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Topic:Veterinary Research
Veterinary research in horses encompasses the study of diseases, health management, and medical treatments specific to equine species. This field investigates various aspects of horse health, including infectious diseases, metabolic disorders, and musculoskeletal conditions. Researchers focus on understanding the pathophysiology of equine ailments, developing diagnostic tools, and evaluating therapeutic interventions. The study of horse health also involves examining preventive measures such as vaccination protocols and nutritional management to promote overall well-being. This page collects peer-reviewed research studies and scholarly articles that explore the diverse areas of veterinary science related to horses, providing insights into disease mechanisms, treatment strategies, and advancements in equine healthcare.
Neurologic examination of the horse. Methodology for the neurologic examination in the equine species is described. Information is organized to assist the reader in defining neurologic deficits and in localizing lesions to the major subdivisions within the central or peripheral nervous system. Numerous examples of deficits are presented to assist the reader in recognition of common neurologic disease states.
A review of the pharmacology and clinical uses of ivermectin. The avermectins were introduced in 1981 and constitute a potent new class of anthelmintic agents. They are naturally-derived products of microbial action displaying an exceptionally wide range of antiparasitic efficacy against internal and external parasites of domestic animals. This paper reviews their isolation and chemistry, mechanism of action, chemical efficacy and safety in cattle, sheep, swine, horses and dogs.
Heterogeneity of amino acid transport in horse erythrocytes: a detailed kinetic analysis of inherited transport variation. 1. Thoroughbred horses were divisible into five distinct amino acid transport subgroups on the basis of their erythrocyte permeability to L-alanine, measured uptake rates ranging from 5 to 625 mumol l cells-1 h-1 (0.2 mM-extracellular L-alanine, 37 degrees C). 2. Erythrocytes from animals belonging to the lowest L-alanine permeability subgroup (5-15 mumol l cells-1 h-1) (transport-deficient type) exhibited slow nonsaturable transport of this amino acid. In contrast, cells from horses of the four transport-positive subgroups possessed additional high-affinity (apparent L-alanine Km (Michaelis c...
Convulsive and allied syndromes of the neonatal foal. This article discusses the clinical signs, etiology, management, and prognosis for the neonatal foal afflicted with a convulsive or allied syndrome.
Seizures in the horse. This article discusses the diagnosis and treatment of extracranial, intracranial, and idiopathic seizures.
Viability of stored equine embryos. Equine embryos were recovered nonsurgically 6.5 d after ovulation (Exp. 1) and those greater than 200 microns were stored in one of three media: 1) Ham's F10 + 10% fetal calf serum (FCS) under 5% CO2, 5% O2 and 90% N2 at 24 C (Ham's F10); 2) Minimal Essential Medium with Hank's balanced salts + 10% FCS in air (MEM) at 24 C or 3) MEM at 5 C n = 10/treatment). Embryos less than or equal to 200 micron (n = 10) were bisected microsurgically; one-half of each embryo was stored in Ham's F10 and the other half in either Dulbecco's phosphate-buffered saline + 10% FCS in air at 24 C (DPBS), or MEM in a...
Selective mechanical ventilation of dependent lung regions in the anaesthetized horse in dorsal recumbency. The effect of selective mechanical ventilation of dependent lung regions were studied in anaesthetized horses (mean weight 486 kg) in dorsal recumbency. Blood-gas measurements were performed with the horse in the lateral position during spontaneous breathing (before selective intubation) and in dorsal recumbency during spontaneous breathing, general mechanical ventilation, and spontaneous breathing + selective mechanical ventilation. Arterial oxygen tension (PaO2) was 32.3 kPa in the lateral position during spontaneous breathing with a high inspired oxygen fraction (FlO2 greater than 92%). In ...
Evaluation of granulocyte transfusion in healthy neonatal pony foals. Granulocyte transfusions (GT), 0.98 X 10(9) neutrophils/kg of body weight, were performed on 7 healthy pony foals between 2 and 7 days old. The mean neutrophil count of the foals was significantly (P less than 0.05) greater than base line (4,830 +/- 1,260/microliter) 1 hour after GT (8,870 +/- 3,350/microliter) and was similar to base line by 15 to 18 hours after GT (6,550 +/- 2,310/microliter). Leukocyte concentrates (LC) used for GT were harvested from clinically normal adult horses by continuous-flow centrifugation leukapheresis (CL), 3 to 6 hours after hydrocortisone sodium succinate was a...
Head tilt in horses. Head tilt in the horse is commonly a sign of either central or peripheral vestibular disease. The confirmation of vestibular disease is based on physical findings, including results of cranial-nerve function evaluation and observation of stance, posture, and gait. Further localization is made by ancillary tests such as cerebral spinal fluid analysis, electrodiagnostic testing, and radiography. The normal anatomy and physiology of the vestibular system, the abnormal clinical signs demonstrated during physical examination, and the various etiologies are discussed.
