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Topic:Equine Health
Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
Developmental changes in pulmonary and renal angiotensin-converting enzyme concentration in fetal and neonatal horses. Angiotensin-converting enzyme (ACE) has an active role in the control of blood pressure and body fluid homeostasis both before and after birth. This study investigated the ontogeny of pulmonary and renal ACE concentrations in fetal and neonatal horses. Fetal pulmonary ACE concentration increased from 250 days towards term (c. 335 days). Newborn foals showed significantly higher mean concentrations of pulmonary ACE (4.40 +/- 0.62 nmol min(-1) mg protein(-1)) than both fetuses during late gestation (1.23 +/- 0.51 nmol min(-1) mg protein(-1)) and animals aged 1 day to 2 weeks of postnatal age (0....
Comparative expression of liver cytochrome P450-dependent monooxygenases in the horse and in other agricultural and laboratory species. The apoprotein expression and the catalytic activities of cytochrome P450s involved in the biotransformation of xenobiotics were investigated in horse liver microsomes and compared with those of food producing (cattle, pigs, broiler chicks, and rabbits) and laboratory species (rats). Western blot analysis revealed the presence of proteins immunorelated to rat CYP 1A, CYP 2B, CYP 2E, and CYP 3A subfamilies in hepatic microsomes from horses and from any other examined species. With the exception of the N-demethylation of N-nitrosodimethylamine in broiler chicks, all the recorded interspecies dif...
Characterization of equine cDNA sequences for alphaS1-, beta- and kappa-casein. Here we report the entire cDNA sequences for equine alphaS1-, beta- and kappa-casein. Based on interspecies comparison, nine exons were found in equine beta-casein and five in kappa-casein. In equine alphaS1-casein cDNA the exon 5 was missing, which resulted in the total of 18 exons instead of 19 theoretically possible exons in alphaS1-casein cDNA. Comparison of DNA sequences representing exon 5 in other species with corresponding equine genomic region confirmed the presence of cryptic exon in horse genomic DNA. Equine alphaS1-casein mRNA was present in three forms in the lactating mammary gla...
The Australian paralysis tick may be the missing link in the transmission of Hendra virus from bats to horses to humans. Hendra virus is a new virus of the family Paramyxoviridae. This virus was first detected in Queensland, Australia, in 1994; although, it seems that the virus has infected fruit-eating bats (flying-foxes) for a very long time. At least 2 humans and 15 horses have been killed by this virus since it first emerged as a virus that may infect mammals other than flying-foxes. Hendra virus is thought to have moved from flying-foxes to horses, and then from horses to people. There is a reasonably strong hypothesis for horse-to-human transmission: transmission of virus via nasal discharge, saliva and/or...
Analysis of atresia in equine follicles using histology, fresh granulosa cell morphology and detection of DNA fragmentation. Follicular atresia has been examined previously by various biochemical and histological methods. The aim of this study was to compare, for the first time, detection of granulosa cell apoptosis by biochemical DNA analysis and microscopic examination of fresh granulosa cell morphology with the established method of detecting atresia by histology in equine follicles. DNA extracted from granulosa cells was examined by staining with ethidium bromide and end-labelling with [(32)P]dideoxy-ATP, which labels the free 3'-end of DNA fragments. In 25 of 26 follicles (96%) there was agreement between end-l...
Dose-dependent effects of corticosteroids on the expression of matrix-related genes in normal and cytokine-treated articular chondrocytes. To assess the effects of glucocorticoids on the expression of multiple matrix-related genes in normal and cytokine-treated cultured equine articular chondrocytes in a phenotypically correct suspension culture. Methods: Articular cartilage harvested from the joints of 15 foals, 7 yearling horses, and 16 adult horses. Methods: Glucocorticoids (dexamethasone, prednisolone, triamcinolone) at 10(-10) to 10(-4) M. Methods: Equine articular chondrocytes maintained in suspension cultures were treated with glucocorticoids with and without human recombinant interleukin 1-beta (IL1-beta) and tumor necros...
Arterial hypoxemia in exercising thoroughbreds is not affected by pre-exercise nedocromil sodium inhalation. It has been reported that pulmonary injury (i.e. capillary stress failure) evoked histamine release from airway inflammatory/mast cells contributes to exercise-induced arterial hypoxemia (EIAH) and that pre-exercise inhalation of nedocromil sodium mitigated EIAH in human subjects 'Med. Sci. Sports Exercise 29, (1997) 10-16'. Because exercise-induced pulmonary hemorrhage due to capillary stress failure is routinely observed in racehorses, we examined whether nedocromil inhalation would similarly benefit EIAH and desaturation of hemoglobin in horses. Two sets of experiments, namely, placebo stud...
