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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.
Lateralized suckling in domestic horses (Equus caballus). Brain lateralization enables preferential processing of certain stimuli and more effective utilization of these stimuli in either the left or the right cerebral hemisphere. Horses show both motor and sensory lateralization patterns. Our aim was to determine whether a lateralized response could be detected in foals during the naturally side-biased behaviour, suckling. The foals' preferred suckling side could be the effect of either visual or motor lateralization. In the case of a visual lateralized response, foals are expected to suck more often from the mother's right side, so potential danger...
Response to injection of the navicular bursa with corticosteroid and hyaluronan following high-field magnetic resonance imaging in horses with signs of navicular syndrome: 101 cases (2000-2008). To determine treatment outcome on the basis of pathological changes identified on MRI and lameness duration in horses with navicular syndrome that underwent injection of corticosteroid and hyaluronan into the navicular bursa. Methods: Retrospective case series. Methods: 101 horses with navicular syndrome. Methods: Medical records of horses with signs of navicular syndrome evaluated between January 2000 and December 2008 were reviewed. Data on signalment, use of the horse, history, affected limbs, duration of lameness, findings on lameness examination, radiographic findings, MRI findings, treat...
Perioperative risk factors for mortality and length of hospitalization in mares with dystocia undergoing general anesthesia: a retrospective study. This study investigated associations between perioperative factors and probability of death and length of hospitalization of mares with dystocia that survived following general anesthesia. Demographics and perioperative characteristics from 65 mares were reviewed retrospectively and used in a risk factor analysis. Mortality rate was 21.5% during the first 24 h post-anesthesia. The mean ± standard deviation number of days of hospitalization of surviving mares was 6.3 ± 5.4 d. Several factors were found in the univariable analysis to be significantly associated (P < 0.1) with increased prob...
An investigation of risk factors for foot-related lameness in a United Kingdom referral population of horses. Lameness relating to the foot of the horse is common, but the majority of information concerning risk factors for injury is anecdotal. The objectives of this study were to investigate risk factors for foot-related pain in a referral population of horses, with particular reference to injury/disease of the podotrochlear apparatus (PTA), by comparison with the remainder of the clinic population. It was hypothesised that there would be an increased risk of foot pain associated with breed, work discipline, age, height and bodyweight (BW). A retrospective study of all horses examined at a referral c...
Cardiotoxicity, inflammation, and immune response after rattlesnake envenomation in the horse. Cardiac abnormalities are reported in rattlesnake-bitten horses. The prevalence and cause are unknown. Objective: To detect cardiac damage in rattlesnake-bitten horses by measuring cardiac troponin I (cTnI) and evaluating ECG recordings for presence of arrhythmias, and explore causes of this cardiac damage by measuring venom excretion, anti-venom antibodies, and tumor necrosis factor alpha (TNFα). Methods: A total of 20 adult horses with a clinical diagnosis of rattlesnake bite and 6 healthy adult horses. Methods: In a prospective clinical study, bite site swabs, blood samples, and urine samp...
Stimulatory effect of PGF2α on PRL based on experimental inhibition of each hormone in mares. During the luteolytic period in mares, the peak of 65% of pulses of a PGF2α metabolite (PGFM) and the peak of a pulse of PRL have been reported to occur at the same hour. It is unknown whether the synchrony reflects an effect of PGF2α on PRL or vice versa. Controls, a flunixin meglumine (FM)-treated group (to inhibit PGF2α), and a bromocriptine-treated group (to inhibit PRL), were used at 14 days postovulation in June and in September (n = 6 mares/group/mo). Blood samples were collected hourly from just before treatment (Hour 0) to Hour 10. Concentrations of PGFM in the FM group were lower ...
Sex-dependent insulin like growth factor-1 expression in preattachment equine embryos. An adjustment of sex ratio of offspring to the conditions present at conception is seen in many mammals including horses. This depends on preferential survival of male embryos under conditions of high energy intake. In several species, growth factors including insulin like growth factor (IGF)-1 have been shown to promote embryonic development by decreasing apoptosis and increasing cell proliferation. We hypothesized that sex-related differences in IGF-1 expression in equine embryos during the phase of maternal recognition of pregnancy might exist and thus contribute to preferential survival of...
Evaluation of growth models for follicle development and ovulation in Lusitano mares. Several growth models are commonly used in the biological sciences, to model the follicle growth occurring in the estrous cycle. The aim of this project was to find the model that best fit the follicular size growth data for Lusitano mares. Retrospective data collected from reproduction book records of n=84 mares and n=124 cycles was used to find the series to be fitted to the models. The exponential, Gompertz, logistic, von Bertalanffy, Richards and Weibull models were used, and the most parsimonious and best fit was achieved with the logistic model (r(2)=0.999). The logistic model fits the L...
