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.
Knight DA, Weisbrode SE, Schmall LM, Reed SM, Gabel AA, Bramlage LR, Tyznik WI.The potential role of dietary copper in the development of cartilage defects in foals was investigated. Twenty-one mares were fed rations containing 13 ppm copper (CuC, control) or 32 ppm copper (CuS, supplemented) during the last three to six months of gestation and first three months of lactation. Their foals were fed pelleted concentrate containing 15 or 55 ppm Cu and were destroyed at 90 (5 CuC and 5 CuS foals) or 180 (6 CuC and 5 CuS foals) days. Focal cartilage lesions were found at multiple sites on necropsy. In foals killed at 90 days, there were over twice (9 versus 4) as many lesions...
Brewer BD, Clement SF, Lotz WS, Gronwall R.The glomerular filtration rate (GFR) was estimated in eight full-term neonatal foals by the single injection inulin plasma clearance method at two days of age, the continuous infusion plasma and urinary clearance methods at three days of age, and the 12-hour endogenous creatinine clearance method at four days of age. The effective renal plasma flow (ERPF) was estimated simultaneously by the single injection para-aminohippuric acid (PAH) plasma clearance method in the eight two-day old foals and the continuous PAH infusion plasma and urinary clearance method in the eight three-day old foals. Th...
Ekfalck A, Rodriguez-Martinez H, Obel N.Explants from the matrix of the stratum medium of the wall of the equine and bovine hoof each were cultured on a microporous membrane, using a standard culture medium. After incubation at 37 C, the outgrowth was a mixture of keratinocytes and fibroblasts, with predominance of the latter. After incubation at 34 C, the keratinocytes dominated, covering the lateral surfaces of the explant as well as the basal surface. Lateral outgrowth of keratinocytes was observed at the borderline of the original epidermis and at the borderline of the explant's contact with the membrane. Epithelial outgrowth fr...
Foreman JH, Weidner JP, Parry BW, Hargis A.A 17-year-old Quarter Horse mare was examined nearly 3 years after excision and cryotherapy of a papillary mammary gland adenocarcinoma. The mare had been used for pleasure riding since surgery, but had recently developed progressive dyspnea. The mare had clinical evidence of pleural effusion, but died before further clinical examination and treatment were instituted. Necropsy revealed deep mammary masses with similar nodules in the deep inguinal, renal, and mediastinal lymph nodes and in the lungs, pericardium, visceral and parietal pleurae, and left ovary. The masses were identified as papil...
Vörös K, Holmes JR, Gibbs C.This study was designed to evaluate the accuracy of two-dimensional echocardiography (2DE) in determining the left ventricular volume (LVV) of the horse in vitro. After examining the shape of the left ventricular silicon rubber casts of four equine hearts, two modified Simpson's rule methods (Model A and Model B) as combinations of conical shapes and one biplane area-length method as a single cone (Model C) were chosen for volume calculations. One long axis and three short axis planes were used for linear and area 2DE measurements, respectively. The ventricular length (L) was calculated from t...
Monteiro-Riviere NA, Bristol DG, Manning TO, Rogers RA, Riviere JE.Studies in dermatology, cutaneous pharmacology, and toxicology utilize skin from different animal species and body sites. However, regional differences exist in topical chemical percutaneous absorption studies in man and in animal. The objective of this study was to compare epidermal thickness and number of cell layers across species and body sites using both formalin-fixed paraffin and frozen sections. Cutaneous blood flow determined by laser Doppler velocimetry (LDV) was compared to histologic data. Six animals of each of the following species were used: monkeys, pigs, dogs, cats, cows, hors...
Frank M, Weckman TJ, Wood T, Woods WE, Tai CL, Chang SL, Ewing A, Blake JW, Tobin T.Hordenine is an alkaloid occurring naturally in grains, sprouting barley, and certain grasses. It is occasionally found in post race urine samples, and therefore we investigated its pharmacological actions in the horse. Hordenine (2.0 mg/kg bodyweight [bwt]) was administered by rapid intravenous (iv) injection to 10 horses. Typically, dosed horses showed a flehmen response and defecated within 60 secs. All horses showed substantial respiratory distress. Respiratory rates increased about 250 per cent and heart rates were approximately double that of resting values. All animals broke out in a sw...
