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.
Silver M, Fowden AL.The production of uterine PGFM during different dietary states has been investigated in pregnant mares in late gestation. Arterial and uterine venous plasma concentrations of PGFM rose when food was withdrawn for 12-30 h and the V-A difference widened significantly. There was an inverse correlation between the rise in PGFM and the fall in plasma glucose during a fast, and a significant decrease in the A-V plasma glucose differences across the uterus. Plasma PGFM and free fatty acid concentrations before and during food withdrawal were also correlated but no uterine A-V difference in free fatty...
Setchell BP, Cox JE.In 3 testes of 2 adult Pony stallions under halothane anaesthesia, catheters were inserted into a vein and a lymphatic vessel in the spermatic cord and into a vein on the surface of the testis. Lymph and venous blood were collected from the catheters in the cord and p-aminohippurate (2% w/v, 0 . 1 ml/min) was infused into the vein on the testis to determine blood flow by dilution. After 1 h, 6000 i.u. hCG was injected i.v. and collections continued for 45 min. The testes weighed 126-176 g. Lymph flow was 20-150 microliter/min before hCG and 100-270 microliter/min after hCG; the range of blood ...
Roberts CJ.Manual crushing of one blastocyst performed on 181 bicornuate twin pregnancies between Days 24 and 45 has shown that the uncrushed blastocyst can either survive and develop normally to full term or may be rejected and resorbed like its crushed twin, depending mainly on the stage of pregnancy. Crushing, which causes rupture of fetal membranes, results in a rapid fall in the survival rate of the uncrushed blastocyst when performed after Day 31. In some mares rupture is not possible after Day 35 even if extreme pressure is used. Crushed, but unruptured, blastocysts mainly between Days 35 and 45 m...
Naval J, Calvo M, Lampreave F, Piñeiro A.1. A high concentration Cibacron Blue-Sepharose derivative has been used to study the affinity chromatography of albumin from eight animal species. 2. The apparent affinity constants for albumin varies between 3.9 x 10(4) M-1 and 0.9 x 10(4) M-1, in the order: Human greater than rabbit greater than horse greater than pig = dog greater than bovine greater than rat greater than chicken. 3. Other serum proteins were also bound to the gel, particularly lipoproteins and alpha 2-macroglobulin.
Michell AR, Taylor EA.In the presence of vanadate, the optimum pH of renal (Na+, K+)-ATPase in rats is reduced and lies in the range of intracellular pH. This explains the difference in optimum pH observed with ATP extracted from equine muscle. Removal of vanadate from such ATP (with noradrenaline) raises the optimum to the accepted range obtained with synthetic ATP. Changes in the sensitivity of the enzyme to potassium concentration contribute to the alterations in optimum pH. The optimum pH of Mg-ATPase is unaffected by vanadate. Since vanadate may be an intracellular regulator of (Na+, K+)-ATPase changes of opti...
Bosu WT, Van Camp SC, Miller RB, Owen RR.A five year prospective study of equine ovarian problems requiring surgical correction was undertaken at the Ontario Veterinary College. Thirty mares were studied, of which 14 had granulosa cell tumors, six were with anovulatory persistent follicular "structures", five had ovarian hemotoma, two presented ovarian hypoplasia and one each of ovarian dysgerminoma, teratoma and abscessation. The clinical signs manifested by the affected animals were varied. The affected ovaries were removed via flank or midline laparotomy or through colpotomy. Their morphology was studied and representative portion...
Perryman LE, Magnuson NS.Significant contributions to understanding the role of lymphocyte subpopulations in the immune response and to the characterization of immunodeficiencies in children have been achieved through study of animal models of immunodeficiency. Additional contributions can be made in two important areas. One is through identification of relevant, naturally-occurring models of adenosine deaminase deficiency and purine nucleoside phosphorylase deficiency. The second, and potentially more important contribution, would be the identification of the metabolic basis for existing immune deficiencies. The nece...
