"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
Medda R, Cara N, Floris G.Ceruloplasmin is a blue copper-containing serum glycoprotein with oxidase activity. It as been proposed that the physiological function of ceruloplasmin involves the oxidation of ferrous iron and its incorporation into apotransferrin. There are several reports demonstrating that ceruloplasmin is made up of multiple chains. Ryden has questioned the multichain structure of ceruloplasmin from human, pig, horse and rabbit sera, arguing that the dissociation observed by previous workers could be attributed to cleavage of labile bands in the protein by enzymatic contaminants present in commercial pr...
Morris DD, Moore JN.Equine peritoneal macrophages were isolated and cultured in vitro to assess their ability to produce thromboxane (TxA2) and prostacyclin (PGI2) in response to endotoxin. Peritoneal macrophages (2.5 x 10(6)/ml) were incubated in tissue culture media, containing 1) no additive (nonstimulated control), 2) endotoxin (0.5 to 100 ng/ml) or 3) the calcium ionophore, A23187 (0.95 microM) for two and six h. Concentrations of the stable metabolites of TxA2 and PGI2 thromboxane B2 (TxB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), in the incubation media were determined by radioimmunoassay. Th...
Deuel NR, Lawrence LM.Bilateral asymmetry in gallop stride limb contact patterns of four Quarter Horse fillies was documented by high-speed cinematography. Horses were filmed with rider by two cameras simultaneously while galloping along a straightaway. Even though signaled for each gallop lead an equivalent number of times, horses frequently switched leads, selecting the left lead nearly twice as often as the right. Velocities and stride lengths were greater for the left lead than the right, but stride frequencies did not differ between leads. Velocity effects were partitioned out in limb contact data analysis to ...
Mitchell CJ, Monath TP, Sabattini MS, Daffner JF, Cropp CB, Calisher CH, Darsie RF, Jakob WL.Mosquitoes were collected in Santa Fe and Rio Negro provinces, Argentina, in 1982-1983 during a western equine encephalitis (WEE) epizootic. Totals of 153,084 mosquitoes from Santa Fe Province and 484 from Rio Negro Province were tested for virus in 2,351 pools. Seventeen virus strains were isolated, all from Santa Fe collections, as follows: 4 WEE, 6 Venezuelan equine encephalitis, 1 St. Louis encephalitis, 2 Antequera, 1 Maguari, 1 Melao, 1 new vesiculovirus (Calchaqui), and 1 Gamboa. The WEE virus isolates were from Aedes albifasciatus, Anopheles albitarsis, Mansonia species, and Psorophora...
Richards KS, Ilderton E, Yardley HJ.Lipids extracted from the laminated layers of horse liver and lung hydatids, including a daughter liver cyst, were analysed using TLC. No differences in lipid composition was detected in 11 liver cysts, whether from the same or different livers, and di- and triacylglycerols, cholesterol, wax and steryl esters, oleic acid, sphingomyelin, phosphatidyl choline, phosphatidyl inositol and ceramide hexosides were detected. The daughter cyst differed from its "parent" cyst in lacking diacylglycerols and wax and steryl esters. The lung cyst differed from the liver cysts in that cholesterol, wax and st...
Ellis DR, Simpson DJ, Greenwood RE, Crowhurst JS.A retrospective study of 119 cases of fracture of the proximal phalanx is described. The short incomplete sagittal fracture (split pastern) was most common and carried a good prognosis for a return to racing following conservative treatment. Longer incomplete fractures also had a good prognosis but complete fractures, either through the lateral cortex of the proximal phalanx or through the bone into the proximal interphalangeal joint, required internal fixation. Careful assessment of these and comminuted fractures was essential before surgery was undertaken. Most comminuted fractures were trea...
Jemmerson R.To gain a better understanding of the diversity of epitopes on a protein, the specificities of 103 monoclonal antibodies to a model antigen, horse cytochrome c(cyt c), were analyzed. The antibodies were generated in in vitro monoclonal, secondary antibody responses against horse cyt c coupled to hemocyanin in splenic fragment cultures. For this assay, horse cyt c-primed murine B lymphocytes were transferred to irradiated, hemocyanin-primed recipients. A panel of seven mammalian cyts c differing at one to six residues out of 104 and cyanogen bromide-cleaved fragments of horse cyt c containing r...
