"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.
Deardorff ER, Weaver SC.The mosquito Culex (Melanoconion) taeniopus is a proven vector of enzootic Venezuelan equine encephalitis virus (VEEV) subtype IE in Central America. It has been shown to be highly susceptible to infection by this subtype, and conversely to be highly refractory to infection by other VEEV subtypes. During the 1990s in southern coastal Mexico, two VEE epizootics in horses were attributed to subtype IE VEEV. These outbreaks were associated with VEEV strains with an altered infection phenotype for the epizootic mosquito vector, Aedes (Ochlerotatus) taeniorhynchus. To determine the infectivity for ...
Albayrak H, Ozan E.Equine infectious anaemia is a retroviral infection of horses. All infected horses, including those that are asymptomatic, become carriers and are infectious for life. In this study, blood samples of all equines in the province of Ardahan were collected. The material consisted of 8,947 equines, including 8,769 horses and 178 donkeys, from Ardahan province in northeastern Turkey. Blood was collected from all horses and donkeys and the sera were analysed for the presence of antibodies to equine infectious anaemia virus (EIAV) using an enzyme-linked immunosorbent assay. The results revealed that ...
Grinninger P, Skalicky M, Nell B.To assess natural variations in degree of refraction, corneal curvature, corneal astigmatism, corneal radius, and intraocular distance of healthy equine eyes. Methods: 159 horses with healthy eyes that were admitted to a veterinary teaching hospital for nonophthalmic surgeries. Methods: Eyes of horses were examined with a retinoscope prior to anesthesia and with a keratograph and A- and B-scan ultrasonographic biometers during surgery. In addition, manual caliper measurements of horizontal and vertical corneal radii were obtained. Results: Mean +/- SD degree of refraction in the horizontal mer...
Burgess BA, Lohmann KL, Blakley BR.Sudden deaths and an outbreak of diarrhea in horses occurred in southern Saskatchewan in 2006. Five horses died while survivors presented with diarrhea and, in 1 case, acute neurologic signs attributed to hyponatremia. Diagnostic testing of affected horses and environmental testing suggested poor water quality, specifically high salinity and high sulfate concentration as the cause. Des morts soudaines et une éclosion de diarrhée se sont produites chez des chevaux du Sud de la Saskatchewan en 2006. Cinq chevaux sont morts tandis que les survivants ont présenté de la diarrhée et, dans 1 ca...
Brosnan RJ, Steffey EP, Esteller-Vico A, Vaughan B, Liu IK.Digital perfusion pressure (DPP) equals mean arterial pressure (MAP) at the hoof coronet minus digital interstitial pressure (DIP) within the hoof. To test whether lamellar blood flow (LBF) changes proportionately to DPP, anesthesia was induced and maintained with isoflurane in six horses to target a MAP of 60 mmHg. Arterial, venous, and hoof interstitial pressures were measured in each pelvic limb. LBF was measured using fluorescent microspheres during dobutamine infusions targeting either 60 (low), 80 (medium), or 100 (high) mmHg MAP. Following euthanasia, hoof lamina was collected for micro...
Chen T, Ward DA.To determine tear volume, turnover rate, and flow rate in ophthalmologically normal horses by use of fluorophotometry. Methods: 12 mares free of ophthalmic disease. Methods: 2 microL of 10% sodium fluorescein was instilled onto 1 eye of each horse, and tear samples were collected via microcapillary tubes from the inferonasal conjunctival culde-sac at 0, 2, 4, 6, 10, 15, and 20 minutes after instillation. Collected tear samples were then measured for fluorescein concentrations with a computerized scanning ocular fluorophotometer. A decay curve plot of concentration changes over time was used to...
