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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.
Regional differences in wound oxygenation during normal healing in an equine model of cutaneous fibroproliferative disorder. Wound repair in horse limbs is often complicated by the development of exuberant granulation tissue (EGT) and excessive scarring while body wounds tend to repair uneventfully. EGT resembles the human keloid. While the events leading to keloid formation are not fully elucidated, tissue hypoxia has been proposed as a major contributing factor. The objective of this study was to investigate tissue oxygen saturation in healing full-thickness wounds created on the horse limb and body, using near-infrared spectroscopy. Spectroscopic reflectance data were collected from both anatomic sites at specifi...
Pilot immunization of mice infected with an equine strain of Corynebacterium pseudotuberculosis. This pilot study evaluated protection of an equine autogenous bacterin-toxoid vaccine against Corynebacterium pseudotuberculosis infection. Twenty-four BALB/c mice were inoculated with two doses of bacterin-toxoid vaccine or two injections of a placebo. Clinical, microbiologic, and pathologic outcomes were assessed after intradermal infection with one of two equine-origin C. pseudotuberculosis strains. Mice receiving bacterin-toxoid from fast-growing C. pseudotuberculosis showed significant protection from challenge infection, as evidenced by a higher survival rate, fewer gross and histopathol...
Selective cloning, characterization, and production of the Culicoides nubeculosus salivary gland allergen repertoire associated with equine insect bite hypersensitivity. Salivary gland proteins of Culicoides spp. have been suggested to be among the main allergens inducing IgE-mediated insect bite hypersensitivity (IBH), an allergic dermatitis of the horse. The aim of our study was to identify, produce and characterize IgE-binding salivary gland proteins of Culicoides nubeculosus relevant for IBH by phage surface display technology. A cDNA library constructed with mRNA derived from C. nubeculosus salivary glands was displayed on the surface of filamentous phage M13 and enriched for clones binding serum IgE of IBH-affected horses. Ten cDNA inserts encoding putat...
Prevalence of and risk factors for MRSA carriage in companion animals: a survey of dogs, cats and horses. We investigated the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage in a convenience sample of purposely selected populations of dogs, cats and horses in the Greater London area. Swabs from carriage sites were pooled, enriched and processed by standard bacteriological methods. The presence of nuc and mecA was confirmed for MRSA. Risk factors were investigated among veterinary treatment group animals using exact logistic regression analysis. Twenty-six (1.53%) MRSA carriers were identified in the 1692 animals (15/704 dogs, 8/540 cats, 3/152 horses). Animals presenting ...
Immunohistochemical localization of aromatase during the development and atresia of ovarian follicles in prepubertal horses. Ovarian steroidogenesis from the neonatal to pubertal period in horses is poorly understood. This study was designed to immunolocalize cytochrome P450 aromatase in the ovarian follicles of slaughtered fillies ages approximately (I) 6-9 mo (5 mm in diameter. Staining intensity was dependent on the size and morphology of the follicle. In nonatretic follicles 5-10 mm in diameter, the reaction was weak and heterogeneous, while most intense staining was observed in preovulatory follicles. In follicles (diameter <20 mm) in the groups <10MF and 1YF, the reaction was less intense than in adult m...
The cosmopolitan maternal heritage of the Thoroughbred racehorse breed shows a significant contribution from British and Irish native mares. The paternal origins of Thoroughbred racehorses trace back to a handful of Middle Eastern stallions, imported to the British Isles during the seventeenth century. Yet, few details of the foundation mares were recorded, in many cases not even their names (several different maternal lineages trace back to 'A Royal Mare'). This has fuelled intense speculation over their origins. We examined mitochondrial DNA from 1929 horses to determine the origin of Thoroughbred foundation mares. There is no evidence to support exclusive Arab maternal origins as some historical records have suggested, or a sign...
Comparison of the osteogenic potential of equine mesenchymal stem cells from bone marrow, adipose tissue, umbilical cord blood, and umbilical cord tissue. To determine the optimal osteogenic source of equine mesenchymal stem cells (eMSCs) and optimize collection of and expansion conditions for those cells. Methods: 10 adult Quarter Horses and 8 newborn Thoroughbred foals. Methods: eMSCs were isolated from bone marrow (BM), adipose tissue, and umbilical cord blood and tissue, and the osteogenic potential of each type was assessed. Effects of anatomic site, aspiration volume, and serum type on eMSC yield from BM were investigated. Results: BM-eMSCs had the highest overall expression of the osteogenic genes Cbfa1, Osx, and Omd and staining for ALP ...
