Veterinary medicine for horses encompasses the study and application of medical practices to diagnose, treat, and prevent diseases in equine species. This field involves a comprehensive understanding of equine anatomy, physiology, pathology, and pharmacology. Veterinary practitioners employ a range of diagnostic tools and therapeutic interventions to address health issues in horses, including lameness, gastrointestinal disorders, respiratory conditions, and infectious diseases. Preventative care, such as vaccination and deworming programs, is also a significant aspect of equine veterinary medicine. This page gathers peer-reviewed research studies and scholarly articles that explore various aspects of veterinary medicine as it pertains to horses, including advancements in diagnostic techniques, treatment protocols, and preventive health strategies.
Nyman G, Funkquist B, Kvart C, Frostell C, Tokics L, Strandberg A, Lundquist H, Lundh B, Brismar B, Hedenstierna G.The anatomical basis of gas exchange impairment in the anaesthetised horse was studied by computerised tomography (CT; three shetland ponies) and morphological analysis (one pony and three horses). By means of CT, densities were seen in dependent lung regions early during anaesthesia, both with spontaneous breathing and with mechanical ventilation. The densities remained for some time where they had initially been created when the animal was turned from dorsal to sternal recumbency. Deep insufflation of the lungs reduced the dense area. Gas exchange was impaired roughly in proportion to the de...
Daels PF, Shideler S, Lasley BL, Hughes JP, Stabenfeldt GH.Oestrogen secretion was determined by oestrogen conjugate (EC) analysis of urine in three groups of pregnant mares: Group I (N = 6), animals ovariectomized on Day 18-19 of gestation with pregnancy maintained by daily administration of an oral progestagen, altrenogest; Group II (N = 9), untreated, pregnant mares; Group III (N = 5) intact, pregnant mares treated daily with altrenogest. The mean EC concentrations in the ovariectomized mares in Group I increased in a constant linear manner from 17 ng/mg Cr on Day 20 to 291 ng/mg Cr on Day 70, with no apparent surge in oestrogen secretion around Da...
du Plessis DH, van Wyngaardt W, Bremer CW.African horsesickness virus (AHSV), an important disease of equines is caused by an orbivirus. Because of the need to contain the spread of the disease, it is often essential to make a rapid diagnosis. For this purpose, an ELISA capable of detecting viral antigen in animal tissue and in cell culture fluid was developed. Immobilised F(ab')2 fragments prepared by digestion of AHSV-specific IgG with pepsin were used to trap virus from tissue homogenates or cell culture supernatant. After addition of intact IgG as detecting antibody, Staphylococcus aureus protein A labelled with horseradish peroxi...
Levine JF, Levy MG, Nicholson WL, Gager RB.Larval Dermacentor variabilis (Say) (n = 327) were fed on Balb/C mice inoculated with Ehrlichia risticii, the etiologic agent of equine monocytic ehrlichiosis (Potomac horse fever). All mice displayed clinical signs of E. risticii infection at the time of feeding. After molting, resulting nymphs (n = 74) were fed on susceptible mice. No clinical signs were observed, and the mice remained seronegative for 6 wk after feeding.
Riley CB, Yovich JV, Huxtable CR.A fusion defect of the proximal and middle phalanges of both hindlimbs, osteochondrosis dissecans of the distal interphalangeal joints of the forelimbs, and subluxation of all 4 distal interphalangeal joints occurred in a Standardbred filly. Lameness was the first abnormality noted and was observed at one week of age in the left forelimb and progressed until all 4 limbs were affected by 5 weeks of age. On radiographs of both forelimbs, the distal interphalangeal joints were subluxated with irregularity and lucency of subchondral bone. On radiographs of the distal hindlimbs, there was a subluxa...
Milne EM, Doxey DL, Gilmour JS.The analysis of peritoneal fluid is of value in the differential diagnosis of equine colic but its characteristics have not been evaluated in grass sickness. Peritoneal fluid was collected from 15 normal horses and from 11 cases of medical colic, 11 cases of surgical colic, 20 cases of acute grass sickness and 13 cases of subacute grass sickness. The fluid was analysed for its appearance, total and differential white cell count, specific gravity, total protein concentration and total and intestinal alkaline phosphatase activity. Fluid from cases of medical colic was normal in these respects. S...
Holt PE, Mair TS.Bladder paralysis and sabulous urolithiasis were diagnosed in 10 horses with urinary incontinence. Additional neurological deficits in the hindquarters were detected in five of them. Treatment by catheter drainage and bladder lavage was unsuccessful, and all the horses were destroyed within 14 months of presentation. Neuritis of the cauda equina was diagnosed post mortem in one horse, but the cause of the paralysis was not identified in the others, although radiography revealed abnormal lumbosacral vertebral angulation in one case.