Terpstra AH, Sanchez-Muniz FJ, West CE, Woodward CJ.1. By means of density gradient ultracentrifugation, the density profile of the serum lipoproteins was studied in 14 species of domestic and laboratory animals: the pig, chicken, rhesus monkey, rabbit, dog, horse, sheep, cat, mouse, goat, cow, guinea-pig, trout and rat. 2. The concentration of cholesterol in whole serum and the lipoprotein fractions of these animal species was also determined. 3. There were large differences in the density profile of the serum lipoproteins among the various animals studied and the results indicate that the density limits employed for human serum lipoproteins a...
Reglero A, Hueso P, Rodrigo M, García-Alonso J, Llanillo M, Cabezas JA.The ganglioside patterns of the forebrain, cerebellum and brain stem from horse, donkey, mule and goat have been determined by thin-layer chromatography. GM1, GD1a, GD1b and GT1b are the four major brain gangliosides. N-acetylneuraminic acid as the predominant sialic acid (congruent to 97%) and traces of N-glycolyneuraminic acid were found. The four above mentioned major gangliosides were also found in the forebrain, cerebellum and brain stem of adult rats. This pattern is not modified in rats under stress situation (at 4 degrees C for 3 months). In other extraneural organs from rats such as l...
Klingel H.The basic social unit in feral horses is the family group consisting of one stallion, one to a few unrelated mares and their foals. Surplus stallions associate in bachelor groups. Stallions are instrumental in bringing mares together in a unit which then persists even without a stallion. The similarity of social organization in populations living in a variety of different habitats indicates that feral horses have reverted to the habits of their wild ancestors, and that domestication has had no influence on this basic behavioural feature.
Raeside JI, Gofton N, Liptrap RM, Milne FJ.Direct connection of the artery of a fetal ovary to the carotid artery of the mare allowed collection of a large volume of blood over a 30-min period. Extraction of steroids and their fractionation was followed by separation of the steroids by alumina adsorption chromatography, and Sephadex LH-20 and Celite partition chromatography. Further resolution of the material by HPLC led to the identification of dehydroepiandrosterone (DHA) by nuclear magnetic resonance and mass spectrometry. Other compounds were isolated, which remain to be identified fully, but in the 8th month of pregnancy the princ...
Johnson KG, Creed KE.1. In intact horses, heat-induced sweating occurred initially as pulses, then as a continuous, synchronously fluctuating discharge. 2. I.V. adrenaline (Adr) induced sweating immediately; isoprenaline (Isop) elicited sweating after a delay; and phenylephrine (PhE) had no sudorific effect. 3. In isolated perfused skin, PhE induced an immediate small sweat discharge, Isop a slower sustained output and Adr a biphasic discharge. alpha- and beta-adrenergic antagonists blocked the first and second phases, respectively, of Adr-induced sweating. 4. The observed sweating patterns are consistent with ind...
Jeffcott LB, Kold SE.Thirty-three cases with subchondral bone cysts in the stifle are reported. The condition was most commonly seen in young Thoroughbreds and produced intermittent lameness of varying degree. Radiographically distinct areas of radiolucency were found in the distal femur or proximal tibia adjacent to the femorotibial joint. Lesions were usually unilateral but 5 horses had cysts in both stifles. The cases could be divided into 2 distinct groups. Horses in Group A (28 cases) had a large circular or dome-shaped cyst in the medial femoral condyle with a distinct communication with the femorotibial joi...
Chevalier F, Palmer E.Ultrasonic echography in the mare allows pregnancy diagnosis as early as Day 14 after ovulation. In the 1980 and 1981 breeding seasons, a total of 7438 examinations of 4688 mares were performed on several farms with the same apparatus. The accuracy of positive pregnancy diagnosis was estimated to be greater than 95% and of non-pregnancy diagnosis greater than 84%. When abnormal pictures of vesicles are found, it has to be decided whether it is a conceptus or a cystic structure. Most small vesicles do not develop, whereas large ones, deformed shapes, presence of some echoes, or a division insid...
Goulden BE, Anderson LG.During the years 1971-1979, 127 horses with left laryngeal hemiplegia were studied. The physical characteristics and clinical signs observed in this study were recorded in Part I and Part II of ths series of papers. Of these 127 horses, 81 were treated by the laryngoplasty procedure. Complications of surgery are described and the effects of the operation on respiratory noise and performance are evaluated. In 54.8% of horses the chronic respiratory noise observed during exercise was apparently diminished or eliminated post-operatively. The performance of 44% of horses was apparently improved af...