Heart rate variability after horse trekking in leading and following horses. Horse trekking (HT) is having a stroll on a horse along a walking trail in a forest, field, and/or sandy beach. Generally in HT, horses exercise in tandem line outside the riding facilities. Because the leading horse will be confronted with stressors in the forefront, we hypothesized that the leading horse shows higher stress responses than the following one. In order to verify the hypothesis, we compared short-term stress responses between each position in six horses. Exercise consisted of 15 min of ground riding and 45 min of HT with walking and trotting. Heart rate variability was analyzed ...
A linear laser scanner to measure cross-sectional shape and area of biological specimens during mechanical testing. Measure of the cross-sectional area (CSA) of biological specimens is a primary concern for many biomechanical tests. Different procedures are presented in literature but besides the fact that noncontact techniques are required during mechanical testing, most of these procedures lack accuracy or speed. Moreover, they often require a precise positioning of the specimen, which is not always feasible, and do not enable the measure of the same section during tension. The objective of this study was to design a noncontact, fast, and accurate device capable of acquiring CSA of specimens mounted on a ...
Evaluation of virulence factor profiling in the characterization of veterinary Escherichia coli isolates. Escherichia coli has been used as an indicator organism for fecal contamination of water and other environments and is often a commensal organism in healthy animals, yet a number of strains can cause disease in young or immunocompromised animals. In this study, 281 E. coli isolates from bovine, porcine, chicken, canine, equine, feline, and other veterinary sources were analyzed by BOXA1R PCR and by virulence factor profiling of 35 factors to determine whether they had utility in identifying the animal source of the isolates. The results of BOXA1R PCR analysis demonstrated a high degree of dive...
Comparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge. In horses, serum cortisol concentration is considered to provide an indirect measurement of stress. However, it includes both free and bound fractions. The sampling method is also invasive and often stressful. This is not the case for salivary cortisol, which is collected using a more welfare-friendly method and represents a part of the free cortisol fraction, which is the biologically active form. Objective: To compare salivary and serum cortisol assays in horses, in a wide range of concentrations, using an adrenocorticotropic hormone (ACTH) stimulation test, in order to validate salivary cor...
Effects of a supplement containing chromium and magnesium on morphometric measurements, resting glucose, insulin concentrations and insulin sensitivity in laminitic obese horses. Obesity and insulin resistance are risk factors for laminitis in equids and supplements containing chromium and magnesium might improve insulin sensitivity. Objective: A supplement containing chromium, magnesium and other nutraceuticals would alter morphometric measurements, blood variables, and insulin sensitivity in laminitic obese horses. Methods: Twelve previously laminitic obese (body condition score ≥ 7/9) horses were randomly allocated to treatment (n = 6) and control (n = 6) groups and 2 obese horses with clinical laminitis were included in the treatment group. Treated animals receiv...
Cyclooxygenase-2 expression in animal cancers. Cyclooxygenase (COX; also known as prostaglandin endoperoxide synthase) is a key enzyme in the biochemical pathway leading to the synthesis of prostaglandins. A large amount of epidemiological and experimental evidence supports a role for COX-2, the inducible form of the enzyme, in human tumorigenesis, notably in colorectal cancer. COX-2 mediates this role through the production of PGE(2) that acts to inhibit apoptosis, promote cell proliferation, stimulate angiogenesis, and decrease immunity. Similarly, COX-2 is believed to be involved in the oncogenesis of some cancers in domestic animals. H...
A pressure plate study on fore and hindlimb loading and the association with hoof contact area in sound ponies at the walk and trot. The aim of this study was to evaluate the association between fore- and hind-hoof contact area and limb loading. Data from a previous study on forelimb loading and symmetry were compared with data on hindlimb kinetics, and the fore- and hind-hoof contact area at the walk and trot was evaluated. Five sound ponies, selected for symmetrical feet, were walked and trotted over a pressure plate embedded in a custom-made runway. The hindlimb peak vertical force (PVF) and vertical impulse (VI) were found to be significantly lower than in the forelimb, whereas their high symmetry ratios (>95%) did n...
