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Topic:Comparative Study
Comparative studies in equine research involve the systematic analysis of different horse breeds, management practices, or physiological responses to identify variations and similarities. These studies are instrumental in understanding how different factors influence health, performance, and behavior in horses. Common areas of comparison include genetic traits, nutritional requirements, disease resistance, and response to training. By evaluating these differences, researchers can develop targeted strategies for breeding, healthcare, and training. This page aggregates peer-reviewed research studies and scholarly articles that focus on the methodologies, findings, and implications of comparative studies in the context of equine science.
Molecular cloning and sequencing of equine cDNA encoding serum amyloid A (SAA). The serum amyloid A (SAA) protein is a characteristic and sensitive acute phase reactant in all vertebrates investigated. We molecularly cloned the equine cDNA encoding SAA from the liver of a healthy horse by polymerase chain reaction (PCR). The cloned cDNA is 480 bases in length, and contains an open reading frame (ORF) of 387 nucleotides encoding a precursor SAA protein of 128 amino acids. The precursor of horse SAA seems to have an 18-residue signal peptide and differs from the reported amino acid sequences of the horse SAA by substitution of valine at residue 81. It shows high homology wi...
Identification of twelve O-glycosylation sites in equine chorionic gonadotropin beta and equine luteinizing hormone ss by solid-phase Edman degradation. The O-glycosylation sites for equine LHss (eLHss) and eCGss were identified by solid-phase Edman degradation of four glycopeptides derived from the C-terminal region. Both subunits were O-glycosylated at the same 12 positions, rather than the 4-6 sites anticipated. These sites were partially glycosylated, with carbohydrate attachment ranging from 20% to 100% for eCGss and from 10% to 100% for eLHss. When the C-terminal peptide containing all but one of the O-linked oligosaccharides was removed by mild acid hydrolysis of either eLHss or eCGss, hybrid hormones could be obtained by reassociating ...
Equine P450 cholesterol side-chain cleavage and 3 beta-hydroxysteroid dehydrogenase/delta(5)-delta(4) isomerase: molecular cloning and regulation of their messenger ribonucleic acids in equine follicles during the ovulatory process. The preovulatory LH rise is the physiological trigger of follicular luteinization, a process during which the synthesis of progesterone is markedly increased. To study the control of follicular progesterone biosynthesis in mares, the objectives of this study were to clone and characterize the equine cholesterol side-chain cleavage cytochrome P450 (P450(scc)) and 3 beta-hydroxysteroid dehydrogenase/Delta(5)-Delta(4)-isomerase (3 beta-HSD), and describe the regulation and cellular localization of their transcripts in equine follicles during hCG-induced ovulation. Complementary DNA cloning and pr...
In vitro comparison of transfixation and standard full-limb casts for prevention of displacement of a mid-diaphyseal third metacarpal osteotomy site in horses. To compare transfixation and standard full-limb casts for prevention of in vitro displacement of a mid-diaphyseal third metacarpal osteotomy site in horses. Methods: 6 forelimbs from 6 horses euthanatized for reasons not related to the musculoskeletal system. Methods: A 30 degrees osteotomy was performed in the mid-diaphysis of the third metacarpal bone. Two 4.5-mm cortical bone screws were placed across the osteotomy site to maintain alignment during casting. Two 6.35-mm Steinmann pins were placed from a lateral-to-medial direction in the distal aspect of the radius. A full-limb cast that inc...
Significance of plasmalemma disruption in bovine and equine spermatozoa. We have investigated fresh and cryopreserved bovine and equine spermatozoa using light and transmission soft X-ray microscopy. Spermatozoa were examined, in the presence or absence of semen, after using Percoll gradient centrifugation and re-suspending in medium. X-ray microscopy provided high resolution (30 nm) transmission images of whole cells in solution with high contrast, while retaining the simple preparation techniques used in light microscopy. We demonstrated translucent, membrane-bound vesicles in the acrosomal and midpiece regions that were similar in size and we noted their inciden...
