Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
Hoffman AM, Viel L.Field diagnostic tests for respiratory diseases are constantly evolving. With each new application, equine patients with sinusitis, acute and chronic bacterial and fungal pneumonia SAID, chronic obstructive pulmonary disease, pleuropneumonia or poor performance are managed with greater proficiency. All of these problems can be investigated adequately in the field. This article is a guide to sampling techniques relevant to the ambulatory clinician.
Cassotis NJ, Stick JA, Arnoczky SP.A 4-month-old Quarter Horse colt was admitted for repair of an open, comminuted fracture of the proximal portions of the diaphyses of the left second, third, and fourth metatarsal bones. Initial repair included internal fixation and cancellous bone graft. However, the third metatarsal bone became infected and failed to heal. After removal of infected portions of the bone, a 5-cm, fullthickness cortical allograft was placed in the defect. Rigid internal fixation provided stability for the allograft and remaining fracture fragments so that the horse was able to bear weight on the second and four...
Singer ER, Livesey MA.To determine, in a population of young horses, whether a variation exists among neonates, sucklings, weanlings, and yearlings regarding recovery from anesthesia, short- and long-term survival rates, and postoperative adhesion formation following exploratory laparotomy. Methods: Retrospective study. Methods: 102 horses < 25 months old that underwent exploratory laparotomy. Methods: Pre-, intra-, and postoperative information was retrieved from medical records, conversations with referring veterinarians, owners, or trainers, and race records. Survival rates (recovery from anesthesia and short- a...
Sedrish SA, McClure JR, Pinto C, Oliver J, Burba DJ.A 12-year-old Morgan mare was examined because of stallion-like behavior of 45 days' duration. Palpation per rectum and transrectal ultrasonographic examination revealed a large left ovary with multiple cystic areas and crepitus. A granulosa-theca cell tumor was suspected. During hospitalization for further evaluation of the affected ovary, the mare developed signs of abdominal pain. Exploratory surgery revealed a large left ovary, which was black with a necrotic and friable surface, and a 720 degrees clock-wise torsion of the ovarian pedicle. Torsion was corrected, and oophorectomy was perfor...
Demeulenaere D, Vercruysse J, Dorny P, Claerebout E.The control of naturally acquired cyathostome infections in horses by treatments with ivermectin and moxidectin was evaluated in three field studies. In a first study the efficacy of both drugs was assessed in a faecal egg count reduction test. Both ivermectin and moxidectin demonstrated efficacies greater than 99 per cent for up to 60 days after treatment. In a second study, the period required for strongyle eggs to reappear was estimated in horses treated either with ivermectin or moxidectin. For the horses treated with ivermectin the period varied between 10 and approximately 13 weeks, and ...
Ennulat D, Brown CA, Brown SA.To evaluate the effects of epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) on canine and equine mesangial cell (MC) proliferation in vitro. Methods: Third- through eighth-passage canine and equine MC were obtained from explant outgrowth after differential sieving of glomeruli isolated from the kidneys of clinically normal dogs and horses. Methods: Mitogenic effects of serum, insulin, EGF, and PDGF were evaluated in MC by induction of DNA synthesis, measured as stimulation of [3H]thymidine incorporation and increase in cell numbers. Results: Epidermal growth factor was a...
Shimizu A, Kawano J, Yamamoto C, Kakutani O, Anzai T, Kamada M.Pulsed-field gel electrophoresis (PFGE) was used to determine genetic relationships among 15 methicillin-resistant Staphylococcus aureus (MRSA) isolates from mares with metritis and from a stallion with dermatitis in Hokkaido. All the 15 isolates showed phage pattern 6/47/54/75, coagulase type IV, and enterotoxin type A. The restriction endonuclease SmaI cut their genomic DNAs into 15 or 16 fragments ranging in size from 8 to 630 kb. Fourteen of the 15 isolates showed the same PFGE pattern, whereas the remaining one appeared to be closely related. The 9 human MRSA isolates showing the same phe...
Barton MH, Moore JN, Norton N.To evaluate the effect of pentoxifylline on response of horses to in vivo challenge exposure with endotoxin. Methods: 24 healthy horses in 3 treatment groups: pentoxifylline, endotoxin, or endotoxin and pentoxifylline. Methods: Horses of the pentoxifylline group were given a bolus of pentoxifylline (7.5 mg/kg of body weight, i.v.), followed by an infusion (3 mg/kg/h) over 3 hours, and those of the endotoxin group were given 20 ng of endotoxin/kg i.v. over 30 minutes. Those of the combination group were given both of the aforementioned compounds; pentoxifylline was administered immediately afte...
