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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.
Reticulocyte changes after experimental anemia and erythropoietin treatment of horses. Availability of recombinant human erythropoietin (EPO) has facilitated use to enhance red blood cell production, and therefore aerobic performance, in human and equine athletes. Recombinant human EPO promotes growth and differentiation of equine erythroid precursor cells, but in some horses repeat administration induces immune interference with endogenous EPO resulting in fatal anemia. Although blood reticulocyte parameters acquire unique changes in humans treated with EPO, with manual enumeration methods, horses were not considered to release reticulocytes from the bone marrow into circulatio...
Carpal collateral ligament desmopathy in three horses. The radiographic and ultrasonographic findings in three horses with severe damage to the collateral ligaments of the carpus, associated with degenerative joint disease, are described. The horses remained lame despite prolonged rest and medical management, primarily because of the progression of the joint disease. Ultrasonography was found to be an accurate method for diagnosing the injury to the ligaments and is recommended as part of a routine examination in suspected carpal injuries.
IgA Fc receptors in cattle and horses. The biological role of IgA depends, at least partly, on the interaction with specific receptors (FcalphaRs) on the surface of leukocytes. The human FcalphaR, CD89, was the first IgA Fc receptor to be identified, and binding of IgA-coated particles to CD89 triggers numerous cellular effector functions including phagocytosis, antibody-dependent cell-mediated cytotoxicity (ADCC), and release of inflammatory mediators. Recently, CD89 orthologs have been identified in a number of other species, including cows and horses. This brief review will summarize our current knowledge regarding the structure...
Temporal regulation of cytokine mRNA expression in equine recurrent airway obstruction. Acute and chronic inflammation of the airway remains an important health problem for equids. "Heaves" or recurrent airway obstruction (RAO) remains one of the most commonly diagnosed conditions affecting the lung of older horses in Europe and the United States. The typical clinical signs of RAO include non-productive coughing, serous nasal discharge, labored expiratory effort, and flaring of the nostrils. Auscultation of the lungs of the affected horse often reveals abnormal respiratory sounds, described as crackles and wheezes, throughout the area of the lung field. These clinical signs occur...
Phylogenetic relationships of Sarcocystis neurona of horses and opossums to other cyst-forming coccidia deduced from SSU rRNA gene sequences. Phylogenetic analyses based on sequences of the nuclear-encoded small subunit rRNA (ssurRNA) gene were performed to examine the origin, phylogeny, and biogeographic relationships of Sarcocystis neurona isolates from opossums and horses from the State of Michigan, USA, in relation to other cyst-forming coccidia. A total of 31 taxa representing all recognized subfamilies and genera of Sarcocystidae were included in the analyses with clonal isolates of two opossum and two horse S. neurona. Phylogenies obtained by the four tree-building methods were consistent with the classical taxonomy based on ...
[The issue of continuity in ancient horse medicine: the treatment of diseases of the extremities described in the Kităb al-furŭsĭya wa-l-baytara by Muhammad ibn Ya’qŭb ibn ahĭ Hizăm al-Huttulĭ]. Since the late 9th century, scientific literature in Arabian language, based on the translation and compilation of works of the Classical, Persian and Indian culture considerably increased. This also applies to the field of veterinary medicine, as is illustrated by a number of hippological and hippiatric treatises. Affinities between texts on horse medicine in Antiquity and in Arabian literature have been mentioned by philologists, but the degree of dependence on classical texts could not be verified due to the lack of translations of the Arabian texts. In this respect, the oldest available te...
Hemangiosarcoma in 11 young horses. Hemangiosarcoma is a rare neoplasm of horses and hemangiosarcoma in young horses might behave differently than in mature horses. The purpose of this study was to identify the characteristics of hemangiosarcoma occurring in horses < or = 3 years of age. Medical records from 1982 to 2004 were searched for horses < or = 3 years of age with a histopathologic diagnosis of hemangiosarcoma. Eleven records were identified. Thoroughbred and Thoroughbred crosses predominated. Age ranged from 9 days to 3 years. All horses presented with cutaneous or leg swellings or joint effusion. Physical examina...