Beeler-Marfisi J, Clark ME, Wen X, Sears W, Huber L, Ackerley C, Viel L, Bienzle D.To evaluate experimental induction of recurrent airway obstruction (RAO) with inhaled fungal spores, lipopolysaccharide, and silica microspheres in horses. Methods: 7 horses with and 3 horses without a history of RAO. Methods: RAO-susceptible horses ranged in age from 17 to approximately 30 years, and control horses ranged in age from 7 to approximately 15 years. Pure mold cultures were derived from repeated culture of hay and identified via gene amplification and sequencing. Pulmonary function testing and bronchoalveolar lavage were performed before and after nebulization with a suspension of...
Aleman M, Nieto JE.To investigate gene expression of the major proteolytic systems and growth regulators in skeletal muscle of horses with myopathy associated with pituitary pars intermedia dysfunction (PPID). Methods: 14 horses with PPID-associated myopathy and 7 healthy control horses. Methods: Horses with PPID and controls were age matched (15 to 28 years old). Muscle biopsy specimens were collected from both groups and processed for RNA and cDNA extraction. Validation of the most stable housekeeping genes for skeletal muscle was performed and used to compare gene expression of the following proteolytic syste...
Byron CR, Barger AM, Stewart AA, Pondenis HC, Fan TM.To determine concentrations of receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegerin (OPG) in equine chondrocytes and synoviocytes and to quantify changes in the OPG:RANKL ratio in response to exogenous factors. Methods: Samples of articular cartilage and synovium with grossly normal appearance obtained from metacarpophalangeal and metatarsophalangeal joints of 5 adult (1- to 8-year-old) horses. Methods: Cell cultures of chondrocytes and synoviocytes were incubated with human recombinant interleukin-1beta (hrIL-1beta; 10 ng/mL), lipopolysaccharide (LPS; 10 microg/mL), ...
Poulin MF, Boivin G.Human infections with Streptococcus equi subspecies zooepidemicus, a group C streptococcus, are very rare and are generally associated with contact with horses, and consumption of unpasteurized milk products, goat cheese or pork. In most cases S zooepidemicus leads to fulminant infections. The case of a middle-aged woman who had sporadic contact with horses is described in the present report. She developed a bacteremia with severe and extensive complications that included meningitis, mitral endocarditis and blindness due to bilateral endophthalmitis. To the authors' knowledge, this is the firs...
Wang Z, Chandrasena ER, Yuan Y, Peng KW, van Breemen RB, Thatcher GR, Bolton JL.Metabolic activation of estrogens to catechols and further oxidation to highly reactive o-quinones generates DNA damage including apurinic/apyrimidinic (AP) sites. 4-Hydroxyequilenin (4-OHEN) is the major catechol metabolite of equine estrogens present in estrogen replacement formulations, known to cause DNA strand breaks, oxidized bases, and stable and depurinating adducts. However, the direct formation of AP sites by 4-OHEN has not been characterized. In the present study, the induction of AP sites in vitro by 4-OHEN and the endogenous catechol estrogen metabolite, 4-hydroxyestrone (4-OHE), ...
Brault SA, Blanchard MT, Gardner IA, Stott JL, Pusterla N, Mapes SM, Vernau W, Dejong KD, Maclachlan NJ.Equid herpesvirus-2 (EHV-2) infection is ubiquitous in horses. Although EHV-2 infection has been associated with several disease syndromes, its true pathogenic significance in horses remains uncertain. Epstein-Barr virus (EBV), another gammaherpesvirus, has been shown to cause febrile illness in humans related to its immunopathologic effects. Thus, the purpose of this study was to describe the ontogeny of the immune response of a cohort of 9 foals to natural infection with EHV-2 by evaluating serial complete blood counts, lymphocyte morphology, cytokine gene expression in peripheral blood mono...
Bryant NA, Rash AS, Woodward AL, Medcalf E, Helwegen M, Wohlfender F, Cruz F, Herrmann C, Borchers K, Tiwari A, Chambers TM, Newton JR, Mumford JA....Like other influenza A viruses, equine influenza virus undergoes antigenic drift. It is therefore essential that surveillance is carried out to ensure that recommended strains for inclusion in vaccines are kept up to date. Here we report antigenic and genetic characterisation carried out on equine influenza virus strains isolated in North America and Europe over a 2-year period from 2008 to 2009. Nasopharyngeal swabs were taken from equines showing acute clinical signs and submitted to diagnostic laboratories for testing and virus isolation in eggs. The sequence of the HA1 portion of the viral...
