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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.
Effect of a single dose of dexamethasone on glucose homeostasis in healthy horses by using the combined intravenous glucose and insulin test. Sustained dexamethasone administration to horses results in insulin resistance, which may predispose them to laminitis. A single dose of dexamethasone is commonly used as a diagnostic aid, yet the effect of a single dose of dexamethasone on glucose homeostasis in horses is not well defined. The objective of this study was to characterize the change in glucose dynamics over time in response to a single dose of dexamethasone. A combined glucose-insulin tolerance test (CGIT) was performed on 6 adult geldings before and at 2, 24, and 72 h postdexamethasone (40 microg/kg of BW, i.v.); a minimum of ...
Myonuclear domain size and myosin isoform expression in muscle fibres from mammals representing a 100,000-fold difference in body size. This comparative study of myonuclear domain (MND) size in mammalian species representing a 100,000-fold difference in body mass, ranging from 25 g to 2500 kg, was undertaken to improve our understanding of myonuclear organization in skeletal muscle fibres. Myonuclear domain size was calculated from three-dimensional reconstructions in a total of 235 single muscle fibre segments at a fixed sarcomere length. Irrespective of species, the largest MND size was observed in muscle fibres expressing fast myosin heavy chain (MyHC) isoforms, but in the two smallest mammalian species studied (mouse and r...
ASAS Centennial Paper: The future of teaching and research in companion animal biology in departments of animal sciences. Departments of animal sciences must be relevant to a society in which a small number of people can raise almost all the food animal products needed. The declining number of people involved in animal agriculture has decreased enrollment of students interested in food animals in many departments of animal science. However, several departments welcomed students from a diverse background and began research on animals other than food animals. In many states, the undergraduate enrollment is made up primarily of students interested only in companion animals. A benefit of this is that we have recruite...
Trypanosoma evansi: A comparison of PCR and parasitological diagnostic tests in experimentally infected mice. Trypanosoma evansi is the causative agent of equine trypanosomosis, disease that affects horse's productivity and health. Parasitological and molecular methods are mostly used to detect the infection. The aim of this work was evaluate PCR sensitivity to detect T. evansi using the primers 21/22-mer, ITS1, ESAG 6/7 and TBR 1/2 designed from repetitive (multicopies) genomic sequences. The results were compare with two parasitological tests in mice, micro-haematocrite centrifugation technique and direct microscopic examination. The results shows (a) that the minimum amount of DNA from blood of hig...
Contractile behavior of the forelimb digital flexors during steady-state locomotion in horses (Equus caballus): an initial test of muscle architectural hypotheses about in vivo function. The forelimb digital flexors of the horse display remarkable diversity in muscle architecture despite each muscle-tendon unit having a similar mechanical advantage across the fetlock joint. We focus on two distinct muscles of the digital flexor system: short compartment deep digital flexor (DDF(sc)) and the superficial digital flexor (SDF). The objectives were to investigate force-length behavior and work performance of these two muscles in vivo during locomotion, and to determine how muscle architecture contributes to in vivo function in this system. We directly recorded muscle force (via ten...
Anaplasma phagocytophilum in horses and ticks: a preliminary survey of Central Italy. Anaplasma phagocytophilum, the causative agent of granulocytic ehrlichiosis, affects several species of wild and domesticated mammals, including horses. In this work we compared direct and indirect methods to evaluate A. phagocytophilum presence in Central Italy: 135 sera were screened by IFA for A. phagocytophilum and other haemopathogens (Theileria equi and Babesia caballi). Each horse was also tested for A. phagocytophilum 16S rRNA with a nested-PCR technique. In order to examine the risk of A. phagocytophilum transmission, 114 ticks were examined for the presence of A. phagocytophilum by P...
Missense mutation in exon 2 of SLC36A1 responsible for champagne dilution in horses. Champagne coat color in horses is controlled by a single, autosomal-dominant gene (CH). The phenotype produced by this gene is valued by many horse breeders, but can be difficult to distinguish from the effect produced by the Cream coat color dilution gene (CR). Three sires and their families segregating for CH were tested by genome scanning with microsatellite markers. The CH gene was mapped within a 6 cM region on horse chromosome 14 (LOD = 11.74 for theta = 0.00). Four candidate genes were identified within the region, namely SPARC [Secreted protein, acidic, cysteine-rich (osteonectin)], SL...