Pan LG, Forster HV, Wurster RD, Murphy CL, Brice AG, Lowry TF.We addressed the role of spinal afferent information in the exercise hyperpnea. Arterial PCO2 (PaCO2) was assessed in 10 normal ponies during low (1.8 mph 7% or 17% grade) or moderate (6 mph 7% grade) treadmill exercise. After control studies, bilateral spinal ablation (SA) of the dorsolateral sulcus and dorsolateral funiculus at L2 was performed in seven ponies. In normal ponies within the first 90 s of exercise, PaCO2 initially decreased 2.7, 4.1, and 5.2 Torr below rest at the three work loads, respectively (P less than 0.05). PaCO2 thereafter increased toward resting levels but remained 1....
French DA, Fretz PB.A retrospective study was conducted on 35 equine patients with lower leg wounds that were managed utilizing skin graft procedures. Two pinch graft, five punch graft, seven tunnel graft, eight split-thickness mesh graft and thirteen full-thickness mesh expansion graft procedures were performed in the initial treatment. The average wound size was 188 cm(2). Twentyfour cases had pregrafting complications: 10 wounds developed sequestra; three wounds were grossly contaminated and infected; and 11 cases developed granulation tissue complications prior to grafting. Graft failure following the initial...
Collatos C, Clark ES, Reef VB, Morris DD.A foal with vegetative bacterial endocarditis affecting the wall of the left atrium was treated successfully with cefotaxime, erythromycin, and rifampin. Bacterial isolates included Escherichia coli from blood and Rhodococcus equi from a P-type osteomyelitic lesion of the left third metatarsal bone and from synovial fluid from the left metatarsophalangeal joint. Cardiac complications included cardiomegaly and atrial fibrillation, which responded to treatment with digoxin and quinidine sulfate. Cardiac function was considered normal 18 months after treatment. Bacteriologic cure of osteoarthriti...
Spier SJ, Carlson GP, Holliday TA, Cardinet GH, Pickar JG.Eleven horses (3 mares, 7 stallions, 1 gelding) with clinical and biochemical evidence of hyperkalemic periodic paralysis were studied. Each horse had history of episodic weakness, muscular tremors, or collapse, which lasted for periods of a few minutes to hours. Diagnosis was based on hyperkalemia in association with a spontaneous episode of paralysis or by precipitation of an episode by oral administration of potassium chloride. Clinical and biochemical events were documented during spontaneous and induced episodes of muscular weakness. During episodes, electrocardiographic findings were con...
Heath SE, Bell RJ, Clark EG, Haines DM.Clinical signs of generalized granulomatous disease in a horse included depression, generalized lymphadenopathy, scaly skin, and dependent edema. Diagnosis was confirmed histopathologically by diffuse granulomas in more than one organ system (lymph nodes and skin), and by ruling out etiologic agents. Response to treatment with corticosteroids was favorable. The clinical features and response to treatment in this horse were different from classic textbook descriptions of equine generalized granulomatous disease. Equine granulomatous disease appears to be comparable to human sarcoidosis. To avoi...
Valverde A, Boyd CJ, Dyson DH, Pascoe PJ.Dantrolene, a drug used in the prevention and treatment of malignant hyperthermia, was believed responsible for prolonged postanesthetic recumbency in a horse. Prophylactically, dantrolene was given orally before induction of anesthesia. Dantrolene has been recommended for use in horses at risk of developing postanesthetic myopathy. Side effects, including ataxia, may result from dantrolene administration.
Cornick JL, Seahorn TL.During a 3 1/2-year period, cardiac arrhythmias were identified in 6 of 67 horses diagnosed with duodenitis/proximal jejunitis (DPJ). Arrhythmias were detected by auscultation of irregular cardiac rhythm and subsequently were characterized by electrocardiographic evaluation. Arrhythmias included frequent second-degree atrioventricular block, ventricular ectopic depolarizations, and atrioventricular conduction disturbance. In 4 horses, arrhythmias resolved with recovery from the primary problem. One horse died suddenly 66 hours after admission, and another was euthanatized at 72 hours after adm...