Accuracy of indirect measurement of blood pressure in neonatal foals. The objectives of this study were to assess, in anesthetized neonatal foals, the accuracy of 2 automated indirect oscillometric monitors for measurement of mean arterial pressure (MAP), to determine the optimal site of cuff placement for MAP monitoring, and to determine the relationship between arterial blood pressure and cardiac output. Ten neonatal foals were anesthetized and instrumented with a catheter in the metatarsal artery for direct MAP monitoring and measurement of cardiac output by lithium dilution. Concurrent MAP measurements were obtained with Cardell and Dinamap oscillometric mon...
Biochemical markers of cardiac injury in normal, surviving septic, or nonsurviving septic neonatal foals. The cardiac biomarkers cardiac troponin T (cTnT) and I (cTnI) and the cardiac isoenzyme of creatine kinase (CKMB) are used extensively in human medicine to diagnose and provide valuable prognostic information in patients with ischemic, traumatic, and septic myocardial injury. We designed a study to establish normal values for these markers in healthy, neonatal foals and to compare them with values obtained from septic neonates in a referral hospital population. The 25th, 50th, 75th, and 95th percentiles for cTnI and CKMB in the healthy-foal population were 0.08, 0.14, 0.25, 0.49 ng/mL and 1.4,...
Analysis of yearly changes in levels of antibodies to Japanese encephalitis virus nonstructural 1 protein in racehorses in central Japan shows high levels of natural virus activity still exist. Recent reductions in numbers of human and equine Japanese encephalitis (JE) cases in Japan have seen calls to end JE vaccination. Here, we analyzed yearly variations of natural JE virus activity, using sera collected serially in 1998-2003 from racehorses residing in Ibaraki and Shiga prefectures, both located in central Japan. A total of 208 sera from 24 individuals in Ibaraki and 259 from 27 in Shiga were examined for antibodies to JE virus nonstructural 1 (NS1) protein, a marker of natural infection. The natural infection rate in epizootic seasons, which was determined by a significant incre...
Microvascularization and angiogenic activity of equine corpora lutea throughout the estrous cycle. Corpus luteum growth and endocrine function are closely dependent on the formation of new capillaries. The objectives of this study were to evaluate (i) tissue growth and microvascular development in the equine cyclic luteal structures; (ii) in vitro angiogenic activity of luteal tissues in response to luteotrophic (LH, PGE(2)) and luteolytic (PGF(2alpha)) hormones and (iii) to relate data to luteal endocrinological function. Our results show that microvascular density was increased in the early and mid luteal phase, followed by a fall in the late luteal phase and a further decrease in the cor...
The use of a systemic prime/mucosal boost strategy with an equine influenza ISCOM vaccine to induce protective immunity in horses. In horses, natural infection confers long lasting protective immunity characterised by mucosal IgA and humoral IgGa and IgGb responses. In order to investigate the potential of locally administered vaccine to induce a protective IgA response, responses generated by vaccination with an immunostimulating complex (ISCOM)-based vaccine for equine influenza (EQUIP F) containing A/eq/Newmarket/77 (H7N7), A/eq/Borlänge/91 (H3N8) and A/eq/Kentucky/98 (H3N8) using a systemic prime/mucosal boost strategy were studied. Seven ponies in the vaccine group received EQUIP F vaccine intranasally 6 weeks after...
The use of impulse oscillometry for separate analysis of inspiratory and expiratory impedance parameters in horses: effects of sedation with xylazine. To improve the outcome of parameters measured by the impulse oscillometry system (IOS) in horses by separate assessment of inspiratory and expiratory impedance spectra in the frequency range between 1 and 10 Hz. As basis for further studies, the influence of sedation with xylazine on respiratory impedance was also investigated. Methods: (i) The respiratory impedance of 11 horses was measured using IOS before and 6 min after sedation (xylazine; 0.6 mg/kg b.w.). (ii) The time course of impedance parameters in a period of 24 min after administration of xylazine was evaluated in 12 horses at regul...
