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Topic:Animal Studies
Animal studies involving horses encompass a range of research focused on understanding equine biology, behavior, and health. These studies often investigate various aspects of horse physiology, genetics, nutrition, and disease pathology. Researchers utilize animal studies to explore the effects of different treatments, management practices, and environmental factors on horse welfare and performance. The findings from such studies contribute to the development of improved care strategies and health interventions. This page gathers peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of animal studies conducted on horses, providing insights into their application in advancing equine science.
Embryogenesis and the first-stage larva of Thelazia lacrymalis. The female reproductive system of Thelazia lacrymalis (Nematoda: Thelaziidae) was investigated by light and scanning electron microscopy (SEM) with regard to the developmental stages and the stage deposited by the gravid nematode. Female T. lacrymalis have a didelphic and opisthodelphic type of reproductive system with paired ovaries, oviducts and uteri and a single vagina and vulva. Round and spindle-shaped primary oocytes are documented within the ovaries and oviducts, respectively. The distal part of each uterus provides a fertilization chamber filled with spermatozoa, followed by a sphinct...
[Analysis of the population structure of the Black Forest Draught Horse]. Gene contributions of foreign populations as well as coefficients of inbreeding and relationship were evaluated in 699 Black Forest Draught horses of Baden-Württemberg actually registered in the year 2002. Based on nearly complete 5-generation-pedigrees and after taking into account the remaining incompleteness, the mean coefficient of inbreeding for the total population was 6.5%. The recently by incrossing with different breeds newly established lines of stallions showed significantly lower mean coefficients of inbreeding. High rates of inbreeding of about 1.6% in the last five generations c...
Muscarinic receptor subtypes mediate vasorelaxation in isolated horse deep dorsal penile vein. To investigate the effect of acetylcholine (ACh) on horse deep dorsal penile vein and to characterize the muscarinic receptor subtypes involved in this response. Methods: Vein rings were mounted in an organ bath chamber, and the isometric tension was recorded. Results: In phenylephrine-contracted veins, ACh (1 nM to 1 microM) induced endothelium-dependent relaxation. The muscarinic receptor antagonist, atropine, produced parallel rightward shifts of the ACh response curves (pA2 = 10.04; pK(B) = 9.98). Carbachol (10 nM to 100 microM) also evoked relaxation in the vein segments, but showed a low...
Effects of topical perineural capsaicin in a reversible model of equine foot lameness. Capsaicin is a local substance P depleter with dramatic analgesic effects. We tested the hypothesis that the topical application of capsaicin ointment over the palmar digital nerves would attenuate the clinical effects of a reversible model of equine foot lameness. Seven healthy adult horses shod unilaterally with adjustable heart bar shoes were studied in a crossover design for 2 weeks. Grade 5.0/5.0 lameness (nonweight bearing) was induced by tightening the adjustable heart bar shoe. One hour later, capsaicin ointment was applied over the medial and lateral palmar digital nerves 3 cm proxima...
Analysis of ELA-DQB exon 2 polymorphism in Argentine Creole horses by PCR-RFLP and PCR-SSCP. The second exon of equine leucocyte antigen (ELA)-DQB genes was amplified from genomic DNA of 32 Argentine Creole horses by PCR. Amplified DNA was analysed by PCR-restriction fragment length polymorphism (RFLP) and PCR-single-strand conformation polymorphism (SSCP). The PCR-RFLP analysis revealed two HaeIII patterns, four RsaI patterns, five MspI patterns and two HinfI patterns. EcoRI showed no variation in the analysed sample. Additional patterns that did not account for known exon 2 DNA sequences were observed, suggesting the existence of novel ELA-DQB alleles. PCR-SSCP analysis exhibited se...
The effects of maternal age and parity on placental and fetal development in the mare. The normality of equine placentation is essential for fetal health and development. Substantial information exists on the gross morphological status of the placenta but few studies have addressed the problem of degenerative lesions that interfere with placental morphology and placental efficiency. Objective: Degenerative changes in the endometrium with increasing age and parity are reflected in the morphology and density of the placental microcotyledons. Objective: To assess placental efficiency on the basis of foal birthweight as a function of total microscopic area of fetomaternal contact. M...