Loftin MK, Levine JF, McGinn T, Coggins L.State veterinarians in 11 southeastern states completed a questionnaire designed to determine the proportion of equids in the region that were seropositive for equine infectious anemia (EIA). Cases of EIA were diagnosed in each of the states surveyed. Distinct geographic clusters of cases were apparent in Tennessee and Kentucky adjacent to the Mississippi River, in the Piedmont of North Carolina at the Virginia border, in north central Georgia, and throughout the Florida peninsula. It is suggested that the national EIA program could be improved by standardization and wider application of unifo...
Sweeney RW, Hansen TO.Six horses with dysphagia (attributable to botulism, glossitis, or guttural pouch mycosis) were given a commercially available liquid diet as the sole source of nutrition. Seven horses with hypophagia caused by severe bacterial pleuropneumonia or peritonitis were given the liquid diet to supplement food consumed voluntarily. The liquid diet was administered through a nasogastric tube 2 or 3 times daily. Body weight did not change significantly, and pertinent laboratory values remained at satisfactory concentrations throughout the feeding period. Serious complications were not encountered. Thre...
Hinrichs K, Watson ED, Kenney RM.A functional corpus luteum was found in the ovary contralateral to the ovary with a granulosa cell tumor in a 24-year-old Standardbred mare. The mare was ovariectomized because she was to be used as a jump mare for collection of semen from stallions. The blood concentration of progesterone was 2.2 ng/ml, and the luteal tissue progesterone concentration was 6.3 micrograms/mg. Atrophy of the contralateral ovary is one of the major signs used in diagnosis of granulosa cell tumor; however, our findings indicate that the ovary contralateral to a granulosa cell tumor is not invariably nonfunctional....
Marr CM, Love S, Pirie HM, Northridge DB.Regurgitation of blood through the left atrioventricular valve owing to the rupture of one of the chordae tendineae of the valve was diagnosed in a horse with sudden-onset respiratory distress and a holosystolic cardiac murmur. Severe regurgitation was confirmed with Doppler echocardiography and prolapse of part of the valve leaflet was identified with B-mode ultrasonography. The rupture of one of the chordae tendineae of a right accessory cusp of the left atrioventricular valve was confirmed post mortem. Bronchiolitis, multifocal haemorrhages and haemorrhagic fibrous plaques were found in the...
Pereira A, Braekman JC, Dumont JE, Boeynaems JM.The incorporation of iodide into proteins (PBI) and lipids (LBI) of horse thyroid slices was measured in various conditions. Their dependency on the concentration of extracellular iodide was strikingly different. For PBI the relationship was biphasic with a decrease above 10 microM, likely to correspond to the Wolff-Chaikoff effect. On the contrary, LBI increased as a function of iodide concentration up to 100 microM. Methimazole (MMI) inhibited the incorporation of iodide into both LBI and PBI, but higher concentrations of MMI were required to depress LBI as compared to PBI. The inhibition of...
Verma RD, Sharma JK, Venkateswaran KS, Batra HV.A dot enzyme-linked immunosorbent assay (dot ELISA) was developed for diagnosis of glanders in equines. The test was based on the detection of IgG antibodies to Pseudomonas mallei antigens bound to nitrocellulose coated on plastic strips (dipsticks), the reaction being amplified by an avidin-biotin system with biotinylated anti-horse IgG and horseradish peroxidase-avidin D. Sera from 810 normal, six naturally infected and 48 sensitized equines were tested by this assay, and results were compared with complement fixation, indirect haemagglutination and counter-immunoelectrophoresis tests. Dot E...
Little CB, Hilbert BJ, Wickstrom S, Hedlund BE.An alcian blue precipitation method for quantifying the hyaluronic acid (HA) and sulphated glycosaminoglycan concentration (SGAG) in solutions containing both compounds was assessed. The assay was found to be rapid and reliable in solutions containing 0 to 200 mg of HA/dl and 50 to 1,000 micrograms of SGAG/dl, and was not affected by the presence of protein, hemoglobin, or methemoglobin in concentrations normally found in synovial fluid. The HA and SGAG concentrations in intercarpal synovial fluid from 13 clinically normal and 11 arthritic horses were evaluated. A relationship was not found be...