Combie J, Blake JW, Nugent TE, Tobin T.We have investigated the action of five sources of beta-glucuronidase enzymes on the hydrolysis of glucuronides of apomorphine, butorphanol, hydromorphone, nalbuphine, oxymorphone and pentazocine in equine urine. For all glucuronides tested, Patella vulgata beta-glucuronidase yielded the largest thin layer chromatographic (TLC) spots. For oxymorphone, P. vulgata was the only treatment to yield detectable TLC spots under test parameters. For these six drugs, TLC spot size and chromatographic quality were compared between control horses and horses pretreated with furosemide four hours earlier. F...
Acland HM, Allen PZ, Kenney RM.Twenty-three of 24 mares were infected experimentally with contagious equine metritis organisms by intrauterine inoculation, and killed 2-116 days later. From mares killed within 14 days after infection the organism could be recovered from many sites in the uterus, and most sites in the cervix, a few sites in the vagina and oviduct and from one clitoral sinus. At this time the endometrial folds were swollen and there were 10-20 ml of fluid in the uterus. In mares killed after 14 days, the organism was recovered from the ovarian surface (1 mare), oviduct (4 mares), uterus (2 mares) and the clit...
Silver IA.Wound healing is part of the normal general repair process of the body. Its efficient completion depends on many factors, some physical, eg, pH, oxygen tension and tissue tension, and some biological, eg, cell-cell interaction and feedback of extracellular matrix on to the cells which produce it. The factors which affect healing are discussed and failures and anomalies in the process described. New techniques which may improve the quality of healing in specialised tissues are explained. Recent research on wound healing has concentrated on the role of the different cell types in the process and...
Asbury AC, Schultz KT, Klesius PH, Foster GW, Washburn SM.Ten mares, 5 resistant and 5 susceptible to bacterial endometritis, were examined for differences pertaining to the efficiency of phagocytosis of bacteria by neutrophils in the uterus. An assay for chemiluminescence was used to evaluate various schemes of opsonization and relate them to phagocytic rate. 123I-labelled albumin was used to measure protein migration to the inoculated uterus. Neutrophil numbers moving to the uterine lumen were determined. Before inoculation resistant mares were found to have substances in their uterine secretions that opsonized bacteria, resulting in effective phag...
Brownlow MA, Hutchins DR, Johnston KG.Cells in the peritoneal fluid from 159 horses were examined in Giemsa stained preparations using light microscopy. Normal mesothelial cells showed an oval nucleus with finely reticular chromatin and pale blue cytoplasm. Activated mesothelial cells occurred in fluids derived from mesothelium under acute or subacute, non-septic stimulus and were remarkable for their pleomorphism and intense basophilia which may mimic neoplasia. Transformed mesothelial cells seen in chronic inflammatory fluids were sometimes phagocytic and showed conspicuous cytoplasmic vacuolation.
Dowsett KF, Pattie WA.A study of stallion fertility was conducted on commercial studs in eastern Australia over 4 breeding seasons (1974/75-1977/78). Data from 47 stallions (66 stallion seasons) aged 2-26 years and representing 7 breeds and 1664 mares were used to relate seminal characteristics to fertility. Percentage pregnancies per service was the most sensitive measure of fertility with stallions on commercial studs. Breed and age of stallion, breeding season and the referral status of the stallion ('suspect' or 'normal') had significant (P less than 0.01) effects on fertility. The semen characteristics that we...
Mantovani A, Caporale V, Ciuchini F, Di Trani L, Irsara A, Prosperi S.The results of antibody titrations in different animal species vaccinated against rabies are reported. The following points are considered: (1) antibody titration may be used to detect an immunity status in dogs, (2) equines should be vaccinated in infected areas, (3) experiments in progress are comparing ERA vaccine and an inactivated vaccine in bovines, and (4) the vaccination of fallow deer (Dama dama) and moufflons (Ovis ammon musimon) produced results suggesting an extension of the experiment with the purpose of vaccinating wild ruminants whenever possible.