[Rayer’s studies on the contagion of glanders (1837-1843)]. P. Rayer (1795-1867) had never thoroughly published his experimental studies on the contagion of glanders. His recently un-earthed hand written papers allow us to depict his experimental approach and its results. He was not the first who transmitted glanders from a patient to horses or donkeys. But he did it systematically with glander secretions from acute and chronic cases. Whatever was the disease of the donors the transmitted forms were unpredictably either chronic or acute. His conclusion was that the two forms were two symptomatic aspects of a unique disease. Clinically dormant states we...
UV measurements in microplates suitable for high-throughput protein determination. An UV spectrophotometric method for protein determination using microplates is described. Using the SPECTRAmax PLUS reader, the UVStar 96- and 384-well microplates and a 96 or 384 parallel channel liquid handling technique, large-scale determinations can be performed with intraassay precision better than 3% CV (coefficient of variation) in the range from 1 to 8000 microg of protein/ml, measuring at 205, 215, and 280 nm and using different volume-dependent light-path lengths. Since the absorbance coefficient at 205 nm is found to be 30 ml/(mgxcm) for eight different proteins with a CV of 5.6% o...
Hysteresis and calcium set-point for the calcium parathyroid hormone relationship in healthy horses. Abnormalities in calcium (Ca(2+)) homeostasis are reported in horses with several pathological conditions; however, there is little information on Ca(2+) regulation in horses. The objectives of the present study were to determine the Ca(2+) set-point in healthy horses, to determine whether the Ca(2+)/parathyroid hormone (PTH) response curves were characterized by hysteresis, and to determine if the order of experimentally induced hypocalcemia or hypercalcemia had an effect on PTH secretion. The Ca(2+) set-point and hysteresis were determined in 12 healthy horses by infusing Na(2)EDTA and calci...
A mutation in the MATP gene causes the cream coat colour in the horse. In horses, basic colours such as bay or chestnut may be partially diluted to buckskin and palomino, or extremely diluted to cream, a nearly white colour with pink skin and blue eyes. This dilution is expected to be controlled by one gene and we used both candidate gene and positional cloning strategies to identify the "cream mutation". A horse panel including reference colours was established and typed for different markers within or in the neighbourhood of two candidate genes. Our data suggest that the causal mutation, a G to A transition, is localised in exon 2 of the MATP gene leading to an...
Antifungal agents of use in animal health–practical applications. The purpose of this paper is to provide an overview of antifungal agents currently in use in veterinary medicine. The practical applications and the therapeutic regimens that have proved successful in the treatment and prevention of fungal infections in dogs and cats, cattle and sheep, horse, pig, poultry and other birds, rodents, rabbits and fur animals are summarized.
Comparison of electroacupuncture and butorphanol on respiratory and cardiovascular effects and rectal pain threshold after controlled rectal distention in mares. To compare effects of electroacupuncture and butorphanol on hemodynamic and respiratory variables and rectal analgesia in mares after controlled rectal distention. Methods: 8 healthy mares. Methods: Each horse received saline (0.9% NaCl) solution (0.01 mL/kg, IV; control treatment), butorphanol tartrate (0.1 mg/kg, IV), or 2 hours of electroacupuncture (EA) at acupoints Bladder 21, 25, and 27 on both sides of the vertebral column, Bai hui, and Stomach 36 (right side only). Order of treatments in each mare was randomized. At least 7 days elapsed between treatments. A balloon was inserted in the...
Equine amplification and virulence of subtype IE Venezuelan equine encephalitis viruses isolated during the 1993 and 1996 Mexican epizootics. To assess the role of horses as amplification hosts during the 1993 and 1996 Mexican Venezuelan equine encephalitis (VEE) epizootics, we subcutaneously infected 10 horses by using four different equine isolates. Most horses showed little or no disease and low or nonexistent viremia. Neurologic disease developed in only 1 horse, and brain histopathologic examination showed meningeal lymphocytic infiltration, perivascular cuffing, and focal encephalitis. Three animals showed mild meningoencephalitis without clinical disease. Viral RNA was detected in the brain of several animals 12-14 days after...
Interactions of morphine and isoflurane in horses. To quantitate dose- and time-related magnitudes of interactive effects of morphine (MOR) and isoflurane (ISO) in horses and to characterize pharmacokinetics of MOR in plasma and the ventilatory response to MOR during administration of ISO. Methods: 6 adult horses. Methods: Horses were anesthetized 3 times to determine the minimum alveolar concentration (MAC) of ISO in O2 and then to characterize the change in anesthetic requirement as defined by the alteration in ISO MAC following IV administration of saline (0.9% NaCl) solution and 2 doses of MOR (low dose, 0.25 mg/kg; high dose, 2.0 mg/kg). ...