Western Equine Encephalitis submergence: lack of evidence for a decline in virus virulence. The incidence of Western Equine Encephalitis (WEE) in humans and equids peaked during the mid-20th century and has declined to fewer than 1-2 human cases annually during the past 20 years. Using the mouse model, changes in WEE virus (WEEV) virulence were investigated as a potential explanation for the decline in the number of cases. Evaluation of 10 WEEV strains representing a variety of isolation locations, hosts, and all decades from the 1940's to the 1990's yielded no evidence of a decline in virulence. These results suggest that ecological factors affecting human and equine exposure should...
Allometric scaling of echocardiographic measurements in healthy Spanish foals with different body weight. Scaling in biology is usually allometric, and therefore, the size of the heart may be expressed as a power function of body weight (BW). The present research analyses the echocardiographic measurements in 68 healthy Spanish foals weighed between 70 and 347kg in order to determine the correct scaling exponent for the allometric equation. The echocardiographic parameters measured were: left ventricular internal dimensions (LVID), free wall thickness (LVFWT), interventricular septum thickness (IVST) at systole (s) and diastole (d), EPSS (distance between the point E of the mitral valve and the in...
Effect of selenium source and dose on selenium status of mature horses. This study was conducted to determine the effects of either dietary Se source or dose on the Se status of horses. Twenty-five mature horses were blocked by BW and randomly allocated to 1 of 5 dietary treatments that comprised the same basal diet that differed only in Se source or dose. Treatments were as follows: negative control (0.085 mg of Se/kg of DM), 3 different dietary concentrations of supplemental organic Se (Se yeast; 0.2, 0.3, and 0.4 mg of total Se/kg of DM), and positive control (0.3 mg of total Se/kg of DM) supplemented with Na selenite. Horses initially received the control diet...
Heritability and repeatability of insect bite hypersensitivity in Dutch Shetland breeding mares. Insect bite hypersensitivity (IBH) is a seasonal recurrent allergic reaction of horses to the bites of certain Culicoides spp. and is found throughout the world. The aim of our study was to estimate the heritability and repeatability of IBH in the Dutch Shetland pony population. A total of 7,924 IBH scores on 6,073 mares were collected during foal inspections in 2003, 2005, and 2006. Mares were scored for clinical symptoms of IBH from June until February by 16 inspectors. Of all mares, 74.4% (n = 4,520) had a single observation, 20.7% (n = 1,255) had 2 observations, and 4.9% (n = 298) had 3 ob...
[Occurrence of nematodes in horses from the Northern region, State of Tocantins, Brazil]. The occurrence of nematodes in horses of Northern Region, State of Tocantins was studied. Fecal samples were collected from 70 horses and 31 donkeys, in a total of 101 animals of different ages, in the municipalities of Nova Olinda, Araguanã, Babaçulândia and Santa Tereza. Fecal examination was carried out for counting of eggs per gram of faeces, identification and quantification of larvae, diagnosis of habronemosis and lungworms. Significant occurrence of large and small strongyles and Dictyocaulus sp. was observed but no Habronema spp. larvae was detected.
[Quantitative prevalence of Anoplocephala sp. and egg shedding consistency in horses]. The objective of this work was to determine the quantitative prevalence of Anoplocephala sp. in thoroughbred horses raised in São José dos Pinhais, PR using the modified centrifugal-flotation technique. Repeatability values for the eggs per gram (EPG) were evaluated at 28-day intervals. The coproparasitological tests were made in 28 one-year old animals, 25 two-year old animals and 28 mares during the 2007 period of January 31st and June 15th. In the comparison of EPG, all mares presented low values than the foals (P = 0.04). The prevalence results indicated 50, 18 and 40% Anoplocephala sp. ...
