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.
Roser JF, Evans JW, Mikuckis GM, Adams TE, Hughes JP.As quantified by Scatchard analysis, a 27 000 g crude luteal membrane fraction contained a single population of unoccupied LH receptors characterized by high affinity, ka = 0.647 +/- 0.158 X 10(11) M-1 and low binding capacity, Rt = 4.91 +/- 0.78 X 10(-11) M/mg membrane fraction. Acceptable hormonal specificity, reversibility, saturability, high affinity and tissue specificity indicated that the binding protein was a physiological receptor. To ensure that the methods used for Scatchard analysis were valid, hCG was characterized for specific activity and maximum bindability, non-specific bindin...
Leishman D, Miller RB, Doig PA.The density of uterine glands, height of surface epithelium, numbers of hemosiderin laden macrophages, inflammatory cells and layers of periglandular fibrosis were evaluated in uterine biopsies from 40 mares. These features were found to be highly variable in normal equine endometrium. Minor pathological changes appeared to be masked by this normal variability. Atrophy of uterine glands was recognized in mares which had been barren for more than three years. No significant differences were found between barren and normal mares in the height of epithelium, number of hemosiderin laden macrophage...
Weitkamp LR, MacCluer JW, Guttormsen S, McKnight J, Wert N, Witmer J, Boyce P, Egloff J.Reproductive performance of 10 Standardbred stallions was related to the probability that the embryo resulting from a given mating would be heterozygous for transferrin or plasma esterase. Fertility, measured by foaling rate per insemination or by foaling rate per year, showed a highly significant regression on the probability of offspring heterozygosity for transferrin and, to lesser extent, for esterase. Substantial differences between stallions in the slope of the regression line and no deficiency of foals homozygous for either protein suggests that the relationship to fertility is indirect...
Zavy MT, Sharp DC, Bazer FW, Fazleabas A, Sessions F, Roberts RM.Uterine secretions were obtained on Days 4, 8, 12, 14, 16, 18 and 20 of the oestrous cycle and early pregnancy. Acid phosphatase activity was significantly affected by day of the cycle, reaching a maximum at days 12-14 during the luteal phase and then declining to almost undetectable levels, by Day 20. In pregnant animals, activity continued to increase beyond Day 14. Two-dimensional polyacrylamide gel electrophoresis showed that albumin was a major component. However, a number of unique proteins of non-serum origin appeared in mid-cycle but had disappeared by Day 20. One of these was a basic ...
Driancourt MA, Paris A, Roux C, Mariana JC, Palmer E.Five pony and 5 saddle-type mares were used to compare total ovarian follicular populations between breeds. The animals were hemi-ovariectomized at the preovulatory stage during the breeding season and the ovary bearing the large preovulatory follicle was studied using histological techniques. Pony and saddle-type mares did not differ as to mean number of primordial follicles, mean number of growing follicles, the variability of these numbers and follicular distribution into various size classes. No difference was detected either in the initiation processes of follicular growth, oocyte growth,...
DiPietro JA, Todd KS, Lock TF, McPherron TA.The anthelmintic activity of ivermectin was evaluated in 18 female horses with naturally acquired parasitic infections. Horses were treated once (IM) with vehicle only (n = 6), 200 microgram/kg of body weight (n = 6), and 300 microgram/kg (n = 6). Efficacy of both dosages of ivermectin was greater than 99% against Gasterophilus spp, 100% against Trichostrongylus axei, Habronema muscae, H majus, and Draschia megastoma, 98% to 99% against adult cyathostomes, 86% to 97% against 4th-stage cyathostomes, and 100% against adult large strongyles. Although ivermectin was incomplete in its activity agai...
Peters GJ, Oosterhof A, Veerkamp JH.1. Adenosine inhibits thymidine and uridine incorporation of PHA-stimulated lymphocytes of man and horse at concentrations higher than 50 and 10 microM, respectively. Deoxyadenosine is inhibitory at concentrations higher than 100 microM. Thymidine and uridine incorporation of porcine lymphocytes are elevated 5-7-fold by 25-100 microM adenosine, deoxyadenosine, inosine and hypoxanthine. Leucine incorporation of PHA-stimulated lymphocytes was affected by adenosine and deoxyadenosine in the same way, but to a lower extent. 2. Effects of adenosine and deoxyadenosine were more pronounced at shorter...
Bader H.A total of 23 mares were inseminated once within 0-6 h after clinical detection of ovulation, 14 with fresh and 9 with deep-frozen semen containing 0.1 x 10(9) to 4.7 x 10(9) motile spermatozoa. Within these two groups, the mares were slaughtered 2, 4 or 6 h after insemination and their genital tracts removed. The utero-tubal junction, isthmus and ampulla ipsilateral to the ovary in which ovulation occurred were flushed separately for sperm recovery. In 1 or 2 mares of each group, the uterine horn and corpus uteri, the cervix and vagina were also flushed. Tissue samples were collected from the...
