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.
Lee YH, Clarke KW, Alibhai HI.Clenbuterol (0.8 microg kg(-1) intravenously) was investigated in ponies (small horses) anaesthetised with acepromazine, detomidine and thiopentone, then halothane in oxygen alone (hyperoxic group) or with nitrous oxide (hypoxic group). Following instrumentation, ponies were placed in dorsal recumbency for 60 minutes, clenbuterol (both groups) or a saline control (hyperoxic group) given, and cardiopulmonary parameters monitored for a further 60 minutes. In the hyperoxic group, clenbuterol administration resulted in a transitory (<five minutes) 15 per cent fall in arterial blood pressure and...
East LM, Savage CJ.Neoplasia of the equine gastrointestinal tract and abdominal organs occurs predominantly in geriatric horses, although lymphoma and hepatocellular carcinoma and a few other neoplasms can be found in young horses. This article discusses diagnostics that can be used in weight-loss situations, suspicious of neoplasia, as well as tumors themselves including clinical signs, diagnostic tools, histopathologic appearance, and management.
Savage CJ.Nomenclature regarding neoplasia of the hematopoietic and lymphoid tissues in the horse is confusing. This article will clarify terminology, and discuss the individual lymphoproliferative and myeloproliferative disorders recognized in the horse. Diagnostic techniques that are useful in cases in which hematopoietic or lymphoid tissue neoplasia are suspected include histochemical staining profiles, bone marrow aspiration, and bone marrow biopsy.
Schooley EK, Hendrickson DA.Tumors of the musculoskeletal system are rare in horses; however, they must be taken seriously. Diagnosis requires observation of clinical signs, radiographic findings, and histological examination. Veterinarians must realize prognosis is not favorable for most tumors; however, some of these tumors can be treated or at least ameliorated. Tumors discussed in this article include: osteoma and osteosarcoma; osteoblastoma; chondrosarcoma; fibroma and fibrosarcoma; plasma cell myeloma; synovioma; rhabdomyosarcoma and tumors metastatic to the musculoskeletal system.
Théon AP.This article covers the principles and applications of radiation therapy in horses. The goal in treating tumors by irradiation is tumor control with minimum treatment complications. Various treatment techniques are available to achieve this goal. The prognosis depends on many factors such as the extent and location of the tumor, tumor type and tumor cell proliferation. Radiation therapy is a very effective treatment modality for equine tumors but logistical reasons limit its impact in equine oncology.
Traub-Dargatz JL.This article is a review of reports on neoplasia of the equine urinary tract. Clinical signs associated with equine patients with urinary tract neoplasia are summarized along with a description of diagnostic methods used in such patients. The prognosis for treatment of urinary tract neoplasia is guarded. A review of the limited treatments that have been reported to date are also provided in this article.
Scarratt WK, Crisman MV.Tumors of the equine respiratory tract occur infrequently. An accurate diagnosis of neoplasia of the respiratory tract is critical because the prognosis is usually grave. The clinical signs and diagnostic procedures are discussed for tumors of the nasal and paranasal sinuses, nasopharynx/larynx, guttural pouch and thorax including lung, pleura, and thymus.
Ogilvie GK.The importance of paraneoplastic syndromes is often underestimated in the horse. Clinically, paraneoplastic syndromes can cause greater morbidity than the actual physical presence of the malignant tumor. The appearance may be the first sign of a malignancy and may be so severe that appropriate therapy for the underlying cancer is not initiated. This article reviews some of the most common paraneoplastic syndromes that are likely to occur in the horse.
Paradis MR.Neoplasia of the central nervous system (CNS) can be divided into two main categories: nonpituitary CNS neoplasia and pituitary adenomas. Nonpituitary CNS neoplasias are generally compressive in nature, although some are also invasive. The majority of reported CNS tumors are secondary with only a few originating from nervous tissue. Pituitary adenomas predominantly occur in the pars intermedia of the older horse. Clinical signs, diagnostic testing, and possible treatments are discussed.
McCue PM.Granulosa cell tumors of the ovary and SCC and melanoma of the external genitalia are the most common neoplasms in the mare. Tumors of the tubular reproductive tract and the mammary gland are rare.