Merchán A, Voss JK, Dubois MS.The satisfactory outcome of fungal osteitis in an 8-year-old American Quarter Horse is described. The horse was admitted with a grade 4 out of 5 lameness and exhibited metacarpophalangeal synovial effusion, indicative of a mild suppurative inflammation. Results of initial radiographic and ultrasonographic examination were unremarkable. Intra-articular anesthesia of the metacarpophalangeal joint allowed localization of the insult. It was not until day 6 of hospitalization when lytic changes on the axial aspect were observed on radiographic examination. Arthroscopic examination permitted identif...
Moslemi S, Silberzahn P, Gaillard JL.Explants of equine full-term placenta have been shown to synthesize 19-norandrogens from labelled androgens. Steroid metabolites were purified by silica-gel column chromatography then analysed and quantified by c18-reverse-phase HPLC coupled to a radioactive flow detector. 19-Norandrostenedione was subsequently recrystallized to constant specific activity, providing unequivocal evidence of its synthesis by the equine placenta. 19-Norandrostenedione synthesis appeared to be localized in the microsomal fraction. Regardless of the substrate used, formation of 19-norandrogens was far weaker than t...
Pawlas-Opiela M, Sołtysiak Z, Gorczykowski M.Gasterophilus sp. constitute a group of specific parasites, which larval forms are found in horses and other phylogenetically related species--donkeys, mules and zebras. Their invasion is associated with marked fluctuations of hematological and biochemical blood parameters, including the activity of many enzymes and the electrolyte concentration. The purpose of the study was to analyze changes in selected biochemical and morphological blood parameters of horses infected with botfly larvae. The experimental group was formed of horses infested by Gasterophilus sp. larvae whereas the control grou...
Rosenfeld G, Reichmann CE, Jaria LJ, Andrade SO.Hematological studies were developed on two mares and twelve adults castrate sheeps of "Ideal" breed. The animals had been on a pasture formed with Brachiaria radicans Napper for one and two months respectively. This experiment was developed in winter time, so the leaves of the graminea had a yellow-green color. Clinical and hematological observations were made weekly. The typical symptoms of intoxication failed to present as observed in the former investigation when the plant was green (3). The hematological exames showed only for ovines a slight anemia, it was also characterized as being mac...
Martin-Pelaez S, Rabow Z, de la Fuente A, Draheim P, Loynachan A, Fiehn O, Meyers S, Lyman C, Dini P.Postmortem and pre-euthanasia oocyte retrieval provides the last opportunity to preserve the genetic material in mares. Pentobarbital (PB) is the most common euthanasia agent; however, its effect on the developmental competence of oocytes has not been determined. Here, we evaluated the concentration of PB in equine follicular fluid (FF) and investigated its effect on the developmental competence of oocytes using a bovine IVF model to overcome the low availability of equine oocytes. The concentration of PB was measured by gas-chromatography/mass-spectrometry in FF collected from mare ovaries im...
Balssa F, Fischer M, Bonnaire Y.5α-Estrane-3β,17α-diol is the major metabolite of nandrolone in horse urine. The presence of 5α-estrane-3β,17α-diol in female and gelding urines is prohibited by Racing Rules and its natural presence in male urine led regulation authorities to establish a concentration threshold of 45 ng/mL. This paper describes a rapid, simple and stereoselective synthesis of 5α-estrane-3β,17α-diol, providing horseracing laboratories with an essential reference material for their antidoping performance.
Cullimore AM, Lester GD, Secombe CJ, Campbell K.A 7-year-old Clydesdale gelding was referred with a history of progressive lethargy and ventral oedema. The horse developed diarrhoea after treatment with antibiotics by the referring veterinarian. History, clinical signs, imaging and laboratory findings were consistent with hypertrophic cardiomyopathy complicated by antibiotic-associated colitis. Progression of clinical signs prompted euthanasia and the antemortem diagnosis of hypertrophic cardiomyopathy was confirmed at postmortem examination. Conclusions: Primary HCM is reported as rare in horses, but specific descriptions are lacking. The ...
Szeredi L, Makrai L, Dénes B.The first objective of this study was to develop an immunohistochemical procedure for rapid detection of Rhodococcus equi in impression smears from affected organs of foals on postmortem examination. The second aim was to demonstrate whether R. equi can be detected in smears of tracheal exudates collected from the same foals using an immunohistochemical method. Impression smears and cryostat and paraffin-embedded sections were made from the lungs and mediastinal lymph nodes of three foals (A, B and C) that had died of respiratory disease caused by R. equi, and also from the caudal mesenteric l...
