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Topic:Veterinary Research
Veterinary research in horses encompasses the study of diseases, health management, and medical treatments specific to equine species. This field investigates various aspects of horse health, including infectious diseases, metabolic disorders, and musculoskeletal conditions. Researchers focus on understanding the pathophysiology of equine ailments, developing diagnostic tools, and evaluating therapeutic interventions. The study of horse health also involves examining preventive measures such as vaccination protocols and nutritional management to promote overall well-being. This page collects peer-reviewed research studies and scholarly articles that explore the diverse areas of veterinary science related to horses, providing insights into disease mechanisms, treatment strategies, and advancements in equine healthcare.
Mitogenic effects of epidermal growth factor and platelet-derived growth factor on canine and equine mesangial cells in vitro. To evaluate the effects of epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) on canine and equine mesangial cell (MC) proliferation in vitro. Methods: Third- through eighth-passage canine and equine MC were obtained from explant outgrowth after differential sieving of glomeruli isolated from the kidneys of clinically normal dogs and horses. Methods: Mitogenic effects of serum, insulin, EGF, and PDGF were evaluated in MC by induction of DNA synthesis, measured as stimulation of [3H]thymidine incorporation and increase in cell numbers. Results: Epidermal growth factor was a...
Hemagglutination with equine arteritis virus. Equine arteritis virus (EAV) grown on RK13 cell cultures was tested for hemagglutination (HA) with erythrocytes from a variety of species at 4 degrees C, room temperature and 37 degrees C. HA was observed at all temperatures with erythrocytes from mouse and chicken but not with those of cattle, horse, rabbit, guinea pig, mongolian gerbil, goose or chick embryo. Chickens showed an individual variation in agglutinability of their erythrocytes, requiring selection of birds to obtain erythrocytes for HA. The HA activity was enhanced by treatment of virus materials with Tween 80 followed by treatme...
Effects of high-dose gentamicin sulfate on neuromuscular blockade in halothane-anesthetized horses. To evaluate effects of a single high dose of gentamicin on neuromuscular function in horses anesthetized with halothane. Methods: 6 healthy adult horses. Methods: Halothane-anesthetized horses were positioned in left lateral recumbency, and the right hind limb was immobilized in a reusable fiberglass cast fixed to a steel frame. The hoof was attached to a force transducer, and resting tension of 0.93 +/- 0.16 kg was maintained. A supramaximal train-of-four stimulus of 2 Hz for a duration of 0.25 millisecond was applied to the superficial peroneal nerve every 20 seconds by a square-wave stimula...
Risk factors associated with musculoskeletal injuries in Australian thoroughbred racehorses. Risk factors for musculoskeletal injury in racing Thoroughbreds were investigated in a case-control study conducted at racetracks administered by the Australian Jockey Club. Univariable analysis of 137 cases from the official Veterinary Surgeon's reports and an equal number of randomly selected controls from the Australian Race Results identified field size, barrier position and class of race as being significantly associated with breakdown (P < 0.05). Multiple logistic regression was then used to investigate the effect of each putative risk factor whilst controlling for all others. Horses at ...
Effects of various feeding regimens on the energy balance of equine neonates. To determine the effect of diet on energy intake, loss, and metabolism in foals 2 to 7 days old. Methods: 14 pony foals. Methods: Group-A foals suckled their dams, group-B foals were fed milk replacer, and group-C foals were fed by total parenteral nutrition (TPN). Energy balance studies were performed over 8-hour periods on postpartum days 2, 4, and 7. Results: Mean gross energy (GE) intake of group-A foals increased between days 2 and 7. Approximately 3% of GE was excreted in urine and feces, and energy expenditure remained constant. These foals were in positive energy balance, and mean body...
Pharmacokinetics of intravenous and intragastric cimetidine in horses. I. Effects of intravenous cimetidine on pharmacokinetics of intravenous phenylbutazone. Cimetidine was administered intravenously and by the intragastric route to six mares at a dose of 4.0 mg/kg of body weight (bw). Specific and sensitive high performance liquid chromatographic methods for the determination of cimetidine in horse plasma and urine and cimetidine sulfoxide in urine are described. Plasma cimetidine concentration vs. time data were analysed by non-linear least squares regression analysis to determine pharmacokinetic parameter estimates. The median (range) plasma clearance (Cl) was 8.20 (4.96-10.2) mL/min.kg of body weight, that of the steady-state volume of distribu...
Comparative morphometry of coxal joint angles. The angles related to the coxal joints were comparatively studied in four-limbed walking animals and two-limbed ones including man and birds. Between animals with both types of walking, no significant difference was observed in the neck-shaft angles (NSA), which was equivalent to the acetabulum angles (ACA) at the connection of the femoral head with the acetabulum. The anteversion angles (AVA) were equivalent to the horizontal ACA. Canine species showed two different forms of the femoral neck with or without modification by the femoral AVA, probably being breed-specific and nutrition-dependent...
