"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.
Kurachi K, Schmer G, Hermodson MA, Teller DC, Davie EW.A comparison of the physical-chemical properties of human, bovine, and horse antithrombin III has been made. These three plasma proteins are strong inhibitors of bovine factor Xa and form a 1:1 molar complex with this coagulation enzyme. Human, bovine, and horse antithrombin III are glycoproteins containing hexose, hexosamine, and neuraminic acid. The total carbohydrate was 9, 12, and 16% for human, bovine, and horse antithrombin III, respectively. These proteins have a similar amino acid composition, although some monor variations were noted. Each antithrombin III is composed of a single poly...
Wetz K, Crichton RR.In apoferritin, but not in ferritin, 1.0 +/- 0.1 cysteine residue per subunit can be modified. In ferritin 3.3 +/- 0.3 lysine residues and 7.1 +/- 0.7 carboxyl groups per subunit can be modified, whilst the corresponding values for apoferritin are 4.4 +/- 0.4 lysine residues and 11.0 +/- 0.4 carboxyl groups per subunit. Modification of lysine residues which maleic anhydride and carboxyl groups with glycineamide in apoferritin which has been dissociated and denatured in guanidine hydrochloride leads to the introduction of 9.1 +/- 0.5 maleyl groups per subunit and 22.0 +/- 0.9 glycineamide resid...
Sells DM, Hildebrandt PK, Lewis GE, Nyindo MB, Ristic M.The ultrastructure of the etiological agent of equine ehrlichiosis, Ehrlichia equi, was studied in equine peripheral leukocytes. The organisms occurred within membrane-lined cytoplasmic vacuoles of neutrophils and eosinophils. Ovoid, round, and rod-shaped profiles were observed. From 1 to 33 organisms were present in a thin-section profile of a cytoplasmic vacuole. Many cells contained multiple organism-containing vacuoles. The organisms had a cell wall and plasma membrane, and internally they consisted of electron-dense and lucid areas. A great variation in size was observed. The morphologica...
Seybert DW, Moffat K, Gibson QH.The reactions of horse globin reconstituted with proto-, deutero-, and mesoheme have been examined by equilibrium and kinetic methods. In virtually all reactions studied, mesohemoglobin displays the more extreme functional behavior, whereas deuterohemoglobin exhibits behavior which is either very similar to native hemoglobin or intermediate between the two. Our kinetic and equilibrium results indicate that the primary effect of heme modification on the functional properties of hemoglobin is to alter the intrinsic reactivities of the deoxy and liganded conformations. Heme modification does not,...
Hawkins JA, Adams WV, Wilson BH, Issel CJ, Roth EE.The mechanical transmission of equine infectious anemia (EIA) virus by Tabanus fuscicostatus was investigated. In 1 of 7 transmission trials, a single horsefly transmitted EIA virus from an acutely infected pony to a susceptible pony. Groups of horseflies isolated for 3, 10, or 30 minutes before refeeding transmitted EIA virus, whereas those isolated for 4 or 24 hours did not. Data from field studies indicate that the home range or flight distance of horseflies may exceed 4 miles. That information together with our observations suggest that segregation of infected horses (usually defined as at...
Walthall JC, McKenzie RA.Horses grazing manily Cenchrus ciliaris and/or Panicum maximum var. trichoglume pastures on over 30 properties in southern central Queensland developed lesions of osteodystrophia fibrosa. Horses on individual properties in coastal Queensland grazing Setaria anceps, Brachiaria mutica or Pennisetum clandestinum also developed the disease. Ill-thrift, lameness, and fibrous swellings of nasal bones, maxillae and mandibles were observed. Calcium and phosphorus levels of pasture were normal but all the above pasture species contained oxalates which were suspected of causing the disease.