A comparison of the palmaroproximal-palmarodistal view of the isolated navicular bone to other views. A collection of 69 isolated navicular bones, normal or affected with navicular disease, was examined radiographically using dorsopalmar, lateromedial and palmaroproximal-palmarodistal views. Radiographic findings on each view were recorded. A radiographic diagnosis of normality or navicular disease was made, first on each view separately and afterwards based on the combination of the 3 views. Forty-four navicular bones were considered radiographically normal and 25 navicular bones had distinct signs of radiographic navicular disease. The dorsopalmar and the lateromedial views of each navicular...
Topography of ganglion cells in the retina of the horse. Topography of ganglion cells in the retina of the horse (Thoroughbred) was analyzed in the wholemount retina stained with cresyl violet, and a total number of ganglion cells were estimated. Sizes of ganglion cells were also measured and size spectra were analysed. The main results showed that: (1) a common point in 4 wholemount retinae, based on cell densities and retinal locations, was that a retina could be divided into 5 regions, namely visual streak, nasal, temporal, dorsal and ventral region to the visual streak. A maximum cell density of 4,000 cells/mm2 was found in the visual streak. An...
Expression of vasoactive intestinal peptide, calcitonin gene-related peptide, substance P, and intermediate neurofilaments in nasal mucosal nerve fibers of horses without nasal disease. To determine the distribution of nerve fibers containing calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP), and intermediate neurofilaments in nasal mucosa of horses. Methods: 6 horses without evidence of nasal disease. Methods: Full-thickness nasal tissue specimens were obtained from the rostral portion of the nasal septum at necropsy, and fluorescence immunohistochemistry was performed to assess mucosal distribution of nerve fibers. Results: Nerve fibers with CGRP-like immunoreactivity (CGRP-Li) formed a dense subepithelial network, and a large num...
Cytogenetic localization of 44 new coding sequences in the horse. The purpose of this study was to increase the number of genes assigned by in situ hybridization to equine chromosomes and thus the number of links for comparative mapping with other species. Forty-four new sequences were added to the horse cytogenetic map by FISH mapping of BAC clones containing genes (35) or ESTs (9). Three approaches were developed: use of horse BAC clones screened with (i) horse EST primers, (ii) interspecific consensus intraexonic primers, and (iii) use of goat BAC containing genes previously localized on goat chromosomes. Present data suggest that the second approach is t...
Phenylephrine eyedrops as a diagnostic test in equine grass sickness. The effect of an ocular administration of the alpha-1 adrenergic agonist phenylephrine was studied in 23 cases of grass sickness and 12 control horses. In the horses with grass sickness there was a significantly greater mean increase in the size of the palpebral fissure, as measured by the change in the angle of the eyelashes to the head observed from a frontal view.
Investigation of romifidine and detomidine for the clinical sedation of horses. The effects of two intravenous doses of romifidine (80 and 120 microg/kg) and one dose of detomidine (20 microg/kg) were compared in a blinded study in 30 horses requiring to be sedated for routine dental treatment. Several physiological parameters were assessed before and for two hours after the administration of the drugs, and the horses' teeth were rasped 30 minutes after they were administered. Romifidine produced a dose-dependent effect on most parameters. Detomidine at 20 microg/kg was similar to romifidine at 120 microg/kg in the magnitude of its sedative effects, but was similar to rom...
Comparative disposition of tripelennamine in horses and camels after intravenous administration. The pharmacokinetics of tripelennamine (T) was compared in horses (n = 6) and camels (n = 5) following intravenous (i.v.) administration of a dose of 0.5 mg/kg body weight. Furthermore, the metabolism and urinary detection time was studied in camels. The data obtained (median and range in brackets) in camels and horses, respectively, were as follows: the terminal elimination half-lives were 2.39 (1.91-6.54) and 2.08 (1.31-5.65) h, total body clearances were 0.97 (0.82-1.42) and 0.84 (0.64-1.17)L/h/kg. The volumes of distribution at steady state were 2.87 (1.59-6.67) and 1.69 (1.18-3.50) L/kg, ...
