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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.
Endotoxin induced expression of tumour necrosis factor, tissue factor and plasminogen activator inhibitor activity by peritoneal macrophages. Peritoneal fluid was collected aseptically from 30 healthy adult horses and 115 horses with acute gastrointestinal disease and supernatant was separated from cells by centrifugation followed by freezing until assayed for endotoxin and tumour necrosis factor activity. Peritoneal macrophages obtained from healthy horses were incubated in vitro for 3, 6, 12 or 24 h in the absence (media control) or presence of Escherichia coli 055:B5 endotoxin (final concentrations of 1, 10, 100 or 1000 ng/ml). Macrophages obtained from horses with acute gastrointestinal disease were incubated for 12 h in the abs...
Pulmonary blood flow distribution in standing horses is not dominated by gravity. Recent studies using microspheres in dogs, pigs and goats have demonstrated considerable heterogeneity of pulmonary perfusion within isogravitational planes. These studies demonstrate a minimal role of gravity in determining pulmonary blood flow distribution. To test whether a gravitational gradient would be more apparent in an animal with large vertical lung height, we measured perfusion heterogeneity in horses (vertical lung height = approximately 55 cm). Four unanesthetized Thoroughbred geldings (422-500 kg) were studied awake in the standing position with fluorescent microspheres injected ...
A retrospective evaluation of the surgical management of equine carpal injury. Records of 220 thoroughbred horses presented to the Randwick Equine Centre or the University of Queensland Veterinary Teaching Hospital for surgical management of carpal injury were reviewed. Details of racing performance were obtained, enabling evaluation of racing success following surgery. Age and sex matched control horses not known to have suffered carpal injury were selected from the Australian Stud Book and the Australian Racehorse Register. Control and treated populations were compared in terms of overall career racing success. Radiographs or xeroradiographs from 198 horses were availa...
Equine cytochrome P450 aromatase exhibits an estrogen 2-hydroxylase activity in vitro. Aromatase (estrogen synthetase) is a steroidogenic enzyme complex which catalyzes the conversion of androgens to estrogens (termed aromatization). This enzyme was purified from adult equine testis to homogeneity by five chromatographic steps. The ability of purified and reconstituted equine aromatase to exhibit an estrogen 2-hydroxylase activity was tested and compared to testosterone aromatization. Enzymatic activities were assessed by tritiated water release from labelled estradiol and testosterone. Kinetic analysis of estradiol 2-hydroxylation showed an apparent K(m) of 23 microM and a V(ma...
Effects of ozone and airway inflammation on glutathione status and iron homeostasis in the lungs of horses. To investigate the effects of ozone and airway inflammation on indices of oxidant injury in horses. Methods: 5 clinically normal horses and 25 horses referred for poor performance. Methods: Blood, tracheal wash, and bronchoalveolar lavage fluid samples were collected before and after ozone exposure (n = 5) or from clinical cases (n = 25), and were analyzed for reduced glutathione (GSH), glutathione disulfide (GSSG), and free and total iron (Fe) values. A scoring system (0 to 5) was used to assess airway inflammation on the basis of clinical signs and cytologic analysis of the tracheal wash and...
Prerace venous blood acid-base values in standardbred horses. The administration of sodium bicarbonate (NaHCO3) or 'milk shakes' to Standardbred horses before racing is widespread. This study analysed nonrace day (CTL) and prerace venous acid-base values from Standardbred horses racing in Pennsylvania (PA) and New Jersey (NJ). Mean +/- s.d. CTL bicarbonate (HCO3) and base excess (BE) values, for a group of horses stabled during the 1993 racing season at Pocono Downs, Pennsylvania, were 28.6 +/- 1.9 and 2.6 +/- 1.7 mmol/l, respectively. In the same population of horses, mean +/- s.d. values for prerace HCO3- and BE values were 33.1 +/- 2.8 and 7.0 +/- 2.3...
