Veterinary research in horses encompasses the study of diseases, health management, and medical treatments specific to equine species. This field investigates various aspects of horse health, including infectious diseases, metabolic disorders, and musculoskeletal conditions. Researchers focus on understanding the pathophysiology of equine ailments, developing diagnostic tools, and evaluating therapeutic interventions. The study of horse health also involves examining preventive measures such as vaccination protocols and nutritional management to promote overall well-being. This page collects peer-reviewed research studies and scholarly articles that explore the diverse areas of veterinary science related to horses, providing insights into disease mechanisms, treatment strategies, and advancements in equine healthcare.
McGuire TC, Crawford TB, Hallowell AL, Macomber LE.Failure in colostral immunoglobulin G (IgG) transfer was found in 9 of 87 Thoroughbred foals. Seven (78%) of these 9 foals acquired infections requiring therapy. Twelve of the foals had partial failure in colostral IgG transfer, and 3 of these had infections requiring therapy. The remaining 66 foals had normal transfer of colostral IgG, and only 2 had detectable infections. The failure of colostral IgG transfer was attributable to nursing problems in only one case. When presuckle postpartum colostrum was collected, 2 of 4 failures of colostral IgG transfer and 4 of 6 partial failures of colost...
Jackson TA, Osburn BI, Cordy DR, Kendrick JW.Experimental infection with equine herpesvirus 1 (rhinopneumonitis) resulted in neurologic disease in 8 of 15 inoculated horses. Nonpregnant animals did not develop clinical disease, and microscopic examination of tissues revealed no changes. In all mares between 3 and 9 months of gestation, a neurologic syndrome appeared 6 to 8 days after inoculation. Mares inoculated when 10 months pregnant did not develop neurologic disorders, but several aborted. The histopathologic change common to both sequelae was vasculitis, involving smaller arteries and veins. Although blood vessel changes were detec...
Hughes JP, Trommershausen-Smith A.Reproductive failure was studied in 12 phenotypically normal mares (9 Arabian, 3 Quarter horses, 1 Appaloosa and 1 pony). Karyotyping was performed using lymphocytes isolated from peripheral blood by density gradient procedures, followed by standard culture methods for karyotyping. Nine mares had karyotypes of 63,XO; 1 had 63,XO/64,XX; 1 had 63,XO/64,XY and 1 had 64,XY. All mares had small, firm ovaries that when removed and examined from 4 mares, lacked germ cells and consisted of undifferentiated ovarian stroma.
Lyons ET, Drudge JH, Tolliver SC.Thirteen critical tests were conducted in horses naturally infected with helminths and bots. Single doses of thiabendazole (44 mg/kg of body weight) and trichlorfon (40 mg/kg of body weight) powder formulations were administered as suspensions sequentially given via stomach tube to evaluate the efficacy of the combination against the large parasites of horses. Parasite removal efficacies were 100% against 2nd instar Gasterophilus intestinalis and 2nd and 3rd instar Gasterophilus nasalis and 82 to 100% against 3rd instar G intestinals. There were complete removals of mature and immature Parasca...
Garner HE, Hahn AW, Salem C, Coffman JR, Hutcheson DP, Johnson JH.Acute laminitis-hypertension was produced experimentally by carbohydrate overloading of the gastrointestinal tract in 8 horses, and the resulting hemodynamic changes were measured. Statistically significant (P less than 0.01) increases in cardiac output, left ventricular ejection rate, heart rate, and arterial pressure were related to statistically nonsignificant changes in peripheral resistance and a delayed (Obel grade 3 plus 24 hours) decrease in plasma volume. When compared with control values, the doubling of cardiac output and left ventricular ejection rate simultaneous with little or no...
Chapman DI, Whiteside J.A radioimmunoassay method has been developed that enables the administration of therapeutic doses of synthetic corticosteroids to be detected in horse urine. Fourteen proprietary preparations of these steroids have been given by intramuscular injection to ponies and thoroughbreds. The administration of some preperations could still be detected six days after a single intramuscular injection of a therapeutic dose. The route of injection of dexamethasone-21-sodium phosphate, whether intramuscular, intravenous or intra-articular, did not appear to alter the length of time over which the steroid o...