Bartolomé E, Goyache F, Molina A, Cervantes I, Valera M, Gutiérrez JP.A method to quantify the contribution of subpopulations to genetic diversity in the whole population was assessed using pedigree information. The standardization of between- and within-subpopulation mean coancestries was developed to account for the different coat colour subpopulation sizes in the Spanish Purebred (SPB) horse population. The data included 166264 horses registered in the SPB Studbook. Animals born in the past 11 years (1996 to 2006) were selected as the 'reference population' and were grouped according to coat colour into eight subpopulations: grey (64 836 animals), bay (33 633...
Bryan J, Leonard N, Fanning S, Katz L, Duggan V.The objective of this study was to examine the impact of hospitalisation and antimicrobial drug administration on the prevalence of resistance in commensal faecal E. coli of horses. Faecal samples were collected from ten hospitalised horses treated with antimicrobials, ten hospitalised horses not treated with antimicrobials and nine non-hospitalised horses over a consecutive five day period and susceptibility testing was performed on isolated E. coli. Results revealed that hospitalisation alone was associated with increased prevalence of antimicrobial resistance and multidrug resistance in com...
Halling Thomsen M, Tolver Jensen A, Sørensen H, Lindegaard C, Haubro Andersen P.Detection and quantification of lameness in horses consists primarily of a subjective assessment, whereby both intra- and inter-observer disagreements exist, especially with low grade lameness. Therefore, clinically applicable methods are needed for reliable, objective assessments. The aim of this study was to describe three symmetry indices derived from a simple accelerometric method and investigate these in sound trotting horses. The indices describe the overall symmetry of the gait, the symmetry of loads placed on the limbs and the symmetry in timing between left and right steps. These symm...
Roelfstra L, Vlimant M, Betschart B, Pfister K, Diehl PA.A morphological study of the midgut and salivary glands of second and third instars of Gasterophilus intestinalis (De Geer) (Diptera: Oestridae) was conducted by light, scanning and transmission electron microscopy. The midgut is anteriorly delimited by a proventriculus, without caeca, and is composed of posterior foregut and anterior midgut tissue from which a double-layered peritrophic matrix is produced. The midgut can be divided into anterior, median and posterior regions on the basis of the structural and physiological variations of the columnar cells which occur along its length. Two oth...
Boeta M, Zarco L.The objective of this study was to monitor and compare the concentrations of equine chorionic gonadotropin (eCG), progesterone and estrone sulphate during normal and failed pregnancies of mares impregnated with donkey or horse semen, relating their individual endocrine profiles to the time of pregnancy loss, and to the histopathologic findings in the aborted fetuses and placenta. Mares (n=54) were used, 32 of them impregnated with donkey semen and 22 impregnated with horse semen. Blood samples were taken twice a week from Day 35 to 120 of pregnancy. Ultrasonographic observations of the fetus w...
Annear MJ, Wilkie DA, Gemensky-Metzler AJ.To evaluate the outcome of diode laser transscleral cyclophotocoagulation (TSCP) for the treatment of glaucoma in horses. Methods: Medical records at The Ohio State University were reviewed. All horses that underwent diode laser TSCP between the years of 1995 and 2007 were included. Preoperative, procedural and clinical follow-up data were collected, and telephone follow-up was performed. Results: Forty-two eyes of 36 horses were included. Twenty-four hours prior to surgery mean intraocular pressure (IOP) was 37.17 + or - 13.48 mmHg (42 eyes). Forty-one of 42 eyes (98%) were sighted and 39 of ...