Measuring the height at the withers of ponies at a competition and at home using a laser device. Measuring the height of ponies at the withers is currently a prerequisite at Fédération Equestre Internationale (FEI) competitions. A pony measured at a competition site must not measure more than 151 cm with, or 150 cm without horse shoes. When a pony exceeds the regulated height, it is excluded from participation in the competition. Moreover, the sale value of a pony can decrease dramatically if by height measurement it is designated as a 'horse'. The aim of this study was firstly to determine whether measuring ponies at the withers with a laser device is repeatable; secondly, to evaluate ...
Habitat-specific population growth of a farmland bird. To assess population persistence of species living in heterogeneous landscapes, the effects of habitat on reproduction and survival have to be investigated. Results: We used a matrix population model to estimate habitat-specific population growth rates for a population of northern wheatears Oenanthe oenanthe breeding in farmland consisting of a mosaic of distinct habitat (land use) types. Based on extensive long-term data on reproduction and survival, habitats characterised by tall field layers (spring- and autumn-sown crop fields, ungrazed grasslands) displayed negative stochastic population ...
The effect of mixing and changing the order of feeding oats and chopped alfalfa to horses on: glycaemic and insulinaemic responses, and breath hydrogen and methane production. The aim of this study was to investigate the effects of feeding oats alone before or after feeding chopped alfalfa or, in admixture with the alfalfa on the glycaemic and insulinaemic responses of horses as well as post-prandial breath hydrogen and methane excretion. Horses were fed in a randomized order, chopped alfalfa as a source of dietary fibre and unprocessed oats as a source of starch. Chopped alfalfa intake was adjusted to a crude fibre intake of 0.5 g/kg bodyweight (BW) per meal and the oats intake was adjusted to a starch intake of 2 g/kg BW per meal. The feeds were offered in three d...
Quantitative intradermal terbutaline sweat test in horses. The aim of the current study was to quantify sweating responses to intradermal terbutaline in normal horses. Seven Thoroughbred horses were used. Terbutaline (10-fold dilutions from 1000-0.001 mg/l) and a saline control were injected intradermally (0.1 ml/site) and sweat collected for 30 min into absorbent pads taped over each injection site. Tests were performed monthly for 11 successive months and temperature, relative humidity and dewpoint were measured at the time of testing. There was no significant effect (P<or=0.05) of environmental variables or time of year on sweat responses at any...
Oestrogens in faeces as an indicator of the foeto-placental unit function in mares. Total of 30 pregnant mares were used in this study: 17 Thoroughbred and 13 Primitive Polish Horse. The concentration of total unconjugated oestrogens was determined by radioimmunoassay in faecal samples obtained every second week after mating until delivery or interruption of pregnancy. Concentration of oestrogens in pregnant healthy mares ranged from 40 to 200 ng/g and showed typical profiles for pregnancy. In 5 of 30 mares (16.6%) of either breed abortions and cases of embryonic death occurred. Abortions were preceded by sharp or gradual decrease in oestrogen concentration, whereas prior to ...
Fat content and fatty acids profile of colostrum and milk of primitive Konik horses ( Equus caballus gmelini Ant.) during six months of lactation. The effect of the stage of lactation, the number of foals and age of the mare on changes in the fat content and fatty acid composition of colostrum and milk of primitive Konik horses was investigated. Colostrum and milk samples from 12 lactating mares were collected at the beginning of lactation, on the days 1 and 2 after foaling and then, starting from the first month of lactation, at 4-week intervals up to the sixth month of lactation. Significant differences were observed in fat content as well as the composition of some analysed fatty acids between colostrum and milk of mares of the Konik ...
Plasma vasopressin concentrations in healthy foals from birth to 3 months of age. Arginine vasopressin (AVP) has received increased attention in equine critical care but there is minimal information of AVP concentration in foals. The clinical usefulness of measuring AVP in ill foals depends on knowledge of age-related changes in AVP concentrations in healthy foals. Objective: Plasma AVP concentrations will be significantly different when measured from birth to 3 months of age in healthy foals. Methods: Thirteen healthy university-owned foals. Methods: Prospective, observational study. Blood was collected from healthy foals at birth and 3, 5, 7, 10, 14, 21, 28, 42, 56, and 8...
