"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
Henry MM, Moore JN, Fischer JK.Because certain inflammatory processes are dependent on the fatty acid composition of the cellular membrane, dietary manipulations that replace omega-6 fatty acids with omega-3 fatty acids may modify inflammatory responses. We investigated the effect of supplemental dietary linseed oil, containing the omega-3 fatty acid, alpha-linolenic acid, on in vivo responses of horses to endotoxin. One group of horses (n = 6) was fed a control pelleted ration (0% linseed oil), and another group of horses (n = 6) was fed an 8% linseed oil pelleted ration. After 8 weeks of consuming these rations, all horse...
Beech J.COPD continues to be a severe condition in horses. Despite increased understanding of its pathogenesis, there is relatively little information on effective treatment regimens. Management and prevention are critical, and more emphasis should be placed on improved housing, bedding, and feeding. More sophisticated accurate methods also are required for identifying specific causative allergens.
Tate LP.The advantages and disadvantages of various surgical lasers are discussed. Included are aspects of laser safety, anesthesia and analgesia considerations for laser surgery, and diagnostic considerations. Horses with lesions such as ethmoid hematomas, nasal polyps, and lymphoid masses are ideal candidates for laser treatment. Other conditions that are suitably treated with lasers, such as dorsal displacement of the soft palate and entrapment of the epiglottis, are described.
Watson ED, Sertich PL.This study investigated the sequence of hormonal changes within the preovulatory follicles of mares. Mares were injected i.v. with 2500 IU human chorionic gonadotrophin (hCG) when a preovulatory follicle of 35 mm in diameter was detected. Fluid was aspirated from preovulatory follicles before (0 h), and 12, 24 and 36 h after administration of hCG. Concentrations of progesterone, prostaglandin (PG) E2, PGF, 6-keto-PGF1 alpha and thromboxane B2 in follicular fluid increased significantly (P less than 0.01) between 0 and 36 h. At 36 h, PGE2 was present in highest concentrations, followed by PGF a...
Jensen T, Washino RK.Daily survivorship, duration of the gonotrophic cycle, absolute abundance and season-long relative abundance were estimated for Aedes melanimon in the Sacramento Valley of California in 1987 and 1988 using mark-release-recapture (MRR) techniques and by monitoring changes in the abundance and parity rate of the native population. One objective of these studies was to determine the extent to which A. melanimon was biologically capable of serving as a horizontal arbovirus vector. Daily survivorship was estimated to be 0.90 and 0.84 in MRR studies conducted in September 1987 and August 1988, 0.89 ...
Schneider C, Müller FP, Bertschi I.We describe the utilization of the Abbott Vision system in a horse clinic and a comparison with the Compur M 2000 CS (Bayer Diagnostics and Electronics). Discrepancies were found in respect to precision and accuracy of results. Both systems showed good practicability during routine operation but different cost-effectiveness.
Hunt RJ, Allen D, Mueller PO.Heterotopic polyodontia is typically associated with a sinus and a fistulous tract with a secreting membrane which extends to an ectopic tooth attached to the temporal bone. Recommendations for treatment include complete excision of the tract, the dental component, and the lining of the alveolar socket. Iatrogenic cerebral trauma was encountered during surgical extraction of an ectopic tooth. At post-mortem examination a second ectopic tooth was found compressing the right side of the cerebellum.
Thiel PG, Marasas WF, Sydenham EW, Shephard GS, Gelderblom WC, Nieuwenhuis JJ.Fumonisins B1 (FB1) and B2 (FB2), two structurally related mycotoxins with cancer-promoting activity, were recently isolated from corn cultures of Fusarium moniliforme MRC 826. These toxins have been reported to be produced also by isolates of F. proliferatum. Contamination of foods and feeds by F. moniliforme has been associated with human esophageal cancer risk, and FB1 has been shown to be the causative agent of the neurotoxic disease leukoencephalomalacia in horses. Because of the toxicological importance of the fumonisins, the potential to produce FB1 and FB2 was determined in a study of ...