Fourier analysis of acetabular shape in native American Arikara populations before and after acquisition of horses. The goal of this study was to identify changes in acetabular morphology associated with the use of horses by Native Americans. Previous studies reported "elongate" acetabula in horseback-riding members of the Omaha and Ponca populations. Such a difference in acetabular shape is a potentially useful osteological marker of habitual horseback riding. This report compares acetabula of adult males from two Native American Arikara populations known to have differed substantially in their use of horses. Population samples were from separate sites in South Dakota: Larson (nonriding) and Leavenworth (r...
Characterization of a coronavirus isolated from a diarrheic foal. A coronavirus was isolated from feces of a diarrheic foal and serially propagated in human rectal adenocarcinoma (HRT-18) cells. Antigenic and genomic characterizations of the virus (isolate NC99) were based on serological comparison with other avian and mammalian coronaviruses and sequence analysis of the nucleocapsid (N) protein gene. Indirect fluorescent-antibody assay procedures and virus neutralization assays demonstrated a close antigenic relationship with bovine coronavirus (BCV) and porcine hemagglutinating encephalomyelitis virus (mammalian group 2 coronaviruses). Using previously des...
Screw fixation in lag fashion of equine cadaveric metacarpal and metatarsal condylar bone specimens: a biomechanical comparison of shaft and cortex screws. To compare acute fixation stability and insertion effort of cortex bone screws with and without a shaft inserted in lag fashion in equine metacarpal (metatarsal, MC(T)III) bone. Methods: Screw types with independent variables of screw diameter (4.5 or 5.5 mm) and shaft type (without shaft, with 20-mm shaft, or with 25-mm shaft) were studied. Bone specimens cut from distal equine MC(T)III condyles were used. After screw insertion in lag fashion into 2 bone blocks with an instrumented device, shear tests were conducted in a mechanical testing machine. Outcome variables of peak insertion torque, ...
Comparison of culture and insemination techniques for equine oocyte transfer. This study was designed to test 3 approaches for insemination and transfer of oocytes to recipient mares. Oocytes were recovered transvaginally from naturally cycling donor mares 24 to 26 h after an intravenous injection of 2500 IU of hCG when follicles reached 35 mm in diameter. Multiple oocytes (1 to 4) were transferred surgically into the oviducts of 4 or 5 recipient mares per group. Three groups of transfers were compared: 1) transfer of oocytes cultured in vitro for 12 to 14 h postcollection with insemination of the recipient 2 h postsurgery; 2) transfer of oocytes into the oviduct within...
Effects of maternally administered depot ACTH(1-24) on fetal maturation and the timing of parturition in the mare. The aims of this study were to ascertain 1) whether fetal maturation could be induced precociously by maternal administration with adrenocorticotrophic hormone (ACTH) and 2) whether maturation could be achieved without significant risk to mare or fetus. Twenty-two mares received either 1 mg (low dose, LD, n = 6) or 4 or 5 mg (higher dose, HD, n = 16) synthetic Depot ACTH(1-24) at 300, 301 and 302 days gestation. Because, during the course of the study, ACTH appeared to have a greater influence on mares mated during the later part of the breeding season, the HD group were divided retrospectivel...
Dynamics of follicle populations and gonadotropin concentrations in fillies age two to ten months. Follicle populations and concentrations of circulating gonadotropins were studied during age 2-10 months in 10 spring-born pony fillies. Blood sampling and ultrasound scanning were done every 4 days and daily for four 30 day periods. During 5-12 weeks, FSH concentrations were lower in 6 fillies with follicles > or = 6 mm (mean +/- s.e. 1.4 +/- 0.1 ng/ml) than in 4 fillies with follicles 10 mm and gonadotropin concentrations increased. Waves of follicular growth were identified during the 30 day periods by significant increases in the diameter of the 10 largest follicles. The waves did not ...