Efficacy of montelukast in the treatment of chronic obstructive pulmonary disease in five horses. Five horses with moderate to severe chronic obstructive pulmonary disease (COPD) were treated with 0.11 (0.01) mg/kg bodyweight of montelukast, a cysteinyl leukotriene receptor antagonist, once a day for 26 days. The horses were evaluated clinically and endoscopically and subjected to arterial blood gas analysis and lung function tests before and after the period of treatment, and the plasma concentrations of montelukast were determined by high-performance liquid chromatography with fluorescence detection. The treatment did not result in statistically significant differences in the total score...
Equine infectious anemia in mules: virus isolation and pathogenicity studies. There appears to be a lack of information concerning responses of mules to natural infection or experimental inoculation with equine infectious anemia virus (EIAV). In the present study EIAV was isolated from mules, for the first time, and its pathogenicity in naturally infected and experimentally inoculated animals was investigated. Two naturally infected (A and B) and three EIAV free mules (C, D and E) were used for this purpose. Mule A developed clinical signs, whereas mule B remained asymptomatic until the end of the study. Mules C and D were each inoculated with 10ml of blood from mule A ...
A non-lethal method for assessment of efficacy of antiparasitics against parasites in horses such as Anoplocephala perfoliata and Gasterophilus intestinalis. Sourcing of horses naturally infected with parasites such as Anoplocephala perfoliata and Gasterophilus intestinalis for antiparasitic efficacy slaughter studies is often difficult, expensive, and usually excessive numbers of animals must be slaughtered before significant data can be obtained. To overcome this problem a "Modified Critical Treatment Method" was developed. This method does not require the horses to be sacrificed, but relies on the collection and processing of all faecal material containing expelled parasites from test animals. Efficacy is assessed by comparing, in the same horse...
Influence of topically applied cold treatment on core temperature and cell viability in equine superficial digital flexor tendons. To determine rate and degree of cooling for the superficial digital flexor tendon (SDFT) during a standard cryotherapy application in horses and evaluate in vitro effects of cooling on survival of tendon cells. Methods: 6 limbs of 5 adult horses and cultured cells obtained from SDFT of 3 adult horses during necropsy. Methods: In vivo data were acquired by use of a thermocouple temperature probe inserted into the SDFT of a forelimb of each standing sedated horse. After baseline temperatures were recorded, a commercial compression splint with circulating coolant was placed on each selected limb,...
Glucose clearance in grazing mares is affected by diet, pregnancy, and lactation. The glucose tolerance test in the horse may be used to determine metabolic responses to diet, disease, or physiologic state. The objective of this study was to determine the effect of reproductive stage (gestation and lactation) and supplemental dietary energy source (sugar and starch [SS] or fiber and fat [FF]) on glucose metabolism in grazing mares using an oral glucose tolerance test. Twelve mares, six on each supplement, were examined on three occasions: one in the third trimester of pregnancy, the second in early lactation, and the third in late lactation. During each test, venous samples...
The effect of stimulus height on visual discrimination in horses. This study investigated the effect of stimulus height on the ability of horses to learn a simple visual discrimination task. Eight horses were trained to perform a two-choice, black/white discrimination with stimuli presented at one of two heights: ground level or at a height of 70 cm from the ground. The height at which the stimuli were presented was alternated from one session to the next. All trials within a single session were presented at the same height. The criterion for learning was four consecutive sessions of 70% correct responses. Performance was found to be better when stimuli were...
Melanocortin receptor variants with phenotypic effects in horse, pig, and chicken. The melanocortin system is of considerable interest in domestic animals because their energy metabolism and pigmentation have been under strong selection. This article reviews our work on MC1R variants in horse, pig, and chicken, as well as a study on MC4R polymorphism in the pig. The chestnut coat color in horses is caused by an MC1R missense mutation (S83F). In the pig, we have described seven MC1R alleles controlling four different coat color phenotypes (wild type, dominant black, black spotting, and recessive red). The most interesting allele is the one causing black spotting because it ca...
Species comparison of vitamin K1 2,3-epoxide reductase activity in vitro: kinetics and warfarin inhibition. A comparative study of vitamin K(1) 2,3-epoxide reductase (VKOR) activity in vitro was conducted across species. The apparent kinetic constants K(m app), V(max), and Cl(int app) were determined in bovine, canine, equine, human, murine, ovine, porcine, and rat hepatic microsomes. In addition to these enzyme kinetic constants, the IC(50) of warfarin for VKOR was determined in human, murine, porcine, and rat hepatic microsomes. Interspecies differences were observed when comparing the K(m app) (range, 2.41-6.46 microM), V(max) (range, 19.5-85.7 nmol/mg/min), and Cl(int app) (range, 8.2-18.4 ml/mg...