Meade BJ, Timoney PJ, Donahue JM, Branscum AJ, Ford R, Rowe R.In 1998, a newly identified bacterium Taylorella asinigenitalis was isolated from the external genitalia and reproductive tracts of nurse mares, a stallion and donkey jacks in Kentucky. An extensive regulatory effort was implemented to contain the outbreak including the tracing and testing of 232 horses and donkeys on 58 premises. T. asinigenitalis was isolated from the reproductive tract of 10 adult equids, including two donkey jacks, one Paint Quarter-horse stallion and seven draft-type breeding mares. None of the infected horses had clinical signs of reproductive tract disease. The odds of ...
Scandella M, Lazzaretti SS, De Zani D, Cassano M, Zani DD, Ravasio G, Gualtieri M.Tenoscopy of the navicular bursa has been recently introduced as a diagnostic and therapeutic treatment in cases of palmar foot pain syndrome. A deep digital flexor tendon transthecal approach was suggested in 1999, and the endoscopic technique has been reviewed. Smith and coworkers have recently reported good and promising results. An anatomic cadaver limb study was performed, and the endoscopic technique was evaluated. Subsequently, a 14-year-old Argentine mare, affected by palmar foot pain syndrome, was treated. Clinical data, MRI and endoscopic findings, and a 6-month follow-up evaluation ...
Jahn P, Zeman P, Bezdekova B, Praskova I.Twelve confirmed cases of equine granulocytic anaplasmosis (EGA) and five additional suspected cases, showing a compatible clinical history and specific IgG titres of 1280 or above, were recorded in the Czech Republic during the period 2002 to 2008. The diagnosis was based on clinical signs, the detection of Anaplasma phagocytophilum morulae in neutrophils in blood smears, serology and molecular methods. Pyrexia (39.8 to 41.3 degrees C), depression, partial or total anorexia, limb oedema and icterus were the most frequently observed clinical abnormalities. Haematological examination revealed t...
Torres SM, Malone ED, White SD, Koch SN, Watson JL.Aural plaques affect at least 22% of horses and can be asymptomatic or cause ear sensitivity. Immunohistochemical and electron microscopy studies have shown a strong association between aural plaques and papilloma virus. The purpose of this study was to investigate the efficacy of imiquimod 5% cream, an immune response modifier with potent antiviral activity, in the treatment of equine aural plaques. Twenty-one horses were enrolled and 16 completed the study. Imiquimod 5% cream was applied three times a week, every other week. When both ears were affected only the worst affected ear was treate...
Minces LR, Brown PJ, Veldkamp PJ.Streptococcus equi subsp. zooepidemicus rarely causes meningitis in humans by contact with domestic animals or their unpasteurized products. In this paper we reviewed the literature pertaining to the epidemiological and clinical aspects relating to this infection on previously reported cases of human disease. Additionally, the case of a 51-year-old female who acquired meningitis with this organism after contact with a horse is described. This patient was successfully treated with ceftriaxone, yet penicillin remains the treatment of choice. This aetiological agent should be considered in the pr...
Barrandeguy M, Vissani A, Lezica FP, Salamone J, Heguy A, Becerra L, Olguin Perglione C, Thiry E.The temporary disruption of reproductive activities due to equine coital exanthema (ECE), caused by equid herpesvirus 3 (EHV-3), at thoroughbred breeding facilities and embryo transfer centres, has an appreciable economic impact. The aim of the present study was to estimate the prevalence of excretion of EHV-3 in mares without clinical symptoms under field conditions and the re-excretion patterns of the virus in two seropositive (presumably latently infected) mares maintained in isolation for 11 mo. The EHV-3 virus was detected in perineal-vaginal swabs by real time PCR in 14 (6%) of 220 thoro...
Liberg P, Magnusson LE, Schougaard H.Synovial fluid and blood were collected from 18 clinically healthy brood mares in resting conidition. The following parameters were analysed: total leucocytes, glucose, alkaline phosphatase (AP), lactate dehydrogenase (LDH), total protein, albumin, total globulin, albumin/globulin ratio and electrophoretic protein picture. The serum/synovia ratios were calculated for all parameters. It was considered to be of greater diagnostic value to compare these serum/synovia ratios rather than to look at the individual concentrations in synovia. The results obtained did not materially differ from those i...