Reduction of renal function in exercising horses. Glomerular filtration rate (GFR) and extracellular volume (ECFV) were measured before, during and after treadmill exercise in 5 trained Thoroughbred horses (mean weight 483 kg). GFR/ECFV was determined by plasma disappearance of Tc-DTPA and ECFV was measured independently as thiocyanate space. Resting GFR averaged 1.6 l/min (3.3 ml/kg/min) and fell by over 40% during exercise, moreover the fall was severe even during the first walk, prior to trotting. The results suggest that rather than being protected, GFR is allowed to fall, even with mild exercise and that this is probably an adaptation to...
Serum markers of lamellar basement membrane degradation and lamellar histopathological changes in horses affected with laminitis. In order better to evaluate the extent to which degradation of the lamellar basement membrane (LBM) by matrix metalloproteinases (MMP) occurs in equine laminitis, we determined the concentration of type IV collagen and laminin in normal and laminitic horses, using specific immunoassays. Blood samples were obtained from both the jugular and the cephalic veins of horses (n = 10) before and after the induction of acute alimentary laminitis by carbohydrate overload. Jugular and cephalic venous blood samples were also obtained from horses affected with naturally occurring laminitis (n = 16) and non...
Sialic acid species as a determinant of the host range of influenza A viruses. The distribution of sialic acid (SA) species varies among animal species, but the biological role of this variation is largely unknown. Influenza viruses differ in their ability to recognize SA-galactose (Gal) linkages, depending on the animal hosts from which they are isolated. For example, human viruses preferentially recognize SA linked to Gal by the alpha2,6(SAalpha2,6Gal) linkage, while equine viruses favor SAalpha2,3Gal. However, whether a difference in relative abundance of specific SA species (N-acetylneuraminic acid [NeuAc] and N-glycolylneuraminic acid [NeuGc]) among different animal...
Internal ribosomal entry site-mediated translation initiation in equine rhinitis A virus: similarities to and differences from that of foot-and-mouth disease virus. Equine rhinitis A virus (ERAV) has recently been classified as an aphthovirus, a genus otherwise comprised of the different serotypes of Foot-and-mouth disease virus (FMDV). FMDV initiates translation via a type II internal ribosomal entry site (IRES) and utilizes two in-frame AUG codons to produce the leader proteinases Lab and Lb. Here we show that the ERAV 5' nontranslated region also possesses the core structures of a type II IRES. The functional activity of this region was characterized by transfection of bicistronic plasmids into BHK-21 cells. In this system the core type II structures, ...
Changes in the plasma membrane proteins of stallion spermatozoa during maturation in the epididymis. The present paper reports modifications in the electrophoretic and cytochemical characteristics of mature and immature stallion spermatozoa. Some sperm surface glycoproteins (36, 32, 29, 21, 20, 18 kDa) detected in cauda epididymidis spermatozoa, were either absent or present in a very low relative concentration in immature sperm cells. A major 14 kDa protein band, observed in sperm extracts obtained from ductus efferentes, progressively decreased along the epididymal ductus. The nature and distribution of carbohydrate residues on the sperm membrane, during epididymal maturation, was also stud...
A novel uterine lipocalin supporting pregnancy in equids. Horses, donkeys, and therefore, probably all equids, secrete a nonglycosylated, progesterone-dependent, 19-kDa protein (P19) into the uterine lumen during early pregnancy, and significant quantities of it are taken up by the developing conceptus. Sequence analysis and structural modelling have identified P19 as a lipocalin with greatest similarity to the murine major urinary protein lipocalins. However, lack of strong identity with any particular group of lipocalins and several unusual structural features, including a unique amino acid triplet within one of the invariant domains and an unusual...