Japanese encephalitis in a racing thoroughbred gelding in Hong Kong. A horse in Hong Kong that had been vaccinated against Japanese encephalitis suffered a pyrexic episode that culminated in a hyperexcitable state and self-inflicted trauma. Japanese encephalitis was diagnosed on the basis of clinical, pathological and serological observations, and confirmed by the detection of genomic sequences of the virus in spinal cord tissue. Phylogenetic analyses of E gene and NS5-3'UTR sequences revealed divergent clustering of these segments with previously described genotypes, suggesting the possibility that the horse might have been infected with a recombinant between ...
Design and demonstration of a dynamometric horseshoe for measuring ground reaction loads of horses during racing conditions. Because musculoskeletal injuries to racehorses are common, instrumentation for the study of factors (e.g. track surface), which affect the ground reaction loads in horses during racing conditions, would be useful. The objectives of the work reported by this paper were to (1) design and construct a novel dynamometric horseshoe that is capable of measuring the complete ground reaction loading during racing conditions, (2) characterize static and dynamic measurement errors, and (3) demonstrate the usefulness of the instrument by collecting example data during the walk, trot, canter, and gallop fo...
Alpha-melanocyte stimulating hormone release in response to thyrotropin releasing hormone in healthy horses, horses with pituitary pars intermedia dysfunction and equine pars intermedia explants. Thyrotropin releasing hormone (TRH) stimulates an increase in plasma cortisol in horses with pars intermedia dysfunction (PPID, Cushing's disease). A similar phenomenon is observed in humans with Cushing's disease or Nelson's syndrome. The mechanism of the response in humans is not known, but an alteration in receptor expression, selectivity or responsiveness in abnormal corticotropes has been proposed. Horses with PPID, unlike humans, almost exclusively have adenomas of pars intermedia (PI) rather than pars distalis (PD) origin. Therefore, the mechanism responsible for the TRH response observ...
Regulated expression of the beta2-toxin gene (cpb2) in Clostridium perfringens type a isolates from horses with gastrointestinal diseases. Recent epidemiological studies suggested that cpb2-positive Clostridium perfringens isolates are associated with gastrointestinal (GI) diseases in horses. These putative relationships, indicated by PCR genotyping, were tested in the present study by further genotyping and phenotyping of 23 cpb2-positive C. perfringens isolates from horses with GI disease (referred to hereafter as horse GI disease isolates). Our beta2-toxin (CPB2) Western blot analyses demonstrated that all of the tested isolates were unable to produce detectable levels of CPB2. However, Southern blot and nucleotide sequencing ...
Ability of the vector tick Boophilus microplus to acquire and transmit Babesia equi following feeding on chronically infected horses with low-level parasitemia. The protozoan parasite Babesia equi replicates within erythrocytes. During the acute phase of infection, B. equi can reach high levels of parasitemia, resulting in a hemolytic crisis. Horses that recover from the acute phase of the disease remain chronically infected. Subsequent transmission is dependent upon the ability of vector ticks to acquire B. equi and, following development and replication, establishment of B. equi in the salivary glands. Although restriction of the movement of chronically infected horses with B. equi is based on the presumption that ticks can acquire and transmit the ...
Separation and detection of the isomeric equine conjugated estrogens, equilin sulfate and delta8,9-dehydroestrone sulfate, by liquid chromatography–electrospray-mass spectrometry using carbon-coated zirconia and porous graphitic carbon stationary phases. Equilin-3-sulfate and delta8,9-dehydroestrone-3-sulfate are two isomers found in equine conjugated estrogens that differ in structure only by the position of a double bond in the steroid B-ring. These geometric isomers were not resolved on a C18 column during the analysis of conjugated estrogen drug products by LC-MS using acetonitrile-ammonium acetate buffer as the mobile phase. While no separations of these two isomers were observed on C18 or other alkyl-bonded silica based phases using a variety of mobile phase conditions, partial separations were achieved on phenyl bonded silica phases wit...