Snyder JR, Pascoe JR, Olander HJ, Harmon FA, Hinds DM, Vatistasa NJ, Tyler WS.The ultrastructural injury that develops sequentially in the ascending colon during experimentally induced ischemia was examined in 6 halothane-anesthetized horses. Colonic ischemia was created by 2 types of vascular occlusion 24 cm proximal and distal to the pelvic flexure. In all horses, transmural vascular compression was created. The colonic venous circulation was obstructed in 3 horses, whereas in the other 3 horses, arterial and venous circulation was obstructed. Two additional horses were anesthetized as controls for determination of any morphologic alterations associated with the exper...
Ohmura H, Okano A, Mukai K, Fukuda K, Takahashi T.This study evaluated induction of anesthesia and cardiorespiratory and anesthetic effects during maintained anesthesia with the combination of alfaxalone, medetomidine, and butorphanol. Alfaxalone (1.0 mg/kg) was administered to induce anesthesia after premedication with medetomidine (7.0 µg/kg), butorphanol (25 µg/kg), and midazolam (50 µg/kg) in six Thoroughbred horses. Intravenous general anesthesia was maintained with alfaxalone (2.0 mg/(kg∙hr)), medetomidine (5.0 µg/(kg∙hr)), and butorphanol (30 µg/(kg∙hr)) for 60 min. Electrical stimulation of the upper oral mucosa was used to...
Villa L, Gazzonis AL, Allievi C, De Maria C, Persichetti MF, Caracappa G, Zanzani SA, Manfredi MT.Tick-borne diseases in horses are considered an emergent problem worldwide; the geographical redistribution of ticks, due to climatic and ecological changes, and the movements of infected horses between different nations play important roles in the spread of tick-borne diseases affecting these hosts. In this study, a survey was planned to estimate the seroprevalence of the Gram-negative bacterium Anaplasma phagocytophilum and the piroplasmid protozoa Babesia caballi and Theileria equi in Italian horses, as well as to evaluate possible risk factors associated with seropositive cases. Serum samp...
Muñoz J, Iglesias M, Chao EL, Bussy C.To assess ultrasound guided transarterial coil placement (UGTACP) for occlusion of the internal carotid artery (ICA) and external carotid artery (ECA) in horses. Methods: Cadaveric and in vivo study. Methods: Cadaveric horses (n = 10), healthy horses (3), and 1 clinical case. Methods: Cadaveric and in vivo (healthy horses): UGTACP was performed in the caudal part of the ICA and ECA. Coil placement in the rostral part of the ICA was performed blindly and controlled by conventional radiography. No coils were placed in the rostral part of the ECA. Methods: UGTACP of the ICA was in a horse with gu...
Nagel C, Trenk L, Wulf M, Ille N, Aurich J, Aurich C.In mares, foaling is associated with changes in hematology, plasma electrolytes, blood pressure and heart rate and it has been hypothesized that these are induced by oxytocin. To test this hypothesis, mares (n = 8-14/group) were treated with oxytocin (OT; 20 I.U.) or saline (CON) at 1 h (test A) and 12 h after foaling (test B) and during first postpartum diestrus (test C). Heart rate, heart rate variability (HRV), atrioventricular blocks, salivary cortisol concentration, blood pressure, plasma electrolytes and blood count were determined. Heart rate decreased from test A to C (P < 0.001)...
Marliani G, Vannucchi I, Kiumurgis I, Accorsi PA.Affective states are of increasing interest in the assessment of animal welfare. This research aimed to evaluate the possible limitations in the application of a spatial judgment bias test (JBT) in horses, considering the influence of stress level, personality traits, and the possible bias due to the test structure itself. The distinction between two positions, one rewarded (Positive) and the other not (Negative), was learned by 10 horses and 4 ponies,. Then, the latency to reach three unrewarded ambiguous positions (Near Positive, Middle, Near Negative) was measured. Furthermore, the validate...
