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Topic:Veterinary Medicine
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.
Equine model of inducing ulceration in alimentary squamous epithelial mucosa. Ulceration of the gastric squamous epithelial mucosa was induced in 10 horses using a feeding protocol previously shown to expose the gastric mucosa to repeated periods of high acidity. The feeding protocol consisted of alternating feed deprivation with free access to hay. Over a period of seven days, each horse was provided hay for 84 hr and deprived of hay for 84 hr. Hay was never withheld for longer than 24 hr at a time. Gastroscopy was performed on each horse at the beginning of the protocol after 12 hr of feed deprivation, and after a total of 36 hr, 60 hr, and 84 hr of feed deprivation. ...
Sequence analyses of the p24 gene of Borna disease virus in naturally infected horse, donkey and sheep. By reverse transcriptase/PCR amplification and subsequent sequence determination of the p24 gene, the relatedness of Borna disease virus (BDV) in various naturally infected animal species was determined. These results are indicative of a common ancestral virus pool and a remarkably low species barrier of BDV. Comparison of 11 sequences to that of tissue culture adapted virus revealed that the homology among all isolates was at least 96.2% at the nucleotide level, and 97% at the amino acid level. Viral sequences from sheep, donkey and horse were found to be not more distantly related to each ot...
Soft tissue emergency in adult horses. Equine practitioners are frequently called to attend to soft tissue injuries. The majority of these cases are routine and straightforward; however, a certain percentage may present as a life-threatening situation with potentially serious complications. Client communication, adequate preparation, patient stabilization, accurate injury assessment and appropriate wound preparation are key factors to expedite recovery and achieve a favorable outcome. Understanding the limitations of field therapy and deciding when to transport the case to a clinic or referral center plays an important role in the ...
Evidence that the agent of equine grass sickness may reach neurons by retrograde axonal transport. Sera from acute and chronic cases of natural grass sickness or normal horses were injected into the parotid salivary gland of ponies. This gland receives its sympathetic innervation from the ipsilateral cranial cervical ganglion. None of the ponies showed any local or systemic signs of illness. After one week the cranial cervical ganglia, stellate and coeliaco-mesenteric ganglia were removed for histological study. Pathological changes were found only in the cranial cervical ganglion ipsilateral to a parotid salivary gland which had received an injection of grass sickness serum. Four out of fi...
Sonographic findings in horses with mediastinal lymphosarcoma: 13 cases (1985-1992). Sonographic findings correlated with necropsy findings in 8 of 9 horses in which the cranial portion of the mediastinum was evaluated by use of both methods. Cranial mediastinal masses were imaged as multilobular and homogeneously hypoechoic; a complex echogenic pattern was observed with necrosis within the mass. Pleural effusion was a common finding in horses with mediastinal lymphosarcoma. Cytologic evaluation of pleural fluid samples was useful in diagnosis of lymphosarcoma in 10 of 12 horses that had thoracentesis. Sonographic examination of the thorax and cranial portion of the mediastinu...
[Renal tubular acidosis (type 2) in a Friesian mare]. A 2-year-old Friesian mare was examined because she had been sluggish for a few weeks. Blood biochemistry showed that concentrations of creatinine (136 mumol.L-1) and urea nitrogen (6.1 mmol.L-1) in plasma were within their normal limits. Severe metabolic acidosis was apparent; the venous pH was 7.154 and the bicarbonate concentration was 13 mmol.L-1. The base excess amounted to -15.3 mmol.L-1 and the venous pCO2 measured 5.1 kPa. Plasma sodium was normal (135 mmol.L-1) and plasma chloride (113 mmol.L-1) was slightly elevated, but there was a hypokalaemia (2.9 mmol.L-1). The urine had a specif...
