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Topic:Horses
"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.
A rapid, non-invasive method for measuring total respiratory impedance in the horse. Total respiratory impedance was measured rapidly and noninvasively in conscious horses over the frequency range 3 to 40 Hz by the forced random noise method. The shape of curve of impedance versus frequency in horses was markedly different from that of humans. Respiratory resistance was readily found as the real part of impedence and both its absolute value and frequency dependence are useful indices of pulmonary function. It was difficult to obtain meaningful results in intubated animals with the method because of the mechanical properties of the endotracheal tube itself.
Effects of ischemia and dimethyl sulfoxide on equine jejunal vascular resistance, oxygen consumption, intraluminal pressure, and potassium loss. Physiologic effects of 1 hour of ischemia and 1 hour of reperfusion on equine jejunum and protective effects of systemic administration of dimethyl sulfoxide (DMSO, 1 g/kg of body weight) were investigated in 18 ponies, using neurally intact segments of jejunum perfused at constant flow with heparinized blood. Ponies were allotted to 4 groups: group 1, saline solution administered (control, n = 3); group 2, DMSO administered (DMSO, n = 3); group 3, ischemia induced and saline solution administered (ischemia, n = 6); and group 4, ischemia induced and DMSO administered (ischemia-DMSO, n = 6). In...
Development of an equine nuclear medicine facility for gamma camera imaging. A nuclear medicine facility constructed specifically for the application of a gamma camera system to the radioisotope imaging of bone, pulmonary circulation and ventilation in the horse is described. The gamma camera was previously used for human nuclear medicine, and a support for the gamma camera head was specifically designed for this work. Imaging protocols are suggested and the necessary materials for bone and lung studies are described. Images of bone and lung are shown and computer analysis of the data indicated. Imaging times are approximately 1 to 2 mins and typical bone and lung stud...
Small-colon rupture attributable to granulosa cell tumor in a mare. A large granulosa cell tumor was believed to be responsible for causing obstruction and subsequent rupture of the small colon in a 10-year-old Quarter Horse mare. Two months earlier, a mass, tentatively diagnosed as granulosa cell tumor of the left ovary, had been identified by means of rectal palpation and ultrasonography. The mare was evaluated for clinical signs of acute, severe, abdominal pain, increased heart rate, cyanotic mucous membranes, clinical dehydration, with high PCV, leukopenia, and extreme abdominal distension. A large soft tissue mass and taut band that constricted the lumen ...
Myoelectric activity of the cecum and right ventral colon in female ponies. The myoelectric activity of the cecum and right ventral colon (RVC) was studied in 4 female ponies. Eight, bipolar Ag-AgCl electrodes were sequentially placed on the seromuscular layer of the cecum (6 electrodes) and RVC (2 electrodes), and recordings were begun 14 days after surgery. The myoelectric activity for each pony was recorded during 12, 60-minute recording sessions done during the interdigestive period (3 to 7 hours after the morning feeding). Coordinated series of spike bursts were recognized as independent motility patterns in the cecum and in the RVC. Local haustra-haustra myoelec...
Mechanism of exercise-induced hypoxemia in horses. Arterial hypoxemia has been reported in horses during heavy exercise, but its mechanism has not been determined. With the use of the multiple inert gas elimination technique, we studied five horses, each on two separate occasions, to determine the physiological basis of the hypoxemia that developed during horizontal treadmill exercise at speeds of 4, 10, 12, and 13-14 m/s. Mean, blood temperature-corrected, arterial PO2 fell from 89.4 Torr at rest to 80.7 and 72.1 Torr at 12 and 13-14 m/s, respectively, whereas corresponding PaCO2 values were 40.3, 40.3, and 39.2 Torr. Alveolar-arterial PO2 di...
Serum amyloid A protein (SAA) in horses: objective measurement of the acute phase response. A sensitive and precise immunoassay for equine serum amyloid A protein (SAA) was established and used to determine, for the first time, the circulating concentration of this protein in health and disease. As in other species, equine SAA was present only at trace levels in healthy animals but behaved as an extremely sensitive and rapidly responding acute phase reactant following most forms of tissue injury, infection and inflammation, objectively reflecting the extent and activity of disease. Measurements of SAA should make a significant contribution to diagnosis and management of viral and bac...
Equine zygomycosis caused by Conidiobolus lamprauges. A 15-year-old Arabian mare from southern Louisiana with a 2-month history of periodic epistaxis and severe weight loss had a large, fibrosing, granulomatous mass containing numerous nodules ("kunkers") projecting dorsally into the nasopharynx, and was euthanized at the owner's request. In addition to these kunkers, the mass contained a single trematode tentatively identified as Fasciola hepatica. Several kunkers were removed, washed thoroughly in sterile water and embedded in nutrient agars; the fungus that grew out of them was identified as Conidiobolus lamprauges Drechsler (Entomophthorales:...
Evaluation of total plasma bile acid concentrations for the diagnosis of hepatobiliary disease in horses. Plasma bile acid concentrations were measured in normal horses. There was no diurnal variation in values, and age and sex had no effect. There was no significant difference between serum and plasma bile acid concentrations in clinically normal horses. Plasma bile acids were stable on storage for one month at -20 degrees C. The total plasma bile acid concentrations together with total and direct bilirubin concentrations and plasma activities of aspartate aminotransferase, glutamate and iditol dehydrogenase were evaluated in horses with various types of hepatobiliary disease (hepatic necrosis, l...