Kubota T, Inaba Y, Uwatoko K, Akashi H, Fukunaga Y.Equine arteritis virus (EAV) grown on RK13 cell cultures was tested for hemagglutination (HA) with erythrocytes from a variety of species at 4 degrees C, room temperature and 37 degrees C. HA was observed at all temperatures with erythrocytes from mouse and chicken but not with those of cattle, horse, rabbit, guinea pig, mongolian gerbil, goose or chick embryo. Chickens showed an individual variation in agglutinability of their erythrocytes, requiring selection of birds to obtain erythrocytes for HA. The HA activity was enhanced by treatment of virus materials with Tween 80 followed by treatme...
Sellon DC, Walker K, Suyemoto M, Altier C.To evaluate the ability of nucleic acid amplification techniques to detect Rhodococcus equi in equine buffy coat, blood, and tracheal wash fluid and to differentiate between virulent and avirulent strains of the bacteria. Methods: Blood anticoagulated with EDTA and tracheal wash fluid from healthy horses. Methods: Logarithmic dilutions of virulent and avirulent strains of R equi were added to equine buffy coat and tracheal wash fluid samples. The DNA was extracted and amplified by polymerase chain reaction (PCR), using primers specific for the 16S ribosomal subunit gene and the virulence plasm...
Baskett A, Barton MH, Norton N, Anders B, Moore JN.To compare effects of a single dose of pentoxifylline (PTX), flunixin meglumine (FM), and their combination (FM/PTX) in a model of equine endotoxemia. Methods: 24 healthy horses, aged 2 to 15 years. Methods: 4 groups (n = 6/group) received 30 ng of Escherichia coli O55:B5 endotoxin/kg of body weight, i.v., over 30 minutes, and 1 of the following preparations 15 minutes before and 8 hours after endotoxin infusion: FM, 1.1 mg/kg; PTX, 8 mg/kg; FM/PTX, 1.1 mg of FM and 8 mg of PTX/kg; and saline solution bolus (ENDO). Clinical and hematologic variables were measured over 24 hours. Results: Compar...
Hague BA, Martinez EA, Hartsfield SM.To evaluate effects of a single high dose of gentamicin on neuromuscular function in horses anesthetized with halothane. Methods: 6 healthy adult horses. Methods: Halothane-anesthetized horses were positioned in left lateral recumbency, and the right hind limb was immobilized in a reusable fiberglass cast fixed to a steel frame. The hoof was attached to a force transducer, and resting tension of 0.93 +/- 0.16 kg was maintained. A supramaximal train-of-four stimulus of 2 Hz for a duration of 0.25 millisecond was applied to the superficial peroneal nerve every 20 seconds by a square-wave stimula...
Bailey CJ, Reid SW, Hodgson DR, Suann CJ, Rose RJ.Risk factors for musculoskeletal injury in racing Thoroughbreds were investigated in a case-control study conducted at racetracks administered by the Australian Jockey Club. Univariable analysis of 137 cases from the official Veterinary Surgeon's reports and an equal number of randomly selected controls from the Australian Race Results identified field size, barrier position and class of race as being significantly associated with breakdown (P < 0.05). Multiple logistic regression was then used to investigate the effect of each putative risk factor whilst controlling for all others. Horses at ...
Ousey JC, Prandi S, Zimmer J, Holdstock N, Rossdale PD.To determine the effect of diet on energy intake, loss, and metabolism in foals 2 to 7 days old. Methods: 14 pony foals. Methods: Group-A foals suckled their dams, group-B foals were fed milk replacer, and group-C foals were fed by total parenteral nutrition (TPN). Energy balance studies were performed over 8-hour periods on postpartum days 2, 4, and 7. Results: Mean gross energy (GE) intake of group-A foals increased between days 2 and 7. Approximately 3% of GE was excreted in urine and feces, and energy expenditure remained constant. These foals were in positive energy balance, and mean body...
Sams RA, Gerken DF, Dyke TM, Reed SM, Ashcraft SM.Cimetidine was administered intravenously and by the intragastric route to six mares at a dose of 4.0 mg/kg of body weight (bw). Specific and sensitive high performance liquid chromatographic methods for the determination of cimetidine in horse plasma and urine and cimetidine sulfoxide in urine are described. Plasma cimetidine concentration vs. time data were analysed by non-linear least squares regression analysis to determine pharmacokinetic parameter estimates. The median (range) plasma clearance (Cl) was 8.20 (4.96-10.2) mL/min.kg of body weight, that of the steady-state volume of distribu...
