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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.
Antibody response to Ehrlichia risticii and antibody reactivity to the component antigens in horses with induced Potomac horse fever. The antibody response and the antibody reactivity to component antigens of Ehrlichia risticii were studied in horses with induced Potomac horse fever. These horses had no detectable antibodies to E. risticii in their preinoculation (PrI) sera by indirect fluorescent-antibody assay and enzyme-linked immunosorbent assay (ELISA). All the horses exhibited typical disease features following experimental infection and responded with specific antibodies, as measured by ELISA and indirect fluorescent-antibody assay. A primary antibody response was detected in 70% of the horses, while a secondary-type ...
[Minimum health and sexual requirements for breeding stallions]. The rules for the minimal requirements in health and genital potency for stallions formulated by GOTZE (1950) are reformulated, taking into consideration the results achieved by KLUG (1982) and KENNEY (1983). A stallion must be free of phenotypic hereditary faults. Furthermore he has to be in general and genital health and must be fit in both, potentia coeundi and generandi. The figures are based on the examination of thoroughbred and so called "warmblood" stallions. However, they can be adapted to other breeds like draughthorses and ponys.
Cecal torsion in a horse as a consequence of cecocolic fold hypoplasia. Cecal torsion in horses is relatively rare. This clinical report describes cecocolic fold hypoplasia, producing increased cecal mobility, as a predisposing cause of cecal torsion in a horse.
Chronic ileocecal intussusception in horses. Ten young horses with signs of simple partial obstruction of the small intestine were found upon surgical exploration of the abdomen to have chronic intussusception of the distal ileum into the cecum. Poor general physical condition, intermittent or continual abdominal pain of varying degree, depression, and poor appetite were consistent clinical findings. Rectal palpation in eight animals was suggestive of an incomplete or intermittent obstruction of the small intestine. Laboratory determinations were not helpful in making a diagnosis. Dilatation and hypertrophy of the distal jejunum and ileu...
Difference in content ratio of components among horse serum transferrin variants. Each of five genetic variants of horse serum transferrin (Tf), D, F, H, O, and R, was separated into two bands by polyacrylamide gel isoelectric focusing (PAGIEF). The more acidic band, termed component a, was more abundant than the other one, termed component b, in all variants. Components a and b of TFO variant were immunologically indistinguishable from each other by double immunodiffusion test. Determination of the content ratio of component a to component b in each variant revealed that the variants were classified into two groups: one group (D, F, and H) had a relatively high ratio withi...
Leptospira abortion in horses. Leptospira infection was diagnosed as the cause of 4 late-term equine abortions/stillbirths and 1 neonatal death in Louisiana. The most consistent gross and microscopic lesions were icterus and interstitial nephritis, respectively. Diagnoses were based on visualization of compatible spirochetes in Warthin-Starry-stained sections of kidney, liver, and placenta. Confirmation by immunofluorescence was made in 2 cases.
Molecular confirmation of an abortigenic strain of equine herpesvirus 1 (subtype 1) in a pregnant mare study. Four pregnant mares were inoculated intranasally and/or intravenously with equine herpesvirus 1 (EHV-1), subtype 1 during the third trimester of gestation. One mare aborted on postinfection day 15, one mare delivered a sick, weak full term foal, and two mares delivered healthy, full term foals. EHV-1, subtype 1 was isolated from several tissues of the aborted fetus and from the thymus of the sick foal. DNA restriction endonuclease patterns of the recovered EHV-1 viruses were identical to those of the EHV-1 challenge strain, documenting the origin of the abortigenic viruses.
Urinary eCG patterns in the mare during pregnancy. Blood and urine samples collected from 12 mares at frequent intervals from 25 to 210 d of pregnancy were analyzed for equine chorionic gonadotropin (eCG). Blood and urine samples were collected daily through two consecutive ovulatory periods from five cyclic mares for comparative purposes. Separate radioimmunoassays (RIA) were developed to detect eCG in the urine and plasma. A simple and quick commercial dipstick enzyme-linked immunospecific assay (ELISA), developed for eCG in the blood, was also utilized in this study to detect eCG in the urine. In the 12 pregnant mares, eCG concentrations in...