Receptor specificity in human, avian, and equine H2 and H3 influenza virus isolates. The receptor specificity of 56 H2 and H3 influenza virus isolates from various animal species has been determined to test the relevance of receptor specificity to the ecology of influenza virus. The results show that the receptor specificity of both H2 and H3 isolates evaluated for sialic acid linkage specificity and inhibition of hemagglutination by horse serum correlates with the species of origin, as postulated earlier for H3 strains based on a limited survey of five human, three avian, and one equine strain. Elucidation of the amino acid sequence of several human H2 receptor variants and a...
Investigations on naturally occurring Trypanosoma evansi infections in horses, cattle, dogs and capybaras (Hydrochaeris hydrochaeris) in Pantanal de Poconé (Mato Grosso, Brazil). The prevalence of Mal de Cadeiras--Portuguese for Trypanosoma (T.) evansi infections in horses--as well as the prevalence of T.evansi infections in cattle, dogs and free-ranging capybaras (Hydrochaeris hydrochaeris) was investigated in Pantanal de Poconé (Mato Grosso, Brazil). In 0.3, 8.6 and 8.0% of the horses, dogs and capybaras, respectively, infection was detected using standard parasitological methods. A seroprevalence of 4.1, 2.3, 7.1 and 22.0% was found in horses, cattle, dogs and capybaras, respectively, using an enzyme-linked immunosorbent assay for the detection of T.evansi antigen ...
Endotoxin-induced platelet aggregation in heparinised equine whole blood in vitro. Endotoxaemia is a leading cause of death among horses. Thrombocytopenia is a common finding in clinical and experimentally-induced cases of endotoxaemia and can lead to coagulopathies, including disseminated intravascular coagulopathy which is usually fatal. In this study it was shown that endotoxin (3 ng ml-1 to 25 micrograms ml-1) can aggregate equine platelets in heparinised whole blood in vitro. The endotoxin-induced aggregation (EIA) was shown to be dependent on the presence of leucocytes in the blood and did not occur when detoxified endotoxin was used, suggesting that lipid A was necess...
Modulation of K(+)-Cl- cotransport in equine red blood cells. Potassium transport was measured in equine red blood cells, using 86Rb+ influx as a convenient assay. A significant component of volume- and pH-sensitive K(+)-Cl- cotransport to the overall K+ flux was observed in all blood samples studied, although fluxes were variable between animals, and within individuals when measured at intervals over a period of weeks. The aryloxyacetic acid [(dihydroindenyl)oxy]alkanoic acid (DIOA), at a final concentration of 100 microM, inhibited most (> 95%) of the Cl(-)-dependent K+ flux, and DIOA sensitivity was therefore used to define the activity of the K(+)...
Observations on the anatomy and pathology of the palmar intercarpal ligaments in the middle carpal joints of thoroughbred racehorses. Ten carpi from juvenile Thoroughbred horses were dissected in detail to record the anatomy of the palmar intercarpal ligaments (PICLs). These were found not to be substantially attached to the palmar carpal ligament. The lateral PICL was sited at the convergence of the palmar aspects of the third, fourth, intermediate and ulnar carpal bones and aligned predominantly in a proximodistal direction. The medial PICL had a large origin distally on the lateral aspect of the radial carpal bone (Cr) and attached to third (C3) and second (C2) carpal bones with apparently separate fibre orientations. Fib...
Genetic and antigenic analysis of the influenza virus responsible for the 1992 Hong Kong equine influenza epizootic. An outbreak of influenza occurred among thoroughbred racehorses in Hong Kong in November-December 1992, with morbidity of 37%. All horses involved had been vaccinated against equine-1 and equine-2 influenza viruses but not against the virus responsible for the 1989 equine influenza outbreak in northern China (influenza A/equine/Jilin/89, subtype H3N8). Therefore the source and nature of the virus causing the Hong Kong outbreak was investigated. Virus isolated from a horse infected during the outbreak was used for genetic analysis. All the viral gene segments were similar to those of equine-2 (...