Singh AK, McArdle C, Ashraf M, Granley K, Mishra U, Gordon B.Equine plasma and urine samples were analyzed by using a high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent assay (ELISA) and particle concentration fluorescence assay (PCFIA). Although ELISA and PCFIA were rapid, simple and sensitive for the screening of furosemide, they did not give reproducible quantitative results. The HPLC method, which required relatively longer analysis time, provided simple and reproducible quantitative analysis of furosemide in plasma and urine. The performance of the three methods was compared for the quantitation of furosemide in plasma obtai...
Kohn CW, Jacobs RM, Knight D, Hueston W, Gabel AA, Reed SM.At birth, 24 Standardbred foals were assigned at random to 1 of 2 groups and were given a placebo supplement (group 1) or an iron supplement (248 mg of iron/treatment; group 2). Foals were given iron supplement or placebo 4 times during the second and third weeks after birth. Hematologic variables and general health were monitored until foals were 4 months old. Mean PCV in foals of both groups decreased during the first 2 weeks after birth, but values remained within adult horse reference ranges. During the first 6 weeks after birth, foal erythrocytes were smaller than adult horse erythrocytes...
Hamada M, Itakura C.The morphology of hypomelanosis occurring in experimentally induced equine papillomas was investigated. Histologically, dopa-positive functioning melanocytes were decreased in number from the basal layer in the epidermis. Electron-microscopically, melanogenic organelles in the melanocytes were degenerate and melanosomes were decreased in number and size. In addition, the melanocytes had some abnormal melanosomes including melanosome complexes and giant melanosomes. Some abnormal melanosomes were also present in the keratinocytes. The hypomelanosis seemed to be related to a disturbance in melan...
Lalatta Costerbosa G, Barazzoni AM, Clavenzani P, Callegari E.In this study the histochemical fiber type analysis of the articularis humeri muscle of the horse was performed. This muscle is composed of type I and type IIA fibers. A large number of spindles has been observed and the presence of these receptors could help to understand the role played by this muscle.
Cuvelliez SG, Eicker SW, McLauchlan C, Brunson DB.Anesthesia of equids is associated with pulmonary dysfunction. Cardiovascular and respiratory effects of inhalation anesthetic agents and duration of anesthesia have been studied, using oxygen as the carrier gas. To our knowledge, the effects of inspired oxygen have not been determined. We studied the cardiovascular and respiratory effects of 2 inspired oxygen fractions (0.30 and greater than 0.85) in 5 laterally recumbent, halothane-anesthetized horses. Mean systemic arterial blood pressure, cardiac output, central venous pressure, pulmonary arterial pressure, arterial pH, and arterial base e...
Lawrence LM.Substrate depletion and end product accumulation are two important factors in exercise fatigue. Fatigue during long-term exercise results from a depletion of muscle and liver glycogen and coincides with an inability to maintain blood glucose levels. During high intensity exercise, the rapid catabolism of carbohydrate and the resultant production of lactate and hydrogen ions cause a reduction in muscle pH that inhibits maximum force generation. Dietary manipulations that can influence carbohydrate status or lactate accumulation may be beneficial to performance. In human athletes, carbohydrate l...
Bürki F, Rossmanith E.Selected sets of serum samples of horses were tested blindly in a comparative investigation for antibodies against Equine Infectious Anemia (EIA) virus. Three commercial kits were used, a well-established agar-gel immuno-diffusion kit which our laboratory has been using routinely for 14 years on one hand, a competitive ELISA kit (CELISA) and a non-competitive ELISA kit on the other hand. The American EIA Reference Laboratory in Ames cotested 56 serum samples with the same 3 products, with highest-level correlation, thereby ascertaining full dependability of our own results. Five EIA experts su...
Ekfalck A, Appelgren LE, Funkquist B, Jones B, Obel N.The distribution of 35-S-labelled cysteine and methionine in the epidermis of the equine hoof following 2 hours of intra-arterial injection was studied by microautoradiography. Material for autoradiography was obtained by biopsy about 1 hour after termination of the intra-arterial injection and also 10 and 40 days later. In the specimens obtained one hour after the injection of labelled cysteine and methionine, the amount of radioactivity in the matrix and in the most proximal part of the laminar layer was very high. There was a clear difference between the distribution of the two labelled ami...
