly VE, Tyler WS, Gillespie JR.EBERLY, V. E., W. S. TYLER, AND J. R. GILLESPIE. Cardio-vascular parameters in emphysematous and control horses. J. Appl. Physiol. 2 1 (3) : 883-889. I 966.—Horses with clinical signs of chronic pulmonary emphysema were demonstrated to have heart rates, total peripheral vascular resistance, pulmonary vascular resistance, and mean pulmonary artery blood pres-sure highly significantly greater than normal. They also had a highly significant decrease in central blood volume, stroke volume, stroke index, and left ventricular work. Cardiac out-put was significantly lower than in control (normal) h...