Comparative bone histology of adult horses (Equus caballus) and cows (Bos taurus). Bone microstructure of domestic herbivores is still not completely understood. Indeed, works focused on the bone histology of numerous Mammalian species frequently led to misunderstandings because of the high number of variations such as the kind of bone, section orientation, species, breed and age. Moreover, attempts to identify the species in archaeozoological studies by a mere qualitative approach have not been encouraging and in recent years quantitative methods, based on image processing and statistical analysis, have appeared. The present study was undertaken to determine whether morphom...
Walk-run classification of symmetrical gaits in the horse: a multidimensional approach. Walking and running are two mechanisms for minimizing energy expenditure during terrestrial locomotion. Duty factor, dimensionless speed, existence of an aerial phase, percentage recovery (PR) or phase shift of mechanical energy and shape of the vertical ground reaction force profile have been used to discriminate between walking and running. Although these criteria work well for the classification of most quadrupedal gaits, they result in conflicting evidence for some gaits, such as the tölt (a symmetrical, four-beat gait used by Icelandic horses). We use established pattern recognition meth...
Differential gene expression of TRPM1, the potential cause of congenital stationary night blindness and coat spotting patterns (LP) in the Appaloosa horse (Equus caballus). The appaloosa coat spotting pattern in horses is caused by a single incomplete dominant gene (LP). Homozygosity for LP (LP/LP) is directly associated with congenital stationary night blindness (CSNB) in Appaloosa horses. LP maps to a 6-cM region on ECA1. We investigated the relative expression of two functional candidate genes located in this LP candidate region (TRPM1 and OCA2), as well as three other linked loci (TJP1, MTMR10, and OTUD7A) by quantitative real-time RT-PCR. No large differences were found for expression levels of TJP1, MTMR10, OTUD7A, and OCA2. However, TRPM1 (Transient Recept...
Mechanisms for dominant follicle selection in monovulatory species: a comparison of morphological, endocrine and intraovarian events in cows, mares and women. The selection of a single ovarian follicle for further differentiation and finally ovulation is a shared phenomenon in monovulatory species from different phylogenetic classes. The commonality of dominant follicle (DF) development leads us to hypothesize that mechanisms for DF selection are conserved. This review highlights similarities and differences in follicular wave growth between cows, mares and women, addresses the commonality of the transient rises in FSH concentrations, and discusses the follicular secretions oestradiol and inhibin with their regulatory roles for FSH. In all three spe...
Complementary DNA cloning, functional expression and characterization of a novel cytochrome P450, CYP2D50, from equine liver. Members of the CYP2D family constitute only about 2-4% of total hepatic CYP450s, however, they are responsible for the metabolism of 20-25% of commonly prescribed therapeutic compounds. CYP2D enzymes have been identified in a number of different species. However, vast differences in the metabolic activity of these enzymes have been well documented. In the horse, the presence of a member of the CYP2D family has been suggested from studies with equine liver microsomes, however its presence has not been definitively proven. In this study a cDNA encoding a novel CYP2D enzyme (CYP2D50) was cloned f...
The prokinetic effect of mosapride citrate on horse gastric emptying rates. The prokinetic effect of the 5-HT4 receptor agonist mosapride was evaluated in seven healthy thoroughbreds. Mosapride was orally administered at doses of 0.5, 1.0 or 1.5 mg/kg. The breath 13CO2/12CO2 rate (Delta13CO2), an indirect indicator for the rate of gastric emptying, was measured at appropriate points for 4 hr after drug administration. There was a significant increase compared with the control value at 15, 20 and 165 min for 0.5 mg/kg, 30 min at 1.0 mg/kg and 165 min for 1.5 mg/kg. The results suggest that mosapride may facilitate the gastric emptying in horses.
A musculoskeletal model of the equine forelimb for determining surface stresses and strains in the humerus-part II. Experimental testing and model validation. The first objective of this study was to experimentally determine surface bone strain magnitudes and directions at the donor site for bone grafts, the site predisposed to stress fracture, the medial and cranial aspects of the transverse cross section corresponding to the stress fracture site, and the middle of the diaphysis of the humerus of a simplified in vitro laboratory preparation. The second objective was to determine whether computing strains solely in the direction of the longitudinal axis of the humerus in the mathematical model was inherently limited by comparing the strains measured...