Meijler FL, van der Tweel I.Atrial fibrillation is one of the most common cardiac arrhythmias in humans. It also occurs quite frequently in dogs and horses. Comparative study of this arrhythmia may contribute to better understanding of the pathophysiological mechanisms involved. In this study, we present a quantitative analysis of atrial fibrillation in humans, dogs, horses, and in a kangaroo, making use of histograms and serial autocorrelograms of the ventricular rhythm with and without digitalis medication. Increase in the size of the animal and thus in the size of the heart is accompanied by a decrease in ventricular ...
Eichhorn W.Infections and clinical diseases caused by equine 2 influenza A viruses are observed worldwide. The frequency of these outbreaks supports the hypothesis that antigenic variation of the surface proteins may play an important role. For the demonstration of these variations, monoclonal antibodies (Mabs) were prepared. They are directed against the hemagglutinin or the neuraminidase of the prototype strain a/eq/Miami/1/63. In hemagglutination-inhibition assays with Mabs two reaction patterns were observed: four Mabs inhibited 14 out of 17 strains tested. Another Mab recognized the hemagglutinin of...
Pretzman CI, Rikihisa Y, Ralph D, Gordon JC, Bech-Nielsen S.An enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) and IgM in natural and experimental infections of equids with Ehrlichia risticii was developed. Ehrlichial organisms purified from an infected mouse macrophage cell line were used as the antigen. IgM was separated from serum IgG by the expedient of spun-column chromatography, allowing the use of an indirect ELISA for quantitation of both IgG and IgM in the test sera. Among 16 paired sera from horses exhibiting clinical signs of Potomac horse fever, 8 were positive by the indirect fluorescent-antibody test (IFA), 11 were po...
Haack D.For the inoculation of the dermatophyte-test-medium Fungassay, 200 skin scrapings from horses, 13 from cattle and 13 from artificially infected guinea pigs were used. As control methods, the alkali method, the fluorescent microscope technique and the usual mycological culture were available. For the analysis of skin scrapings, the Fungassay culture mediums are clearly inferior to the usual mycological culture. Fewer dermatophytes were isolated and false positive as well as false negative results occurred. The cultivation of Trichophyton verrucosum failed on the dermatophyte-test-medium.
Romagnano A, Richer CL, Messier PE, Jean P.Silver staining shows the presence in the domestic horse of six NORs located on chromosomes 1, 26 and 31 as identified after R-banding. Following electron microscopy, the argyrophilic material was observed outside the terminal secondary constrictions (satellite stalks) on the terminal portion of the short arm of chromosome 1, outside the secondary constrictions on the proximal region of the long arms of chromosome 31, and beside the proximal region of the long arms of chromosome 26. Satellite staining applied to these chromosomes appears to reveal only the active NORs.
Sentsui H, Kono Y.Horse erythrocytes treated with equine infectious anemia virus hemagglutinin were phagocytized by cultivated horse leukocytes (mainly macrophage-like cells and partly polymorphonuclear cells) after incubation with fresh horse serum but not with inactivated horse serum. The phagocytosis began as soon as the erythrocytes were added to the leukocyte cultures, and the majority of the reaction proceeded within 30 minutes. Addition of antiserum showed a slightly suppressing but no enhancing effect on the phagocytosis. Phagocytosis seemed to be caused by the recognition of the third complement compon...
Duncan ID, Schneider RK, Hammang JP.The suprascapular nerve from 14 horses, which had no clinical evidence of spinatus muscle atrophy, were obtained to determine whether the nerve was sub-clinically compressed at the scapular edge. The nerves were divided into three portions, proximal and distal to the scapular edge and as it reflected around it. In nine horses there was evidence of a chronic neuropathy which varied in severity and which was most severe at the site of reflection, where the nerve appeared constricted by a tendinous band. At this site the predominant change was that of chronic demyelination and remyelination, with...