Effect of aerosolized albuterol sulfate on resting energy expenditure determined by use of open-flow indirect calorimetry in horses with recurrent airway obstruction. To evaluate effects of sedation on stability of resistance of the respiratory system (RRS) and measures of resting energy expenditure (REE) by use of open-flow indirect calorimetry (IC) and treatment with aerosolized albuterol on REE in horses with recurrent airway obstruction (RAO). Methods: 9 clinically normal horses and 8 horses with RAO. Methods: In phase 1, RRS was measured by using forced oscillometry (FOT) in 5 clinically normal horses before and after sedation with xylazine. In phase 2, REE was measured in 4 clinically normal horses between 20 and 25 minutes and again 35 to 40 minutes ...
Antagonism of adenosine receptors by caffeine and caffeine metabolites in equine forebrain tissues. To determine the presence of adenosine receptor subtypes A1 and A2a in equine forebrain tissues and to characterize the interactions of caffeine and its metabolites with adenosine receptors in the CNS of horses. Methods: Brain tissue specimens obtained during necropsy from 5 adult male research horses. Methods: Membrane-enriched homogenates from cerebral cortex and striatum were evaluated by radioligand binding assays with the A1-selective ligand [3H]DPCPX and the A2a-selective ligand [3H]ZM241385. Functional responses to adenosine receptor agonists and antagonists were determined by a nucleot...
Detection of papillomavirus-DNA in mesenchymal tumour cells and not in the hyperplastic epithelium of feline sarcoids. We examined 12 formalin-fixed paraffin-embedded feline skin tumours which had the histopathological features of fibropapillomas for the presence of papillomavirus (PV) DNA using touchdown polymerase chain reaction (PCR), DNA sequencing and nonradioactive in situ hybridization. Nine of the tumours contained a 102-bp PCR product demonstrated using consensus PV primers that amplify a portion of the L1 gene. The nucleotide sequences are closely related, but not identical to that of ovine PV type 2, rabbit oral PV and reindeer PV. The deduced amino acid sequences had strong homologies with the majo...
Epidemiologic study of results of pulsed-field gel electrophoresis of isolates of Rhodococcus equi obtained from horses and horse farms. To compare isolates of Rhodococcus equi on the basis of geographic source and virulence status by use of pulsed-field gel electrophoresis (PFGE). Methods: 290 isolates of R equi (218 virulent isolates from foals and 72 avirulent isolates from feces, soil, and respiratory tract samples) obtained between 1985 and 2000 from horses and horse farms from 4 countries. Methods: DNA from isolates was digested with the restriction enzyme Asel and tested by use of PFGE. Products were analyzed for similarities in banding patterns by use of dendrograms. A similarity matrix was constructed for isolates, and...
A serological survey of Rhodococcus equi infection in foals in central Italy: comparison of two antigens using an ELISA test. A serological survey of Rhodococcus equi infection was carried out on 602 blood samples collected from foals in central Italy. The assay was performed with an ELISA test using two different antigens prepared with reference strains of R. equi, ATCC 33071 and ATCC 6939. A positive reaction was obtained on 81 serum samples (13.45%) (OD > or = 0.3) using antigen ATCC 33071, and on 73 serum samples (12.12%) using antigen ATCC 6939. Although the frequency of the disease was not high, the serological positivity was about 13%. There was no statistically significant difference between males and fema...
Determination of ‘irritant’ threshold concentrations for intradermal testing with allergenic insect extracts in normal horses. Sixteen healthy horses with no history of skin or respiratory disease were used for an intradermal testing (IDT) threshold study, in order to determine the concentrations of 13 commercial allergenic insect extracts most appropriate for IDT. Five dilutions of each extract were used, which included the manufacturer's recommended concentrations for equine IDT, plus one dilution higher and three lower than these standard concentrations. Allergens tested included caddisfly (Trichoptera spp.), mayfly (Ephemeroptera spp.), horsefly (Tabanus spp.), deerfly (Chrysops spp.), fire ant (Solenopsis invicta...
Identification of sperm subpopulations with specific motility characteristics in stallion ejaculates. The aim of this study was to test the presence of separate sperm subpopulations, with specific motility characteristics, in stallion ejaculates by using a computer-assisted semen motility analysis (CASA) system. Motility data were analyzed with a hierarchical clustering of variables based on a correlation or covariance matrix to select like parameters of sperm motility descriptors that better explain the kinetics of spermatozoa. The statistical analyses clustered the whole motile sperm population in both fresh and 24 h stored ejaculates into four separate groups. There were significant differe...