Rabb MH, Thompson DL, Barry BE, Colborn DR, Hehnke KE, Garza F.Six pony geldings were actively immunized against GnRH conjugated to bovine serum albumin (BSA) to study 1) the relative dependency of LH and FSH storage, secretion and response to GnRH analog on GnRH bioavailability and 2) the effects of reduced GnRH bioavailability on GnRH storage in the hypothalamus. Five geldings were immunized against BSA. Geldings were immunized in December and 4, 8, 14, 20, 26 and 32 wk later. Ponies immunized against GnRH had increased (P less than .01) GnRH binding in plasma within 6 wk. By June, plasma concentrations of LH and FSH in ponies immunized against GnRH had...
Zhang J, Boyle MS, Smith CA, Moore HD.The acrosome of the stallion spermatozoon was visualized by indirect immunofluorescence with monoclonal antibody (18.6) which recognized an integral acrosomal membrane component. Localization was confirmed by electron microscopy using peroxidase labelled antibody. In fresh semen samples (n = 19), 73.9 +/- 9.1% of the spermatozoa from five fertile stallions displayed a uniform bright fluorescence over their acrosome region. In two semen samples from an infertile stallion only 28% and 35% of spermatozoa showed the same pattern of fluorescence. Spermatozoa from fertile stallions incubated for up ...
Anderson WI, Scott DW, Crameri FM.Two rare equine cutaneous neoplasms, an apocrine gland adenocarcinoma and a carcinosarcoma were diagnosed in a 17-year-old pony and a 14-year-old mare, respectively. The apocrine gland adenocarcinoma was present on the prepuce. Histologically, papillary projections of low cuboidal to columnar epithelial cells were generally well differentiated, and surrounded dilated acini. Stromal invasion was present, but vascular and lymphatic invasion was not seen. The carcinosarcoma was present in the right flank of the mare. Two discrete cell populations were characterized histologically. One portion of ...
Stolk PW, Firth EC.Intra-osseous pressure measurements in the third metatarsal bone of anesthetised young and mature ponies demonstrated that a pressure gradient exists along the bone, the pressure being highest at the level of the nutrient foramen and decreasing distally and proximally from this point. The height of the intra-osseous pressure pulse also decreased toward the bone ends. It is concluded that the sites of measurement of the intra-osseous pressure in clinical and experimental studies should be standardized.
Busch NA, Ranu HS, Silver IA.Evidence indicating that comparison of a particular animal trace with a population average is an insufficient test of the health of a limb is presented. The methodology involves representing each of three recorded force components (vertical, lateral, and transverse) as a Fourier-Legendre series; the coefficients in the series represent the trace. A history for the horse is built by accumulating the coefficients (along with pertinent experimental data such as date, sex, weight, height, and in the case of race horses the date of last race) over a long duration. Then, on each subsequent recording...
Irby NL.A complete neuro-ophthalmologic assessment is relatively simple, requires minimal instrumentation and should be performed as part of every complete ophthalmic and neurologic examination. This article has summarized the tests that comprise and the species-specific details of the complete neuro-ophthalmologic of the equine patient. Selected causes of sudden blindness in the horse were summarized and some common neuro-ophthalmic conditions with significant ophthalmic consequences, such as facial nerve paralysis, were discussed. Split-lid tarsorrhaphies, which are indicated but rarely used in case...
Geary RT, Weber JA, Woods GL.The purposes of this experiment were 1) to test the hypothesis that placing rabbit embryos into the mare's uterus would hasten oviduct transport and 2) to determine if placing fluid into the uterus of bred mares on Day 4 and/or Day 5 would subsequently disrupt the mare's pregnancy. The hypothesis that placing rabbit embryos into the mare's uterus would hasten oviduct transport was not supported, since the uterine recovery rate of equine embryos on Day 5 was not significantly higher (P>0.05) for mares receiving rabbit embryos on Day 4 than for mares receiving no uterine infusion on Day 4 (1 10 ...