Effect of progesterone on prostaglandin F2 alpha secretion and outcome of pregnancy during cloprostenol-induced abortion in mares. To determine the role of progesterone in the regulation of endogenous prostaglandin F2 alpha (PGF2 alpha) secretion during cloprostenol-induced abortion and to investigate use of progestins to prevent prostaglandin-associated abortion. Methods: 16 pregnant mares. Methods: To induce abortion, cloprostenol (250 micrograms/d) was administered daily until fetal expulsion or for up to 5 days. In experiment 1, 8 mares, 98 to 153 days' pregnant, received progesterone (300 mg/d) at 24-hour intervals for 5 days, starting 18 hours after the first cloprostenol administration. In experiment 2, 8 mares, 93...
Magnetic motor evoked potentials in ponies. Magnetic stimulation of motor pathways was used to effect motor unit action potential recordings from forelimb and hindlimb muscles in unanesthetized ponies. Motor pathway conduction velocities to the forelimb and hindlimb were determined to be 53.8 +/- 9.6 m/s-1 and 63.4 +/- 8.3 m/s-1, respectively. This noninvasive technique will enable more precise evaluation of motor deficits in clinical patients than is possible with the neurological examination.
Effects of platelet activating factor on the distribution of radiolabelled leucocytes and platelets in normal horses and asymptomatic horses with chronic obstructive pulmonary disease. Antigen challenge is known to cause the recruitment of neutrophils to the lungs of horses with chronic obstructive pulmonary disease (COPD). To evaluate a possible role of platelet activating factor (PAF) in this process, the effects of PAF on the distribution of radiolabelled neutrophils were compared in normal horses and asymptomatic horses with COPD. Changes in lung function, heart rate and the distribution of platelets and eosinophils were also measured. PAF (5 ng kg-1 intravenously) caused immediate but transient increases in the number of radiolabelled neutrophils in the lungs and a conc...
A 16S rRNA-based PCR assay for detection and identification of granulocytic Ehrlichia species in dogs, horses, and cattle. A PCR-based assay was developed for detecting DNA of granulocytic ehrlichiae in blood samples from dogs, horses, and cattle, Primers were designed from 16S rRNA sequence information to specifically amplify DNA from a newly identified Swedish Ehrlichia species. The 16S rRNA nucleotide sequence of this Swedish species differs in only two and three positions from the sequences of Ehrlichia phagocytophila and Ehrlichia equi, respectively, which were also amplified by this PCR system. For evaluation, PCR results were compared with microscopic examination of stained blood smears for the detection of...
Use of a virulence-associated protein based enzyme-linked immunosorbent assay for Rhodococcus equi serology in horses. An enzyme-linked immunosorbent assay (ELISA) was developed against Rhodococcus equi using Triton X-114 detergent extracted whole cell material, in which the virulence associated protein (VapA) predominated. Enzymelinked immunosorbent assay titres corresponded to antibody reacting with VapA on Western blots. There was considerable variation in antibody titres of nonimmunised mares and in the time when the colostrally derived antibody of their foals had declined to low or undetectable titres. In general, antibodies in foals declined to their lowest levels at age 4-8 weeks. Seroconversion occurre...
Factors associated with gastric lesions in thoroughbred racehorses. Gastroscopic examinations were performed on 67 Thoroughbred horses in training at a race track and repeat examinations performed in 35 horses, 2 to 3 months later. Horses were age 2-9 years and included 16 two-year-olds, 32 three-year-olds and 19 horses > or = 4-years-old. Forty-two of the 67 horses had raced within the 2 months before the initial examination and the remaining 25 horses were in training. Sixty-two of the 67 horses (93%) had one or more lesions present in the gastric mucosa and lesions were present in all of the 42 horses that had raced. Thirty-two of the 35 horses, examined...