Effects of polymyxin B on selected features of equine carbohydrate overload. Gram negative endotoxins play a contributory role in the syndrome which results from over consumption of carbohydrates by horses and ponies. Since the antibiotic polymyxin B exerts a direct anti-endotoxin effect by chemically modifying the active lipid A moiety of endotoxin, it might be expected to protect horses after carbohydrate overload and provide a new therapeutic and experimental tool for this condition. The present study was undertaken to evaluate the effect of polymyxin B on hemostatic, hemodynamic, acid-base, and clinical aspects of the syndrome resulting from carbohydrate overload. ...
A retrospective study of nineteen ataxic horses. A retrospective study of 19 ataxic horses admitted to the College of Veterinary Medicine of the University of Montreal during the period of January 1985 to December 1988 is presented. There were 11 cases of cervical vertebral malformation, four of equine degenerative myeloencephalopathy, two of equine protozoal myeloencephalitis, one each of vertebral osteomyelitis and intervertebral disc protrusion. The clinical diagnosis of ataxia in horses requires neurological, radiographic, myelographic, and laboratory examinations.
Transcervical embryo transfer in performance mares. Pregnancy was established by transcervical transfer of embryos from performance mares into recipient mares. Estrus was synchronized between donor (n = 17) and recipient (n = 43) mares. After a greater than or equal to 25-mm follicle was detected, donor mares were bred artificially daily until ovulation. Day of ovulation was recorded. Uterine flushes (n = 111) were performed on donor mares 7 days after ovulation, and recovered embryos were transferred transcervically to recipient mares within 2 hours. Embryos were recovered from 40.5% of uterine flushes. Of transferred single embryos, 65.7% res...
Ovarian function in captive feral mares. Ovarian function was monitored for 33 mo in captive feral mares (Equus caballus) by following serum progesterone (P) levels. A P level greater than 2.0 ng/ml was considered indicative of ovulation. Feral mares were seasonally polyestrus with the majority of animals ovulating between May and October. During the first year after capture, none of the mares ovulated during the anestrous season. However, in subsequent years, approximately 10% of mares ovulated during the months of November, January and February. P levels during the luteal phase of the cycle ranged from 2.0 to 21.0 ng/ml which were ...
Effect of probenecid administration on cephapirin pharmacokinetics and concentrations in mares. Cephapirin (20 mg/kg of body weight, IV) was administered before and after 3 doses of probenecid (25, 50, or 75 mg/kg, intragastrically, at 12-hour intervals) to 2 mares. Clearance and apparent volume of distribution, based on area under the curve, were negatively correlated with probenecid dose. Clearance of cephapirin was decreased by approximately 50% by administration of 50 mg of probenecid/kg. Serum, synovial fluid, peritoneal fluid, CSF, urinary, and endometrial concentrations of cephapirin were determined after 5 doses of cephapirin (20 mg/kg, IM, at 12-hour intervals) without and with ...
Complications of a permanent transvenous pacing catheter in a horse. Gross and histopathological findings in a 9-year-old horse implanted with permanent transvenous pacing cardiac catheters, 18 and 34 months before its death, are described. Lesions consisting of extensive fibrino-haemorrhagic thrombi with large numbers of bacterial colonies were present along the electrode wires and on mural and valvular endocardial surfaces of the right heart. There was a locally extensive area of suppurative endocarditis around the attachment site of the atrial electrode, which was loosely attached by a thin band of membranous tissue to the endocardium. The ventricular electr...