Sweeney CR.This article addresses many aspects of exercise-induced pulmonary hemorrhage (EIPH). Reports of the prevalence, effect on performance, and the clinical signs and means of diagnosis of EIPH are included. Radiologic and scintigraphic findings in horses with EIPH are reported. Pathogenesis and treatment are discussed.
Freeman DE, Spencer PA.Age, breed, and gender distributions of 168 horses with umbilical hernia treated at the University of Pennsylvania School of Veterinary Medicine were analyzed to determine risk factors for this disease. For the 3 breeds that constituted the largest proportion of hospital and case populations, Thoroughbred, Standardbred, and Quarter Horse, the overall ratio of females to males was 1.63. In a hospital population of the same age group, 0 to 48 months, the female to male ratio was 0.93. Compared with males, females were at significantly higher risk for umbilical hernia after adjustment for breed a...
Imai Y, Kurosawa H, Fujiwara T, Fukuchi S, Matsuo K, Kawada M, Ohtsuka G.Successful palliative repair of aortic atresia and hypoplastic aortic arch associated with tricuspid atresia in a neonate is described. The repair consisted of reconstruction of the hypoplastic aortic arch with an equine pericardial patch, division of the patient ductus arteriosus, connection of the pulmonary artery to the aorta, implantation of the proximal part of the ascending aorta into the main pulmonary artery, and anastomosis of a polytetrafluoroethylene graft 5 mm in diameter between the right ventricular outflow tract and the central pulmonary artery, which was transferred anteriorly ...
Hamblin C, Mellor PS, Graham SD, Hooghuis H, Montejano RC, Cubillo MA, Boned J.A total of 256 sera collected from three species of domesticated equidae in four different Spanish provinces were examined 1-4 months after the administration of attenuated monovalent African horse sickness virus (AHSV) serotype 4 vaccine. Approximately 10% of the sera were negative by ELISA, virus neutralization, agar gel immuno-diffusion and complement fixation tests. Similar negative reactions were recorded with sera from two ponies after experimental primary vaccination. The rapid rise in antibodies in sera from these two ponies, after a second dose of vaccine, suggested they would probabl...
Galey FD, Whiteley HE, Goetz TE, Kuenstler AR, Davis CA, Beasley VR.Twelve light horse geldings developed laminitis within 8 to 12 h of being dosed by nasogastric tube with an aqueous extract of black walnut (Juglans nigra). Four of the 12 horses developed the severe signs of grade 3 laminitis (lame at a walk, refused to lift feet). Laminitis was accompanied by mild depression and limb oedema. There was no evidence of shock or colic. The horses developed neutropenia by 4 h after dosing with the extract, which shifted to a relative neutrophilia by 8 to 12 h. Minimal increases in plasma epinephrine and cortisol concentrations were suggested in severely affected ...
Kirkpatrick JF, Shldeler SE, Lasley BL, Turner JW.This study was carried out to develop an accurate, rapid and inexpensive method for diagnosing pregnancy in uncaptured feral horses by analysis of fecal steroid metabolites and to compare the accuracy of this method with diagnosis by urinary estrone conjugates (E(1)C). Paired urine and fecal samples were collected from 40 sexually mature feral mares during August and October. Urine samples were extracted directly from the soil and analyzed by enzymeimmunoassay (EIA) for E(1)C. Water extracts of fecal samples were assayed by EIA for E(1)C and nonspecific progesterone metabolites (iPdG). Urinary...
Guo YJ, Wang M, Zheng SL, Wang P, Ji WJ, Chen QH.About thirty thousands horses were affected and hundreds of them died in an epidemic caused by equine 2 influenza virus (H3N8) in China. The estimated morbidity and mortality accounted for 81% and 2%, respectively. The viral protein and RNA electrophoresis patterns revealed that the new isolates were antigenically different from the prototype strain influenza A/eq/Miami/1/63(H3N8). Therefore, the representative strain of the equine 2 subtype of influenza A virus recommended for producing reference reagents, vaccines, and for serological diagnosis must have been altered by antigenic drift.