Effect of the inseminate and the site of insemination on the uterus and pregnancy rates of mares. In this review, effects of the composition of the inseminate on uterine response and pregnancy rates in mares are discussed. The inseminate can differ for volume, sperm concentration, total sperm numbers, presence, absence, or proportion of seminal plasma, and extender composition. Semen can be used as fresh, cooled, or frozen. The site of semen deposition also plays a role; semen is deposited either into the uterine body (standard artificial insemination (AI)) or into the tip of the uterine horn ipsilateral to the preovulatory follicle (deep AI) using the hysterocopical or transrectally guide...
Estimation of genetic parameters for the prevalence of osseous fragments in limb joints of Hanoverian Warmblood horses. Genetic parameters were estimated for the prevalence of osseous fragments in distal (DIJ) and proximal interphalangeal (PIJ), fetlock (FJ) and hock joints (HJ) of Hanoverian Warmblood horses by using residual maximum likelihood (REML) with linear animal models. The analyses were based on the results of 10 standardized radiographs of all four limbs of 3725 young riding horses selected for sale at auction. Transformation factors onto the underlying liability scale were verified by a simulation study. The heritability estimates of osseous fragments on the liability scale were in the range of h2 =...
Differentiating among horse (Equus caballus), donkey (Equus asinus) and their hybrids with combined analysis of nuclear and mitochondrial gene polymorphism. A novel and brief method of differentiating among horse (Equus caballus) and donkey (Equus asinus) and their hybrids (mule, E. asinus x E. caballus and hinny, E. caballus x E. asinus) with combined analysis of nuclear and mitochondrial gene polymorphism (CANMGP) was reported in the present report. A nuclear gene, protamine P1 gene of donkey was sequenced and compared with the known horse sequence from GenBank while a published equid mitochondrial gene, cytochrome b gene of donkey was compared with that of horse. In each of the two genes, a fixed nucleotide substitution within an exon that coul...
Resuscitation and emergency management for neonatal foals. Early intervention can dramatically alter outcome in foals. Cardio-pulmonary cerebral resuscitation can be successful and clinically worthwhile when applied to foals that arrest as part of the birthing process. Readily available equipment and an ordered plan starting with addressing the respiratory system (airway and breathing) followed by the circulatory system (circulation and drugs) are the keys to success. Hypoglycemia is common in foals that are not nursing and in septic foals. Support of serum glucose can be an important emergency treatment. Respiratory support with oxygen therapy should...
Neonatal foal diarrhea. Diarrhea is a significant cause of morbidity and mortality in the neonatal foal. Numerous noninfectious and infectious agents are responsible for enterocolitis and enteritis. This article provides an overview of the differential diagnoses for neonatal diarrhea and general and specific guidelines for therapy.
Nondiarrheal disorders of the gastrointestinal tract in neonatal foals. Neonates can have a variety of gastrointestinal disorders, primary and secondary in nature. Important primary disorders include con-genital abnormalities and meconium retention. One of the most important secondary lesions is generalized ileus. Gastric ulceration can occur as a primary or secondary event. This article addresses the pathophysiology, diagnosis, and treatment of gastrointestinal problems commonly observed in neonatal foals.
Immunologic disorders in neonatal foals. Foals live in an environment heavily populated by bacteria, many of which are capable of causing disease. Development of infection,however, is the exception rather than the rule. The ability of the foal to prevent infection by most pathogens is the result of a sophisticated set of defense mechanisms. These defense mechanisms can be divided into adaptive and innate immunity. Innate immunity encompasses defense mechanisms that pre-exist or are rapidly induced within hours of exposure to a pathogen. Conversely, adaptive or acquired immunity represents host defenses mediated by T and B lymphocytes...
Equine neonatal sepsis. Neonatal infection remains a leading cause of morbidity and mortality in the equine industry, despite advances in prevention and treatment. Many factors can influence a foal's risk for the development of sepsis in the peripartum period. This article discusses those factors, causative organisms, and therapeutic options. Factors that influence prognosis and potential preventative strategies also are addressed.