Müller Z.Semen of 16 stallions collected by the fractionated method and frozen in liquid nitrogen was used to inseminate 175 mares of different ages and in various reproductive conditions. Pregnancy was recorded in 91 mares of which 72 delivered a foal. Pregnancy followed by resorption occurred in another 10 mares and 9 aborted. The best results were obtained in the young primiparous and in older mares inseminated in the oestrous cycle that followed the post-partum oestrus. Overall, 64% of mares became pregnant and 56% gave birth to a living foal. The highest occurrence of fetal death and resorption we...
Heyneman RA, Vercauteren RE.The subcellular components of purified neutrophil leukocytes from horse blood were fractionated by isopyknic equilibration in sucrose and metrizamide gradients. Five classes of particles have been identified: dense azurophil granules containing the bulk of the lysosomal acid hydrolase and peroxidase activity (A); less dense particles, containing all the lysozyme activity, but not resolved from a second population of azurophils B, and particles of low density, biochemically characterized as a plasma membrane fraction (C). Isopyknic equilibration in sucrose disclosed a minor membrane fraction (D...
Attenburrow DP.Techniques developed for the detection and simultaneous recording of certain events in the respiratory and limb cycles are presented. The respiratory cycle and limb cycle were found to be in-phase only at the canter and gallop. The significance of any time relationship between events in respiration and in locomotion is discussed.
Blue MG, Brady AA, Davidson JN, Kenney RM.Forty uterine fluid samples were obtained during oestrus and dioestrus of successive cycles from 4 mares classified as resistant to bacterial infection of the uterus. The flushings were assayed for peroxidase activity and ability to influence phagocytosis by polymorphonuclear neutrophils. Uterine fluid volumes and protein concentrations and serum oestrogen values were similar during oestrus and dioestrus. Serum progesterone concentrations were depressed during oestrus. Equine neutrophils adherent to glass slides were exposed to a genital strain of Streptococcus zooepidemicus suspended in salin...
Asa CS, Ginther OJ.Dexamethasone, a synthetic glucocorticoid, was administered (30 mg/day) from Day 10 after ovulation to assess the involvement of the adrenal glands in the ovulatory cycle. Only 1 of 8 mares treated in this way exhibited behavioural oestrus, compared to 7 of 8 control mares. Mean maximum LH concentration and follicle size were significantly reduced. Ovulation occurred in 1 and possibly in 2 other treated mares, compared to all 8 control mares. The results demonstrated that dexamethasone can interfere with ovulation and associated events in the mare, but the mechanism of action is uncertain.
Kilmer DM, Sharp DC, Berglund LA, Grubaugh W, McDowell KJ, Peck LS.Melatonin concentrations in intact (N = 3) and sham-operated (N = 3) mares during March were greater (P less than 0 . 05) during the night than during the day, but this pattern was not seen in 3 mares from which the superior cervical ganglia had been removed bilaterally. When 4 Pony mares were exposed to a photoperiod of 10L:14D for 3 weeks and then to continuous darkness (0L:24D) for another 3 weeks, melatonin levels were greater (P less than 0 . 05) at the end of the 0L:24D period than during the earlier period and still displayed rhythmic fluctuations but were no longer co-ordinated with eq...
Laegreid WW, Breeze RG, Counts DF.1. Equine alpha 1-antitrypsin was isolated from horse plasma by a combination of ammonium sulfate and acidification precipitation followed by ion-exchange chromatography on DEAE-cellulose, molecular sieve chromatography on Sephadex G-200 and affinity chromatography on Cibacron Blue-agarose. 2. The purified protein showed a single precipitin arc on immunoelectrophoresis in agarose but gave two bands on discontinuous polyacrylamide gel electrophoresis (PAGE). 3. Both bands appeared to interact equally with trypsin and were thought to represent two isoinhibitors of equine alpha 1-AT.
Wilks CR, Barton MD, Allison JF.Immune responses to Rhodococcus equi were assayed in mares and foals on 7 studs in south-eastern Australia using skin test reactivity to the intradermal injection of culture filtrate and an indirect fluorescent antibody test. The prevalence of positive skin-test reactions did not differ between studs with a history of R. equi disease and those without but there were more mares with high antibody titres on studs with a disease history. A leucocyte extract prepared from mares that were skin-test positive was evaluated for its ability to protect foals exposed to experimental or natural challenge:...