Motivation for hay: effects of a pelleted diet on behavior and physiology of horses. The natural diet of free-ranging horses is grass, which is typically high in fiber and calorically dilute, however diets for high performance domestic horses are often low in fiber and calorically dense. The aim of the study was to determine the motivation of horses for hay when fed a low roughage diet. Their motivation could be used to determine if low roughage diets compromise the welfare of horses. Eight mares were fed two different diets in counterbalanced order: ad libitum orchard grass hay; a complete pelleted feed (pellets). Each trial lasted three weeks, with a one-week transition peri...
Adaptation of Staphylococcus aureus to ruminant and equine hosts involves SaPI-carried variants of von Willebrand factor-binding protein. Staphylococci adapt specifically to various animal hosts by genetically determined mechanisms that are not well understood. One such adaptation involves the ability to coagulate host plasma, by which strains isolated from ruminants or horses can be differentiated from closely related human strains. Here, we report first that this differential coagulation activity is due to animal-specific alleles of the von Willebrand factor-binding protein (vWbp) gene, vwb, and second that these vwb alleles are carried by highly mobile pathogenicity islands, SaPIs. Although all Staphylococcus aureus possess c...
Isolation and characterization of equine amniotic fluid-derived multipotent stem cells. Amniotic fluid (AF) is a well-known source of stem cells. However, there have been no reports regarding equine AF stem cells. We have isolated equine AF-derived multipotent stem cells (MSC) (eAF-MSC) and show that these cells exhibit self-renewal ability and multilineage differentiation. Methods: AF was obtained from thoroughbred mares and mononuclear cells (MNC) were isolated by Ficoll-Paque density gradient. We measured the cumulative population doubling level (CPDL) and characterized the immunophenotype by flow cytometry. To investigate differentiation ability, a trilineage differentiation ...
West Nile virus lineage 2 as a cause of zoonotic neurological disease in humans and horses in southern Africa. West Nile virus (WNV) is widely distributed in South Africa, but since a few cases of neurological disease have been reported from this region, endemic lineage 2 strains were postulated to be of low virulence. Several cases of nonfatal encephalitis in humans as well as fatal cases in a foal, dog, and ostrich chicks have, however, been associated with lineage 2 WNV in South Africa. The pathogenesis of lineage 2 WNV strains was investigated using mouse neuroinvasive experiments, gene expression experiments, and genome sequence comparisons which indicated that lineage 2 strains that are highly pa...
A component of Premarin(®) enhances multiple cognitive functions and influences nicotinic receptor expression. In women, ovarian hormone loss at menopause has been related to cognitive decline, and some studies suggest that estrogen-containing hormone therapy (HT) can mitigate these effects. Recently, the Women's Health Initiative study found that conjugated equine estrogens, the most commonly prescribed HT, do not benefit cognition. Isolated components of conjugated equine estrogens (tradename Premarin(®)) have been evaluated in vitro, with delta(8,9)-dehydroestrone (∆(8)E1) and equilin showing the strongest neuroprotective profiles. It has not been evaluated whether ∆(8)E1 or equilin impact cogn...
Equine embryonic stem-like cells and mesenchymal stromal cells have different survival rates and migration patterns following their injection into damaged superficial digital flexor tendon. Injury to the superficial digital flexor tendon (SDFT) is common in racing and sport horses and poor tendon regeneration leads to high reinjury rates. Autologous mesenchymal stromal cells (MSCs) are being used clinically to improve tendon regeneration but they have some practical limitations. Embryonic stem cells (ESCs) may overcome these limitations but their fate following injection into the damaged SDFT is unknown. Objective: To inject MSCs and ESCs into distinct areas of damage in the SDFT and monitor their survival over a 3 month period. Methods: MSCs and ESCs expressing different reporte...
Horses (Equus caballus) use human local enhancement cues and adjust to human attention. This study evaluates the horse (Equus caballus) use of human local enhancement cues and reaction to human attention when making feeding decisions. The superior performance of dogs in observing human states of attention suggests this ability evolved with domestication. However, some species show an improved ability to read human cues through socialization and training. We observed 60 horses approach a bucket with feed in a three-way object-choice task when confronted with (a) an unfamiliar or (b) a familiar person in 4 different situations: (1) squatting behind the bucket, facing the horse (2) ...
Gene delivery in the equine cornea: a novel therapeutic strategy. To determine if hybrid adeno-associated virus serotype 2/5 (AAV5) vector can effectively deliver foreign genes into the equine cornea without causing adverse side effects. The aims of this study were to: (i) evaluate efficacy of AAV5 to deliver therapeutic genes into equine corneal fibroblasts (ECFs) using enhanced green fluorescent protein (EGFP) marker gene, and (ii) establish the safety of AAV5 vector for equine corneal gene therapy. Methods: Primary ECF cultures were harvested from healthy donor equine corneas. Cultures were maintained at 37°C in humidified atmosphere with 5% CO(2). Metho...