Zentek J.In this case report on myopathies in 6 saddle-horses, a combined dietary vitamin E and selenium deficiency is presumed. Other disorders, such as exertional myopathy ("Monday morning disease") due to excessive energy intake or ionophore intoxication could be excluded by calculating the energy supply or by a simple colour test. The selenium requirement of horses is estimated to 0.1-0.2 mg/kg dry matter (Meyer 1986). If natural feed compounds are low in selenium, adequate amounts of this trace element can be supplied by means of supplemental feeds, sodium selenite (20 mg/500 kg BW/week) or bruise...
Blythe LL, Hultgren BD, Craig AM, Appell LH, Lassen ED, Mattson DE, Duffield D.A clinical, viral, hematologic , and genetic study was conducted over a 4-year period on a family of Appaloosas with high incidence of clinical ataxia and pathologic features of equine degenerative myeloencephalopathy. Marginal to deficient serum vitamin E (alpha-tocopherol) and blood selenium values were the only other consistent antemortem abnormalities in the affected horses. Members of this family were all descendants of a clinically normal mare and were raised in 3 separate environments with variable quality of feed. All horses had access to pasture grasses. Normal chromosomal karyotypes ...
Sweeney RW, Sweeney CR, Weiher J.Case records of 200 horses treated with metronidazole were reviewed. Horses were treated for respiratory tract infections (90 cases), peritonitis or abdominal abscess (39 cases), celiotomy (49 cases), orthopedic infections (6 cases), and miscellaneous soft tissue infections (16 cases). Bacteria of the genus Bacteroides were most prevalent (55 of 167 anaerobic isolates). Metronidazole was always used in combination with other antimicrobial drugs. Only 4 of the 200 horses had signs of adverse effects associated with metronidazole treatment. Those 4 horses had poor appetite that resolved when met...
Sweeney CR, Maxson AD, Soma LR.The frequency of upper respiratory tract abnormalities was determined in a selected population of racing Thoroughbreds. The prevalence of pharyngeal lymphoid hyperplasia was 34.2%; left laryngeal hemiplegia was 1.8%; and epiglottic entrapment was 0.74%. Excluding pharyngeal lymphoid hyperplasia and tracheal exudate, 3.7% of the population examined had upper respiratory tract abnormalities.
Rossier Y, Sweeney CR, Ziemer EL.Bronchoalveolar lavage was performed in 22 horses with pneumonia or pleuropneumonia. All horses had clinical evidence of pneumonia or pleuropneumonia on the basis of physical, radiographic, ultrasonographic, tracheobronchial aspirate or post-mortem findings. Results of lavage fluid analysis were normal in 9 horses, equivocal in 3 horses, and abnormal in 10 horses. Abnormal lavage fluid had increased total cell count, increased relative and absolute neutrophil counts, degenerative neutrophils, and decreased relative and absolute macrophage and lymphocyte counts.
Blanchard TL, Schumacher J, Edwards JF, Varner DD, Lewis RD, Everett K, Joyce JR.A Thoroughbred stallion developed priapism that was unresponsive to medical treatment and lavage of the corpus cavernosum penis with heparinized 0.9% NaCl solution. Three weeks after onset of priapism, the penis was firm and noncompliant, and penile pain sensation and ability to retract the penis were lost. Ultrasonography confirmed thrombosis of the corpus cavernosum penis. The stallion was euthanatized because of poor prognosis for return to breeding soundness. Necropsy revealed enlargement of numerous lymph nodes. The dorsal penile nerves were demyelinated distal to the crura of the penis. ...
Peyton DH.Specific heme protons for the majority of resonances in the downfield resolved region of equine met-azido myoglobin have been assigned using solely the two-dimensional 1H NMR experiments NOESY and COSY. Metazido myoglobin provides a useful test case for the applicability of these techniques to paramagnetic proteins for the following reasons. First met-azido myoglobin is a mixed spin-state protein, with significantly shorter relaxation times and broadened lines relative to pure low-spin systems (eg., met-cyano myoglobin). Second, met-azido hemoglobin and met-azido myoglobin are important as mod...