Hypereosinophilia in a horse with intestinal lymphosarcoma. Paraneoplastic eosinophilia is reported in dogs, cats, and humans. Hypereosinophilia (an eosinophil count greater than 1.5 x 10(9) L) is often associated with metastasis and a poor prognosis. This report describes a case of paraneoplastic hypereosinophilia in a pony. Neoplasia should be included in the differential diagnoses in a horse with eosinophilia.
The equine immune response to endometrial cups. Out of all the areas of comparative immunological study in the horse, the field of reproductive immunology has proven to be one of the most fertile and exciting. Maternal immunological interactions with the fetus involve a set of events which prevent maternal rejection of trophoblastic tissue invading the uterus, and at the same time control this invasion to regulate growth and prevent damage to maternal tissues. Unique features of equine placentation make it exceptionally well-suited to studying these immunological interactions.
Development and characterization of an equine behaviour chamber and the effects of amitraz and detomidine on spontaneous locomotor activity. This report describes the development of a behaviour chamber and the validation of the chamber of measure locomotor activity of a horse. Locomotor activity was detected by four Mini-beam sensors and recorded on a data logger every 5 min for 22 h. Horses were more active during daytime than in the evening, which was at least partially related to human activity in their surroundings. To validate the ability of the chambers to detect changes in activity, fentanyl citrate and xylazine HCl, agents well-characterized as a stimulant and a depressant, respectively, were administered to five horses. Fe...
Cartilage canals in equine articular/epiphyseal growth cartilage and a possible association with dyschondroplasia. Cartilage canals have been described in most mammals and contain the vascular elements necessary for the maintenance of epiphyseal growth cartilage. The presence and longevity of cartilage canals in developing articular/epiphyseal cartilage of horses is described for the first time. Growth cartilages from 30 normal horses (from 130 days gestation to age 2 years) and 6 cases of dyschondroplasia (age 6 months. Cartilage canals were associated with retained cartilage of dyschondroplastic lesions found in animals age < 15 months. The presence of cartilage canals in association with dyschondrop...
An introduction to mammalian interspecific hybrids. Haldane's law states that in interspecific hybrids, it is the heterogametic sex that is likely to be absent, rare, or sterile. In mammals, there is increasing evidence to suggest that this may be due to the high mutation rate of male sex-determining genes on the Y chromosome. The mule, humanity's first successful attempt at genetic engineering, provides some support for this concept. Interspecific hybrids may also shed new light on the importance of the maternal transmission of mitochondrial DNA and the phenomenon of genomic imprinting.
Pharmacokinetics of enrofloxacin in horses after single intravenous and intramuscular administration. Pharmacokinetic behaviour of enrofloxacin was studied in 6 horses after intravenous (i.v.) or intramuscular (i.m.) administration of enrofloxacin (5 mg/kg bwt). Concentration of enrofloxacin and ciproflaxin were measured by high performance liquid chromatography in serum. Antimicrobial activity of the samples was determined with an agar-diffusion technique. Reactions at the site of i.m. injection were monitored clinically and by determination of serum creatine kinase (CK) activity. After i.v. administration, elimination half-life of enrofloxacin was 4.4 h and volume of distribution was 2.3 1/k...
Flow cytometric method for detecting thiazole orange-positive (reticulated) platelets in thrombocytopenic horses. To evaluate a method for detecting thiazole orange-positive (TO+, reticulated) platelets in equine blood, using flow cytometry. Methods: 16 healthy, equine infectious anemia virus (EIAV)-negative horses and ponies; 9 thrombocytopenic, EIAV-positive horses and ponies; and 2 thrombocytopenic, EIAV-negative horses. Methods: Blood from healthy and thrombocytopenic horses was collected by jugular venipuncture. Appropriate sample requirement and incubation time for the assay were evaluated, using blood anticoagulated with EDTA or sodium citrate, or platelet-rich plasma in sodium citrate. The sample ...
The effect of pulsatile gonadotropin-releasing hormone and estradiol administration on luteinizing hormone and follicle-stimulating hormone concentrations in pituitary stalk-sectioned ovariectomized pony mares. Hourly pulses of gonadotropin-releasing hormone (GnRH) or bi-daily injections of estradiol (E2) can increase luteinizing hormone (LH) secretion in ovariectomized, anestrous pony mares. However, the site (pituitary versus hypothalamus) of positive feedback of estradiol on gonadotropin secretion has not been described in mares. Thus, one of our objectives involved investigating the feedback of estradiol on the pituitary. The second objective consisted of determining if hourly pulses of GnRH could re-establish physiological LH and FSH concentrations after pituitary stalk-section (PSS), and the th...