L'Ami JJ, Vermunt LE, van Loon JP, Sloet van Oldruitenborgh-Oosterbaan MM.A single dose of 40 μg/kg bodyweight (BW) of oromucosal detomidine gel was administered sublingually to 10 healthy Dutch Warmblood mares aged 7 ± 4 years (mean ± SD) and BW 580 ± 69 kg. Blood and urine samples were collected before and for 8 days following administration and evaluated qualitatively in an FEI Reference Laboratory and quantitatively in a research laboratory. Clinical effects were evaluated at baseline and for 24 h after administration. Sedation was determined using head height and scores of reaction to auditory and mixed auditory/sensory stimuli. Mechanical nociceptive thres...
Dulin JA, Drost WT, Phelps MA, Santschi EM, Menendez MI, Bertone AL.To determine the effects of exercise on the distribution and pharmacokinetics of technetium Tc 99m medronate ((99m)Tc-MDP) following intra-articular (IA) injection in horses. Methods: 5 horses. Methods: 1 antebrachiocarpal joint (ACJ)/horse was assigned to the exercised group (n = 5), and the contralateral ACJ was evaluated in the nonexercised group (5) after a minimum washout period of 7 days. Following IA injection of (99m)Tc-MDP (148 MBq), blood and scintigraphic images of the carpus were obtained at 5, 10, 15, 20, 25, 30, 45, 60, 90, 120, 240, 360, 480, 600, 720, and 1,440 minutes. Plasma ...
Palmero J, Pusterla N, Cherry NA, Kasten RW, Mapes S, Boulouis HJ, Breitschwerdt EB, Chomel BB.Experimental infection of horses with Bartonella species is not documented. Objective: Determine clinical signs, hematologic changes, duration of bacteremia, and pattern of seroconversion in Bartonella henselae or Bartonella bovis-inoculated horses. Methods: Twelve (2 groups of 6) randomly selected healthy adult horses seronegative and culture negative for Bartonella spp. Methods: Experimental/observational study: Group I: B. henselae or saline control was inoculated intradermally into 4 naïve and 2 sentinel horses, respectively. Group II: same design was followed by means of B. bovis. Daily ...
Vaughn SA, Norton NA, Hart KA.Mechanisms resulting in breed predispositions to insulin dysregulation (ID) are poorly characterized. Cortisol antagonizes insulin, and free, biologically active cortisol can be increased in ID. Breed-related differences in serum free cortisol fraction (FCF) could contribute to ID, but FCF has not been quantified in equidae predisposed to ID, such as ponies. To compare FCF and other hypothalamic-pituitary-adrenal (HPA) axis hormones between horses and ponies during health and ID. We hypothesized: (1) FCF is higher in ponies than horses in health, and is higher still in ponies with ID and obes...
Hörnicke H, von Engelhardt W, Ehrlein HJ.Carotid loops were prepared in 3 horses several months prior to the experiments. Systemic blood pressure was recorded at rest and during exercise by insertion of a plastic cannula into the carotid artery. The pressure transducer was fixed at the neck of the animal. The blood pressure signal was transmitted by telemetry. When the horses were standing under the rider, the following results were obtained: heart rate 38 +/- 5 beats-min-1, systolic pressure 115 +/- 15, disstolic pressure 83 +/- 10, mean pressure 97 +/- 12, and pulse pressure 32 +/- 9 mm Hg. During steady gallop at a mean speed of 5...