A study of the biomechanical properties of the adult equine linea alba: relationship of tissue bite size and suture material to breaking strength. The purposes of this study were to mechanically determine the optimal tissue bite size and to evaluate seven suture materials at their largest commercially available size for breaking strength and stiffness using cadaveric adult equine linea alba. Soft tissues were removed from the abdominal fascia of 16 adult horses. Individual test sections were created from the entire linea alba and labeled (1 through 6) starting at the umbilicus and extending craniad. A single biomechanical test was performed on each test section. Tissue bite size (3, 6, 9, 12, 15, 18, and 21 mm) significantly altered brea...
Relationships between electrocardiographic findings, racing performance and training in standardbred horses. 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...
Surgical repair of iatrogenic soft palate defects in two horses. A 4-year-old Thoroughbred filly was referred for evaluation of a soft palate defect that had been created several weeks earlier during surgical correction of epiglottic entrapment, performed transorally. Surgical correction of the defect was performed via mandibular symphysiotomy. At 85 days after repair, the horse raced successfully. A 2-year-old Thoroughbred filly was admitted for evaluation and treatment of epiglottic entrapment. The soft palate was lacerated during transnasal division of the entrapping membrane. A 2-cm full-thickness soft palate laceration was repaired transorally.
An immunohistochemical study of an equine B-cell lymphoma. The tissues of an 8-year-old thoroughbred castrated male horse with equine lymphoma were examined immunohistochemically. Neoplastic masses were observed in the mediastinum, mesenteric lymph nodes, gastric mucosa and serosa, liver capsule, and spleen capsule with associated lymph nodes. Histopathologically, the neoplastic cells were seen to consist predominantly of a mixture of well differentiated small and large types. Immunohistochemically, the small lymphoid cells were MHC class IIlow+ and PanT- and the large lymphoid cells were MHC class IIhigh+ and PanT-. These findings revealed that the n...
Modulation of bronchial smooth muscle function in horses with heaves. Four mechanisms that modulate airway smooth muscle function in normal horses were studied in the bronchi of horses affected by the airway obstructive disease heaves. Results were compared with data from historical controls studied by the same personnel in the same laboratory. Rings from the left cranial lobar bronchus (LB1) and small bronchi (5 mm OD) were suspended in muscle baths, and the isometric tension were measured. The inhibitory nonadrenergic noncholinergic (iNANC) function was studied in LB1. After the LB1 segments were pretreated with atropine and contracted with histamine, electric...
Lipofuscin and abnormalities in colloid in the equine thyroid gland in relation to age. Lipofuscin accumulation and other histological changes in thyroid tissue, previously reported to be age-related, were studied in 31 horses aged up to 35 years. The number of lipofuscin granules relative to thyrocytes increased from birth to 5 years of age. There was a wide individual variation in the number of lipofuscin granules in thyrocytes in mature horses, but this was not directly related to age. Several abnormalities were identified in thyroid colloid. The prevalence of spherites, lipofuscin granules, nucleated cells and shreds of colloid increased with age, but the prevalence of calciu...
The cross-sectional areas of normal equine digital flexor tendons determined ultrasonographically. Fifty-two animals, comprising 22 Irish Draught crosses (Group A), 15 Thoroughbreds (Group B) and 15 ponies (Group C) were examined ultrasonographically using a 7.5 mHz linear array probe and stand-off pad. All animals were free of tendon disease as determined from clinical and ultrasonographical examination. The superficial (SDFT) and deep (DDFT) digital flexor tendons were scanned at 7 transverse (axial) levels between the carpus and metacarpophalangeal joint. Each transverse image was digitised using a commercially available frame grabber and the cross-sectional areas of each tendon at each ...