Transrectal ultrasonography of the cranial mesenteric artery of the horse. Transrectal ultrasonography was performed on the cranial mesenteric artery and its major branches in 23 conscious adult horses. Ultrasonographically, 25 arterial segments were classified as either normal or abnormal. These ultrasonographic classifications were later compared with the gross and histologic evaluations of each artery following necropsy of each horse. In this study, transrectal ultrasonography as a diagnostic test for verminous arteritis had a 90% sensitivity for detecting normal arteries and an 86% specificity for detecting abnormal arteries, suggesting that ultrasonography may b...
Breed, age, and gender differences in plasma antithrombin-III activity in clinically normal young horses. Plasma antithrombin-III activity was quantitated in plasma samples obtained from 165 clinically normal horses 3 years old or younger. In the horses as a group, antithrombin-III activity ranged from 63 to 131% of a species-specific reference plasma. Thoroughbred horses had significantly higher antithrombin-III activity (103.3 +/- 18.3; mean +/- SD) than did Standardbred horses (92.3 +/- 14.2). The plasma antithrombin-III activities were significantly lower in horses younger than 16 months old when compared with those in more mature horses (3 years old). There was no statistically significant ge...
The effects of cervical dilation on plasma PGFM, progesterone and the duration of luteal function in diestrous mares. Transcervical diagnostic techniques may alter the length of the equine estrous cycle and affect subsequent luteal function. Therefore, nine mares were used to determine the effect of cervical dilation on plasma 13, 14-dihydro, 15-keto-prostaglandin F(2) (PGFM), progesterone (P(4)) and posttreatment duration of luteal function. Mares were given a daily score of 0 to 4 based on sexual receptivity. Five days following the end of receptivity, mares were randomly assigned to one of three, 3 x 3 latin squares. Control mares received no cervical dilation. Cervically stimulated mares recieved cervical...
Pasteurella caballi, a new species from equine clinical specimens. The name Pasteurella caballi is proposed for a group of organisms represented by 29 strains isolated from respiratory and other infections in horses. P. caballi strains are gram-negative, oxidase-positive, nonmotile, fermentative rods with the key characteristics of the genus Pasteurella. These strains differed from other Pasteurella species in that all were aerogenic and catalase negative, and some strains produced acid from myo-inositol and L-rhamnose. The levels of DNA relatedness of 28 P. caballi strains with labeled DNA from the proposed type strain averaged 91 and 85% (hydroxyapatite met...
Cantharidin content of two species of Oklahoma blister beetles associated with toxicosis in horses. Cantharidin content of male and female Epicauta occidentalis and E conferta was determined. Aspects of the life cycle of blister beetles, taxonomy, pheromonal and adaptive functions of cantharidin relative to the medico-legal aspects of cantharidin poisoning, prevention and control in horses are discussed.
Growth performance of yearling horses grazing bermudagrass pastures at different grazing pressures. Body weight gains and height at the withers were measured in yearling geldings grazing bermudagrass (Cynodon dactylon [L.] Pers.) pastures with neither energy nor protein feed supplementation at stocking rates of 6.7, 8.0, 9.5 and 12.4 yearlings per hectare. Weekly forage samples were taken to estimate the quantity and quality of available forage. These samples were clipped and separated into three equal lengths to characterize upper, middle and lower thirds of the canopy and to determine relationships between available forage and yearling growth rate. Average daily gain was influenced by stoc...
Epithelium- and mucosa-dependent relaxation and contraction of normal equine trachealis muscle in vitro. Strips of trachealis muscle were dissected from the mid-cervical portion of the trachea from horses that were free of respiratory tract disease. The epithelium and mucosa were removed from one group of tissues and were left intact in a second group of tissues. Each tissue was suspended in a bath filled with Krebs-bicarbonate solution that was aerated with 5% CO2 in oxygen and maintained at 37 degrees C. Isometric tension was continuously recorded. The contractile response to square-wave electrical stimulations increased as frequency (3, 5, 10, 15, 20, 25, and 30 Hz), voltage (10, 15, 18, and 2...