Asari M, Sasaki K, Kano Y, Nishita T.The immunolocalization of carbonic anhydrase isozymes in equine salivary glands was investigated for assessment of their biologic functions. In parotid glands, duct segments showed reactivity with CA-I and CA-III. CA-III was selectively located in duct segments, particularly in the basal cells of the interlobular duct. Serous acinar cells were positive for CA-I and CA-II. In submandibular glands, CA-I and CA-II were present in serous demilune and duct segments. CA-II was selectively located in the duct segments, as also noted in the parotid gland. In sublingual glands, CA-I and CA-II were loca...
Bürki F, Nowotny N, Hofer A.The commercial vaccine "Resequin F Konz." devised against viral respiratory infections of horses contains the abortigenic Equine Herpesvirus-1 (EHV-1). Therefore we had used it in our protection project of the Austrian Lipizzaners+ primarily to prevent abortions. Taking into account the recent perception that for young horses the respiratory-pathogenic EHV-4 type is essential Behringwerke Marburg added this particular virus to their market product to produce a multicomponent experimental vaccine. We examined this vaccine for its antibody induction as well as their persistence against each of i...
Freestone JF, Carlson GR.Case records of horses with muscle disorders presenting to the Veterinary Medical Teaching Hospital of the University of California, Davis, over a nine year period were evaluated. The objectives of the review were to identify the common myogenic muscle problems and their clinical features. Muscle disease of idiopathic aetiology following exercise was by far the most common condition noted. Other causes of myogenic muscle disorders included congenital, infectious, immune-mediated and nutritional factors.
Slone DE, Humburg JM, Jagar JE, Powers RD.Rectal tears were detected in three horses treated for colic. Based on historical, clinical, and postmortem findings, the tears could not be attributed to the attending veterinarian and were therefore not iatrogenic (physician induced). One tear was attributable to an infarction that presumably resulted from thromboembolism; 1 tear occurred without any evidence of external cause and resulted in such severe peritonitis that the cause and resulted in such severe peritonitis that the cause could not be determined, and 1 tear occurred during rectal palpation by the owner, before he called the vete...
McKinney AR, Suann CJ, Stenhouse AM.An investigation has been conducted into the metabolism and urinary excretion of orally administered piroxicam and tenoxicam in the horse. The major component detected in urine after the administration of piroxicam was 5'-hydroxypiroxicam, which was detectable up to 24 h post-administration. Unchanged piroxicam was present only as a minor component. In contrast, unchanged tenoxicam was the major component observed after the administration of tenoxicam, being detectable for 72 h post-administration, while 5'-hydroxytenoxicam was a minor component. Phase II beta-glucuronide conjugation in each c...
Corcoran BM, Mayhew IG, Hahn CN, Prince DR.To determine the distribution of nerve fibers containing calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP), and intermediate neurofilaments in nasal mucosa of horses. Methods: 6 horses without evidence of nasal disease. Methods: Full-thickness nasal tissue specimens were obtained from the rostral portion of the nasal septum at necropsy, and fluorescence immunohistochemistry was performed to assess mucosal distribution of nerve fibers. Results: Nerve fibers with CGRP-like immunoreactivity (CGRP-Li) formed a dense subepithelial network, and a large num...
Boison JO, Dowling P, Matus JL, Kinar J, Johnson R.This study reports the use of two validated LC with tandem MS (MS/MS) methods to study the residue depletion profile of phenylbutazone (PBZ) and its metabolite oxyphenbutazone (OXPBZ) from equine serum, urine, and muscle, kidney, and liver tissues. One LC-MS/MS method, with an LOQ of 1.0 ng/mL for PBZ and 2.0 ng/mL for OXPBZ, was used for the analysis of the two drugs in the biological fluids (equine urine and serum); the other LC-MS/MS method, with an LOQ of 0.5 ng/g for PBZ and OXPBZ, was used for the analysis of the drugs in the equine tissue samples. PBZ was administered intravenously to t...