Stress fractures of the tibia and humerus in Thoroughbred racehorses: 99 cases (1992-2000). To determine clinical characteristics of and outcome in Thoroughbred racehorses with tibial or humeral stress fractures. Methods: Retrospective study. Methods: 99 Thoroughbreds with tibial or humeral stress fractures. Methods: Information obtained from the medical records included history, signalment, and clinical, radiographic, and scintigraphic findings. Outcome was determined by interviewing trainers, performing follow-up examinations, and analyzing race records. Results: Seventy-four tibial stress fractures were identified in 61 Thoroughbreds, and 48 humeral stress fractures were identifie...
Evaluation of equine breeding farm management and preventative health practices as risk factors for development of Rhodococcus equi pneumonia in foals. To determine whether foal management practices, environmental management, and preventative health practices are risk factors for development of Rhodococcus equi pneumonia in foals. Methods: Prospective matched case-control study. Methods: 2,764 foals on 64 equine breeding farms with 9,991 horses. Methods: During 1997, participating veterinarians completed paired data collection forms for comparison; 1 for an affected farm (containing > or = 1 foal with pneumonia caused by R equi) and 1 for a control farm. Information collected pertained to stabling facilities, environmental management, foal hu...
Malignant Sertoli cell tumor in the retained abdominal testis of a unilaterally cryptorchid horse. A 13-year-old Morgan gelding was evaluated because of a mass in the caudal region of the abdomen. The horse had been presumed to be a gelding, but necropsy findings revealed a retained testis in the right retroperitoneal space. Histologically, the retained testis contained neoplastic cells; metastases were identified in the liver, spleen, lungs, and sublumbar lymph nodes. Immunohistochemical examination of the testis and metastatic tissues confirmed the diagnosis of malignant Sertoli cell tumor. Testicular neoplasms are infrequently reported in stallions. Seminomas are most commonly reported, ...
Evaluation of equine breeding farm characteristics as risk factors for development of Rhodococcus equi pneumonia in foals. To identify farm characteristics as risk factors for the development of Rhodococcus equi pneumonia in foals. Methods: Prospective matched case-control study. Methods: 2,764 foals on 64 equine breeding farms with 9,991 horses. Methods: During 1997, participating veterinarians completed paired data collection forms, 1 for a farm with > or = 1 foal with R equi pneumonia and 1 for an unaffected control farm. Matched data were compared by use of conditional logistic regression analysis. Results: Farm characteristics found in bivariate analyses to be associated with increased risk for pneumonia caus...
Venezuelan equine encephalitis virus-vectored vaccines protect mice against anthrax spore challenge. Anthrax, a disease usually associated with herbivores, is caused by the bacterium Bacillus anthracis. The current vaccine licensed for human use requires a six-dose primary series and yearly boosters and causes reactogenicity in up to 30% of vaccine recipients. A minimally reactogenic vaccine requiring fewer inoculations is warranted. Venezuelan equine encephalitis (VEE) virus has been configured for use as a vaccine vector for a wide variety of immunogens. The VEE vaccine vector is composed of a self-replicating RNA (replicon) containing all of the VEE virus nonstructural genes and a multiple...
Molecular cloning, nucleotide sequence and presence of multiple functional polyadenylation signals in the 3′-untranslated region of equine dopamine beta-hydroxylase cDNA. Complementary DNA (cDNA) encoding equine dopamine beta-hydroxylase (DBH) was amplified with a combination of reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) method, and their nucleotide sequences (Accession No. AB029430: the DDBJ nucleotide sequence database) was determined. A total of 3842 bp cDNA sequence was consisted with 5 bp of 5' flanking untranslated sequence, 1833 bp of open reading frame encoding 610 amino acids, and 2004 bp of 3' flanking untranslated sequence. The deduced amino acid sequence of equine DBH was very similar to the ...
Investigations into the biosynthetic pathways for classical and ring B-unsaturated oestrogens in equine placental preparations and allantochorionic tissues. In on-going studies of 'classical' and ring B-unsaturated oestrogens in equine pregnancy, the products of metabolism of [2,2,4,6,6-2H(5)]-testosterone and [16,16,17-2H(3)]-5,7-androstadiene-3 beta,17 beta-diol with equine placental subcellular preparations and allantochorionic villi have been identified. Using mixtures of unlabelled and [2H]-labelled steroid substrates has allowed the unequivocal identification of metabolites by twin-ion monitoring in gas chromatography-mass spectrometry (GC-MS). Two types of incubation were used: (i) static in vitro and (ii) dynamic in vitro. The latter invol...