Murayama JI, Tomita M, Hamada A.The complete amino acid sequence of the major sialoglycoproteins of horse erythrocyte membranes, glycophorin HA, was determined by manual sequencing methods, using tryptic, chymotryptic, and cyanogen bromide fragments. Glycophorin HA is a polypeptide chain of 120 amino acid residues and contains 10 oligosaccharide units attached to the amino-terminal side of the molecule. Its amino terminus is pyroglutamic acid. All of the oligosaccharides are linked O-glycosidically to threonine or serine residues. The amino acid sequence is consistent with the transmembrane orientation of glycophorins. There...
Matsumura T, Mashiko R, Sato T, Itokawa K, Maekawa Y, Ogawa K, Isawa H, Yamamoto A, Mori S, Horita A, Ginnaga A, Miyatsu Y, Takahashi M, Taki H....The redback spider (Latrodectus hasseltii Thorell) reportedly invaded Japan in September 1995. To date, 84 redback spider bite cases have been reported; 7 of these cases employed the antivenom. Antivenom has been imported from Australia in the past, but because of restrictions on exportation it was evident that nearly all of the antivenom present in Japan would expire during 2014. In 2014, a plan was proposed to experimentally manufacture and stockpile a horse antiserum for ourselves, using redback spiders indigenous to Japan. A total of 11,403 female spiders were captured alive: 1,217 from th...
Kau S, Motter KS, Moser VJ, Kunz JR, Pellachin M, Hartl B.Incisor malocclusions are common in horses. As yet, an evidence-based understanding of incisor occlusal surface angle dynamics and normocclusal range is missing. Orthodontic measuring devices could help unravel this information objectively but imply measurement validation. We evaluated intra- and interexaminer variability of repeated sagittal and transversal incisor occlusal surface angle measures using a commercial orthodontic gauge device (). Five examiners (two experienced, three inexperienced) measured six cadaver heads on 2 consecutive days in a blinded block-randomization design, resulti...
Bosch G, van Duijkeren E, Bergwerff AA, Rijkenhuizen AB, Ensink JM.Ceftiofur concentrations in an infected and uninfected environment were compared and the efficacy of locally administered ceftiofur was evaluated in an experimental infection with Staphylococcus aureus in tissue cages. Eight ponies had tissue cages (TCs) implanted s.c. on each side of the neck. Into one of the cages 150 mg of ceftiofur was administered and fluid samples were taken to determine ceftiofur concentrations. After 1 week the other TC was infected with S. aureus and subsequently treated with 150 mg ceftiofur administered locally into the TC once daily for 21 days. Samples of fluid we...
Meier H.The biography of Colonel Hermann Schwyter, equine surgeon of the Swiss Army from 1928 to 1937, and the history of training of farriers in Switzerland since the 18th century are presented. Hermann Schwyters dissertation examined the changes of equine hoof confirmation as a result of standing and gait in approximately 2,000 horses and numerous anatomical specimens. He defines the foot placement, describes possible variations, their causes and effects. Significant is also his study of the compression pathology in horses and mules. His recommendations are still valid today. The present article ref...
Graham S, Solano M, Sutherland-Smith J, Sato AF, Maranda L.Disorders of the stifle are a common cause of lameness in horses yet the accuracy of scintigraphy for diagnosis of stifle conditions is controversial. The aim of retrospective cross-sectional study was to determine the diagnostic sensitivity (Se) of bone scintigraphy in detecting stifle disease and to determine if two orthogonal scintigraphic images improve diagnostic Se. Horses that underwent scintigraphic examination during a two-year period were included. Horses were divided into two groups: group 1 (N = 23) had lameness that was localized to the stifle by intra-articular analgesia and grou...
Moon PF, Snyder JR, Haskins SC, Perron PR, Kramer GC.Conventional fluid resuscitation is unsatisfactory in a small percentage of equine emergency surgical cases because the large volumes of fluids required cannot be given rapidly enough to adequately stabilize the horse. In anesthetized horses, the volume expansion and cardiopulmonary effects of a small volume of highly concentrated hypertonic saline-dextran solution were evaluated as an alternative initial fluid choice. Seven halothane-anesthetized, laterally recumbent, spontaneously ventilating, normovolemic horses were treated with a 25% NaCl-24% dextran 70 solution (HSD) at a dosage of 1.0 m...
Christensen RA, Malinowski K, Scanes CG, Hafs HD.Our goal was to establish a time of day and(or) interval from feeding that would avoid the refractory period after a somatotropin (ST) surge and optimize the responsiveness of horses to ST secretagogues. Two experiments were conducted with eight geldings conditioned to consume grain at 0800 and 1600 daily. In Exp. 1, during a 24-h period, these geldings averaged 3.2 +/- .3 pulses of ST with peak amplitude of 4.2 +/- .4 ng/mL, pulse duration of 55 +/- 6 min, and interpeak interval of 400 +/- 57 min. No ST peaks occurred within 2 h after either grain feeding. In Exp. 2, eight geldings were given...