Squires EL, McKinnon AO, Carnevale EM, Morris R, Nett TM.For embryos collected from mares 7 days after ovulation, embryo recovery for single-ovulating mares was 53% compared to 106% for double-ovulating mares. Pregnancy rates 50 days after surgical transfer were 68 and 129%, respectively. Concentrations of LH were similar during the periovulatory period for cycles which included single or double ovulations. Horse pituitary extract given for 5.5 days resulted in greater than or equal to 2 ovulations (mean 3.8) in 26 of 28 mares and 2.0 embryos were recovered per donor compared to 0.65 for controls. Non-surgical pregnancy rates for embryos collected f...
Johnstone IB, Petersen D, Crane S.Plasma Antithrombin III (ATIII) activity was quantitated in 24 clinically normal Standardbred/Thoroughbred horses using a clotting time technique. ATIII activity ranged from 80 to 106% of the pooled reference standard plasma, with a mean of 94%. Horses presenting with impaction or spasmotic colic (n=17) had normal plasma ATIII activity, while 15 horses presenting with acute diarrhea/colitis had significantly lower plasma ATIII activity with a mean of only 74% of the reference plasma. Seven horses presenting with liver disease had significantly higher plasma ATIII activity with a range of 127 t...
Reinhard F.The conformation of a foal's limbs is of interest beginning in the first days of life. The hoof also must not be neglected. Management and hoof care necessary for normal hoof development are discussed. In addition, pathological hoof shapes and their appropriate treatments are outlined.
Worthy K, Colquhoun K, Escreet R, Dunlop M, Renton JP, Douglas TA.Plasma prolactin concentrations were measured in mares using an homologous radioimmunoassay. An annual rhythm in plasma prolactin was found, with concentrations higher during the summer than during the winter. In addition to this seasonal pattern, occasional high concentrations of prolactin were seen when concentrations were otherwise basal. Blood samples taken from mares during an oestrous cycle in October-November showed that prolactin values were basal for most of the cycle, with a marked rise in prolactin shortly before the onset of oestrus. This prolactin peak was associated with an incre...
Hoffman LS, Adams TE, Evans JW.Blood samples were obtained from 5 mixed-breed, long-term castrated geldings during five 24-h periods between May 1984 and April 1985. Blood samples were collected, beginning at 09:00 h, at 15-min intervals for 8 h and hourly for the remaining 16 h. Plasma concentrations of LH and FSH were determined by RIA. Seasonal changes in hormone concentrations and frequency and amplitude of secretory pulses were evaluated. No diurnal variation in either LH or FSH secretion was observed: however, marked circhoral fluctuations in LH and FSH secretion were noted. Mean LH and FSH concentrations in these lon...
Higgins AJ, Lees P, Sedgwick AD, Buick AR, Churchus R.In a two-part cross-over experiment in six ponies, an acute inflammatory reaction was generated by injecting carrageenin solution into subcutaneously-implanted tissue-cages lined with fibrovascular granulation tissue. In each part of the cross-over, half of the ponies received a novel phenylpyrazoline anti-inflammatory agent (BW540C) orally and half received a placebo treatment. BW540C inhibited platelet cyclo-oxygenase for 24 h but the reductions in exudate eicosanoid concentrations were less pronounced. A significant suppression in the rise of surface skin temperature in BW540C-treated ponie...
Alexander SL, Irvine CH, Turner JE.FSH was measured in the pituitary, and in pituitary venous and jugular blood collected at frequent intervals from mares in various reproductive states, using 3 validated and highly specific radioimmunoassay systems based on different antibodies, 'o', 'h' and 'e'. In the pituitary, 4 forms of FSH were found which differed in isoelectric point and relative potency in the 3 assays. In jugular blood, mean FSH concentrations and short-term patterns depended on the assay used and the reproductive state of the mare. In pituitary venous blood, although FSH concentrations were greatly elevated above ju...
Kiryu K, Nakamura T, Kaneko M, Oikawa M, Yoshihara T.Twenty thoroughbred race horses were selected for postmortem cardiopathological study of sudden cardiac death; ten of the twenty horses died suddenly. In order to define accurately the morphological changes observed in these ten hearts, ten other thoroughbred race horses considered to have normal hearts were selected as a control group and studied by postmortem coronary angiography. Of the ten horses that died suddenly, eight were witnessed to have died either during or shortly after training or racing. The death was instantaneous except in one horse, which showed ventricular tachycardia and d...