Janicek JC, Dabareiner RM, Honnas CM, Crabill MA.To determine clinical history, structures involved, treatment, and outcome of lacerations of the heel bulb and proximal phalangeal region (pastern) in horses. Methods: Retrospective study. Methods: 101 horses. Methods: Medical records of horses with lacerations of the heel bulb and pastern were reviewed, and follow-up information was obtained. Results: 75 horses were Quarter Horses. Most horses were not treated with antimicrobial drugs prior to referral. Mean +/- SD time from injury to referral was 24 +/- 45 hours (range, 1 to 168 hours). Lacerations were most frequently caused by contact with...
Scott-Orr H.The challenges faced in demonstrating Australia's freedom from equine influenza following the outbreak in 2007-08 and the responding strategy developed by the Proof of Freedom Working Group are presented.
de Graaf-Roelfsema E, van Ginneken ME, van Breda E, Wijnberg ID, Keizer HA, van der Kolk JH.To study the possible long-term effect of improved glucose tolerance in horses after long-term training, as the impact of exercise training on glucose metabolism is still unclear in the equine species. It is not known whether there is a direct long-term effect of training or if the measurable effect on glucose metabolism is the residual effect of the last exercise session. Objective: To determine the chronic effect on glucose metabolism and peripheral insulin sensitivity of long-term training in horses by use of the euglycaemic hyperinsulinaemic clamp technique. Methods: Eleven Standardbred ho...
Galosi CM, Norimine J, Echeverría MG, Oliva GA, Nosetto EO, Etcheverrigaray ME, Tohya Y, Mikami T.The genomes of 10 equine herpesvirus 1 (EHV-1) strains isolated in Argentina from 1979 to 1991, and a Japanese HH1 reference strain were compared by restriction endonuclease analysis. Two restriction enzymes, BamHI and BglII, were used and analysis of the electropherotypes did not show significant differences among isolates obtained from horses with different clinical signs. This suggests that the EHV-1 isolates studied, which circulated in Argentina for more than 10 years, belong to a single genotype.
Nielsen SS, Bicout DJ, Calistri P, Canali E, Drewe JA, Garin-Bastuji B, Gonzales Rojas JL, Gortázar C, Herskin M, Michel V, Miranda Chueca MÁ.... () was identified among the most relevant antimicrobial-resistant (AMR) bacteria in the EU for cattle and horses in previous scientific opinions. Thus, it has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on its eligibility to be listed, Annex IV for its categorisation according to disease prevention and control rules as in Article 9, and Article 8 for listing animal species related to the bacterium. The assessment has been performed following a methodology previously published. The outcome...
Dorman D.The central nervous system's extrapyramidal system provides involuntary motor control to the muscles of the head, neck, and limbs. Toxicants that affect the extrapyramidal system are generally clinically characterized by impaired motor control, which is usually the result of basal ganglionic dysfunction. A variety of extrapyramidal syndromes are recognized in humans and include Parkinson's disease, secondary parkinsonism, other degenerative diseases of the basal ganglia, and clinical syndromes that result in dystonia, dyskinesia, essential tremor, and other forms of tremor and chorea. This cha...
Kearns CF, McKeever KH, Malinowski K.Adipose tissue plays complex role(s) in metabolic and endocrine control. To date, little work has been done in the horse regarding adipocytokines. Objective: This study was conducted to determine whether therapeutic levels of chronic beta-agonist administration, exercise, or both could alter their concentrations. Methods: A total of 23 standard-bred mares were divided into four experimental groups: clenbuterol (2.4 microg.kg(-1) bw twice daily for 8 wk) plus exercise (8 wk, 20 min.d(-1) at 50% VO2max; CLENEX; N = 6), clenbuterol only (CLEN; N = 6), exercise only (EX; N = 5), and control (CON; ...