Calcium buffering is required to maintain bone stiffness in saline solution. This work determined whether mineral dissolution due to prolonged testing or storage of bone specimens in normal saline would alter their elastic modulus. In one experiment, small pieces of equine third metacarpal bone were soaked in normal saline supplemented with varying amounts of CaCl2. Changing Ca ion concentrations in the bath were monitored and the equilibrium concentration was determined. In a second experiment, the elastic moduli of twenty 4 x 10 x 100 mm equine third metacarpal beams were determined non-destructively in four-point bending. Half the beams were then soaked for 10 days ...
The structure of the community of strongyloid nematodes of domestic equids. The community structure exhibited by strongyloid nematodes from the large intestines of horses was examined using data from autopsies of 150 horses. Thirty-one species of nematodes were encountered, but they were not clearly divisible into core and satellite species. Multiple congeneric, consubfamilial and confamilial species were a prominent feature of the community and were more common than singleton infections. Multivariate analyses provided evidence of a stable community of helminths dominated by positive interactions but with few negative interactions, suggesting the absence of competitio...
Dopaminergic regulation of gonadotrophin secretion in seasonally anoestrous mares. We have previously demonstrated that daily administration of the dopamine D2 antagonist, sulpiride, during seasonal anoestrus, effectively advances the mean time of onset of the breeding season in mares. The purpose of this study was to examine the effect of sulpiride administration on pulsatile FSH and LH secretion in seasonally anoestrous mares, follicular development, time of first ovulation and the fertility at the first ovulation. Fourteen anoestrous mares were selected based on progesterone concentrations < 1 ng ml-1 for 3 weeks and largest follicle diameter < 20 mm. Starting 30 Ja...
Tumour suppressor gene p53 in the horse: identification, cloning, sequencing and a possible role in the pathogenesis of equine sarcoid. The tumour suppressor protein p53 enhances the genetic stability of the cell and plays a critical role in tumour suppression. Equine p53 was analysed by sequencing exons 5 to 9, a region which includes most known mutations and all the mutational hotspots in the species that have been investigated. The fragment was amplified, cloned and sequenced from genomic and complementary DNA. A comparison of the predicted amino acid sequences between the horse and other species resulted in identities between 66 per cent with the clawed frog and 92 per cent with the cat. Using the single strand conformatio...
Pharmacokinetics of ketoprofen in the donkey (Equus asinus). The pharmacokinetic parameters of ketoprofen were determined in four donkeys after a single intravenous injection of a dose of 2.2 mg/kg body weight. The total body clearance (ClB) was 414.0 +/- 98.70 ml/h/kg (mean +/- SD), the volume of distribution at steady state (Vss) 263.10 +/- 55.43 ml/kg and the elimination half-life 1.30 +/- 0.75 h. These values were compared to those obtained in horses.
A screening test for subclinical liver disease in horses affected by pyrrolizidine alkaloid toxicosis. To evaluate various biochemical tests as indicators of subclinical liver disease in horses exposed to pyrrolizidine alkaloid toxicosis. Methods: A clinical pathology field study. Methods: Twenty-two clinically normal horses from four properties in the Kimberley region of Western Australia. Methods: Serum samples from each horse were assayed for gamma glutamyltransferase, alkaline phosphatase and aspartate aminotransferase activities, and for serum bile acid concentration, albumin and total protein. Serum protein electrophoresis was performed and their amino acid profiles determined. Bromosulph...
Echinococcus granulosus in Spain: strain differentiation by SDS-PAGE of somatic and excretory/secretory proteins. A comparison was made, by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), of excretory/secretory (ES)-crude and immunopurified (with the corresponding anti-host serum) hydatid fluids-and somatic (S)-protoscoleces-proteins, from several ovine, equine, swine, bovine and human Echinococcus granulosus Spanish isolates. Likewise, the host influence on parasitic ES protein expression was studied, comparing purified hydatid fluids from ovine and equine cysts obtained from natural hosts and in RNMI mice. Purified hydatid fluids patterns, under reducing conditions, yielded the mos...