McEntee M, Summers BA, de Lahunta A, Cummings J.A 3-year-old horse presented with intermittent generalized seizures of 2-month duration. During interictal periods, the horse appeared normal and a cause for the seizures could not be identified. Necropsy revealed opacity of the leptomeninges, covering most of one cerebral hemisphere along with thinning and collapse of the cortex in the ipsilateral pyriform lobe. Histopathology demonstrated leptomeningeal vascular proliferation and meningothelial hyperplasia. Prominent tortuous vessels of the gyri and sulci extended into some regions of the subjacent cortex, where there was neuronal loss, ecto...
Les CM, Stover SM, Willits NH.Paired metacarpi obtained at necropsy from 100 horses ranging in age from term fetus to 35 years were examined to estimate the prevalence and sites of metacarpal fusion. Metacarpal fusion was seen in 192 of 200 metacarpi, and 78% of all horses 2 years or older had 2 or more fusions. Fusion of the second metacarpal bone to the third metacarpal bone was significantly (P < 0.001) more common than was fusion of the fourth to the third metacarpal bone. Fusions appeared for the most part in pairs and were bilaterally symmetric. Rooney-Prickett type-A carpometacarpal joint configurations (in which...
Filipović N, Stojević Z, Prvanović N.The changes in blood serum fructosamine concentrations as indicators of glycaemia during a longer period of time were investigated in mares during late pregnancy and early lactation, as well as their relationship to the changes in the concentration of biochemical indicators of energetic status. The samples were taken from eleven mares on 60 +/- 10 and 20 +/- 10 days before foaling, and 20 +/- 10 and 60 +/- 10 days after foaling. Concentrations of serum fructosamine, non-esterified fatty acids and triglycerides were higher during late pregnancy (from P < 0.05 to P < 0.0005), while the con...
Mackey VS, Pascoe JR, Peterson PR.Anastomotic leakage was noted to occur at the junction of the staple lines used to create the stoma during small intestine side-to-side anastomosis. The anastomosis was performed in a clinical equine patient by joining the lateral surfaces of the intestinal segments using a gastrointestinal anastomosis stapling instrument (GIA). The cause of this problem was investigated by performing six anastomoses in the jejunum of a single anesthetized adult horse using the GIA; three anastomoses were created by joining the antimesenteric edges of the bowel segments and three anastomoses were created by jo...
Lewis J, Poland J.The ability of erythromycin in liquid medium to suppress the growth of eight species of acholeplasma and of 13 species of mycoplasma was tested. The Acholeplasma spp and two glycolytic Mycoplasma spp from horses--a slow glucose-metabolising (SGM) mycoplasma and a strain N3, related to M mycoides--were sensitive to erythromycin. Thus the growth of acholeplasmas can be suppressed when attempts are made to isolate pathogens from the porcine respiratory tract, but, in the case of horses, erythromycin would suppress not only Acholeplasma spp but also two Mycoplasma spp of unknown pathogenicity in t...
Pinna AE, Okada CTC, Ferreira CSC, Campos DG, Possidente KS, de Cássia C L Morais R, Oliveira M, Salomão MC, Hataka A.Ovarian tumours in mares represent 2.5% to 6% of the most frequent neoplasms found in the equine species, with a higher chance of benignity. This study aims to describe a case of two different tumours found in the same ovary of a mare that presented clinical signs of suppressed oestrous cycle during 5 years. After unilateral ovariectomy, the ovary was sent to the histopathology examination which determined a mixed tumour of granulosa cell and leiomyosarcoma. After treatment, the mare returned to oestrus and got pregnant in the next season.
Ainsworth DM, Ducharme NG, Hackett RP, Eicker SW, Snedden K.We examined the electromyographic activity of the costal portion of the diaphragm and the transverse abdominal and external oblique muscles in 6 chronically instrumented awake adult horses during eupneic breathing, during 2 levels of hypercapnia (fractional concentration of inspired CO2; FICO2 = 0.4 and 0.6), and during 2 levels of hypocapnic hypoxia (FIO2 = 0.15 and 0.12). Using the inert gas technique, we also measured the end-expiratory lung volumes of the 6 horses during eupnea, 6% CO2 challenge, and 12% O2 breathing. During eupneic breathing, phasic electrical activity of these 3 muscles ...