Jasko DJ, Lein DH, Foote RH.The analysis of breeding records and sperm morphologic classifications from ejaculated semen during 99 stallion seasons, over a 2-year period, revealed a significant correlation (r = 0.34, P less than 0.01) between the percentage of morphologically normal sperm in ejaculates and the per cycle fertility estimate of the stallions studied. In addition, the percentage of sperm classified as having major defects (abnormal heads, proximal droplets, and abnormal midpieces) was significantly inversely correlated (r = -0.36, P less than 0.01) with the same fertility estimates. Multiple variable regress...
Donoghue S, Meacham TN, Kronfeld DS.Cumulative nutritional demands on good brood mares are unrivalled among domestic livestock, but little attention has been given to the influence of nutrition on their reproductive performance and efficiency. We suggest that part of the decline in racing performance of progeny of mares over 10 years of age may be caused by suboptimal nutrition. This article contrasts the concepts of minimal and optimal nutrient requirements, revives Hammond's concept of nutrient partitioning to the conceptus and mammary gland, and discusses energy and nutrient requirements during gestation and lactation. Furthe...
Schryver HF.Horses are subject to poisoning from many sources. This article considers poisonings from minerals and vitamins of nutritional significance and from minerals as environmental contaminants.
Gasthuys F, de Moor A, Parmentier D.Haemodynamic and respiratory responses to halothane were investigated in dorsally recumbent, ventilated ponies during 2 hours. Normocapnia was maintained using intermittent positive pressure ventilation. Compared to the base line values at 30 minutes of constant dose halothane, no significant changes in heart rate, systemic blood pressure, cardiac output, cardiac index, stroke volume and left ventricle work were observed during a 2 hours anaesthesia. Arterial oxygenation increased initially (greater than 300 mm Hg) but tended to decrease non-significantly during the rest of the anaesthesia. Bl...
Seethanathan P, Bottoms GD, Schafer K.Direct effects of endotoxin (lipopolysaccharide [LPS]) on equine WBC are known to stimulate the release of a variety of mediators including thromboxane, prostacyclin, and leukotrienes. In this study, 0.1 microgram of LPS/ml stimulated an early increase in tumor necrosis factor, succeeded by an increase in interleukin-1, but concentrations of LPS up to 5.0 micrograms/ml caused no significant increase in superoxide anion release. The concentration of LPS (0.1 microgram/ml) used in this experiment was in the range of concentrations measured in plasma of some horses with gastrointestinal problems....
Shires GM, Adair HS, Patton CS.In an attempt to ablate the laryngeal saccule as an alternative method of sacculectomy (conventially done through a laryngotomy incision for laryngeal hemiplegia) a neodymium:yttrium aluminum garnet laser was used transendoscopically in noncontact fashion in 6 horses. The procedure was easy, quick, and labor-saving, with few complications. Endoscopically, the lased sacculectomy site appeared healed at postsurgical day 42. On postsurgical day 42, microscopic examination revealed mucosal remnants under the granulation bed. Laser energy caused thermal damage to tissues adjacent to the lased saccu...
Mfitilodze MW, Hutchinson GW.A postmortem survey of 57 horses in tropical northern Queensland revealed 41 (89%) infected with intestinal strongyles. Thirty-five strongyle species (8 large strongyles and 27 small strongyles [Cyathostominae]) were recorded of which 9 species are reported from Australia for the first time. The 14 most prevalent small strongyles were Cyathostomum catinatum (in 76% of horses), Cyathostomum coronatum (65%), Cyathostomum pateratum (33%), Cyathostomum labiatum (30%), Cylicostephanus calicatus (70%), Cylicostephanus longibursatus (67%), Cylicostephanus goldi (43%), Cylicostephanus minutus (26%), C...
Houpt KA, Zahorik DM, Swartzman-Andert JA.The ability of ponies to learn to avoid a relatively novel food associated with illness was tested in three situations: when illness occurred immediately after consuming a feed; when illness occurred 30 min after consuming a feed; and when illness was contingent upon eating one of three feeds offered simultaneously. Apomorphine was used to produce illness. The feeds associated with illness were corn, alfalfa pellets, sweet feed and a complete pelleted feed. The ponies learned to avoid all the fees except the complete feed when apomorphine injection immediately followed consumption of the feed....
Whitlock RH.The equine practitioner often encounters serious diagnostic and therapeutic challenges regarding the specific origin of a disease. Such challenges may occur when horses become unaccountably ill after consuming what was thought to be acceptable feed but which in fact was contaminated or contained additives intended for other species. Examples of such additives and contaminants are monensin, lasalocid, salinomycin, blister beetles, and such antimicrobics as lincomycin and clindamycin.