Seahorn TL, Cornick-Seahorn J.Fluid therapy is an integral part of treatment of the equine emergency patient. In this article, general principles of fluid therapy are discussed, including formulas for calculation of fluid volumes, fluid types and their indications, and specific therapy for several emergency conditions.
Reilly JD, Cottrell DF, Martin RJ, Cí·¯ord DJ.The effect of dietary biotin supplementation, at a dose rate of 0.12 mg/kg bwt, on growth and growth rate of the hooves of 8 match-paired poines was investigated in a controlled feeding trial. Treatment animals had a mean hoof growth at the midline dead centre of the hoof capsule of 35.34 mm after 5 months of biotin supplementation compared to control animals 30.69 mm (P < 0.05). Comparison of regression analysis also showed that biotin supplementation produced a significantly higher (P < 0.02) growth rate of hoof horn in this trial. Treatment animals had a 15% higher growth rate of hoof horn ...
Amorim GB, Segabinazzi LG, Oliveira OM, Perecmanis S, Arruda R, Canisso IF.Misoprostol, a synthetic PGE1, is becoming a common therapy for mares with suspected uterine tube obstruction. Recently, there have been concerns that uterine administration of misoprostol induces exacerbated uterine inflammation; however, this has not been critically evaluated. This study aimed to assess the inflammatory response and potential systemic reactions after uterine administration of misoprostol, either during prebreeding or immediately after postembryo flushing. Privately owned embryo donor mares (n = 11) were randomly assigned in a crossover design to receive misoprostol (3 mL +...
Mieszkowska M, Abako J, Mieszkowski M, Zhalniarovich Y.Desmopathy of the collateral ligaments of the equine interphalangeal joint is caused by a combination of factors, including hoof shape, excessive loading and ground surface. This complex problem poses a diagnostic challenge due to the non-specificity of perineural analgesia and the limitations associated with the most popular imaging methods such as radiography and ultrasonography. The aim of this study was to retrospectively determine the prevalence of desmopathy of the collateral ligaments of the equine distal interphalangeal joint in Poland between 2016 and 2019, and to establish the freque...
Schryver HF.Recent knowledge regarding the absorption of calcium and phosphorus from the intestine of the horse has been reviewed. Consideration has been given to sites, mechanisms and factors affecting absorption as well as to the availability of calcium and phosphorus from feedstuffs commonly used in Eastern North America. Although the anatomy of the digestive tract might appear to impose restrictions on the ability of the horse to assimilate minerals, studies of absorption show that the horse utilizes the calcium and phosphorus of many feeds very efficiently.
Lintz W.This research article focuses on the study of distemper, also known as influenza or shipping fever, in horses, specifically focusing on its bacteriology and potential vaccine therapies. The research was […]
Wirtu G, Bailey TL, Chauhan MS, Parker NA, Dascanio JJ, Gwazdauskas FC, Ley WB.The in vitro production (IVP) of equine embryos using currently available protocols has met limited success; therefore investigations into alternative approaches to IVP are justified. The objective of this study was to evaluate the feasibility of xenogenous fertilization and early embryo development of in vitro matured (IVM) equine oocytes. Follicular aspirations followed by slicing of ovarian tissue were performed on 202 equine ovaries obtained from an abattoir. A total of 667 oocytes (3.3 per ovary) were recovered from 1023 follicles (recovery rate, 65%). Oocytes underwent IVM for 41 +/- 2 h...
Bell K, Colling DT.An alloimmune reagent has been produced that distinguishes the equine factor Df in the D phenogroup, cfmqr, from that occurring in cefmqr and dfklr. Using this reagent it has been possible to correctly genotype Dc, d, f, k, l, m, q and r positive cells without recourse to family data.
Lepage OM, Hartmann DJ, Eicher R, Uebelhart B, Tschudi P, Uebelhart D.Concentrations of the cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and osteocalcin (OC) have been determined in the serum of one hundred clinically healthy adult Draught or Warmblood horses. The correlation between these two markers has been evaluated and the influence of gender, age and type of horse described. No significant variations were observed between animals of different sex, but a significant inverse correlation (P < 0.0001) with age was observed for both measured parameters. After correction for age, serum levels of OC were found to be lower in Draught [adjuste...