Fernandez NJ, Gilroy CV, Wagg CR, Kwong GPS, Roy MF.The detection of band neutrophils and toxic change via microscopic blood smear review is vitally important, as their presence indicates systemic inflammation. However, in-clinic evaluation of WBC morphology is often limited. Objective: We aimed to determine the agreement between expert raters in the detection of bands and toxic change. Methods: Three board-certified clinical pathologists each evaluated 109 blood smears from horses with acute disease, and 19 control smears from healthy horses. The pathologists determined if bands were present, and if so, the percentage of bands present. They a...
de Melo UP, Ferreira C.Tetanus is a distressing and often fatal disease caused by exotoxins released by the bacterium . is a commensal of the gastrointestinal tract of humans and domestic animals, and its spores are highly resistant to environmental changes, acid, and alkali and may persist in the soil for many years. The disease is characterized by generalized muscular rigidity and spasms, hyperesthesia, convulsions, respiratory arrest, and death. Horses are the most susceptible domestic animals. Treatment is typically directed towards elimination of the source of the toxin, neutralization of any unbound toxin, es...
Watson ZE, Steffey EP, VanHoogmoed LM, Snyder JR.To characterize the effect of general anesthesia and minor surgery on renal function in horses. Methods: 9 mares with a mean (+/- SE) age and body weight of 9+/-2 years and 492+/-17 kg, respectively. Methods: The day before anesthesia, urine was collected (catheterization) for 3 hours to quantitate baseline values, and serum biochemical analysis was performed. The following day, xylazine (1.1 mg/kg, IV) was administered, and general anesthesia was induced 5 minutes later with diazepam (0.04 mg/kg, IV) and ketamine (2.2 mg/kg, IV). During 2 hours of anesthesia with isoflurane, Paco2 was maintai...
Sroka L, Müller C, Hass ML, These A, Aboling S, Vervuert I.Senecio jacobaea contains pyrrolizidine alkaloids that can induce severe hepatic intoxication in horses, either acute when ingested in high amounts or chronic when consumed over a long period. The aim of this study was to determine horses' rejection behaviour towards the presence of Senecio jacobaea in hay when fed ad libitum. We hypothesized that adult horses can sort Senecio jacobaea out of the contaminated hay when hay is fed ad libitum. Six warmblood geldings with a mean (±SD) age of 15 ± 2 years were included. In a randomized study, Senecio jacobaea contaminated hay (5% or 10% con...
Cohen ND, Carter GK, McMullan WC.Between Jan 1, 1984 and Aug 1, 1990, 27 horses were admitted to the veterinary medical center for evaluation of fistulous withers. Nine (37.5%) of 24 horses tested for antibody to Brucella abortus were seropositive. Horses that tested seropositive were significantly (P = 0.046) more likely to have been pastured with cattle that were seropositive for B abortus, and were significantly (P = 0.010) more likely to have had radiographic evidence of vertebral osteomyelitis than were horses that tested seronegative. Five horses that were seropositive for B abortus were administered strain 19 brucella ...
Souza CM, Miotto BA, Bonin CP, Camargo MM.Quantity and variety of environmental antigens, age, diet, vaccine protocols, exercising practice and mucosal cytokine microenvironment are factors that influence serum immunoglobulin (Ig) levels. IgA, IgG, IgG(T) and IgM were quantified in 60 horses, which were classified into two groups, 'intensive' or 'relaxed', according to sanitary standards of the facilities and physical exercise to which animals were subjected to. The 'intensive' group presented lower means for all isotypes, but only IgA presented a significant (P < 0.0064) difference when compared to the 'relaxed' group. T...
Mainguy-Seers S, Boivin R, Pourali Dogaheh S, Beaudry F, Hélie P, Bonilla AG, Martin JG, Lavoie JP.Steroid resistance in asthma has been associated with neutrophilic inflammation and severe manifestations of the disease. Macrolide add-on therapy can improve the quality of life and the exacerbation rate in refractory cases, possibly with greater effectiveness in neutrophilic phenotypes. The mechanisms leading to these beneficial effects are incompletely understood and whether macrolides potentiate the modulation of bronchial remodeling induced by inhaled corticosteroids (ICS) is unknown. The objective of this study was to determine if adding azithromycin to ICS leads to further improvement o...