Walker D.Rectal examination is a reliable method of diagnosing pregnancy in the mare. Also, test kits are available for the simple quick detection of pregnant mare serum gonadotrophin. Nevertheless there is a considerable demand by practitioners for an independent laboratory service in equine pregnancy diagnosis, particularly during the gestational phase when placental gonadotrophin is concentrated in the blood. An initial attempt to provide a service by means of the agar gel diffusion test was disappointing and alternatives were sought. The primary requirements for an ideal alternative technique were ...
Silvestri R.A macromethod and a semimicromethod were developed to measure erythrocyte acetylcholinesterase activity in cattle, sheep, goats, horses, dogs, and swine, and to measure plasma cholinesterase activity in horses, dogs, and swine. Comparison of the 2 methods with erythrocytes of sheep, cattle, goats, and horses indicated both methods gave similar results. They can be done in a shorter time and are more sensitive than Michel's method. Normal deltapH values per minutes, with standard deviations for blood cholinesterase activity of animals of different ages, sexes, breeds, and species, were: 0.76 +/...
Shahrabadi MS, Marusyk RG, Crawford TB.Sequential changes induced by an equine adenovirus in cultured fetal equine kidney cells were studied by electron microscopy. The first morphological change was the appearance of type I inclusions. These inclusions developed to type II inclusions which appeared as ring forms. Type III inclusions were formed within the central part of type II inclusions and finally filled up most of the nuclear space. As the infection proceeded, type IV inclusions which appeared as dense dark-staining spheres were formed at the center of the type III inclusions and also inside the cytoplasm. These dark-staining...
McGuire TC.Isolated equine immunoglobulin (Ig)G(T) antibodies to equine infectious anemia virus P26 antigen did not precipitate with antigen when the ratio of antibody to antigen was high. However, at lower ratios of antibody to antigen precipitation occurred. In addition, complement-fixation by IgG and P26 antigen was inhibited by high concentrations of IgG(T). The unusual reaction pattern noted with IgG(T) antibodies was still detectable by the immunodiffusion test for equine infectious anemia virus. In situations of nonprecipitability by IgG(T), the adjacent positive control line was inhibited, and th...
Lapin DR, Ginther OJ.A crude equine pituitary ethanol extract (EE) was used to induce single and miltiple ovulations in seasonally anovulatory pony mares 3-15 years of age. 12 mares were injected daily for 14 days with EE; 6 of the EE-treated mares were also treated with human chorionic gonadotropin (HCG), and 6 control mares received saline vehicle only. In a 2nd experiment designed to determine if EE treatment could induce multiple ovulations in seasonally ovulatory mares, 7 mares were treated during diestrus, 7 mares were treated beginning on Day 1 of estrus, and 7 remained untreated. The results of experiment ...
Shively JA, Van Sickle DC.The scanning electron microscopy of synovial membrane from the radiocarpal and intercarpal joints near the lateral and medial borders of the tendon of the extensor carpi radialis muscle was studied in 5 ponies. Three different morphologic types of synovial membrane were observed. Type 1 synovial membrane was folded and had a surface mat of fibers separated by 1- to 5-micron-diameter holes. The 2nd and 3rd types of synovial membrane were both villous. The surface of type 2 synovial membrane was fibrillar but the surface of type 3 synovial membrane was cellular. The type of synovial membrane pre...
Mulhern FJ.There is an increasing need for the veterinary profession to meet the new challenges brought about by increased and intensified livestock production. These challenges consist of control and eradication of diseases, the humane treatment of animals and the prevention of transmission of disease from animals or animal products to man. Examples are given of the contribution which regulatory medicine activities have made to the prevention/control/eradication of screw worm, foot-and-mouth disease, Venezuelan equine encephalomyelitis, Newcastle disease, bovine brucellosis, hog cholera, and certain oth...
Allen WE, Newcombe JR.The condition of anoestrus in the mare is described and the various causes of this syndrome are discussed. A regimen for examining systematically the clinically anoestrus mare is proposed, and methods of treatment are suggested.
Pipers FS, Hamlin RL.Echocardiograms were obtained from 25 standing, clinically normal horses, using an ultrasonic recording device. The echobeam penetrated the right thoracic wall in the area of the 4th to 5th intercostal space, with a frequency of 2.5 mHz. Measurements of left ventricular wall thickness generated a mean value of 3.2 +/- 0.18 (SEM)cm, whereas the left ventricular chamber diameter in diastole was 9.3 +/- 0.30 cm and in systole was 5.7 +/- 0.23 cm. The aortic root dimensions had a mean of 7.7 cm, with a SEM of 0.16. Mitral valve closing slope (E-F) was calculated to be 17.7 +/- 0.87 mm/second, and ...