Patterson-Kane JC, Ginn PE.The current report describes a malignant melanoma in the dermis of a 13-year-old bay Thoroughbred mare. Microscopic examination revealed that tumor cells were arranged in cords and packets within an abundant collagenous stroma containing scattered myxomatous foci. Tumor cells stained positively for S-100, neuron-specific enolase, and vimentin and some contained melanin granules. Some clusters of tumor cells were also positive for pancytokeratin. Expression of epithelial cell markers has been described in small numbers of human melanomas but has not been reported previously in equine melanomas....
Marr KA, Lees P, Page CP, Cunningham FM.The leukotrienes (LT) LTD4 and LTB4 have been shown to cause bronchoconstriction and neutrophil accumulation, respectively, in horse lungs. Such changes are characteristic of the equine allergic respiratory disease, chronic obstructive pulmonary disease (COPD). To further investigate the role of these putative mediators in the pathogenesis of equine COPD the effect of a 5-lipoxygenase inhibitor, fenleuton, on antigen-induced changes in horses with this condition has been examined. Six horses with COPD underwent a series of four antigen challenges, one month apart, with placebo pre-treatment on...
Lange L, Marett S, Maree C, Gerdes T.Suspected molluscum contagiosum was diagnosed in 3 horses in the Chingola district of Zambia. The horses were found to be suffering from a slow progressive skin disease with lesions on the chest, shoulders, inner and lateral aspects of the fore- and hindlimbs, the face, fetlocks, pasterns and on the lateral surfaces of the body. The lesions varied from 4 to 20mm in diameter, were hairless but covered by soft keratin projections which, when removed, left a raw elevated base tightly adherent to the epidermis. These lesions bled profusely when the animals were groomed. Older lesions were well cir...
McBeath DG, Best JM, Preston NK, Duncan JL.Examination of faecal egg counts in horses and ponies has shown that after treatment with fenbendazole at dose levels of 7.5, 45 and 60 mg/kg, faeces remained free from strongyle eggs for periods of 6 to 18 weeks. The significance of these results is discussed in relation to routine anthelmintic treatment of horses. In particular, the activity of fenbendazole against mucosal stages of strongyle parasites allows for treatment to be recommended at less frequent intervals than when using other anthelmintics.
Walker WT, Callan RJ, Hill AE, Tisher KB.This study evaluated the effects of administering oral powder electrolytes on packed cell volume (PCV), plasma chemistry parameters, and incidence of colic in horses participating on a 6-day 162-km trail ride in which water was not offered ad libitum. Twenty-three horses received grain with powder electrolytes daily while 19 control horses received grain only. Horses were ridden approximately 32 km a day at a walk or trot. Packed cell volume and plasma chemistry parameters were analyzed daily. Episodes of colic were diagnosed and treated by a veterinarian unaware of treatment group allocation....
McCoy DJ, Beasley R.Hypercalcemia associated with malignancy was diagnosed in a 2-year-old Thoroughbred filly admitted because of weight loss and reduced exercise tolerance of approximately 2 months' duration. Laboratory findings included hypercalcemia, hypophosphatemia, anemia, marked neutrophilia with lymphopenia and eosinopenia, and normal immunoreactive parathyroid hormone concentration. At necropsy, a 53.6-kg tumor was located in the cranioventral aspect of the abdominal cavity. Gross renal lesions were not noticed. Bone tissue appeared to be normal on gross and histologic examinations. The parathyroid gland...
Hof K, Shibly S, Berger S.A 13-year-old Standardbred gelding was referred for evaluation of continuous abdominal pain. Rectal examination revealed a dislocated large colon (Dislocatio coli ad dextram). The horse showed muscle fasciculations and appeared lethargic. It was sent to surgery because of persistent colic. In transit the gelding showed an unstable walk and immediately prior to surgery a wide-based stance in the hindlimbs. Laparotomy revealed a retroflexion of the large colon and a secundary mesenterial volvulus. After surgery the horse remained recumbent. Due to the comatose state and poor prognosis the geldin...