Dart AJ, Strong M, Rose RJ, Hodgson DR.To evaluate the clinical, haematological, and serum biochemical effects of two large doses of recombinant equine growth hormone. Methods: Duplicated Latin square. Methods: Three Thoroughbred and three Standardbred mares aged between 12 and 17 years. Methods: Two horses were randomly assigned into one of three groups. On each of three successive days, each horse pair received one of two dosages of growth hormone or a saline placebo so that by the end of the experiment all three horse pairs had received both dosages and the saline placebo. Dose rates selected were 50 micrograms/kg, and 100 micro...
Attenburrow DP, Flack FC, Portergill MJ.Peak expiratory sound intensity (dB SPL), obtained by means of a radiostethoscope, and peak expiratory flow rate, obtained using a mask incorporating a thermistor flow sensor, were measured in six Thoroughbreds over a range of stride rates from 100 to 140 strides per min. The results show linear relationships between peak dB SPL and stride rate, peak expiratory flow rate and stride rate and also between peak expiratory flow rate and peak dB SPL. Peak expiratory dB SPL can therefore indicate peak expiratory flow rate.
Fitzgerald DM, Pollitt CC, Walsh DM, Sillence MN, de Laat MA.The oral glucose test (OGT) is a useful tool for diagnosing insulin dysregulation (ID) and is somewhat repeatable in ponies under consistent management. This study aimed to determine whether the insulin and incretin responses to an OGT in ponies differed after short-term access to fertilised pasture, compared to unfertilised pasture, by using a randomised, repeated measures study design. Sixteen mixed-breed ponies were classified as severely insulin-dysregulated (SD; post-prandial insulin ≥80 μIU/mL) or not severely insulin-dysregulated (NSD; post-prandial insulin < 80 μIU/mL) using an O...
Smit LA, Wouters IM, Heederik D, Douwes J.Endotoxins are cell-wall components of Gram-negative bacteria that are commonly present in plants and plant products and in faecal matter. This review presents an overview of endotoxin exposure levels, associated health effects, and relevance regarding veterinary practice. Exposure to airborne endotoxin is especially high in the agricultural sector and among veterinarians, and in particular among those working with horses or farm animals. Inhalation of endotoxins may cause acute airway inflammation and respiratory symptoms that can lead to (non-allergic) asthma and chronic obstructive pulmonar...
Löfman CO, Brännström M, Holmes PV, Janson PO.Surface cell changes at the apices of preovulatory follicles and ovulations were documented in isolated perfused ovaries from immature rats treated with pregnant mare serum gonadotropin (20 IU) and 48 h later with human chorionic gonadotropin (hCG) (10 IU). A video camera coupled to an inverted microscope and a video recorder captured the preovulatory and ovulatory events at a cellular level. At around 8 h post-hCG, the follicular apex changed from a smooth and optically homogeneous appearance into a rough surface with bleb formation and extrusions of single cells through minute perforations (...
Breaud TP, Steelman CD, Roth EE, Adams WV.A tissue culture of Culex pipiens quinquefasciatus Say ovarian cells appeared to support the growth of equine infectious anemia (EIA) virus. Shetland ponies inoculated with 2nd, 7th, 9th, and 11th passages of mediums harvested from infected tissue culture had clinical signs of the disease and became EIA positive on 11, 19, 23, and 43 days after inoculation, respectively.
Shiang CA, Bonney C, Lazarus B, Meyers M, Jasiuk I.This study predicts analytically effective elastic moduli of substructures within an equine hoof wall. The hoof wall is represented as a composite material with a hierarchical structure comprised of a sequence of length scales. A bottom-up approach is employed. Thus, the outputs from a lower spatial scale serve as the inputs for the following scale. The models include the Halpin-Tsai model, composite cylinders model, a sutured interface model, and classical laminate theory. The length scales span macroscale, mesoscale, sub-mesoscale, microscale, sub-microscale, and nanoscale. The macroscale re...
Olsen SC, Coyne CP, Lowe BS, Pelletier N, Raub EM, Erickson HH.Furosemide, which commonly is used as a prophylactic treatment for exercise-induced pulmonary hemorrhage in horses, may mediate hemodynamic changes during exercise by altering prostaglandin metabolism. To determine if furosemide's hemodynamic effects during exercise in horses could be reversed, cyclooxygenase inhibitors were administered with furosemide. Four treatments were administered 4 hours prior to treadmill exercise at 9 and 13 m/s. They included a control treatment (10 ml of 0.9% NaCl solution, IV), furosemide (1 mg/kg of body weight, IV) administered alone, and furosemide in combinati...