Archer BG, Crawford TB, McGuire TC, Frazier ME.Equine infectious anemia (EIAV) is shown to have an associated RNA-instructed DNA polymerase similar in its cofactor requirements and reaction conditions to the RNA tumor virus DNA polymerases. Demonstrating this DNA polymerase activity requires a critical concentration of a nonionic detergent, all four deoxyribonucleoside triphosphates, and a divalent metal ion. The reaction is sensitive to RNase, and a substantial fraction of the FNA synthesized is complementary to viral RNA. The detection of a complex of tritium-labeled polymerase product DNA-template RNA, which sedimented at 60S to 70S, pr...
Nagatomo H, Tokita Y, Shimizu T.Although it is known that commercialized bovine serum is sometimes contaminated with mycoplasmas, it is not clear whether mycoplasmas can survive in horse serum. In this study, as a preliminary examination of the survival of mycoplasmas inoculated in horse sera, the survivability of 8 strains of 7 mycoplasmas was tested. The results obtained reveal that two strains of M. bovis and M. gallisepticum were found to survive in non-heated and inactivated sera for 94 to 330 days at 30 or 37 degrees C. Three strains of M. bovirhinis, M. gateae and A. laidlawii lived for 7 to 330 days depending upon th...
Bertone JJ, Traub-Dargatz JL, Wingfield WE.Atrial fibrillation in a pregnant, lactating, 15-year-old mare nursing a 70-day-old foal was converted to normal sinus rhythm, using quinidine sulfate. The maximum concentration of quinidine was 4.3 mg/L in the mare's milk and was 2.6 mg/L in the mare's serum. Treatment with quinidine did not interrupt the pregnancy. Six months after treatment, the mare developed acute volvulus of the large colon and died. At necropsy, the mare did not have macroscopic or microscopic cardiac lesions. The fetus was macroscopically and histologically normal.
McD￮ LA, Dart AJ, Schiffman P, Parrot JJ.Enterolithiasis, as a cause of colic, was diagnosed and treated during surgical intervention in 2 Grant's zebras (Equus burchelli bohmi). The zebras were part of a wild herd in a zoo in the western United States. The clinical signs of enterolithiasis in both zebras were similar to those reported for horses. Analysis of the enterolith from 1 zebra revealed a composition identical to enteroliths that have been analyzed from horses. Three other zebras from this herd had enteroliths at necropsy. Enterolithiasis should be considered as a differential diagnosis for zebras with low-grade obstructive ...
Mayr B, Resch S, Hepperle S, Brem G, Reifinger M, Schaffner G.Tumour suppressor p53 is critical in a broad panel of tumour types in human, mouse and other mammals. Regions of the promoter and exon 1 play an important role in expression of p53. In the present study, the DNA sequences of promoter and exon 1 regions of four domestic animal species (dog, cat, horse and cattle) are determined and compared with experimental rodents (mouse, rat and hamster) and man. A broad panel of tumour types have been investigated for mutations in this regulatory area in 90 canine, 136 feline, 25 equine and 10 bovine patients. No mutation was detected in any of the tumours ...
Palozzo A, Celani G, Guerri G, Straticò P, Varasano V, Petrizzi L.Segmental posthetomy, also referred to as circumcision, reefing or posthioplasty, consists of removing a circumferential segment of the internal preputial lamina (internal preputial fold) followed by end-to-end anastomosis of skin edges. The purpose of this case series is to describe the successful outcome of segmental posthetomy for treating different diseases involving the internal or/and external preputial fold, while restoring the normal telescopic function. In this paper, we report the first case of complete degloving injury of the equine penis in the literature (case 1) and describe thre...
Ross KA, Kolb DS, Macedo A, Anderson M, Klein C.This study tested the hypothesis that the presence of prostaglandin E2 in seminal plasma would aid in the transport of phenolsulfonphthalein (PSP) across the uterotubal junction. Five mares in estrus were inseminated during estrus with PSP dissolved in phosphate-buffered saline and during the subsequent estrus with PSP added to a standard insemination dose. Serum and urine samples were obtained at hours 0, 1, 2, and 3 following treatment and examined for the presence of PSP. Phenolsulfonphthalein could not be detected in any of the urine samples collected from mares following either treatment....