Sugiyama S, Fujiwara K.The angles related to the coxal joints were comparatively studied in four-limbed walking animals and two-limbed ones including man and birds. Between animals with both types of walking, no significant difference was observed in the neck-shaft angles (NSA), which was equivalent to the acetabulum angles (ACA) at the connection of the femoral head with the acetabulum. The anteversion angles (AVA) were equivalent to the horizontal ACA. Canine species showed two different forms of the femoral neck with or without modification by the femoral AVA, probably being breed-specific and nutrition-dependent...
Duckett WM, Matthews HK.Paraneoplastic eosinophilia is reported in dogs, cats, and humans. Hypereosinophilia (an eosinophil count greater than 1.5 x 10(9) L) is often associated with metastasis and a poor prognosis. This report describes a case of paraneoplastic hypereosinophilia in a pony. Neoplasia should be included in the differential diagnoses in a horse with eosinophilia.
Lunn P, Vagnoni KE, Ginther OJ.Out of all the areas of comparative immunological study in the horse, the field of reproductive immunology has proven to be one of the most fertile and exciting. Maternal immunological interactions with the fetus involve a set of events which prevent maternal rejection of trophoblastic tissue invading the uterus, and at the same time control this invasion to regulate growth and prevent damage to maternal tissues. Unique features of equine placentation make it exceptionally well-suited to studying these immunological interactions.
Harkins JD, Queiroz-Neto A, Mundy GD, West D, Tobin T.This report describes the development of a behaviour chamber and the validation of the chamber of measure locomotor activity of a horse. Locomotor activity was detected by four Mini-beam sensors and recorded on a data logger every 5 min for 22 h. Horses were more active during daytime than in the evening, which was at least partially related to human activity in their surroundings. To validate the ability of the chambers to detect changes in activity, fentanyl citrate and xylazine HCl, agents well-characterized as a stimulant and a depressant, respectively, were administered to five horses. Fe...
Shingleton WD, Mackie EJ, Cawston TE, Jeffcott LB.Cartilage canals have been described in most mammals and contain the vascular elements necessary for the maintenance of epiphyseal growth cartilage. The presence and longevity of cartilage canals in developing articular/epiphyseal cartilage of horses is described for the first time. Growth cartilages from 30 normal horses (from 130 days gestation to age 2 years) and 6 cases of dyschondroplasia (age 6 months. Cartilage canals were associated with retained cartilage of dyschondroplastic lesions found in animals age < 15 months. The presence of cartilage canals in association with dyschondrop...
The Journal of heredityNovember 5, 1997
Volume 88, Issue 5 355-357 doi: 10.1093/oxfordjournals.jhered.a023117
Short RV.Haldane's law states that in interspecific hybrids, it is the heterogametic sex that is likely to be absent, rare, or sterile. In mammals, there is increasing evidence to suggest that this may be due to the high mutation rate of male sex-determining genes on the Y chromosome. The mule, humanity's first successful attempt at genetic engineering, provides some support for this concept. Interspecific hybrids may also shed new light on the importance of the maternal transmission of mitochondrial DNA and the phenomenon of genomic imprinting.
Ibrahim A, Mahmoud UT, Ali MM, Ragab SMM.This study described the subcapsular technique for primary closure castration in donkeys with special regard to its efficiency and welfare impacts. The study was conducted on twelve adult male donkeys, allocated randomly into two groups; subcapsular castration (SC) and open castration (OC) groups, whether the donkeys were subjected to surgical castration either by subcapsular or open castration techniques, respectively. Testosterone, cortisol, lactate, glucose, total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), triglyceride (TG), and nitric oxide (NO) were measured before an...
Chavatte P, Brown G, Ousey JC, Silver M, Cottrill C, Fowden AL, McGladdery AJ, Rossdale PD.Clinical and pathological records of 124 foals were studied. The foals were assigned to six groups; normal, premature, dysmature, bacterially infected, neonatal maladjustment syndrome and Equid herpesvirus type 1 (EHV-1) infected. Also, 6 pony fetuses were sampled via catheters in the umbilical vein and artery between 280 and 310 days gestation. Bone marrow aspiration was performed on a further 14 foals. Premature foals had significantly lower neutrophil counts than normal foals up to 5 h. Foals with bacterial infections had significantly lower neutrophil counts up to age 12 h. EHV-1 infected ...
Noble P, Lumay G, Coninx M, Collin B, Magnée A, Lecomte-Beckers J, Denoix JM, Serteyn D.An equine fetlock joint pendulum test was studied and the influence of post mortem time and intra-articular lipid solvent on the viscous frictional response examined. Fresh equine digits (group 1, n=6 controls; group 2, n=6 lipid solvent) were mounted on a pendulum tribometer. Assuming that pendular joint damping could be modelled by a harmonic oscillator fluid damping (HOFD), damping time (τ), viscous damping coefficient (c) and friction coefficient (μ) were monitored for 5h under experimental conditions (400N; 20°C). In all experiments, pendular joint damping was found to follow an expone...