Mitral valvular insufficiency associated with ruptured chordae tendineae in three foals. Mitral valvular insufficiency associated with ruptured chordae tendineae was diagnosed in 3 foals with signs of congestive heart failure, which were believed to be secondary to the development of pulmonary hypertension associated with the valvular insufficiency. The septal leaflet of the mitral valve was affected in all 3 foals, and foal 2 also had ruptured chordae tendineae associated with the caudal mitral valve leaflet. Bacterial endocarditis and myocardial necrosis were associated with the ruptured chordae tendineae in foals 3 and 2, respectively. Idiopathic rupture was considered in foal ...
Temporal effects of halothane and isoflurane in laterally recumbent ventilated male horses. Cardiopulmonary function was monitored in 6 non-medicated, healthy male horses, anesthetized with halothane or isoflurane in O2 at a constant dose (1.2 times the minimum alveolar concentration). Horses were exposed once to each anesthetic agent, and a minimum of 2 weeks separated anesthetic exposures. All horses were studied in left lateral recumbency, and ventilation was mechanically controlled to induce a PaCO2 of 35 to 45 mm of Hg and an inspiratory peak airway pressure of 18 to 22 cm of H2O. After 1 hour of horse preparation, constant conditions were begun. With duration of anesthesia, car...
The meiotic stage of preovulatory oocytes in mares. Confusion exists as to whether the oocytes of the domestic horse are ovulated at the first meiotic metaphase (MI) or the second (MII). In this study eight oocytes were collected from the preovulatory follicles of 16 mares 36 h after human chorionic gonadotropin CG treatment. Six of the eight oocytes were judged to be at MII by the presence of the first polar body and this judgement was confirmed by semithin sectioning in one. Of the two that had no polar body, one was found to be at MII after fixation for chromosomal analysis and the meiotic stage of the other remained undetermined. Since all ...
Pharmacokinetics of phenolsulfonphthalein in horse and pony mares. Pharmacokinetics of phenolsulfonphthalein (PSP) in horse and pony mares was determined after injection of 1 mg/kg of body weight, IV. A plasma PSP concentration vs time curve was described adequately in horses and ponies by an open, 2-compartment model. There were significant differences in the elimination phase parameters, apparent volume of distribution at steady state, and apparent volume of distribution of horses and ponies. The harmonic mean elimination half-life of PSP in horses was significantly longer (P less than 0.001) than that in the ponies (16.4 and 10.0 minutes, respectively). Th...
Humoral immune response of foals to experimental infection with Rhodococcus equi. Humoral immune response to Rhodococcus equi in experimentally infected foals was studied with the enzyme-linked immunosorbent assay (ELISA) method. Class-specific antibodies were measured by ELISA in the sera of foals after intratracheal or oral inoculation with R. equi ATCC 6939 or T 48 and in the lung washings of a foal after intratracheal inoculation or of normal horses. After intratracheal or oral inoculation with R. equi, serum antibodies were first detected in immunoglobulin G (IgG) followed by IgM and IgA classes, but significant levels of IgM and IgA developed only in the foal infected...
The distribution of ventilation-perfusion ratios in the lungs of newborn foals. The distributions of ventilation-perfusion ratios, and the effects of 100% oxygen administration on the distributions, were studied in 3 foals from 4h to 9 days of age, using the multiple inert gas elimination technique. The distributions were calculated from the pulmonary clearance of 6 inert gases following infusion into a peripheral vein of a solution containing the inert gases. The results from a total of 8 studies showed several consistent features. The major findings were (i) the absence of low ventilation-perfusion ratios, i.e. regions where blood flow was greatly in excess of ventilati...
Heterogeneity and linkage of equine C4 and steroid 21-hydroxylase genes. The fourth component of complement (C4) is polymorphic in most species studied, and is encoded by a gene or genes within the MHC. In man and mouse there are two closely linked C4 and steroid 21-hydroxylase (21-OH) genes. Therefore we have used Southern blotting to determine whether equine C4 and 21-OH genes are linked. C4 restriction fragment length polymorphism (RFLP) was found with the enzymes EcoRI and BamHI. Comparison of the sizes of EcoRI-digested fragments of genomic DNA hybridizing with C4 and 21-OH probes revealed that equine C4 and 21-OH genes are separated by no more than 13 kb. Fur...
Medical management of spinal cord disease. In spinal cord disease of horses, a complete history, neurologic examination, and adjunctive diagnostic procedures are very helpful in establishing a tentative diagnosis; however, a definitive diagnosis may be difficult or impossible to establish antemortem. Medical management should be initiated with full consideration of possible etiologies and knowledge of the effects and consequences of medical therapies. This article discusses the drugs commonly used in the management of spinal cord disease and the rationale for their use.