Cockerell GL, MacCoy DM.This report provides a general overview of the pathobiology of neoplasia, and an update on the clinicopathological manifestations of lymphosarcoma, mastocytoma, histiocytoma, melanoma, sarcoid and circumanal gland tumors in domestic animals. Neoplasia represents a continuum of events from reversible hyperplasia to irreversible and pathological changes in tissue growth patterns. In some instances the causes of this disease process have been identified, but the etiology of the majority of naturally occurring neoplasms remain unknown. Surgical excision is the preferred treatment for tumors, but i...
Vasco ACCM, Dubeux JCB, Wallau MO, Wickens CL, Warren LK.This study used an online survey to gather information on forage utilization and pasture management practices implemented on horse farms in Florida. We hypothesized that pastures were inadequately managed and underutilized, resulting in greater reliance on hay. Data from 80 complete responses were submitted to descriptive analysis and Fisher's exact test. Significantly associated variables were also evaluated using multiple correspondence analysis. The primary function of the facility most reported was recreational horse use (62%). Nearly all operations (n = 79) had pasture available, with 57...
Naidoo V, Gehring R.An overview of reports of suspected adverse drug reactions received by the Veterinary Pharmacovigilance and Medicines Information Centre during the period March 2001 to February 2002 is given. A total of 77 reports were received. The majority of reports involved suspected adverse reactions that occurred in dogs and cats. Most products implicated in the reports were Stock Remedies. The products were predominantly administered either by veterinarians or trained paraveterinary professionals. Although the majority of reports were received from veterinary pharmaceutical companies, the proportion of...
Grandy JL, Hodgson DS, Dunlop CI, Chapman PL, Heath RB.The cardiopulmonary effects of intravenous (i.v.) administration of the sympathomimetic drug ephedrine during two different levels of halothane anesthesia [end-tidal concentration of 1.37% (light anesthesia) and 2.1% (deep anesthesia)] were studied in eight horses. Anesthesia was induced and maintained using only halothane in O2. Ventilation was controlled to maintain a Paco2 of 38-42 mmHg. Following instrumentation and stabilization of the horse at the halothane concentration being studied, baseline measurements of cardiac output (Q), arterial blood pressure (AP), pulmonary artery pressure, h...
Moeller S, Patan-Zugaj B, Däullary T, Tichy A, Licka TF.Laminitis is associated with failure of the suspensory apparatus of the distal phalanx (SADP) connecting the distal phalanx to the hoof wall. The specific aim of this study was to examine in vitro whether thinning of the hoof wall leading to increased deformability influences the damage of the laminar tissue created by loading of the hoof. Paired cadaver forelimbs from twelve horses were used. For each pair, the hoof wall from one hoof was thinned by 25%; this was ascertained by radiography. The contralateral hooves were used as controls. In a material testing machine, hooves were loaded in a ...
Marchant EA, Semevolos SA.The marginal transitional zone is peripherally located within the diarthrodial joint, and represents the interface of articular cartilage, periosteum, and the fibrous joint capsule. The purpose of this study is to characterize the protein expression of matrix and molecular regulators in the marginal transitional zone of foals having osteochondrosis (OC) compared to normal foals. Several families of proteins with known roles in cartilage and bone development are investigated, including matrix molecules, Wnt signaling, apoptotic factors and paracrine cell signaling molecules. Our results demonst...
Lisiecki P, Sobiś-Glinkowska M, Mikucki J.Under iron-restricted conditions staphylococcal strains could utilize in vitro several animals body iron sources in form of bovine haemoglobin, hemin, lactoferrin and transferrin, ovotransferrin, horse myoglobin ferritin and cytochrome C. Spectrum of utilized iron sources was not dependent on species affiliation and kind of siderophores system. Strains isolated from clinical materials utilized largest spectrum of animal iron body sources.
Trotter GW, Aanes WA.During an 8-month period, 3 horses were examined because of incomplete cryptorchid castration. Each horse had had surgery to remove 1 retained testis. In each case, the attending veterinarian believed castration had been adequately completed. History, rectal examination findings, and in 2 cases, high serum testosterone concentration were factors that led to the decision to do exploratory surgery on each horse. In each case, initial surgery had resulted in surgical removal of the tail of the epididymis, which was mistaken for testicular tissue.