The effect of intravenous lidocaine infusion on bronchoalveolar lavage cytology in equine recurrent airway obstruction. Lidocaine decreases neutrophilic inflammation in models of acute lung injury and decreases inflammation in asthmatic patients. Neutrophilic bronchiolitis develops in recurrent airway obstruction (RAO), but it remains unknown if lidocaine infusion decreases neutrophil migration into the airways. Objective: Lidocaine decreases neutrophilic inflammation as measured in BALF in RAO-affected horses. Methods: Six RAO-susceptible horses in remission. Methods: In a randomized cross-over design, horses received lactated Ringer's solution (LRS) IV or lidocaine hydrochloride IV with a minimum of 4 weeks a...
The horse as a model of naturally occurring osteoarthritis. Osteoarthritis (OA) is an important cause of pain, disability and economic loss in humans, and is similarly important in the horse. Recent knowledge on post-traumatic OA has suggested opportunities for early intervention, but it is difficult to identify the appropriate time of these interventions. The horse provides two useful mechanisms to answer these questions: 1) extensive experience with clinical OA in horses; and 2) use of a consistently predictable model of OA that can help study early pathobiological events, define targets for therapeutic intervention and then test these putative thera...
Serum protein concentrations as predictors of serum immunoglobulin G concentration in neonatal foals. To determine the predictive value of serum concentrations of total protein (sTP), albumin (sAlb), and globulin (sGlob) measured by automated calorimetric assays to estimate serum immunoglobulin G (sIgG) concentrations in neonatal foals and identify failure of transfer of passive immunity when compared to turbidoimmunometric assay determinations of sIgG. Methods: Retrospective and prospective analysis of laboratory data. Methods: University tertiary care facility. Methods: Group 1 (retrospective): foals (n = 45) ≤7 days of age in which sIgG, sGlob, sAlb, and sTP concentrations were measured o...
Relationship of mixed bacterial infection to prognosis in foals with pneumonia caused by Rhodococcus equi. Isolation of multiple bacterial species is common in foals with Rhodococcus equi pneumonia. Objective: There is no association between isolation of other microorganisms and outcome. Methods: 155 foals with pneumonia caused by R. equi. Methods: Case records of foals diagnosed with R. equi pneumonia based on culture of the respiratory tract were reviewed at 2 referral hospitals (University of Florida [UF] and Texas A&M University [TAMU]). Results: R. equi was cultured from a tracheobronchial aspirate (TBA) in 115 foals and from lung tissue in 38 foals. Survival was significantly higher at UF...
Evaluation of growth models for follicle development and ovulation in Lusitano mares. Several growth models are commonly used in the biological sciences, to model the follicle growth occurring in the estrous cycle. The aim of this project was to find the model that best fit the follicular size growth data for Lusitano mares. Retrospective data collected from reproduction book records of n=84 mares and n=124 cycles was used to find the series to be fitted to the models. The exponential, Gompertz, logistic, von Bertalanffy, Richards and Weibull models were used, and the most parsimonious and best fit was achieved with the logistic model (r(2)=0.999). The logistic model fits the L...
An approach to imaging algorithms for equine lameness diagnosis. Tremendous growth and advancement in equine diagnostic imaging necessitates a systematic approach to the application of these modalities to lameness diagnosis. This systematic approach must include attention to the history, physical and clinical examinations, and parameters set forth by the client. It also must include an understanding of which imaging modality is most appropriate given the details of the case. This article presents a basic framework with an underlying algorithmic foundation that can be applied when selecting imaging modalities during lameness evaluation and includes case exam...
Epidemiological survey of the hoof wall cavity (‘Gidoh’ in Japanese) in racehorses. In October 2001, a survey was conducted about cavities formed within the hoof wall (called GIDOH in Japanese) of racehorses at the Ritto and Miho Training Centres, which are managed by the Japan Racing Association (JRA). Gidoh is defined as a progressive cavity within the deep layers between the stratum medium and stratum internum. A total of 148 out of 5386 surveyed horses (2.75 per cent) were affected. Out of 244 affected feet, fore hooves (84.02 per cent) were more susceptible than hind hooves, and the site most affected was midline dead centre of the toe (59.62 per cent) which tends to pla...
Use of intravenous gadolinium contrast in equine magnetic resonance imaging. The use of intravenous gadolinium contrast during equine magnetic resonance imaging (MRI) is a new technique that has been infrequently used in clinical imaging. This article describes the development of an effective contrast dose and the use of gadolinium contrast in clinical equine MRI. Gadolinium contrast improves lesion conspicuity across a broad range of lesion types. Contrast-enhanced MRI is potentially a valuable imaging tool in the assessment of the equine athlete.
Investigation of hydration processes of the equine hoof via nuclear magnetic resonance microscopy. To examine the distribution of water in hoof wall specimens of horses via nuclear magnetic resonance (NMR) microscopy and determine changes in water distribution during hydration. Methods: 4 hoof wall specimens (2 obtained from the dorsum and 1 each obtained from the lateral quarter and lateral heel regions) of the stratum medium of healthy hooves of 1 horse. Methods: Equine hoof wall specimens were examined via NMR microscopy. Proton density-weighted 3-D images were acquired. Changes during water absorption were assessed on sequential images. Results: The inner zone of the stratum medium had ...
