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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.
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.
Effect of high volume epidural morphine, ketamine and butorphanol on halothane minimum alveolar concentration in ponies. This study determined the effects of epidurally administered morphine, ketamine and butorphanol on halothane minimum alveolar concentration (MAC) in ponies. Seven ponies were anaesthetised with thiopentone and succinylcholine, intubated and anaesthesia maintained with halothane. Ventilation was controlled and blood pressure was maintained within normal limits. Following the determination of baseline halothane MAC for the pelvic and thoracic limbs the ponies were given morphine (0.1 mg/kg bwt), ketamine (0.8 or 1.2 mg/kg bwt), butorphanol (0.05 mg/kg bwt) or saline, epidurally, to a final volum...
Developmental variation in lumbosacropelvic anatomy of thoroughbred racehorses. To describe the incidence and types of gross osseous developmental variations and ages of physeal closure in the caudal portion of the thoracic and lumbosacral spine and the pelvis in a sample of Thoroughbred racehorses. Methods: Thoroughbred racehorses (n = 36) that died or were euthanatized at California racetracks between October 1993 and July 1994. Methods: Lumbosacropelvic specimens were collected, and all soft tissues were removed. The osseous specimens were visually examined. Results: Only 22 (61%) specimens had the expected number of 6 lumbar and 5 sacral vertebrae. Eight (22%) specime...
Multiple vertebral osteochondrosis in a foal. No abstract available
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 ...
Superficial digital flexor tendonitis in thoroughbred race horses: outcome following non-surgical treatment and superior check desmotomy. This study documents the results of non-surgical treatment and treatment by superior check desmotomy in Thoroughbred racehorses with superficial digital flexor (SDF) tendonitis. Methods: A prospective study was made of 124 thoroughbred racehorses with unilateral or bilateral SDF tendonitis. Methods: The flexor tendons were assessed by physical and ultrasonographic examination before treatment, and the lesions detected in affected tendons were characterised according to lesion type, length and cross-sectional area. Ninety three horses were managed non-surgically and 31 by superior check desmoto...
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 ...
Effects of intravenous administration of sodium hyaluronate on carpal joints in exercising horses after arthroscopic surgery and osteochondral fragmentation. To evaluate the effects of arthroscopic surgery, osteochondral fragmentation, and treatment with IV administered hyaluronate on histologic, histochemical, and biochemical measurements within the carpal joints of horses. Methods: 12 clinically normal horses, 2 to 7 years of age. Methods: Horses had an osteochondral fragment created at the distal aspect of the radiocarpal bone of 1 randomly chosen middle carpal joint to simulate osteochondral fragmentation. Horses were treated with 40 mg of hyaluronate or saline solution (placebo) intravenously once a week for 3 consecutive weeks (days 13, 20, a...
Characterisation of equine matrix metalloproteinase 2 and 9; and identification of the cellular sources of these enzymes in joints. The cellular production by resident articular cells and infiltrating inflammatory cells of the gelatinase matrix metalloproteinases (MMP) was investigated by tissue culture methods and analysis of cell supernatants by gelatin zymography. Peripheral blood neutrophils in short term culture produced MMP-9, as did peripheral blood monocytes in culture. Isolated articular chondrocytes in monolayer culture produced both MMP-2 and MMP-9, although articular cartilage maintained as explant culture produced MMP-2 alone. Synovial fibroblasts grown in monolayer culture produced MMP-2 alone, although synov...
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...
Interspecific and extraspecific pregnancies in equids: anything goes. Equids possess the unusual ability to interbreed freely among the phenotypically and karyotypically diverse member species of the genus to produce viable, but usually infertile, offspring. The mule (female horse x male donkey) was humanity's first successful attempt at genetic engineering and its clear expression of both parental phenotypes has contributed much to our understanding of genetic inheritance over the centuries. Even more surprising, mares and donkeys have been shown to be capable of carrying to term a range of true, xenogeneic extraspecies pregnancies created by embryo transfer, i...
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...
Light microscopy of the enteric nervous system of horses with or without equine dysautonomia (grass sickness): its correlation with the motor effects of physostigmine. Light microscopy was undertaken on sections from the caudal flexure of the duodenum and the terminal ileum proximal to the ileocaecal fold in 5 control horses, 5 horses with acute grass sickness (AGS), and 5 horses with chronic grass sickness (CGS). With the exception of the ileal submucous plexus of the CGS group, the AGS group had the lowest number of neurons as measured using a subjective scoring scheme. The proportion of abnormal neurons in the AGS group was similar in both plexuses and both regions, whereas the values for the CGS group were much higher in the duodenal region than in the i...
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...
Effect of acepromazine and butorphanol on halothane minimum alveolar concentration in ponies. The effect of i.v. acepromazine (0.05 mg/kg bwt), butorphanol (0.05 mg/kg bwt) and a combination of acepromazine and butorphanol on halothane minimum alveolar concentration (MAC) was determined in 7 mixed-breed ponies. Ventilation was controlled, and blood pressure and temperature were maintained within normal limits. Following the determination of baseline MAC, treatments were administered to each pony in a random manner. The control treatment was normal saline. The baseline halothane dMAC for the control group was 0.91 +/- 0.04%, and no significant change occurred after saline administration...
Bacterial endocarditis in horses: ten cases (1984-1995). A retrospective study of 10 horses with bacterial endocarditis was performed in order to describe the echocardiographic findings in horses with bacterial endocarditis, in conjunction with clinical signs and post mortem findings, and to evaluate the usefulness and the formulation of a prognosis. Echocardiographic and post mortem examinations were performed in 7 horses. Post mortem examination alone was performed in 2 horses and echocardiographic examination alone performed in one horse. No breed or sex predilection was obvious. Mean age +/- s.d. was 2.12 +/- 3.32 years. Predominant clinical sig...
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...
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...
Mechanisms of echinocytosis induced by Crotalus atrox venom. Transient echinocytosis has been reported in association with snake envenomation in humans and dogs. An in vitro model of echinocytosis induced by venom of crotalus atrox (western diamondback rattlesnake) was established to characterize erythrocyte morphologic changes and to investigate potential mechanisms of echinocytic transformation. Erythrocyte morphologic changes produced after the addition of venom to canine, feline, equine, and human blood were characterized by dose-dependent echinocytosis. Type III echinocytosis were consistently induced in vitro at a dose comparable to in vivo enveno...
Estimation of performance potential of standardbred trotters from blood lactate concentrations measured in field conditions. The purpose of this study was to examine the relationship between V4 (velocity which results in a blood lactate concentration of 4 mmol/l), age and racing performance of Standardbred trotters and to establish V4 normal values to select good and poor performers. The specific influence of racing (RT) and training (T1 and T2) tracks was also examined. A total of 159 horses were divided into 5 age-groups from 2 to 6 and over and performed 330 standardised exercise tests of 3 steps performed at increasing speeds. The velocity of the horses was measured with a tachometer on the sulky. Blood lactate ...