Lotstra RJ, van den Broek J, Power T, Marr CM, Wijnberg ID.Atrial fibrillation is a common equine arrhythmia. Quinidine alone, or with digoxin are common treatments. Studies on outcome in Warmblood populations in which duration of the AF is often unknown are limited. Objective: To identify the factors that are associated with the success of full treatment cardioversion with oral medication, and establish whether there are differences in these factors between institutions. Methods: Retrospective case series using patient records of Equine University Clinic of Utrecht University and Rossdales Equine Hospital, Newmarket. Methods: Forty-nine horses treate...
Hobo S, Hiraga A, Birks EK, Takahashi T, Hada T, Jones JH.A study was undertaken to find if the reason why horses hypoventilate when running is that they experience expiratory flow limitation due to dynamic airway closure. To test this hypothesis, we measured peak expiratory flows on a Thoroughbred galloping on a treadmill and hypoventilating and compared those flows with the peak dynamically-limited flow that the same horse could achieve during a forced expiratory flow-volume manoeuvre. At the approximate lung volumes at which the horse was ventilating while running, it did not appear to be mechanically limited and appeared to have reserve capacity ...
Takizawa T, Ito T.Supposing two mathematical models, additive and multiplicative, the authors estimated the secular trends of annual morbidities (1949 approximately 1975) of twelve infectious diseases of domestic animals. For each diseases ten different trend curves were fitted. It was found that five regression equations, namely, those for bovine trichomoniasis, bovine tuberculosis, equine infectious anemia, pullorum disease in chickens, and foulbrood, gave the coefficient of determination of 97.9, 92.7, 91.0, 93.5, and 85.2%, respectively. Four of them were multiplicative, and the remaining one for equine inf...
Bracamonte JL, Duke-Novakovski T.This study evaluated the use of an articulating automated suturing device for laparoscopic closure of the nephrosplenic space in standing horses. Closure of the nephrosplenic space was performed in 4 horses using an automated suturing device. Second-look laparoscopy was performed at 5 weeks. A smooth fibrous adhesion formed between the spleen, the perirenal fascia, and the nephrosplenic ligament in 3 of the 4 horses in which the nephrosplenic space was closed using the automated suturing device. In 1 horse, closure of the nephrosplenic space was not possible due to constant breakage of the end...
Weatherall KM, Boone LH, Caldwell FJ, Cole RC, Cattley RC, Lascola KM, Clark-Price SC, Farag R, Perkins E, Hanson RR.To compare the biomechanical properties and healing of ventral midline celiotomies (VMC) closed with a self-locking knot combination and forwarder start and Aberdeen end (F-A) vs a traditional knot combination and surgeon's start and end (S-S). Methods: In vivo, experimental. Methods: Twenty-one horses. Methods: Fourteen horses underwent VMC, which was closed with either an F-A (n = 7) or an S-S (n = 7) knot combination. Incisions were subjectively graded by masked evaluators for dehiscence, edema, and drainage. Biomechanical testing was performed on three abdominal segments, and histology was...
Stott ML, Osburn BI.Long-term equine lymphocyte cultures were initiated and maintained in continuous culture with medium containing recombinant human interleukin-2. Cultures were successfully maintained with lectin activation signals and recombinant human interleukin-2 or with recombinant human interleukin-2 alone. All cell cultures that were characterized had a T-lymphocyte phenotype and had lectin-dependent or -independent cytotoxicity directed to various cell types. These findings demonstrate that long-term equine T-lymphocytes cultures can be initiated and maintained easily.
Catena C, Asprea L, Carta S, Tortora G, Conti D, Parasacchi P, Righi E.We have investigated and compared DNA damage and cell killing induced in human and equine lymphocytes after in vitro X-irradiation. Our data show that the cytogenetic and the lethality effects are both greater in equine lymphocytes, but that the difference is wider for lethality. The ratios between doses inducing the same effect are 1.3, 1.7 and 9.4 for the number of binucleated cells with micronuclei, micronucleus frequency in binucleated cells and DNA synthesis inhibition, respectively. The very different radiosensitivity observed for the two mammalian species encourages us to use their lymp...