Assessment of corneal thickness, intraocular pressure, optical corneal diameter, and axial globe dimensions in Miniature Horses. To determine corneal thickness, intraocular pressure (IOP), and horizontal and vertical corneal diameter (HCD and VCD) and to obtain axial measurements of the anterior chamber depth (ACD), crystalline lens thickness (CLT), vitreous chamber depth (VtCD), and axial globe length (AGL) in eyes of Miniature Horses. Methods: 41 healthy Miniature Horses. Methods: Ocular component measurements were obtained via ultrasonic pachymetry, applanation tonometry, ultrasound, and by use of a Jameson caliper. Results: Mean IOP and corneal thickness for all eyes were 26.0 mm Hg and 785.6 microm, respectively. T...
Comparison of nociceptive withdrawal reflexes and recruitment curves between the forelimbs and hind limbs in conscious horses. To compare nociceptive withdrawal reflexes (NWRs) evoked from the distal aspect of the left forelimb and hind limb in conscious standing horses and to investigate NWR recruitment for graded electrical stimulation intensities. Methods: 20 adult horses. Methods: Surface electromyographic (EMG) activity evoked by transcutaneous electrical stimulation of the digital palmar (or plantar) nerve was recorded from the common digital extensor and cranial tibial muscles. Stimuli consisted of 25-millisecond train-of-5 constant current pulses. Current intensity was gradually increased until NWR threshold i...
Mosquitoes captured in a horse-baited stable trap in southeast Louisiana. A mosquito study based on collections from horse-baited stable traps was conducted in 1993 and 1994 at 3 sites in geographically and ecologically distinct areas of St. Tammany Parish (southeastern Louisiana) to determine the major horse-feeding mosquito species that could be possible bridging and epidemic vectors of eastern equine encephalomyelitis virus. A total of 4,535 mosquitoes in 1993 and 23,906 in 1994 involving 26 species were collected, of which, depending on the site, Culex salinarius, Cx. (Melanoconion) spp., Aedes vexans, Psophora ferox, Coquillettidia perturbans, Anopheles quadrim...
MultiPipMaker and supporting tools: Alignments and analysis of multiple genomic DNA sequences. Analysis of multiple sequence alignments can generate important, testable hypotheses about the phylogenetic history and cellular function of genomic sequences. We describe the MultiPipMaker server, which aligns multiple, long genomic DNA sequences quickly and with good sensitivity (available at http://bio.cse.psu.edu/ since May 2001). Alignments are computed between a contiguous reference sequence and one or more secondary sequences, which can be finished or draft sequence. The outputs include a stacked set of percent identity plots, called a MultiPip, comparing the reference sequence with sub...
Histochemical detection of glycoconjugates in the male reproductive system of the horse. Lectins are glycoproteins of plant and animal origin that have the ability to bind specific carbohydrate residues of cell glycoconjugates, particularly in terminal positions. In this study, the binding of lectins, Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), Bandeiraea simplicifolia BS-1 (isolectin B4), Triticum vulgaris (WGA), Arachis hypogaea (PNA), and Ulex europaeus (UEA-I), was studied in the reproductive systems of male thoroughbred horses.DBA was detected in the stereocilia of the caput and corpus epididymis, and in the vas deferens. It was weakly detected in connective...
The effect of dietary energy source on serum concentration of insulin-like growth factor-I growth hormone, insulin, glucose, and fat metabolites in weanling horses. Feeding diets high in soluble carbohydrates to growing horses has been implicated in the development of orthopedic diseases; as a result, substitution of dietary fat for soluble carbohydrates has received attention. Because IGF-I is integral to growth and cartilage development and because it is influenced by nutrition, we evaluated the effect of dietary fat substitution on metabolic endpoints and circulating GH and IGF-I in growing horses. Twelve Quarter Horse weanlings, four female and eight male, 151 to 226 d old, were blocked by sex and age and assigned to two treatment groups. Group one (C...
Expression of the uterine Mx protein in cyclic and pregnant cows, gilts, and mares. Pregnancy and interferon-tau (IFN tau) upregulate uterine Mx gene expression in ewes; however, the only known role for Mx is in the immune response to viral infection. We hypothesize that Mx functions as a conceptus-induced component of the anti-luteolytic mechanism and/or regulator of endometrial secretion or uterine remodeling during early pregnancy. This study was conducted to determine the effects of early pregnancy on uterine Mx expression in domestic farm species with varied mechanisms of pregnancy recognition. Endometrium from cows, gilts, and mares was collected during the first 20 d o...