Respiratory responses to exercise in the horse. Horses are elite athletes when compared with other mammalian species. In the latter, performance is limited by cardiovascular or musculoskeletal performance whereas in athletic horses it is the respiratory system that appears to be rate limiting and virtually all horses exercising at high intensities become hypoxaemic and hypercapnoeic. This is due to both diffusion limitation and a level of ventilation inadequate for the metabolic level that enables horses to exercise at these intensities. In conjunction with these blood gas changes, total pulmonary resistance increases and the work of breath...
Guttural pouch mycosis in horses: a retrospective study of 28 cases. The medical records of 28 horses with guttural pouch mycosis were reviewed. The most commonly observed clinical signs were nasal discharge, epistaxis, dysphagia and/or cough. All 28 horses had the disease unilaterally, however, in five of them, it had spread into the contralateral pouch via the mesial septum. Three horses were treated medically, 11 horses underwent surgery and seven horses were treated both medically and surgically. Fifty percent of horses (14/28) were euthanased or died, fifty percent of horses (14/28) survived. There was no significant correlation between treatment method (m...
Explaining spatial heterogeneity in population dynamics and genetics from spatial variation in resources for a large herbivore. Fine-scale spatial variation in genetic relatedness and inbreeding occur across continuous distributions of several populations of vertebrates; however, the basis of observed variation is often left untested. Here we test the hypothesis that prior observations of spatial patterns in genetics for an island population of feral horses (Sable Island, Canada) were the result of spatial variation in population dynamics, itself based in spatial heterogeneity in underlying habitat quality. In order to assess how genetic and population structuring related to habitat, we used hierarchical cluster analys...
Investigation of forelimb hoof wall strains and hoof shape in unshod horses exercised on a treadmill at various speeds and gaits. To investigate forelimb hoof wall strains and shape changes in unshod horses undergoing regular moderate exercise on a treadmill at selected speeds and gaits. Methods: 6 horses of various body types. Methods: Each horse was exercised on a treadmill (walking, trotting, and cantering, with or without galloping at 12.5 m/s) 3 times a week for 4 consecutive weeks; duration of each exercise session ranged from 10 to 14 minutes. During the 4-week period, the proximal hoof circumference (PHC) and toe angle (TA) of each forelimb hoof were measured weekly with a flexible measuring tape and a hoof gauge...
Mechanical and morphological properties of trabecular bone samples obtained from third metacarpal bones of cadavers of horses with a bone fragility syndrome and horses unaffected by that syndrome. To determine morphological and mechanical properties of trabecular bone of horses with a bone fragility syndrome (BFS; including silicate-associated osteoporosis). Methods: Cylindrical trabecular bone samples from the distal aspects of cadaveric third metacarpal bones of 39 horses (19 horses with a BFS [BFS bone samples] and 20 horses without a BFS [control bone samples]). Methods: Bone samples were imaged via micro-CT for determination of bone volume fraction; apparent and mean mineralized bone densities; and trabecular number, thickness, and separation. Bone samples were compressed to failur...
A predictive model for reproductive performance following abortion in Thoroughbred mares. Pregnancy losses include early embryonic death (EED) and later (postimplantation) abortion. Abortions, particularly Equid herpesvirus (EHV-1) abortion epizootics, cause severe economic and production losses. The long-term effects of EHV-1 and other abortions on subsequent reproductive performance in broodmare populations, however, remain undefined. This study described the relationships of EED and abortion with the following reproductive outcomes in Thoroughbred systems: breeding efficiency, month of last breeding, subsequent pregnancy and live foal rates. A prospective cohort study in broodma...
A review of recent advances and current hypotheses on the pathogenesis of acute laminitis. With the increasing number of studies being published on the different experimental models used to induce and study acute laminitis, the pathophysiological events associated with these various models (i.e. starch overload, oligofructose overload, black walnut extract and hyperinsulinaemia) can be compared more realistically. Within this review, the mechanisms for metabolic vs. inflammatory laminitis are discussed, and the question of how pasture laminitis may fit into any of the proposed mechanisms is addressed.
Genome-wide association study of insect bite hypersensitivity in two horse populations in the Netherlands. Insect bite hypersensitivity is a common allergic disease in horse populations worldwide. Insect bite hypersensitivity is affected by both environmental and genetic factors. However, little is known about genes contributing to the genetic variance associated with insect bite hypersensitivity. Therefore, the aim of our study was to identify and quantify genomic associations with insect bite hypersensitivity in Shetland pony mares and Icelandic horses in the Netherlands. Methods: Data on 200 Shetland pony mares and 146 Icelandic horses were collected according to a matched case-control design. C...