Goodrich L, Gerber H, Marti E, Antczak DF.Sarcoids, the most common tumor of the horse, are fibroblastic, wart-like skin lesions that show variable manifestations. They are often invasive and recurrent, although they do not fulfill all criteria of malignancy. Due to their anatomic location, these tumors can sometimes cause loss of use of the horse. There is very strong evidence that sarcoids are caused by viruses closely related or identical to bovine papilloma viruses, and genetic studies have shown associations between genes in or near the equine major histocompatibility complex (MHC) and susceptibility to sarcoid. Several types of ...
Théon AP.Surgery is the mainstay of treatment for equine tumors. Conservative treatment approaches which preserve function and appearance are increasingly used in clinical practice. This article covers the principles and applications of two conservative treatment modalities including local chemotherapy and immunotherapy. The therapeutic benefit of local chemotherapy is based on the direct drug delivery to tumor tissue, i.e., topical and intratumoral administration of cytotoxic agents in slow release formulation. This treatment modality is very effective for cutaneous tumors and does not result in any p...
Johnson PJ.Cutaneous neoplasia represents a clinical problem with which veterinarians are commonly challenged. This article addresses equine cutaneous squamous cell carcinoma, squamous cell papilloma, melanoma, mastocytosis, and lymphosarcoma. Current concepts regarding the origin, pathogenesis, diagnosis and treatment of each neoplasm is emphasized.
Brinsko SP.Genital neoplasms in the male horse are relatively uncommon. Squamous cell carcinomas and squamous papillomas are the most commonly diagnosed neoplasms of the penis and prepuce. Geldings appear to be overrepresented for these types of neoplasms, and accumulation of smegma may be a contributing factor. Early diagnosis and treatment are essential for salvaging these organs before lesions become excessively large and invasive or are allowed to metastasize. Newer treatment modalities such as 5-fluorouracil appear to be promising alternatives to surgical excision. Although generally considered to b...
Rebhun WC.This article reviews options in dealing with tumors of the cornea and conjunctiva, nictitating membrane neoplasms, and eyelid neoplasms. Orbital tumors, optic nerve and other intraocular tumors are also discussed.
Cole DJ, Snowden K, Cohen ND, Smith R.Feces collected from three asymptomatic horses and seeded with Cryptosporidium parvum oocysts (10(1) to 10(6)/g of feces) were evaluated by acid-fast staining (AF), an immunofluorescent antibody (IFA) technique, and flow cytometry. The thresholds of detection were 5 x 10(5) oocysts/g of feces for the IFA and AF techniques and 5 x 10(4) oocysts/g for flow cytometry.
Desmettre P.The frequent transfers of horses, whether on a permanent or temporary basis, make strict control of infectious diseases essential. Such control needs a reliable and rapid means to accurately diagnose the relevant diseases. Indirect diagnosis based on antibody detection remains certainly the best method to secure the epidemiologic surveillance of the diseases at regional, national, or even world level, while direct diagnosis is the only way to diagnose a new outbreak. New diagnostic methods resulting from advances in biochemistry, molecular biology, and immunology are now available. As far as a...
Herholz C, Miserez R, Nicolet J, Frey J, Popoff M, Gibert M, Gerber H, Straub R.The incidence of a new, yet unassigned toxin type of Clostridium perfringens containing the genes for the alpha-toxin and the recently described beta2-toxin in horses with intestinal disorders is reported. The study included 18 horses suffering from typical typhlocolitis, 7 horses with atypical typhlocolitis, 16 horses with other intestinal disorders, and 58 horses without intestinal disease. In total, 20 samples of ingesta of the small and large intestines, five biopsy specimens of the intestinal wall, and 74 fecal samples were analyzed bacteriologically. C. perfringens isolates were typed fo...