Komárek J, Stros K, Sýkora I, Kynclová I, Jadrný L, Selinger P.By means of the Astrup equilibration method the values of the acid-base balance of the blood were determined in 104 cows, 99 horses, 100 pigs, 15 sheep, 20 goats, and in 101 dogs. The pH values of the blood, the partial pressure of CO2, the base excess, the base buffer, the standard bicarbonate, the actual bicarbonate, and the total CO2 were processed statistically and are presented in tables.
Hart LT, Braymer HD, Larson AD, Broussard EA.Equine infectious anemia (EIA) antigen extracted from the spleen of horses infected with EIA virus was purified by pH treatment, (NH4)2SO4 fractionation and affinity chromatography. The homogeneity of the antigen was indicated by sedimentation rate and sedimentation equilibrium experiments. A S20,w of 0.51 was determined and a molecular weight of 7600 was calculated from sedimentation equilibrium analysis. The amino acid composition of the pure antigen indicated the antigen is an acidic protein. Employing radical immunodiffusion (RID) and pure antigen a method for quantitating antigen content ...
Holmes JR.The paper describes the spatial vector changes during ventricular depolarisation in 190 horses using a semi-orthogonal ECG lead system. The replacement of planar vector loops by a plot of 3 parameters to depict the changing spatial vector, with a time base on the X axis, is described and illustrated. Some horses with diastolic murmurs and some with a history of respiratory problems formed 2 distinct groups. As a result of these findings a possible relationship between the vector changes and the anatomical siting of the ventricles is suggested and discussed. Attention is drawn to certain measur...
Milne DW, Turner AS, Gabel AA.In the horse, surgical approaches for plating fractures of the ulna, radius, metacarpus, tibia, and metatarsus involved a single curvilinear skin incision and incision of the superficial fascia in a manner to prevent postoperative dehiscence. The tension side of the bones, as well as location of nerves, arteries, veins, and muscles, were the major determinants in developing these approaches for atraumatic surgery and short operative time.
Zobel G, Kolb FE.Acid phosphatase of erythrocytes of several species was investigated, with three isozymes having been recorded from swine (three types), three (two types) from horse, four (one type) from dog, two (two types) from cat, two (three types) from duck, and two (one type) from fowl. The Michaelis constant of the enzyme varied between 3.5 and 5 X 10(-4) M for the species involved. The species, however, differed slightly for the optimum pH of the enzyme. The average enzymatic activities were (5.68 +/- 0.42 for dog, 4.46 +/- 1.0 for horse, 3.8 +/- 0.24 for swine, 3.72 for cat, 2.5 +/- 0.62 for duck, an...
Cattabiani F, Cabassi E, Allodi C, Gianelli F.The AA. report the results of taxonomic research conducted on the conjunctival sac of 59 horses for identification of the present bacterial flora. In the controlled animals, it was observed, at the level of the considered niche, a community constituted of normal bacterial populations, but not autochtonous in the significance they attributed from DUBOS et al., relative to the characterization of the indigenous microbiota of the intestine. The isolated normal bacterial flora seems to be constituted of: Micrococcus (subgroup 6 of Baird-Parker, M. luteus, Micrococcus spp.) isolated in 49,15% of th...
Salonen JS, Vuorilehto L, Gilbert M, Maylin GA.Horse urine was investigated for metabolites by chromatography and mass spectrometry following the oral administration of the large animal analgesic sedative detomidine to two stallions and intravenous administration of [3H]-detomidine to a mare. Detomidine carboxylic acid and hydroxydetomidine glucuronic acid conjugate were identified in the urine after the oral doses. In addition, traces of free hydroxydetomidine were observed. About half of the radioactivity of [3H]-detomidine was excreted in the urine in 12 h after the i.v. dose (80 micrograms/kg). Most of the excretion occurred between 5 ...
Blakely JA, Blakely AA.Veterinarians commonly predict mature heart scores for yearling and 2-year-old horses to aid clients in assessing a horse's racing potential. Sixty-six thoroughbreds were assessed as a yearlings or 2-year-olds, then re-assessed as a mature horse (over the age of 3). Of these horses, 82% of the yearlings and 87% of the 2-year-olds had a correctly predicted mature heart score within one heart score range (i.e. three points).