Seasonal translation of equine strongyle infective larvae to herbage in tropical Australia. Longevity in faeces, migration to and survival on herbage of mixed strongyle infective larvae (approximately 70% cyathostomes: 30% large strongyles) from experimentally deposited horse faeces was studied in the dry tropical region of North Queensland for up to 2 years. Larvae were recovered from faeces deposited during hot dry weather for a maximum of 12 weeks, up to 32 weeks in cool conditions, but less than 8 weeks in hot wet summer. Translation to herbage was mainly limited to the hot wet season (December-March), except when unseasonal winter rainfall of 40-50 mm per month in July and Augus...
Neochondrogenesis in free intra-articular, periosteal, and perichondrial autografts in horses. Periosteal autografts were obtained from the medial aspect of the proximal portion of the tibia, and perichondrial autografts were obtained from the sternum. Using arthroscopic visualization, each autograft was placed as a loose body into 1 tarsocrural joint in 6 young horses (2 to 4 years old). Horses were hand-walked daily, starting the day after surgery, for a total of 6 h/wk for 8 weeks. Eight weeks after autograft implantation, radiographs were taken of each tarsocrural joint and were interpreted with regard to mineralization in the transplanted autografts. Autografts were then surgically...
Changes in articular cartilage after intra-articular injections of methylprednisolone acetate in horses. Eight mature horses with no prior signs of joint disease or history of intra-articular therapy were treated with 8 weekly intra-articular injections of methylprednisolone acetate. Treatments were given at a dose of 120 mg/joint into the right radiocarpal and intercarpal joints, with the left joints as untreated controls. Articular cartilage samples were obtained at necropsy 1, 4, and 8 weeks after the last injection. Compared with controls, cartilage from injected joints had a loss of hematoxylin basophilia and decreased intensity of staining in safranin O fast green dye. Chondrocyte necrosis ...
Isoproterenol- and salbutamol-induced relaxation of acetylcholine- and histamine-induced contraction of equine trachealis muscle in vitro. Strips of trachealis muscle were dissected from the midcervical portion of the trachea of horses that were free of respiratory tract disease, and the overlying epithelium and mucosa were removed. Muscle strips were suspended in tissue baths that were filled with Krebs-bicarbonate solution, aerated with 5% CO2 in oxygen and maintained at 37 C. Isometric tension was continuously recorded. The increase in active isometric tension was concentration dependent when acetylcholine (10(-9) to 10(-4) M) or histamine (10(-9) to 10(-4) M) was added to the tissue baths in 0.5-logarithmic increments. When t...
Potential of infra-red thermography for the detection of summer seasonal recurrent dermatitis (sweet itch) in horses. The feasibility of using infra-red thermography for early and out of season detection of summer seasonal recurrent dermatitis (sweet itch) was tested on 13 sensitive and six insensitive horses in Israel. In summer (June, July and September) six affected mares and two unaffected sensitive mares (one of them a pony) were clearly 'warmer' in the affected zones than three insensitive mares. In winter (February and March) unaffected sensitive horses could be differentiated from insensitive mares by the warm areas detected in the affected zones. Small numbers of Culicoides imicola bites may have bee...
Comparison of the use of mass spectrometry and methylene unit values in the determination of the stereochemistry of estranediol, the major urinary metabolite of 19-nortestosterone in the horse. The stereochemistry of an isomer of 5-estrane-3,17 alpha-diol, the major metabolite of 19-nortestosterone in horse urine has been established by the use of methylene unit (MU) values. The empirical MU values of the bis-trimethylsilyl (TMS) derivatives of the eight available isomers of 5-androstane-3,17-diol and four isomers of 5-estrane-3,17 beta-diol were determined by capillary gas chromatography using three different columns. From this data the theoretical MU values for the bis-TMS derivatives of the four 5-estrane-3,17 alpha-diol isomers were predicted. Comparison of the experimentally det...