Examination of cerebrospinal fluid in the horse. The examination of cerebrospinal fluid (CSF) is often part of the diagnostic work-up of a patient exhibiting signs of disease involving the central nervous system. Awareness of the capabilities and limitations of these laboratory tests is important in assessing the benefit-to-risk ratio of performing such procedures. Collection of CSF is a relatively simple procedure, and together with a thorough history, physical examination, and other diagnostic tests, may be a valuable aid in arriving at a diagnosis or prognosis.
Ecology of Rhodococcus equi in horses and their environment on horse-breeding farms. Quantitative culture of R. equi in the feces of dams and foals, in the air of the stalls and in the soil of the paddocks was carried out on three horse-breeding farms during the foaling season. The isolation rates of R. equi from the feces of dams from the 3 farms suddenly increased to approximately 80% at the end of March, when the snow in the paddocks finished melting, and remained at that level during April and May. The mean number of R. equi and the isolation rate of R. equi from the feces of dams on the farms were investigated for 5 weeks before and 5 weeks after delivery. During the 10 w...
The pathogenesis of Rhodococcus equi pneumonia in foals. The pathogenesis of Rhodococcus equi pneumonia in foals is reviewed. The main routes of infection are respiratory and alimentary. The latter is probably the chief route of exposure in all foals and probably leads to development of specific immunity. Susceptible foals, those whose maternal immunity wanes before generation of their own immune response, readily develop disease if exposed aerogenously to sufficient numbers of R. equi. Management and environmental circumstances have a major role to play in determining the magnitude of this challenge and, therefore, in the prevalence of the disease....
Equine viral encephalomyelitis in Canada: a review of known and potential causes. Rabies, equine herpesvirus type I, and eastern and western encephalomyelitis viruses, known causes of equine neurological disease, are reviewed with emphasis on epidemiology, pathogenesis, clinical signs, and diagnosis.Several arboviruses known to be active in Canada and capable of producing neurological disease in humans (Powassan, St. Louis encephalitis, snowshoe hare, and Jamestown Canyon viruses) are discussed as potential causes of encephalomyelitis in horses.
The role of aromatic side chain residues in micelle binding by pancreatic colipase. Fluorescence studies of the porcine and equine proteins. Fluorescence techniques have been employed to study the interaction of porcine and equine colipase with pure taurodeoxycholate and mixed micelles. Nitrotyrosine-55 of porcine colipase is obtained by modification with tetranitromethane (low excess, in the presence of taurodeoxycholate) of the protein followed by gel filtration and ion-exchange chromatography. Verification of the residue modified was obtained by h.p.l.c. peptide purification and sequence analysis. Reduction and quantitative reaction with dansyl chloride yields a fluorescent derivative that is twice as active in conjunction with ...
Effect of halothane, enflurane and isoflurane on bronchomotor tone in anaesthetized ponies. The effects of halothane, enflurane and isoflurane on bronchial calibre were investigated in five anaesthetized ponies using a computer-aided forced airflow oscillation technique to derive specific lower airways conductance (s.Glaw) and expiratory reserve volume (ERV). All the agents tended to increase s.Glaw (indicating bronchodilatation), but ERV was reduced by halothane and enflurane, and increased by isoflurane. It was concluded that the effects of these agents on bronchomotor tone were similar to those which occur in man. However, the reasons for the differences in their effects on ERV co...
Urethral pressure profilometry in mares. A technique was developed for recording urethral pressure profiles (UPP) in mares. Profiles were obtained from 12 clinically normal mares and from 3 mares with urinary incontinence. Variables measured on the profile included intravesicular pressure and maximal urethral closure pressure. The mean maximal urethral closure pressure of the incontinent mares was significantly less (P less than or equal to 0.001) than that of the normal mares. The technique is simple and reliable for objectively evaluating urethral pressures in mares.
Nasopharyngeal cicatrices in horses: 47 cases (1972-1985). Nasopharyngeal cicatrices were observed endoscopically in 47 horses examined because of abnormal respiratory noises and/or exercise intolerance. A review of these cases revealed a correlation between cicatrization and age, sex, and the presence of other upper airway abnormalities. The age of affected horses ranged from 6 to 21 years, with a mean age of 12.7 +/- 7.8 (+/- 2 SD) years. Females were affected 2.7 times more frequently than males. Abnormalities commonly observed with a nasopharyngeal cicatrix included chondritis of the arytenoid cartilage, epiglottic deformity, and deformity of the ...
Echocardiographic detection of tricuspid atresia in two foals. M-mode, 2-dimensional, and contrast echocardiographic studies were used to detect tricuspid atresia in 2 foals. M-mode echocardiographic findings included a small right ventricle, large left ventricle, large mitral valve excursion, large left atrium (foal 2), dropout of the cranial aspect of the aortic root, and a thick band of echoes in the tricuspid valve region. These findings were confirmed by 2-dimensional echocardiography. In addition, a large right atrium, persistent foramen ovale, ventricular septal defect, and large mitral valve apparatus were imaged. One foal also had a thick right a...