Growth hormone and prolactin concentrations in plasma of horses: sex differences and the effects of acute exercise and administration of growth hormone-releasing hormone. Three experiments were conducted to determine 1) the relationship between prolactin and growth hormone (GH) secretion in mares and the response to GH-releasing hormone (GHRH), 2) whether plasma GH and prolactin concentrations differed among mares, stallions, and geldings, and 3) whether sexual differences existed after administration of GHRH and acute exercise. In Exp. 1, 10-min blood samples were collected from 12 mares for 8 h, and GHRH (0, 45, 90, or 180 micrograms) was administered at 6 h. In Exp. 2, 15-min blood samples were collected for 4 h from 10 mares, stallions, and geldings. In Exp...
Equine echocardiography–sound advice at the heart of the matter. Echocardiography is an extremely versatile tool for both the equine clinician and physiologist. There are three useful forms of echocardiography, B mode, M mode and Doppler. Together they provide complementary information on cardiac disease and haemodynamic status. B mode is used to image the cardiac chambers, valves, myocardium and pericardium. M mode allows determination of motion of cardiac structures; it is superior to B mode for timing of events and it is used to make precise measurements of the heart. Doppler echocardiography can assess intracardiac blood flow and its velocity. Echocardi...
Stress failure of pulmonary capillaries as a mechanism for exercise induced pulmonary haemorrhage in the horse. Exercise induced pulmonary haemorrhage (EIPH) is a serious problem in the Thoroughbred industry. The condition apparently occurs essentially in all Thoroughbreds in training but the mechanism has proved elusive. There is now strong evidence that the condition is caused by mechanical failure of the walls of the pulmonary capillaries when the pressure inside them rises to very high levels. It is well known that pulmonary capillaries have extremely thin walls to allow rapid exchange of respiratory gases across them. Recently we have shown that the wall stresses are very large when the capillary t...
Involvement of endogenous opioids in the regulation of LH and testosterone release in the male horse. To investigate the involvement of endogenous opioids in the regulation of gonadotrophin release in male horses, effects of the opioid antagonist naloxone (0.5 mg kg-1 i.v.) on plasma LH and testosterone concentrations and the possible influence of season and of gonadal steroids were investigated. To determine quantitative as well as qualitative changes in gonadotrophin release, LH concentrations were measured by radioimmunoassay and by an in vitro bioassay. Experiments were performed in May, August and December. In stallions, basal LH secretion in May and August was significantly higher than i...
Regulation of equine fibrinolysis in blood and peritoneal fluid based on a study of colic cases and induced endotoxaemia. Much of the pathophysiology associated with equine gastrointestinal diseases is attributed to the effects of endotoxin on haemostasis. Because little is known about the responses of the equine fibrinolytic system to endotoxin, regulation of the system was investigated. Tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type-1 (PAI-1) were identified as the primary plasminogen activator and plasminogen activator inhibitor, respectively, in equine blood. Under experimental conditions, the equine fibrinolytic system responded to endotoxin in a manner similar to that repo...
Histological findings in corneal stromal abscesses of 11 horses: correlation with cultures and cytology. Histopathology was compared to culture results and cytology from horses with corneal stromal abscess at the Auburn University and the Ohio State University Veterinary Teaching Hospitals. Significant bacteria were not isolated in culture or seen on histopathology in any of the horses. Although most bacteria infecting equine corneas can be isolated with blood and MacConkey's agars, failure to detect bacterial growth may not rule out infection because anaerobic or intracellular bacteria would not be isolated. The inability to visualise bacterial organisms on histological sections did not rule out...
Distribution of equid herpesvirus-1 (EHV-1) in the respiratory tract of ponies: implications for vaccination strategies. Twelve adult ponies and 2 conventional foals were exposed to 10(6.6) TCID50 of Equid herpesvirus-1 (EHV-1), strain Ab4 and samples of respiratory tract tissues were recovered. Infectious virus in tissue homogenates was detected using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry of paraffin sections. The results illustrated the rapid dissemination of EHV-1 throughout the respiratory tract, with early replication in the lungs one day after exposure. Endothelial cell infection was prominent in all areas of the nasopharyn...