Sigler DH, Ericson DE, Gibbs PG, Kiracofe GH, Stevenson JS.Lactating mares were assigned as controls or fed altrenogest (.044 mg.kg body wt-1.d-1) for 15 d after foaling. Mares (n = 6) fed altrenogest were inseminated during the first estrus after treatment and mares (n = 6) in the control group were inseminated during the second postpartum estrus. Ovulation during the estrus in which mares were inseminated occurred 26 +/- 1 d postpartum for treated mares and 36 +/- 1 d postpartum for control mares. The percentage of mares conceiving was not different for control (67%) and alternogest-treated (100%) mares. No differences were observed in tone and size...
Belloli C, Arioli F, Beretta C, Madonna M.The contractile effects of the tachykinins eledoisin, substance P and neurokinin A and B were investigated in vitro on circular and longitudinal muscle strips from horse duodenum, ileum and colon. Circular smooth muscle of the small intestine was highly responsive, large intestine circular smooth muscle less so, while longitudinal muscle from all gut segments was much less sensitive. pD2 values and intrinsic activities on small intestine circular muscle indicated differences in receptor distribution between the duodenum and ileum: NK3 and a smaller number of NK2 receptors being present in the ...
Baptiste K.The pharyngeal orifice of the equine auditory tube has not been adequately described. Its larger size and position, further rostral within the nasopharynx compared with other species, cannot be easily explained, but could be important for the proposed brain-cooling function of the guttural pouches; however, unlike other species, it may not be the sole regulator of auditory tube aeration. A 'second orifice' (representing the final entrance to the auditory tube diverticulum) deserves recognition in performing a role in air exchange between the auditory tube, diverticulum and middle ear. The resu...
Keller H, Grundmann S.X-rays of 205 horses having navicular disease and having been reexamined up to six times are evaluated. For this, the x-rays of each foreleg are evaluated in the dorsopalmar (Oxspring) and lateromedial view. Additionally to changes of the navicular bone, changes of the distal part of the toe are also assessed. Differences can be found in the radiographic process in view of the limitation of vascular foramina and cyst-like lesions. Vascular foramina with sclerotic rim grow less frequent than poorly defined ones and therefore allow for easier prognostication. Cyst-like lesions with sclerotic rim...
Cheramie HS, Pleasant RS, Dabareiner RM, Carolan RO.An aberrant branch of the internal carotid artery was detected by angiography in a horse with guttural pouch (auditory tube diverticulum) mycosis after the distal portion of the artery had been occluded by use of a detachable latex balloon. A second balloon was placed to eliminate retrograde hemorrhage from the aberrant branch. The horse recovered and returned to its previous activity. Vascular anomalies of the internal carotid artery my be more common than expected, and have resulted in fatal complications during and after surgical treatment in guttural pouch mycosis. Intraoperative identific...
Reed SM, Robertson JT.This article reviews recent diagnostic procedures that have arisen over the last 10 years. Videoendoscopy of horses on a high-speed treadmill allows observation of some of the changes that take place in a horse's airway during exercise. Measurements of upper airway airflows and transupper airway pressure, the use of an esophageal balloon and a Ventigraph to measure changes in pleural pressure, and pulmonary function testing are new techniques that aid the researcher in understanding the mechanics and pathologic characteristics of airway diseases and help the practitioner in assessing the sever...
Woodley SL, Burns PJ, Douglas RH, Oxender WD.This study was designed to test if oestradiol treatment would prevent or delay luteolysis in mares. Mares (5/group) received 0, 0.1, 1.0 or 10.0 mg oestradiol-17 beta daily from the day of ovulation until the next ovulation or for a maximum of 32 days. This treatment did not prevent luteolysis which occurred 15.8, 16.8, 15.8 and 17.3 days after the previous ovulation for the mares treated with 0, 0.1, 1.0 and 10.0 mg oestradiol respectively. Although oestradiol treatment failed to alter oestrous behaviour after luteolysis, daily treatment with 10.0 mg oestradiol prevented follicular growth and...