Trist DG, Weatherall M.The research studies the effect of a drug called isoprenaline on the intake of a radioactive isotope, 86-Rb, in horse lymphocytes. It finds that isoprenaline has a significant effect increasing […]
Farchati H, Durand B, Marsot M, Garon D, Tapprest J, Sala C.It is essential to have an accurate picture of the spatial distribution of equines to be able to monitor equine health events effectively. In France, this information is only available for certain categories of live equines kept in professional structures and for dead equines removed by renderers. This limits the surveillance, prevention and control methods able to be used to prevent the spread of equine diseases. Our study aimed to provide a realistic estimate of the spatial distribution of the French equine population at the detailed scale of the French commune (France's smallest administrat...
Henry JS, Lance VA, Conlon JM.Within the order Perissodactyla, the primary structure of insulin has been strongly conserved. Insulin from Przewalski's horse and the mountain zebra (suborder Hippomorpha) is the same as that from the domestic horse and differs from insulin from the white rhinoceros and mountain tapir (suborder Ceratomorpha) by a single substitution (Gly-->Ser) at position 9 in the A-chain. A second molecular form of Przewalski's horse insulin isolated in this study was shown to represent the gamma-ethyl ester of the Glu17 residue of the A-chain. This component was probably formed during the extraction of the...
Booth TM, Proudman CJ, Edwards GB.A 6-year-old mare was presented for acute abdominal pain unresponsive to analgesics. Exploratory laparotomy revealed entrapment of the small colon through a 12 cm rent in the mesocolon. The incarcerated small colon was manually reduced and the rent in the mesocolon was sutured closed. The mare made excellent postoperative recovery and was discharged from the hospital 4 days later. The cause of the rent, which was chronic in appearance, is unknown.
Miyakoshi D, Watanabe A, Ikeda H, Mizuguchi Y.An 8-month-old thoroughbred colt presented with sudden onset right forelimb lameness. A radiographic series of the right carpus was performed, and it revealed a slab fracture of the fourth carpal bone and fracture of the proximal part of the third metacarpal bone. Arthroscopically guided repair of the slab fracture of the fourth carpal bone with a 3.5 mm cortex screw and lag screw fixation of the fracture of the proximal part of the third metacarpal bone were performed. The horse started to race at 32 months old and started in 65 races over three years without any trouble associated with the r...
Kawaguchi K, Church S.This research describes three cases of foals, or young horses, that developed septic arthritis caused by an anaerobic bacterium called Clostridium septicum. All foals were successfully treated with joint irrigation […]
Alexander RM.This research presents the hypothesis and findings that short muscle fibers in horses and other large mammals may protect bones and tendons from damaging vibrations during running, negating the previous […]
Mitten LA, Hinchcliff KW, Sams R.Evaluation of a portable blood gas analyzer, (StatPal II, Unifet, Inc, La Jolla, CA) was performed using tonometered solutions and equine blood. Samples were analyzed by the StatPal II and either an Instrument Laboratory IL1306 (Lexington, MA) or a Radiometer ABL50 blood gas analyzer (Radiometer America Inc., Westlake, OH). Comparison of the StatPal II and the IL1306 was done by analysis of 3 tonometered solutions (acidic, normal, and alkalotic) and 27 equine venous blood samples. Blood pH, PCO2, PO2, and [HCO3] values were altered by IV infusion of 5% sodium bicarbonate or exercising the hors...
Erickson HH, Sexton WL, Erickson BK, Coffman JR.The recognition of the horse as a natural athlete has led to increased interest in equine sports medicine, exercise physiology, new training methods, and factors improving the performance of horses (Engelhardt, 1977; Milne et al., 1977; Bayly et al., 1983b; Persson et al., 1983). A considerable amount of research has been performed in recent years in order to describe the physiological responses of the horse to exercise and training (for reviews see Engelhardt, 1977; Physick-Sheard, 1985; Rose, 1985). Most of these studies, however, have examined the effects of acute exercise training rather t...
Krogh HV, Lundegaard HC.A case of guttural pouch mycosis in an 11-year-old horse is described. The fungus isolated was identified as Emericella nidulans. Housing under bad hygienic conditions without ventilation for three years might have been a predisposing factor.