Haire TJ, Hodgskinson R, Ganney PS, Langton CM.The purpose of this study was to compare the structural parameters of fabric and fractal dimension as predictors of the Young's modulus of equine cancellous bone. Eight 15 mm cubes of cancellous bone were obtained from three equine third metacarpal bones. Young's modulus was determined for the three orthogonal directions. The fabric and fractal dimension were calculated for each of the six exposed faces of each cube. Fractal dimension plus porosity provided a higher explanatory power for Young's modulus (R2 = 78.7%. P < 0.0001) than fabric plus porosity (R2 = 69.2%, P < 0.0001). Fractal ...
Martin BB, Freeman DE, Ross MW, Richardson DW, Johnston JK, Orsini JA.To determine the prognosis in horses with cecocolic or cecocecal intussusception. Methods: Retrospective study. Methods: 30 horses with cecocolic intussusception or cecocecal intussusception. Methods: Information on history, physical examination findings, and laboratory values was summarized from the medical records. Laboratory data included results of hematologic examination, serum biochemical analysis, and peritoneal fluid color, total nucleated cell count, and total protein concentration. A one-year follow-up via the telephone was used to determine long-term survival. Results: Horses ranged...
Steel CM, Bolton JR, Preechagoon Y, Charles BG.The purpose of this study was to determine the pharmacokinetics and absolute bioavailability of cisapride after intravenous (i.v.) and intragastric (i.g.) administration in healthy, adult horses. Five animals received single doses of 0.1 mg/kg, 0.2 mg/kg and 0.4 mg/kg cisapride by the i.g. route in an open, randomized fashion on different occasions separated by a washout period of at least 48 h. Four of these horses were also given a single i.v. dose of 0.1 mg/kg cisapride. Jugular venous blood was collected periodically up to 24 h after dosing. Plasma cisapride concentrations were measured by...
Taylor PM.The study was designed to contribute to identification of the stimulus to adrenocortical activity during halothane anaesthesia in equidae. Two groups of six ponies were premedicated with acepromazine before induction of anaesthesia with thiopentone and maintenance for 120 min with halothane in oxygen. In group H Haemaccel modified gelatine plasma replacer was infused (48+/-13 mL/kg) to maintain mean arterial blood pressure (MABP) close to preanaesthetic values. In group DH, blood pressure was maintained close to preanaesthetic levels with a lower dose of Haemaccel (10 mL/kg) combined with an i...
Kimbell-Dunn M, Bradshaw L, Slater T, Erkinjuntti-Pekkanen R, Fishwick D, Pearce N.To examine the prevalence of symptoms of asthma and allergy in different farming groups in New Zealand. Methods: A postal questionnaire was sent to a random sample of 2,500 farmers throughout New Zealand. Results: The response rate was 77% (1,706 of 2,203 eligibles). The 12-month period prevalence of current asthma was 11.8% overall, compared with 15% in the general population. Asthma prevalence was higher for horse breeders/groomers (16.5%), pig farmers (18.2%), poultry farmers (17.4%), and those working with oats (17.4%). Asthma was also significantly elevated among those working with cleani...
Jeffcott LB, Henson FM.The importance of osteochondrosis (dyschondroplasia) to the horse industry has been well documented since it was first recorded 50 years ago. The condition is known to be multifactorial in origin, arising from focal failure of endochondral ossification at predilection sites in articular/epiphyseal growth cartilage, but specific information on its aetiopathogenesis is sparse. This paper reviews the current knowledge of growth cartilage metabolism and the process of normal endochondral ossification in the horse. It highlights the localization of various protein products of chondrocytes and the d...
Hernández-Vidal G, Jeffcott LB, Davies ME.A polyclonal antiserum raised in sheep against human cathepsin B was tested for specificity and cross-reactivity with the horse homologue by SDS-PAGE and Western blotting, prior to being used for immunolocalization of the enzyme in equine articular cartilage. In Western blots, the antiserum recognized the 30 kDa single chain and 25 kDa heavy chain of the mature enzyme in purified bovine cathepsin B, and corresponding bands at 32 and 27 kDa in equine chondrocyte and fibroblast lysates. This antiserum was then used to compare the expression and distribution of cathepsin B in normal and dyschondr...