Gehlen H, Bradaric Z.The evaluation of plasma ACTH and the dexamethasone suppression test are considered the methods of choice to evaluate the course of therapy of pituitary pars intermedia dysfunction (PPID). Sampling protocols as well as vacutainers for analysis differ between the laboratories. To evaluate the reproducability of plasma ACTH measurement between four different laboratories (A, B, C, D) in Germany as well as within the laboratories themselves, ten horses with previously diagnosed PPID and four healthy horses were sampled and analyzed. Each laboratory received two differently labeled samples of each...
Wouters CP, Toquet MP, Renaud B, François AC, Fortier-Guillaume J, Marcillaud-Pitel C, Boemer F, De Tullio P, Richard EA, Votion DM.Atypical myopathy (AM) is a severe rhabdomyolysis syndrome that occurs in grazing horses. Despite the presence of toxins in their blood, all horses from the same pasture are not prone to display clinical signs of AM. The objective of this study was to compare the blood metabolomic profiles of horses with AM clinical signs with those of healthy co-grazing (Co-G) horses. To do so, plasma samples from 5 AM horses and 11 Co-G horses were investigated using untargeted metabolomics. Metabolomic data were evaluated using unsupervised, supervised, and pathway analyses. Unsupervised principal component...
Hall LW, Trim CM.Horses breathing spontaneously under halothane anaesthesia were subjected to expiratory resistance by the introduction of a water-trap into the expiratory limb of a circle absorber. Resistances of 10 and 20 cm H2O produced no significant increase in PaO2 (P greater than 0.05) during halothane/air and halothane/oxygen anaesthesia. The imposition of resistance was associated with an increase in PaCO2 and a significant increase in mixed venous PCO2. In three animals subjected to 20 cm H2O resistance under halothane/air anaesthesia, the cardiac output was reduced (P less than 0.01). It was conclud...
Amano T, Tozaki T, Takasu M, Onogi A, Yamada F, Kawai M, Ueda J.We investigated whether regular changes of the sire in a breeding farm of Hokkaido Native Horses (HKDs) enables the DNA-level genetic variation of the produced animals to be maintained. The genotypes of 31 microsatellite markers were identified and analyzed in 207 animals produced in a breeding farm in which the sire was replaced every 3 to 5 years. The mean allele number indicating the degree of genetic variation was 5.97 and was similar to those reported previously. The mean observed heterozygosity was 0.74 and was higher than the expected heterozygosity, 0.69; F was -0.07, indicating that ...
Lu G, Huang J, Li S.Theiler's disease-associated virus (TDAV) could be the aetiological agent of Theiler's disease. Horses experimentally inoculated with equine plasma containing TDAV develop acute and chronic infections with viraemia. Since its first identification in 2013, TDAV has not been detected in equines in the epidemiological studies that have been conducted. Until now, only one genome sequence of TDAV (HorseA1_serum) had been obtained. In this study, we sequenced the genome of four TDAV strains (A/China, F/China, H/USA and I/USA) in commercial equine sera used for cell culture propagation in China using...
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 ...
Junco M, Iglesias LE, Sagüés F, Zegbi S, Guerrero I, Saumell CA.In horses, the nematodes of the Strongylidae family are the most important due to their prevalence and pathogenicity. Sanitary plans include parasite control based on chemical anthelmintics. Among these, the benzimidazole compounds have been used since the 1960s to control the nematode Strongylus vulgaris. Its inappropriate use resulted in the development of resistance in parasites with a shorter biological cycle, such as the small strongyles. Currently, the genera that make up this group show widespread resistance to all chemical treatments available in veterinary medicine, except for macrocy...
Eksell P, Carlsson S, Lord P, Carlsten J.The aim of this study was to examine the effects of a digital filter on the detectability of a phantom lesion in a scintigram of the equine tarsus. Lateral images containing 50, 100, 150, 500, or 1000 kcounts were acquired. A created phantom lesion of 0 (normal), 10, 15, 20, or 30% increased intensity relative to local background was placed in the centrodistal tarsal joint area in the images of different count levels. Duplicate images were filtered with a Metz filter. The complete set of filtered and unfiltered images totaling 180 images was projected as slides to a group of 9 observers. The s...