Development of a diagnostic DNA probe to detect Setaria digitata: the causative parasite of cerebrospinal nematodiasis in goats, sheep and horses. Two repetitive sequences (IpSdM and IpSdS) have been cloned and sequenced from the genome of Setaria digitata. When IpSdM (214 bp) and IpSdS (201 bp) were aligned, a high degree of homology (85%) was observed, indicating that they belong to the same family of repeats. IpSdM represents a complete repeating element while IpSdS consists of two partial repeating elements arranged in tandem. The elements are present in about 10 000 copies comprising 2.8% of the S. digitata genome. As a diagnostic probe IpSdM detects as little as 100 pg DNA of both S. digitata and S. labiato-papillosa. It can also d...
Suppression of testicular function using two dose rates of a reversible water soluble gonadotrophin releasing hormone (GnRH) vaccine in colts. To investigate the effect of two dose rates (200 and 400 ng) of a gonadotrophin releasing hormone (GnRH) vaccine on testicular function. Methods: A vaccination dose rate experiment. Methods: Two injections were administered 4 weeks apart to six colts in each treatment group. To maintain immunosuppression until the end of the breeding season, a third injection was given if antibody titres fell below 1000. Results: Effective antibody titres were present for 12 to 27 weeks. Testosterone concentrations decreased from 2.22 to 0.31 nmol/L 6 weeks after primary vaccination. Androstenedione concentrat...
Cardiopulmonary effects of desflurane in ponies, after induction of anaesthesia with xylazine and ketamine. Cardiopulmonary parameters were measured in 12 ponies (small horses) before anaesthesia and, following induction with xylazine and ketamine, during maintenance of anaesthesia with desflurane. In six of the ponies (group A) anaesthesia was maintained for three hours with desflurane at an end-tidal concentration of 7.4 per cent. In the other six ponies (group B), anaesthesia was maintained in the same way for one hour and then the effects of end-tidal desflurane concentrations of 7.4 per cent and 9.6 per cent with and without artificial ventilation were investigated. In group A ponies the arteri...
Risk factors associated with development of diarrhea in horses after celiotomy for colic: 190 cases (1990-1994). To determine the incidence of the risk factors for developing diarrhea in horses after celiotomy for colic. Methods: Retrospective cohort study. Methods: 357 adult horses that had celiotomy for colic at the teaching hospital between Jan 1, 1990 and Sep 1, 1994. Methods: Medical records of horses that had celiotomy for colic were reviewed to abstract information regarding development of diarrhea, signalment, history, and treatment. Results: In horses that had celiotomy for colic, the incidence of diarrhea was 53.2% (190/357). Using multiple logistic regression, horses with a disorder of the lar...
Fibronectin mRNA splice variant in articular cartilage lacks bases encoding the V, III-15, and I-10 protein segments. Fibronectin is an extracellular matrix glycoprotein encoded by a single gene. Alternative RNA splicing has been reported at three sites, ED (extra type III domain)-A, ED-B, and the variable or V region. Articular cartilage fibronectin monomers are rarely (ED-A)+, but approximately 25% are (ED-B)+. RNA gel electrophoresis and Northern blot analysis identified two (ED-B)+ and two (ED-B)- fibronectin transcripts in cartilage, each pair differing by approximately 750 bases. This difference results from a previously unreported RNA splicing pattern that eliminates not only the V region but also nucl...
Comparison of media and sera used for in vitro culture of equine superficial digital flexor tendon explants. To compare the effects of different commercial nutrient media and sera on protein synthesis and maintenance of cellular density in cultures of the equine superficial digital flexor tendon (SDFT). Methods: 8 healthy 2- to 4-year-old horses. Methods: First Dulbecco's modified Eagle's medium, Ham's F12 nutrient mixture, RPMI 1640 medium, minimum essential medium with Earle's salts, minimum essential medium with Hanks' salts, and a Dulbecco's modified Eagle's medium/Ham's F12 nutrient mixture with 10% fetal bovine serum (FBS) were compared. Then FBS, fetal equine serum, and donor horse serum, each...