Gregg AS, Jones RS, Snowdon SL.A fault in the assembly of a Matrix Large Animal Circle anaesthetic machine resulted in reversal of fresh gas flow through the vaporizer. The fault was discovered only after the sudden development of excessive depth of anaesthesia in two equine patients. Laboratory investigations were conducted to determine the effect of flow reversal on vaporizer output. Results indicated that output concentration was approximately doubled under these conditions.
McKinney AR, Ridley DD, Suann CJ.The phase I and phase II metabolism of the anabolic steroid methandrostenolone was investigated following oral administration to a standardbred gelding. In the phase I study, metabolites were isolated from the urine by solid-phase extraction, deconjugated by acid catalysed methanolysis and converted to their O-methyloxime trimethylsilyl derivatives. GC-MS analysis indicated the major metabolic processes to be sequential reduction of the A-ring and hydroxylation at C6 and C16. In the phase II study, unconjugated, beta-glucuronidated and sulfated metabolites were fractionated and deconjugated us...
Afonso T, Giguère S, Rapoport G, Brown SA, Coleman AE.Benazepril has been shown to inhibit circulating angiotensin-converting enzyme (ACE) activity in horses but the optimal dosage is unknown. Objective: To determine the lowest tested dose of benazepril that results in ≥75% attenuation in the response of arterial blood pressure (BP) to exogenous angiotensin I (ANG-I) administration. Methods: Prospective experimental study. Methods: A total of 5 healthy horses were instrumented for the direct measurement of BP. Each horse received 4 intragastric doses of benazepril (0.5, 1, 2 and 4 mg/kg bwt) with a washout period of 7 days between doses. Prior ...
Suter M, Fey H.Horse IgE was isolated from a serum pool collected from foals naturally infected with endoparasites. The serum was precipitated with ammonium sulfate, delipidated with dextran sulfate and further purified by gel filtration, anionic exchange, immunosorption or preparative polyacrylamide gelelectrophoresis. By these methods IgE could be isolated at a purity of 81%. The sera from rabbits immunized with the purified horse serum fractions were tested using reversed passive cutaneous anaphylaxis and an enzyme linked immunosorbent assay (ELISA). By the ELISA method cross reaction of rabbit anti horse...
Boatwright RB, Williams DO, Rugh KS, Sarazan RD, Ross CR, Garner HE, Griggs DM.Coronary collateral growth was stimulated in chronically instrumented conscious ponies by a previously validated intermittent coronary occlusion method. Changes in regional myocardial function (sonomicrometry) and reactive hyperemia (Doppler method) were used to monitor collateral growth and to program measurements of regional myocardial blood flow (microsphere method). A serial analysis of the transmural and lateral distributions of collateral blood flow was performed at the native and three superimposed levels of collateral growth. Results in nine animals undergoing an average of 553 +/- 188...
Hunyadi L, Papich MG, Pusterla N.The purpose of this study was to determine if a low dose of diclazuril (0.5mg/kg of 1.56% diclazuril pellets) given to six healthy adult horses every 3-4 days for a total of five administrations would achieve steady-state plasma concentrations known to be inhibitory to Sarcocystis neurona and Neospora caninum. Blood was collected via venipuncture immediately before (trough concentrations) and 10h after (peak concentrations) each diclazuril administration and analysed by high-pressure liquid chromatography. The mean population-derived peak concentration was 0.284μg/mL and the mean terminal hal...
Palmieri G, Panu R, Asole A, Branca A.The proprioceptive innervation of the external cremaster muscle of some domestic animals was studied. Muscle spindles and tendon organs with their well-known features were found, but this finding was uncommon and unexpected in the investigated animals. For this reason, we believe that there is no relationship between the presence of these proprioceptors and the cremasteric reflex.
Cox D.Many clinicians are experiencing consumer resistance to the prescription of equine HRT (that is hormone replacement therapy which has been manufactured from mare's urine). In this paper I consider the ethical implications of prescribing these preparations. I decide that patients should have a right to refuse such treatment but also ask whether a prescribing doctor should choose one preparation over another on moral grounds. I determine that there is prima facie evidence to suggest that mares may suffer and that prescription of equine HRT (instead of synthetic oestrogen-oestriol) would therefor...