Schwarz B, Ihry P.A 26-year-old pony mare (ca. 180 kg bodyweight) was presented as an emergency because it had erroneously received 110 times its standard dose of pergolide (Prascend) per os approximately 4 hours earlier. Clinical examination initially was normal except tachycardia of 52 beats/min. The pony was treated symptomatically with paraffin oil and activated charcoal per nasogastric tube to prevent further systemic absorption and accelerate intestinal excretion of the pergolide. Furthermore, the pony received 400 mg of dopamine antagonist azaperone (Stresnil) intramuscularly (i.m.) followed by 80 mg...
Ensink JM, Moi A, Vulto AG, Tukker JJ.Pivampicillin was administered as an oral paste to five healthy adult horses, and an oral paste with ampicillin trihydrate was administered to three horses. Pivampicillin was administered to both starved and fed horses, ampicillin trihydrate was administered to fed horses only. The dose of pivampicillin was 19.9 mg/kg, and the dose of ampicillin trihydrate was 17 mg/kg. Both doses are equivalent on a molecular basis to 15 mg/kg ampicillin. Ampicillin concentrations in plasma were determined up to 24 hours after administration. After administration of pivampicillin to starved and fed horses the...
Ek N.Selected transferrin phenotypes from 14 horses were investigated by antigen-antibody crossed electrophoresis. Horse sera were subjected to starch gel electrophoresis followed by right angle electrophoresis in agarose gels containing rabbit produced anti-horse transferrin. This technique gave an additional zone in the front as compared with 2 transferrin zones seen after ordinary starch gel electrophoresis. Comparisons of transferrin concentrations in horse sera were performed by an immunodiffusion technique. Values were related to a chosen reference serum. A total of 372 horses (210 Norwegian ...
Hubert JD, Beadle RE, Norwood G.The molecular basis of the pathophysiology of anhidrosis is still not well understood. Therefore, treatments are more often based on clinical impressions than on scientific fact. Treatment options for this condition will improve only when more is known about the molecular events that cause anhidrosis, especially as they relate to beta2-receptor dysfunction and stimulus-secretion coupling in the sweat glands of affected horses. Although this additional information is being attained, sound environmental management will continue to be a very important aspect of the treatment of horses affected wi...
Gaughan EM, Fubini SL, Dietze A.Over an 8-year period, 14 horses were admitted to the New York State College of Veterinary Medicine for evaluation of fistulous withers. Of the 14 horses, 11 were treated surgically and 3 were not treated. Surgical techniques involved radical excision of the affected soft tissue and spinous processes of affected vertebrae. Recurrence rate was 30%, and these horses required additional surgery to resolve the problem.
Dedar RK, Kumar N, Narnaware SD, Tripathi BN.Wound healing in horses is complicated by the excessive growth of granulation tissue, commonly known as proud flesh and is similar to keloids in human beings. At present, there is no satisfactory treatment for proud flesh in horses. In this study, we, for the first time, demonstrated that leaf extract of Aerva javanica suppresses excessive growth of granulation tissue in horses. Many plant flavonoids are claimed to have antiproliferative properties. Kaempferol is a natural flavonoid containing 3-hydroxy flavone backbone found in many plants in its aglycone form and attached with various sugars...
Davidson GS.Anesthetization of large animals, such as the horse, is a challenge for veterinarians and compounding pharmacists. This article discusses the technique of intravenous anesthesia by using a combination of xylazine and ketamine in the horse for short-term unconsciousness; a combination of xylazine, diazepam, and ketamine, for improved sedation and muscle relaxation; and a combination of xylazine, ketamine, and guaifenesin, referred to as Triple Drip, for the maximum 1-hour duration of unconsciousness. Compounding pharmacists that have the facilities and training required to prepare sterile compo...
Méndez-Angulo JL, Swaab ME, Malone E, Olson EJ, Chalkley MD, Aird B, Ward C.A 12-year-old Quarter horse gelding was presented for evaluation of severe right forelimb lameness, 2 draining tracts over the lateral aspect of the right proximal antebrachium, and weight loss. A presumptive diagnosis of blastomycotic osteomyelitis was established based on radiographs and cytology of the exudate. This diagnosis was confirmed at necropsy. Un hongre Quarter horse âgé de 12 ans a été présenté avec une boiterie grave du membre antérieur droit, 2 faisceaux de drainage sur l’aspect latéral de l’avant-bras droit proximal et une perte de poids. Un diagnostic par infér...