Domingues RR, Ginther OJ, Gomez-Leon V, Castro T, Wiltbank MC.In heifers and mares, multiple pulses of prostaglandin F2alpha (PGF) are generally associated with complete luteal regression. Although PGF pulses occur before and during luteolysis, little is known about the role of minor PGF pulses during preluteolysis on subsequent luteal and endometrial PGF production that may initiate luteolysis. Heifers (n = 7/group) and mares (n = 6/group) were treated with a single minor dose of PGF (3.0 and 0.5 mg, respectively) during mid-luteal phase (12 and 10 days postovulation respectively). After treatment, a transient decrease in progesterone (P4) con...
Ginther OJ.Examples of research discoveries and first reports on mare reproduction by the O.J. Ginther team are (1) determined daily circulating concentrations of four hormones during the estrous cycle, (2) showed that mares can be induced to ovulate and superovulate by hormone treatment during both ovulatory and anovulatory seasons, (3) demonstrated that prostaglandin F2α was the luteolysin in mares, (4) described the mare's elaborate hormonal and biochemical mechanism for selecting the ovulatory follicle from a pool of like follicles, (5) developed the method for diagnosing fetal sex by Day 60 using l...
Textor JA, Nixon AJ, Fortier LA.To develop a tenoscopic method to divide the carpal flexor retinaculum and decompress the carpal canal. Methods: Cadaver specimen study and prospective trial. Methods: Twelve cadaveric limbs, 4 clinically normal horses, and 2 clinically affected horses. Methods-A tenoscopic approach to the proximolateral aspect of the carpal sheath was used to identify and facilitate endoscopic division of the inner and outer layers of the carpal flexor retinaculum in cadaver limbs. The technique was further evaluated in 4 normal and 2 clinically affected horses. Results: Anatomic dissection, intraoperative ob...
Cho DY, Hubbard RM, McCoy DJ, Stewart TB.A well-circumscribed proliferative mass was protruding from the body of the mandible of a 4-year-old Appaloosa gelding. The mass was uniformly firm and was ulcerated on the dorsal surface. The horse was euthanatized due to extensive involvement of the jaw and difficulty in eating. Microscopically, the mass consisted of numerous discrete microgranulomas separated by bands of abundant fibrous connective tissue containing lymphocytes, plasma cells, and histiocytic macrophages. Numerous rhabditiform nematodes were in the microgranulomas as well as in the surrounding connective tissue. The nematode...
Giannetto S, Zanghì A, Cristarella S.Adults of S. equina (Spirurida, Setariidae), 1 male and 2 females, collected from vaginal sac of stallion, were studied by soanning electron microscopy (SEM). The amphids, cephalic and cervical papillae, peribuccal ring, fine transverse bands and bosses of the cuticle, as well as caudal papillae were visualized clearly at this examination. The results of the present survey contribute towards the identification of S. equina, improve the definition of the characters which are demonstrated by common light microscopy and give the exact number of male caudal papillae including the lateral cloacal r...
Weiss DJ, Monreal L, Angles AM, Monasterio J.Carbohydrate-induced laminitis has been associated with decreased platelet survival, decreased blood flow to the hoof wall and with the deposition of platelets and microthrombi within venules in the dermal laminae. To evaluate further the systemic prothrombotic events occurring in the prodromal stages of laminitis, plasma samples from control and laminitis-affected ponies and horses were tested for the presence of thrombin-antithrombin (TAT) complexes and fibrin fragment D (D-dimer). No statistically significant differences between the control and laminitis-affected animals were observed for e...
Beazley SG, Focken A, Fernandez-Parra R, Thomas KL, Adler A, Duke-Novakovski T.To determine changes in distribution of lung ventilation with increasing intra-abdominal pressure (IAP) from carbon dioxide (CO) insufflation in standing sedated horses. Methods: Prospective experimental study. Methods: A group of six healthy adult horses. Methods: Each horse was sedated with acepromazine, detomidine and butorphanol and sedation maintained with a detomidine infusion. The horse was restrained in a stocks system and a 32 electrode electrical impedance tomography (EIT) belt was wrapped around the thorax at the fifth-sixth intercostal space. EIT images and arterial blood samples f...
Hong CB, Van Meter PW, Latimer CL.A malignant rhabdoid tumour was diagnosed in the orbit of a 2-year-old Thoroughbred filly. The neoplasm, which was very aggressive, was present in nearly every part of the ocular and periocular structures and had spread to the lymph nodes of the head and neck, the salivary glands and the subcutaneous tissues around the eye. The neoplasm was composed of polygonal cells with abundant eosinophilic cytoplasm. Many cells had a large, vesiculate, indented nucleus and contained a paranuclear globular inclusion. Ultrastructurally, the inclusions were seen to consist of whorls of intermediate filaments...