Wilson WD, Spensley MS, Baggot JD, Hietala SK, Pryor P.The pharmacokinetics and bioavailability of ticarcillin and clavulanate were determined after intravenous (i.v.) or intramuscular (i.m.) administration of ticarcillin disodium (50 mg/kg) combined with clavulanate potassium (1.67 mg/kg) to groups of healthy foals at 3 days and 28 days of age. After i.v. administration of the combination to five foals, the disposition kinetics of ticarcillin and clavulanate were best described using a two-compartment open model. Mean plasma elimination-rate constant (beta) and clearance (ClB) for ticarcillin were significantly less (P less than 0.01), and volume...
Kosec M, Mrkun J.Methods for elimination of one of two embryos in twin pregnancies of mares were studied. Transvaginal ultrasound guided punction of yolk sac or allantoic cavity with fluid aspiration was used. Punction was done in 8 mares, pregnant between 22 and 46 days. In six cases, pregnancy did continue normally with one embryo only while in two cases, both embryos died following the procedure.
Brownlow MA, Turner DM, Hutchins DR.An inhalation anaesthetic apparatus for the horse is described and the physiological concepts pertaining to its design presented. The internal diameter of all breathing components is 6.2 cm with no change in cross sectional area throughout the circle system. The soda lime capacity is 25 litres (approximately 20 kg). In the horse, which is apparently predisposed to alveolar hypoventilation during inhalation anaesthesia, it is apparent that adequate anaesthetic apparatus design should be directed towards minimising resistance and dead space and providing maximal and efficient carbon dioxide elim...
Mullaney TP, Brown CM, Watson GL, Brandt LA.An apparently new and emerging fatal hepatic disease affecting foals is described. Characteristics included evidence of hepatic failure, marked biliary hyperplasia, hepatocellular necrosis and occasionally fibrosis. Generally, the features of the disease appear to differ markedly from other hepatic diseases of neonatal foals.
Abraham G, Broddet OE, Ungemach FR.In this study, beta-adrenoceptors of intact equine lymphocytes were identified and subclassified by (-)-[125I]-iodocyanopindolol (ICYP) binding. ICYP binding to intact equine lymphocytes was rapid, saturable (maximal number of binding sites 320 +/- 20 ICYP binding sites/cell, n = 12) and of high affinity (KD value for ICYP 14.4 +/- 1.7 pmol/l, n = 12). Binding was stereospecific as shown by the 10 times greater potency of (-)-propranolol to inhibit binding than its (+)-isomer. Beta-adrenoceptor agonists inhibited ICYP binding with an order of potency: (-)-isoprenaline >(-)-adrenaline >(-...
Bampidis V, Azimonti G, Bastos ML, Christensen H, Dusemund B, Fašmon Durjava M, Kouba M, López-Alonso M, López Puente S, Marcon F, Mayo B....Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of a feed additive consisting of vitamin K1 (phytomenadione) produced by chemical synthesis when used as a nutritional additive in complementary feed of horses at a maximum supplemental level of 14 mg vitamin K1/horse per day. The use of vitamin K1 is safe when used as a feed additive for horses under the proposed conditions of use. The use of vitamin K1 in nutrition of horses under the proposed co...
Anna C, Martyna P, Marcin S, Dawid W.Free-ranging grazers are increasingly being introduced to areas of high natural value, such as wetlands. There is also growing attention that has been paid to the historical role of herbivores in shaping ecosystems and landscapes. Even though studies on the grazing of free-range horses were carried out in different regions and climates, still little is known about their habitat selection on heterogeneous marshy areas in the temperate region of Europe. The aim of this study was to investigate the habitat use by contemporary Konik horses during the growing season on the basis of three-year GPS d...