Epstein K, Short D, Parente E, Reef V, Southwood L.The objective was to characterize ultrasonographic changes in bowel wall thickness, contractility, degree of distension, luminal contents, and peritoneal fluid associated with exploratory celiotomy in normal ponies. Gastrointestinal ultrasonographic examination was performed in 14 ponies on days 1, 3, 5, and 7 after an exploratory celiotomy. Wall thickness, contractility, degree of distension, and luminal contents were recorded for the duodenum and jejunum. Stomach wall thickness and location, cecal wall thickness, and peritoneal fluid location and character were recorded. Peritoneal fluid was...
Nagy A, Dyson SJ, Murray JK.Information acquired from endurance riders and its relationship with the results of the ride has not been investigated. The aims of this study were to assess associations between data provided by riders and data obtained from the Fédération Equestre Internationale (FEI) website at FEI endurance rides and to identify whether data provided by riders in pre- and post-ride questionnaires was subject to response and/or information bias. Variables were collected from the FEI website and from self-completed pre-ride and post-ride questionnaires at 20 FEI endurance rides in 2011 and 2012. Kappa stat...
Evans DL, Polglaze KE.The presence of abnormal T waves in three or more electrocardiographic leads has been used to diagnose the cause of poor race performance in horses. This study investigated the relationship between previous racing performance in Standardbred horses and T waves, and the effect of training on the T wave. Thirty-two horses were electrocardiographed in two Sydney racing stables. Sixteen horses (50%) had ECGs with three or more leads with abnormal T waves, and these horses had won more races, had a greater ratio of wins per start and a greater number of dollars earned per start than horses with les...
Knospe C, Budras KD.To answer the many open questions concerning the development of the horse's ovary, first the prenatal development was investigated. It resulted that follicles derive from the germinal epithelium and its cords, whereas the Leydig cells and the rete blastema originate from the mesonephros. In the second third of pregnancy the Leydig cells undergo an enormous proliferation, in the last third they degenerate. However this degeneration is not connected with the postnatal development of the ovulation groove.
Rumpel AS, De Carvalho AL, Vassoler JM, Schmidt ML, Mertz CC, Rozo CAC, Campos JK, Alievi MM. The aim of this study was to compare the biomechanical properties of two minimally invasive arthrodesis techniques of the equine proximal interphalangeal (PIP) joint (three transarticular 5.5-mm cortical screws [AO-3TLS] vs. two transarticular 7.0-mm headless cannulated multi-use compression screws [MUC-2TS]) in dynamic non-destructive testing and compression testing to failure. Methods: The experimental study included six pairs of cadaveric adult equine forelimbs; one limb from each horse was randomly assigned to one of the treatments, and the contralateral limb was submitted to the rem...
St Lawrence AC, Lawrence LM, Coleman RJ.Many studies have examined the effect of pre-exercise feeding on glucose and insulin responses of horses. The objective of this study was to determine whether exercise performed one hour prior to a meal would attenuate the glucose and insulin responses to a meal. Data collected from 8 mature geldings in a 2 period crossover design experiment were used to determine the postprandial glucose and insulin responses to a meal of oats offered 1 h postexercise. During each period, 4 horses received a test meal following a 14 h fast (NoEx) or a 14 h fast and exercise bout (PostEx) that consisted of 48 ...
Ysebaert MP, Johnson JP, Abbas G, Cavalcante PH, King R, Oikawa M, Puchalski S, David F.To report the diagnostics, surgical treatment, and outcome of a juvenile foal with solitary osteochondroma (SO) interfering with the podotrochlear apparatus. Methods: Case report ANIMAL: One 36-day-old Arabian colt. Methods: Clinical, radiographic, ultrasonographic, computed tomographic, and histopathologic examinations were required to characterize and treat an SO located at the palmar aspect of the diaphysis of the second phalanx of the left forelimb. This SO caused severe distal interphalangeal joint (DIPJ) inflammation, marked interference with the podotrochlear apparatus, and associated l...
Updike SJ.The deep fascia of the equine crus was dissected grossly and separated into 2 layers, the superficial and deep laminae of the deep fascia. Attachments of these fascial laminae to the tibia and fibula formed 5 separate osteofascial compartments: cranial, lateral, caudal deep, caudal intermediate, and caudal superficial. Cranial tibial vessels and the deep peroneal nerve entered the cranial compartment through separate fascial hiatuses; this may predispose the equine crus to the occurrence of compartmental syndromes with clinically recognizable neural deficits.