Molecular cloning of equine muscle-type phosphofructokinase cDNA. The complete coding region sequence of equine muscle-type phosphofructokinase (ePFKM) was obtained from skeletal muscle of a thoroughbred horse. The deduced amino acid sequence of ePFKM showed 97%, 96%, 96%, 96% and 95% identity to canine, human, mouse, rabbit and rat PFKM, respectively. The amino and carboxyl terminal halves of ePFKM presented a structure of tandem repeat, as other mammalian PFKMs. As the amino acid residues constituting various ligand-binding sites were also conserved, it is thought that ePFKM has enzymatic activity similar to PFKM in other mammals.
Activities of enzymes in the malate-aspartate shuttle and the isoenzyme pattern of lactate dehydrogenase in plasma and peripheral leukocytes of lactating Holstein cows and riding horses. The activities of the enzymes involved in the malate-aspartate shuttle and lactate dehydrogenase (LDH) and the pattern of the isoenzymes of LDH were determined in plasma and peripheral leukocytes of lactating Holstein cows and thoroughbred riding horses as representative herbivorous animals. In the horse plasma, LDH activities were significantly lower and AST activities were significantly higher than those in the cow plasma. The specific activities of cytosolic malate dehydrogenase (MDH), LDH and AST in the horse leukocytes were higher than those in the cows. The cytosolic ratio of MDH/LDH act...
[The occurrence of hemodynamic effective elements in the intestinal blood vessel system]. Arterioles, precapillary sphincters, capillary endothelium, and pericytes probably regulate the blood flow in the intestinal microvascular bed similar to other regions of the body because of their equipment with contractile filaments. Only throttle veins with their arrangement of pools and their characteristics probably exert influence on the hemodynamic qualities of the blood flow in the intestinal mucosa.
Are uniform regional safety factors an objective of adaptive modeling/remodeling in cortical bone? It has been hypothesized that a major objective of morphological adaptation in limb-bone diaphyses is the achievement of uniform regional safety factors between discrete cortical locations (e.g. between cranial and caudal cortices at mid-diaphysis). This hypothesis has been tested, and appears to be supported in the diaphyses of ovine and equine radii. The present study more rigorously examined this question using the equine third metacarpal (MC3), which has had functionally generated intracortical strains estimated by a sophisticated finite element model. Mechanical properties of multiple mid...
The prevalence and transmission to exotic equids (Equus quagga antiquorum, Equus przewalskii, Equus africanus) of intestinal nematodes in contaminated pasture in two wild animal parks. Wild equids maintained in large enclosures may suffer from helminth diseases because common hygiene practices have only limited effects on parasite populations. Weekly monitoring of helminth prevalences and pasture infestation was performed for 1 yr in several extensive maintenance systems of two wildlife parks with similar climates to determine when veterinary intervention to control parasites would be useful. We also sought evidence of natural immunogenic reactions among herds of Chapman zebras (Equus quagga antiquorum), Przewalski's horses (Equus przewalskii) and dwarf donkeys (Equus asinus...
Equine trypsin: purification and development of a radio-immunoassay. Shock is accompanied by generalised splanchnic hypoperfusion, and splanchnic organs like the pancreas can be damaged, as shown in animal experimental models and in humans, by the presence of high plasma concentrations of trypsin and other pancreatic enzymes. In order to design a radioimmunoassay technique (RIA) for the measurement of equine trypsin-like immunoreactivity (TLI) in biological fluids, trypsin was purified (with purity > or = 96%) from the equine pancreas by extraction in an acid medium, ammonium sulfate precipitations, gel filtration chromatography and, after activation of tryp...
Transcranial magnetic stimulation: review of the technique, basic principles and applications. Transcranial magnetic stimulation is rapidly developing as a powerful, non-invasive tool for studying the descending motor tracts in humans. The applications of the test in animals are for the moment restricted to small animals. However, this non-invasive, sensitive and painless technique appears promising as a test of motor tract function in horses where the neurological examination is mainly restricted to clinical evaluation and some ancillary tests, such as radiography, cerebrospinal fluid analysis and electromyography. In this review, we want to discuss the history, basic principles, techn...