Erol E, Williams NM, Sells SF, Kennedy L, Locke SJ, Donahue JM, Carter CN.Nocardioform actinomycetes are significant causes of placentitis and abortions in horses. In the current study, antimicrobial susceptibility patterns of 38 Amycolatopsis spp. and 22 Crossiella equi isolates, the most common nocardioform actinomycetes causing placentitis in horses, were evaluated. Antimicrobial susceptibilities of these isolates were tested by broth microdilution method in a commercial system, which was designed for Nocardia spp., fast-growing Mycobacterium spp., and other aerobic actinomycetes. The minimum inhibitory concentration required to inhibit the growth of 90% of organ...
Martin BB, Beech J, Parente EJ.To evaluate results of cytologic examination of specimens obtained by means of tracheal washes (TW) in 42 horses with a history of poor performance. Methods: Cross-sectional case series. Methods: 42 horses with a history of poor performance. Methods: A TW was performed via endoscopy before and after horses exercised on a high-speed treadmill, and specimens were evaluated microscopically and graded. Results: Ten (24%) horses were considered to be clinically normal before and after exercise. Pulmonary hemorrhage was diagnosed in 8 (19%) horses. One horse had evidence of exercise-induced pulmonar...
Cesarini C, Cotovio M, Ríos J, Armengou L, Jose-Cunilleras E.Disseminated intravascular coagulation (DIC) is frequent in horses with severe gastrointestinal disorders. Postmortem studies have found fibrin microthrombi in tissues of these horses, but studies relating these histopathological findings with antemortem hemostatic data are lacking. Objective: Antemortem classification of coagulopathy is related to the presence and severity of fibrin deposits observed postmortem in horses with severe gastrointestinal disorders. Methods: Antemortem hemostatic profile data and postmortem tissue samples (kidney, lung, liver) from 48 horses with colic. Methods: Ti...
Pascoe RR.A survey of 568 horses in training and 2,535 horses on breeding farms has shown 32 percent of the horses in training to be clinically affected while only 1.1 percent of breeding horses were affected with pathogenic dermatophytes. The majority of lesions on racing horses were located on the girth areas. Trichophyton equinum var. autotrophicum, M. canis and M. equinum were found to be restricted to racing horses only. M. gypseum occurred in racing, riding and breeding horses.
Peck K, Mealey KL, Matthews NS, Taylor TS.To determine whether clearance of capacity-limited drugs in horses differs from that in donkeys by comparing the serum disposition of caffeine and its metabolites, theophylline, theobromine, and paraxanthine after i.v. administration of caffeine to horses and donkeys. Methods: 4 healthy horses and 5 healthy donkeys. Methods: Blood samples were collected from each animal at time 0 (before) and 5, 10, 15, 20, 30, and 45 minutes, and 1, 2, 3, 4, 6, 8, 12, 24, 30, 36, 48, 54, 60, 72, and 96 hours after IV administration of a bolus of caffeine. Serum was analyzed in triplicate by high-performance l...
Ben Said M, Belkahia H, Héni MM, Bouattour A, Ghorbel A, Gharbi M, Zouari A, Darghouth MA, Messadi L.The aim of the present study was to determine the seroprevalence of Anaplasma phagocytophilum in 343 well maintained horses belonging to 11 horse stables located in northern Tunisia with indirect immunofluorescence test. Overall, 16.3% (56/343) of tested animals were positive. Anti-A. phagocytophilum antibodies were present in horses located in all studied governorates except the governorate of Ben Arous. Nine horse stables out of 11 contained positive animals, the seroprevalence of each one varied from nought to 50%. Seroprevalence varied according to gender, breed and type of activity, contr...
Ross WA, Kaneene JB.To evaluate outbreaks of disease attributable to eastern equine encephalitis virus (EEEV) in horses in Michigan, and the associated environmental patterns and weather conditions, so that factors could be identified that may have predisposed horses in specific areas of the state to infections with EEEV. Methods: Epidemiologic retrospective records analysis. Methods: Data on EEEV vectors, wild-bird reservoir hosts, and incidental hosts, including horses and human beings, obtained from census reports and medical records compiled between 1942 and 1991. Methods: Patterns detected during outbreaks o...