Zientara S.After a brief historical account of the outbreak of infectious arteritis of horses which occurred in 1984 in Kentucky (United States of America), the author reports on the present state of knowledge concerning the organisation of the genome of the virus. Clinical signs of the disease are described, as well as modes and routes of transmission. Finally, currently-available vaccination procedures are discussed and their value is assessed.
GARDIKAS C, KALLINIKOU M, KALLINIKOS G.The present experiments seem to indicate that horse blood is deficient in both Factors VIII and IX, the concentration of Factor VIII varying from 30 to 60 per cent of the normal human levels, and the concentration of Factor IX varying from 50 to 80 per cent, the corresponding concentrations in 12 normal human males varying from 60 to 150 per cent and from 70 to 150 per cent, respectively.
The finding that the recalcification time of horse plasma was considerably longer than that of normal human plasma is of interest, since it is known that only very low concentrations of Factor VIII or Fact...
Vazquez de Mercado R, Stover SM, Taylor KT, Zarucco L, Willits NH.To determine anatomic landmarks for a lateral approach for arthrocentesis of the proximopalmarolateral aspect of the distal interphalangeal (DIP) joint in horses and the likelihood of entering synovial structures other than the DIP joint through this approach. Methods: Prospective study. Methods: Paired forelimbs of 8 cadavers and 12 horses. Methods: Anatomic preparations were used to determine anatomic landmarks. Positive-contrast arthrography was used to determine which structures were entered. Results: Landmarks for the lateral approach included a depression in the proximal border of the la...
Shipman E, Burford JH, Bowen M, Duz M.Teaching and learning how to perform examination of the ocular fundus is challenging. Smartphones can support to enhance students' confidence and experience. Following an optional year-4 ophthalmoscopy practical using hand-held ophthalmoscopes, students completed a questionnaire using a visual analogue scale (VAS) investigating if students felt smartphone use aided learning and if student's self-assessed confidence in visualising the ocular fundus had improved. VAS scores were compared using the Wilcoxon signed rank test (significance: P<0.05). All 30 year-4 students attending the practic...
Telfer EE, Watson ED.The aims of this study were to evaluate the use of collagenase treatment to isolate preantral follicles from mare ovaries and to assess the effect of this treatment on follicular morphology. Intact mare ovaries were chopped into pieces, incubated individually with 1, 3 or 5 mg collagenase (type 1A) ml(-1) in a shaking waterbath at 37 degrees C for up to 2 h and passed through a series of stainless steel filters with pore size 50-300 microm to remove large clumps and stromal cells. The samples were prepared for histological analysis and sections were examined by light microscopy. Isolated folli...
Shahriar F, Moore J.Thymic malignancy is rare in horses. Thymic epithelial tumor was diagnosed in an 18-year-old mare with invasion and metastasis to the pericardium and heart. At necropsy, the cranial thoracic cavity was obliterated by a large mass located in the thymic region and the right atrium was also expanded and effaced by a similar mass. Histologically, the neoplasm was composed of sheets of spindle cells with intraparenchymal Hassall's corpuscles and formation of pseudorosettes around blood vessels compatible with type A thymic epithelial tumor according to World Health Organization classification. The ...
Rigg DL, Ramey DW, Reinertson EL.Respiratory distress and laryngeal paralysis were found to be caused by a Streptococcus equi abscess of cranial mediastinal lymph nodes, putting pressure on the trachea at the thoracic inlet. Surgical drainage was required to relieve the compression, and long-term antibiotic therapy was used to treat the bacterial infection. The trachea returned to normal diameter but left laryngeal hemiplegia persisted. Peritracheal abscesses should be considered in the differential diagnosis of inspiratory dyspnea of the horse.
Pickett BW, Voss JL.Experimental and clinical observations were made to treat abnormal sexual behaviour. The most common cause of abnormality was mismanagement of the animal; over-use and rough treatment at service and too-frequent ejaculation during winter had a detrimental effect on the behaviour of young stallions. Pain due to injury incurred at copulation or when associated with mounting attempts was also a common cause of impotence. Most impotent stallions responded well to re-training and recovery can be achieved without pharmacological treatment in most cases.
Bertone AL, Powers BE, Turner AS.An aged Thoroughbred stallion was examined because of progressive lameness, carpal swelling, and weight loss. Radiography revealed a destructive lesion in the caudomedial, distal portion of the radius. Chondrosarcoma was diagnosed by tumor-core biopsy. Gross and histologic evaluation of the neoplasm after necropsy revealed a locally invasive chondrosarcoma at the distal end of the radius that infiltrated the radiocarpal joint capsule and invaded the carpal bones. The malignant nature of this tumor was evident by its invasiveness and histologic features of cell pleomorphism and presence of mito...