Intravenous administration of equine-derived whole IgG antivenom does not induce early adverse reactions in non-envenomed horses and cows. Administration of antivenoms to treat snakebite envenomings has the potential risk of inducing early adverse reactions. The mechanisms involved in these reactions are unclear. In this study, polyspecific antivenom consisting of whole IgG purified from equine plasma by caprylic acid precipitation was administered intravenously to non-envenomed horses (n = 47) and cows (n = 20) at a dose of 0.4 mL/kg. It has been reported that, in humans, this formulation (administered at a dose of 0.4 mL/kg) induces mild noticeable early adverse reactions, such as fever, vomiting, diarrhea, urticaria, generaliz...
Host preferences of tabanid flies based on identification of blood meals by ELISA. Tabanid flies in Australia are potential vectors of the parasite Trypanosoma evansi which causes the animal disease surra. It is endemic to most of south-east Asia and could enter Australia, but evaluation of the potential impact of a surra incursion requires identification of the major hosts of Australian tabanids. This study investigated the natural pattern of feeding and host preference by tabanid flies of Townsville, north Queensland by identification of ingested blood in trap-caught tabanids using ELISA. The assays were developed for identification of horse, cow, macropod and pig blood me...
Estimation of genetic parameters for racing speed at different distances in young and adult Spanish Trotter horses using the random regression model. A total of 71 522 records (from 3154 horses) with the times per kilometre (TPK), recorded in Spanish Trotter horses (individual races) from racing performances held from 1991 to 2007, were available for this study. The TPK values for the different age groups (young and adult horses) and different distances (1600-2700 m) were considered as different traits, and a bi character random regression model (RRM) was applied to estimate the (co)variance components throughout the trajectory of age groups and distances. The following effects were considered as fixed: the combination of hippodrome-dat...
Non-steroidal anti-inflammatory drugs inhibit bone healing: a review. The ability of non-steroidal anti-inflammatory drugs (NSAID) to inhibit bone healing has been established in experimental animal models using mice, rats, and rabbits. The mechanism of action is largely unknown but stems from prostaglandin inhibition and is likely multifactorial. In human medicine NSAID are known to prevent heterotopic ossification, however the clinical importance of their effects on bone healing remains controversial. Although a small handful of reports suggest that NSAID suppress bone healing in dogs and horses, there is little published information to direct veterinary pract...
Assessment of bone response to conditioning exercise in the radius and tibia of young thoroughbred horses using pQCT. To assess the effect of conditioning exercise on bone parameters at multiple sites in the radius and tibia of young Thoroughbred horses. Methods: The left and right radius and tibia were obtained from twelve horses, six of which had received conditioning exercise and six which formed the control group. Each bone was scanned at 5% intervals along its entire length using pQCT. Results: Bone strength, bone area and periosteal circumference were significantly greater for the group of conditioned horses in both the radius and tibia. Volumetric bone mineral density was lower while bone mineral conte...
Physiologic effects of nasopharyngeal administration of supplemental oxygen at various flow rates in healthy neonatal foals. To evaluate the effects of various flow rates of oxygen administered via 1 or 2 nasal cannulae on the fraction of inspired oxygen concentration (FIO2) and other arterial blood gas variables in healthy neonatal foals. Methods: 9 healthy neonatal (3- to 4-day-old) foals. Methods: In each foal, a nasal cannula was introduced into each naris and passed into the nasopharynx to the level of the medial canthus of each eye; oxygen was administered at 4 flow rates through either 1 or both cannulae (8 treatments/foal). Intratracheal FIO2, intratracheal end-tidal partial pressure of carbon dioxide, and a...
Length difference between equine ZFX and ZFY genes and its application for molecular sex determination. we analyzed the sex chromosome-encoding ZFX-ZFY genes and tested molecular sexing using the amplification patterns of intron 9 of ZFX-ZFY in the horse. Results: the amplification of the ZFX-ZFY produced two distinct patterns, reflecting sexual dimorphism based on a length difference between the X and Y chromosomes. The amplification products from foals showed two distinct bands: one was common to all foals and mares, indicating that this band was amplified from ZFX, while the other was specific to some foals, indicating that it was from ZFY. The result based on the PCR assay was identical to t...