Androgen and oestrogen response to a single injection of hCG in cryptorchid horses. Androgen (testosterone and androstenedione) and oestrogen (oestradiol -17 beta and oestrone) concentrations were measured by radio-immunoassay in the peripheral plasma of two geldings (five-years-old), three bilateral cryptorchids (two, two and a half, and five-years-old) and three normal intact stallions (four, five and five and a half-years-old) before and after a single injection of 10,000 iu human chorionic gonadotrophin (hCG). In the stallions, hCG administration resulted in an immediate sharp increase of conjugated oestrogens and a more gradual increase of unconjugated androgens. In the ...
Analysis of N-acetyl-4-O-acetylneuraminic-acid-containing N-linked carbohydrate chains released by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. Application to the structure determination of the carbohydrate chains of equine fibrinogen. The carbohydrate chains of equine fibrinogen were enzymatically released by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. The oligosaccharides obtained were fractionated by a combination of FPLC and HPLC and analyzed by 500-MHz 1H-NMR spectroscopy. Four monosialo and four disialo diantennary N-acetyllactosamine type of carbohydrate chains occur: (formula; see text)
Thyroid hormone periodicity in healthy adult geldings. Serum samples were collected from 10 healthy geldings every 4 h for three consecutive days and the triiodothyronine (T3) and thyroxine (T4) concentrations determined by radioimmunoassay. There were significant differences in the hormone concentrations related to time. The mean (+/- sd) T3 concentration peaked around 08.00 h at a level (54.06 +/- 14.02 ng/dl) significantly (P less than .001) higher than the lowest concentration (38.71 +/- 10.81 ng/dl) around midnight. Although the highest mean T3 level was 08.00 h, this value was not significantly different from the noon and 16.00 h levels. Lik...
Osteochondral fragments within the dorsal pouch or dorsal joint capsule of the proximal intertarsal joint of the horse. The anatomy of the dorsal pouch of the proximal intertarsal joint (PIJ) and its communication with the tarsocrural joint (TCJ) was studied in 15 pairs of hocks from young and mature horses. The mediolateral length of the TCJ-PIJ fenestration was 14 to 29 mm. The potential volume of the dorsal pouch of the PIJ was 3 to 5 ml, and a recess extended 10 to 28 mm medial to the medial commissure of the TCJ-PIJ fenestration. In a correlated clinical study, osteochondral fragments were identified radiographically within the dorsal pouch (category 1) or dorsal joint capsule (category 2) of the PIJ in 17...
Immunoglobulin lambda-light-chain-derived amyloidosis (A lambda) in two horses. Tumorous amyloid deposits in the nasal mucosa of two horses differed from generalized AA-amyloidosis with respect to clinical features, organ distribution, and resistance to KMnO4 treatment. Using a panel of antibodies directed against different human amyloid fibril proteins and employing the peroxidase-anti-peroxidase (PAP) technique, we showed the described equine amyloid to be A lambda-type, as demonstrated by immunohistochemical cross-reactivity. Consequently, we identified a second amyloid class in horses and showed that immunoglobulin light-chain-derived amyloid may also be present in an...
[Ruminal 15N-straw degradation in sacco and the in vivo digestibility of 15N from straw in the sheep and pony]. The nylon-bag method was applied for determination of the rumen degradation of dry matter and nitrogen of 15N-labelled wheat straw. For the experiment 4 wethers fitted with a rumen cannula were used. The bags containing 15N straw were introduced into the rumen and withdrawn 3, 6 or 12 h after incubation. In a second experiment the apparent 15N-digestibility of the same straw was determined in wether and pony. The dry matter disappearance varied between 6 and 23%. For 15N-labelled straw the disappearance of 15N was higher than that of total N. 12 h after incubation 71% of 15N and only 25% of to...
Determination of methandrostenolone and its metabolites in equine plasma and urine by coupled-column liquid chromatography with ultraviolet detection and confirmation by tandem mass spectrometry. Monitoring steroid use requires an understanding of the metabolism in the species in question and development of sensitive methods for screening of the steroid or its metabolites in urine. Qualitative information for confirmation of methandrostenolone and identification of its metabolites was primarily obtained by coupled-column high-performance liquid chromatography-tandem mass spectrometry. The steroids and a sulphuric acid conjugate were isolated and identified by their daughter ion mass spectra in the urine of both man and the horse following administration of methandrostenolone. Spontaneo...
An intersex horse with X chromosome trisomy. An X-trisomy has been detected in an intersexuality Spanish-bred horse by using G- and C-banding methods. The external characteristics and the behavioural and physiological irregularities of the horse are described. This is the first time that an association between an X-trisomy and a case of intersexuality has been reported in any domestic animal.
[Contagious equine metritis in The Netherlands]. Contagious Equine Metritis (CEM) was detected in the Netherlands for the first time in 1987. A total number of five mares (Dutch saddle-horse) were infected in three separate outbreaks. The origin of the infection could not be determined in any of the cases. As the isolates of the causal organism, Taylorella equigenitalis, showed auto-agglutination, diagnosis was difficult. Therefore, an indirect immune fluorescence test as used to diagnose the second isolate. Five strains were isolated, which all were resistant to streptomycin. The prevalence of CEM since 1981 is summarised. The importance of...
Antigenic relationship between Pythium insidiosum de Cock et al. 1987 and its synonym Pythium destruens Shipton 1987. Antigens and rabbit-antisera from holotypes of Pythium insidiosum and P. destruens were prepared to elucidate their antigenic relationship. The antigens and rabbit-antisera of P. insidiosum as well as P. destruens used as a reference system showed that both shared three precipitin bands in common. The antigen and rabbit-antisera of P. destruens and P. insidiosum used as a reference system against other strains isolated from humans and animals with pythiosis, also showed three precipitin bands in common. When we used sera taken from horses with proven pythiosis against antigens of P. insidiosum...