Walsh DM.The author has completed 40 years as a veterinarian treating horses with laminitis. The article is a recollection of his experiences with laminitis and the various treatment methods he came across while trying to treat the disease.
Pedroso RC, Salvadori MC, Andraus MH, Lopez NM.A chromatographic method was developed to detect and confirm the presence of succinonitrile (SDN) in horse urine samples, for antidoping control. The urine samples (5 ml) were extracted with diethyl ether and screened by gas chromatography-nitrogen-phosphorus detector and the confirmation of the drug's presence was accomplished by using gas chromatography-mass selective detection. The recovery of extraction was 78 and 81% for 1.0 and 2.0 micrograms ml-1 (relative standard deviation, < 10%), respectively. Urine samples collected after the administration of Energisan were positive for SDN (1-30 ...
Romaniuk K.The Diptera attacked domestic animals in Poland are: Simuliidae, Culicidae, Tabanidae, Gasterophilidae, Hypoder-matidae and Muscidae. The insect assail the crazing animals, mostly during sunny day dna at close of day. Lack of effective repelents and also difficulties with their usage, makes it impossible to complete extermination of parasitic insects in the environment. It is posible to effectively fight against Hypoderma bovis and Gasterophilus spp.
Legacki EL, Bal BA, Corbin CJ, Loux SC, Scoggin KE, Stanley SD, Conley AJ.The authors apologize for errors in Figure 6 of their article published in the October 2017 issue of Reproduction (vol 154 iss 4 pp 445–454). The authors explain that the addition of data (Figure 6) on steroid concentrations in the chorioallantois to their manuscript on fetal adrenal and fetal gonadal steroids during development of the equine fetus was made in response to reviewer comments. However, in compiling, summarizing and graphing the data, the wrong units were used in the final figure. The manuscript as published represents the data in Figure 6 as “ng/g”, when in fact they are ...
Malekinejad H, Alizadeh-Tabrizi N, Ostadi A, Fink-Gremmels J.The pathogenesis of equine grass sickness (EGS) has not fully understood. A better understanding of the exact pathogenesis of diseases can help to make an accurate diagnosis. Previous studies reported some pathological damage of neuronal cells in EGS patients. In this study, primarily cytotoxicity of serum from three clinically EGS-diagnosed horses on PC12 Tet-off (PTO) cells was assessed. Subsequently, the apoptotic tests including cytochrome C release, caspase-3/7 activity measurement and DNA fragmentation assay were conducted to clarify the apoptotic effect of serum from EGS patients. Addit...
Sharma OP.The concentrations of PGF-2alpha in the peripheral blood of five foaling mares were measured by radioimmunoassay. Low levels of PGF-2alpha were detected as early as 1 week before foaling in two of the mares. These levels increased steadily, reaching a peak (1-74 +/- 0-44 ng/ml) during fetal expulsion. A relatively high PGF-2alpha level was found in samples collected 60 min after foaling.
Evans JA, Lambert MB, Miller J.The anti-inflammatory drug Ibuprofen [(+/-)-2-(p-isobutylphenyl) propionic acid] was estimated in the blood and urine of a horse using gas-liquid chromatography of the silylated derivative. Levels of the drug in the two body fluids were measured over a period of about 24 hours after administering a 12 gm dose of Ibuprofen. Plasma peak levels were observed within 30 to 60 min, and the drug was no longer detectable in the plasma by 8 hr. Urinary peak levels were observed 200 to 300 min after dosing, and the drug was no longer detectable in the urine by about 28 hr. It was observed that only 2% t...
Johansson IM, Schubert B.Flunixin is determined in equine plasma by liquid chromatography on LiChrosorb RP-18 with 70% methanol in phosphate buffer pH 3.1 as the eluent, with detection at 284 nm. Plasma is deproteinized with methanol and the supernatant is then injected directly into the system. With a short pre-column (5 x 3 mm i.d.), which is replaced after 25-40 injections of sample, 420 plasma samples could be analysed on one analytical column. The detection limit in plasma is 0.30 micromol/l (89 ng/ml) and the method can be used in pharmacokinetic studies.
Tivey ML.Mary-Ellen Lloyd Tivey of the Royal Veterinary College, suggests that greater collaboration and encouraging engagement from horse owners and vets is key to strengthening scanning surveillance in equine populations.