Measurement of total body water content in horses, using deuterium oxide dilution. To measure total body water (TBW) content in horses, using deuterium oxide (D2O) dilution. Methods: Six 8- to 10-year-old healthy untrained mixed-breed horses, weighing (mean +/-SD) 503.4 +/- 64.0 kg. Methods: After a 12-hour nonfeeding period, 6 horses were given D2O (0.14 g/kg of body weight) via nasogastric tube. Blood samples were collected from a preplaced indwelling jugular vein catheter prior to and 1 to 8, 10, 12, 14, and 24 hours after administration of D2O. Blood samples were centrifuged immediately, and plasma was collected and stored at -70 C until analysis. The D2O content in plas...
Extraction and quantification of acrosin, beta-N-acetylglucosaminidase, and arylsulfatase-A from equine ejaculated spermatozoa. Acrosin, Arysulfatase A, and beta-N-acetylglucosaminidase are three key enzymes localized within the mammalian acrosome that play a pivotal role in the penetration of the oocyte. The objectives of this study were to compare two methods of enzyme extraction based on the activities of these enzymes from equine spermatozoa. Method A utilized a 0.5 M Tris-maleate buffer containing 0.1% Triton X-100 and Hyamine 2389. Method B used 0.05 M Tris-HCl, 0.05 M MgCl2 in 0.05 M Tris-maleate, followed by 0.05 M Tris-maleate containing 0.1% Triton X-100. Results indicated that acrosin was initially bound in ...
Aerosol deposition in equine lungs following ultrasonic nebulisation versus jet aerosol delivery system. Therapeutic aerosols pay an increasing role in the treatment of equine respiratory disorders. This route of delivery permits concentration of significant amounts of drugs at the site of action without unwanted high systemic concentration and resultant side effects. The efficiency of such a topical therapy depends on the quantity of inhaled drugs deposited in the lungs and, for some drugs, on the proportion retained in specific parts of the lungs. The objective of this study was to define and to compare quantitative (dose deposited) and qualitative (regional distribution) deposition of an aeros...
Matrix metalloproteinases 2 and 9 in equine synovial fluids. Matrix metalloproteinases (MMPs) may be important in the destruction of cartilage seen in equine osteoarthritis and may be detectable in synovial fluid. Synovial fluids were obtained from normal equine joints and from joints of horses with aseptic and septic joint diseases. The total MMP gelatinase enzyme activities were measured by gelatin zymography and image analysis of the gels. The bioactivity of gelatinase in synovial fluid was determined by a gelatin degradation ELISA. Potential MMP-2 & MMP-9 monomer enzyme activities were significantly elevated in both septic and aseptic joint dise...
Failure of lipopolysaccharides to directly trigger the chemiluminescence response of isolated equine polymorphonuclear leukocytes. Divergent results have been reported on the effects of lipopolysaccharides (LPS) on the activation of equine polymorphonuclear leukocytes (PMN). We therefore attempted to determine whether LPS alone can stimulate equine PMN or whether plasma factors are necessary. PMN were isolated from citrated blood on a discontinuous density gradient of Percoll. The luminol (10(-3) mol/L)-enhanced chemiluminescence (CL) of 1.25 x 10(6) cells was measured after addition of Escherichia coli LPS (0.001-10 micrograms/ml) alone or after incubation in autologous plasma (1 h, 37 degrees C). After direct stimulatio...
Role of endothelium and nitric oxide in the in vitro response of equine colonic venous rings to vasoconstrictor agents. To determine in vitro contractile responses of equine colonic veins to various vasoconstrictor agents. Methods: Colonic veins collected from 8 adult horses. Methods: Veins were cut into 4-mm-wide rings, placed in organ baths at 37 C, and attached to a force-transducer interfaced with a polygraph; 2 g of tension was applied, and rings were allowed to equilibrate for 45 minutes. Bath solution was replaced, and tension was reapplied at 15-minute intervals. Cumulative concentration responses (10(-8) to 10(-4) M) were determined for each agent, using separate rings (n = 8). Three vein groups were e...
Preliminary study of ovarian activity in fillies treated with a GnRH vaccine. To investigate the effects of two doses (200 and 400 mg) of a water-soluble gonadotrophin-releasing hormone vaccine on the ovarian activity of 2-year-old fillies. Methods: A controlled vaccination dose rate experiment. Methods: Six 2-year-old Australian Stock Horse fillies were randomly allocated to three treatment groups; unvaccinated controls, those receiving 200 mg of the vaccine and those receiving 400 mg of the vaccine. Results: Ovarian activity of the treated fillies was suppressed at the peak of breeding season while that of untreated controls continued normally. The control fillies dis...