Chiesa OA, Vidal D, Domingo M, Cuenca R.Percutaneous washes of the guttural pouches were obtained from two groups of 15 clinically normal horses, one lightly exercised and the other heavily exercised. Microbiological and cytological studies showed a wide variation in the differential cell counts. The cytological pattern of the normal lavages (< 5 per cent neutrophils) was characterised by a large proportion of ciliated columnar epithelial cells, a few non-ciliated cuboidal epithelial cells, and less than 1 per cent monocytes, lymphocytes, and eosinophils. Abnormal lavages (with more than 5 per cent neutrophils) had higher levels ...
Choi YH, Chung YG, Seidel GE, Squires EL.The objective was to compare culture media for in vitro maturation of equine oocytes and for in vitro culture of zygotes produced from IVF of partially zona-removed oocytes. Cumulus-oocyte complexes from slaughterhouse-derived ovaries were washed in m-Dulbecco's PBS and cultured in TCM-199, F10-DMEM or c-F10-DMEM (50% F10-DMEM + 50% F10-DMEM conditioned medium from culture of an equine trophoblast monolayer for 3 or 4 days). All media included FSH, LH, E2, and 10% FCS. After 28 to 30 h maturation, cumulus expansion was scored from 0 (no expansion) to 4 (fully expanded). Oocytes with a 1st pola...
Wernery U, Rodriguez M, Raghavan R, Syriac G, Miriam Thomas M S, Elizabeth SK, Federico Ronchi G, Muhammed R, Patteril NA, Joseph S.African horse sickness (AHS) is a devastating viral disease of equids that was first recorded in 1327. Currently, prevention and control of the disease are based on attenuated vaccines and midge control. It has been shown that attenuated Orbivirus vaccines are not always safe as they may reverse to virulence. Objective: In the Emirate of Dubai, a vaccination experiment was carried out with an inactivated AHS vaccine produced at the Central Veterinary Research Laboratory (CVRL), Dubai, UAE to investigate the humoral antibody response of AHS-naïve horses to this vaccine. Our vaccination experim...
Viljanto M, Hincks P, Hillyer L, Cawley A, Suann C, Noble G, Walker CJ, Parkin MC, Kicman AT, Scarth J.The use of testosterone and its pro-drugs, such as dehydroepiandrosterone (DHEA), is currently regulated in horseracing by the application of international testosterone thresholds. However, additional steroidomic approaches, such as steroid ratios, to distinguish overall adrenal stimulation from drug administrations and an equine biological passport for longitudinal steroid profiling of individual animals could be advantageous in equine doping testing. Thus, DHEA concentrations and related ratios (testosterone [T] to DHEA and DHEA to epitestosterone [E]) were assessed in the reference populati...
Klug E, Treu H, Hillmann H, Heinze H.Artificial insemination using deep-frozen semen was performed on 116 mares in 1973 using twelve ejaculates from eight stallions of the Hanoverian breed. Despite the fact that the quality of the semen used was poor, the majority of the mares inseminated were subfertile and some mares were inseminated during one oestrus only, 44% nevertheless conceived and gave birth to live foals. Of a small group of ten mares inseminated in the same year with fresh semen, seven conceived.
Chacon SC, Faccini JL, Bittencourt VR.The host relationships for most species of the genus Amblyomma are poorly known in Brazil. The ability of A. pseudoconcolor and A. cooperi to successfully feed on horses was investigated during ongoing research on the life cycle of these two species, which are primarily associated with wildlife. Results of these experiments suggest that horses are potential hosts for the adult stages of both species.
Mas M, Mañé N, Fernández F, Gallego D, Pumarola M, Jiménez M.In the equine large intestine, the knowledge of the basic mechanisms underlying motility function is crucial to properly treat motility disorders. P2Y1 receptors are responsible for mediating purinergic colonic relaxation in several species. In vitro experimental studies of the circular muscle from the equine pelvic flexure (n = 6) were performed to characterize inhibitory and excitatory neuromuscular transmission. Electrophysiological studies showed that electrical field stimulation (EFS) evoked biphasic inhibitory junction potentials (IJPs) in smooth muscle cells: a fast IJP (IJPf) follo...
Santschi EM, Juzwiak JS, Slone DE.Three monorchid colts were admitted for castration as cryptorchids. Two colts each had one normal descended testis, and the third colt had a small testis in the abdomen. Monorchidism was diagnosed at surgery by locating an incomplete epididymis without a testis. After the incomplete epididymis and other testis were removed, the absence of testicular tissue was confirmed by results of a human chorionic gonadotropin response test.
Carmalt JL, Baptiste KE, Chirino-Trejo JM.A 10-year-old pregnant Norwegian Fjord horse was examined for gross swelling of the muzzle of 2 years' duration. Examination of biopsy specimens revealed diffuse dermal fibrosis, micropustule formation, and vascular thrombosis; large numbers of Actinobacillus lignieresii were isolated in pure culture. Prolonged treatment with i.v. administration of sodium iodide and oral administration of trimethoprim-sulfamethoxazole caused regression of the swelling and did not induce abortion. A 5-month-old American Paint filly was examined for swelling in the udder region. Bacteriologic culture of purulent...
Robinson CS, Wylie CE, Compston PC, Payne RJ.To describe a technique of canaliculosinostomy into the caudal maxillary sinus to alleviate epiphora secondary to nasolacrimal duct obstruction and to report the long-term outcome in 5 horses. Methods: Case series. Methods: Five client-owned horses. Methods: Case records of all horses presented for chronic epiphora to a single equine hospital that underwent surgical treatment were reviewed. All included horses had a Jones test or dacryocystography to confirm nasolacrimal duct obstruction. All horses were anesthetized and canaliculosinostomy was created from the medial canthus of the eye into t...
Kotoński B.The purification of alpha-1,4-1,4-glucosyltransferase from the equine serum is presented. Ion-exchange chromatography on DE-11, DE-32 and CM-32 celluloses was applied in the successive steps of isolation. Gel-filtration on Bio-Gel P-200 was the last step of purification; it gave the protein which was homogeneous on disc polyacrylamide gel electrophoresis. The purification degree was of the order 2100 at about 40% yield.
Anderson WI, King JM.Lumbar polyradiculopathy, characterized by ballooning myelin sheaths was diagnosed in multiple aged mammalian species including two horses, a cow, a squirrel, a woodchuck, a rabbit, a guinea pig, a hamster, and a mouse. The lesion was subclinical, and considered an incidental, age-related finding.
Colahan PT, Savage KA, Tebbett IR, Rice BL, Jackson CA, Freshwater L.Adrenergic activity accompanies intense exercise and mediates physiological and metabolic responses to exercise. Guanabenz, an antihypertensive drug marketed for human usage, depresses brain vasomotor and cardioaccelerator centres, blocks peripherally adrenergic neurons and is reportedly used as a calming agent in horses but little is known of its effects in the species. Objective: To determine if guanabenz induces measurable signs of adrenergic suppression on fit Thoroughbred horses undergoing intense exercise. Methods: In a random crossover design, 12 exercise conditioned Thoroughbred horses...
Brock AK, Chamoun-Emanuelli AM, Howard EA, Huntzinger KD, Lawhon SD, Bryan LK, Cosgriff-Hernandez EM, Cohen ND, Whitfield-Cargile CM.To compare: (1) the load and diversity of cultivatable bacterial species isolated from tissue biopsies with cultures from surface swabs, and (2) the ability of each technique to detect methicillin-resistant Staphylococcus aureus (MRSA) in a model of MRSA-infected equine wounds. Methods: Experimental in vivo study. Methods: Three light-breed adult horses. Methods: Four 2.5 × 2.5 cm full-thickness skin wounds were created on the dorsolateral aspect of each forelimb. Five days later, each wound was inoculated with a pure culture of MRSA (ATCC 43300). One hundred microlitres of 0, 5 × 1...