[Comparative study of three feeding methods for draught horses of the Swiss army]. Three feeding methods were compared in 36 4- to 6-year-old Franche-Montagne horses during the military school of St-Luzisteig (GR) of Spring 1992. The horses were separated into 3 groups: a group with the traditional oats-hay ration (OH), a group with a pelleted feed and hay ration (PFH), and a group with the complete diet (CD). Feed analyses were performed and food consumption, eating behavior and digestibility were studied. The horses received their daily amount of feed in 3 portions covering the requirements for a medium work: OH = 8 kg hay and 3 kg oats, PFH = 8 kg hay and 3 kg pelleted fe...
Colonization of the stratified squamous epithelium of the nonsecreting area of horse stomach by lactobacilli. Selective adhesion to only certain epithelia is particularly common among the bacterial members of the indigenous microflora of mammals. We have found that the stratified squamous epithelium of the nonsecreting area of horse stomach is colonized by gram-positive rods. The microscopic features of a dense layer of these bacteria on the epithelium were found to be similar to those reported in mice, rats, and swine. Adhering microorganisms were isolated and identified as Lactobacillus salivarius, L. crispatus, L. reuteri, and L. agilis by DNA-DNA hybridization and 16S rRNA gene sequencing techniqu...
Evaluation of an in-house centrifugal hematology analyzer for use in veterinary practice. To compare CBC results obtained by use of an in-house centrifugal analyzer with results of a reference method. Methods: Prospective study. Methods: Blood samples from 147 dogs, 42 cats, and 60 horses admitted to a veterinary teaching hospital and from 24 cows in a commercial dairy herd. Methods: Results obtained with the centrifugal analyzer were compared with results obtained with an electrical-impedance light-scatter hematology analyzer and manual differential cell counting (reference method). Results: The centrifugal analyzer yielded error messages for 50 of 273 (18%) samples. Error message...
Concentrations of gentamicin in serum and bronchial lavage fluid after intravenous and aerosol administration of gentamicin to horses. To compare concentrations of gentamicin in serum and bronchial lavage fluid after IV and aerosol administration of gentamicin to horses. Methods: 9 healthy adult horses. Methods: Gentamicin was administered by aerosolization (20 ml of gentamicin solution [50 mg/ml]) and IV injection (6.6 mg of gentamicin/kg of body weight) to each horse, with a minimum of 2 weeks between treatments. Samples of pulmonary epithelial lining fluid were collected by small volume (30 ml) bronchial lavage 0.5, 4, 8, and 24 hours after gentamicin administration. Serum samples were obtained at the same times. All sampl...
Equine uteroplacental metabolism at mid- and late gestation. Uptakes of oxygen, glucose and lactate by the gravid uterus, fetus and uteroplacental tissues were measured in chronically catheterized pregnant ponies and their fetuses at mid- and late gestation (term 335 days). Rates of O2 uptake by the gravid uterus, fetus and uteroplacental tissues were significant at both gestational ages and were 2- to 3-fold higher in late gestation than the mid-gestation values of 3338+/-794, 1352+/-258 and 2035 +/- 602 micromol min(-1), respectively (n = 4). Similarly, there were significant uptakes of glucose by the gravid uterus, fetus and uteroplacental tissues at...
In vitro comparison of the use of two large-animal, centrally threaded, positive-profile transfixation pin designs in the equine third metacarpal bone. To compare the in vitro holding power and associated microstructural damage of 2 large-animal centrally threaded positive-profile transfixation pins in the diaphysis of the equine third metacarpal bone. Methods: 25 pairs of adult equine cadaver metacarpal bones. Methods: Centrally threaded positive-profile transfixation pins of 2 different designs (ie, self-drilling, self-tapping [SDST] vs nonself-drilling, nonself-tapping [NDNT] transfixation pins) were inserted into the middiaphysis of adult equine metacarpal bones. Temperature of the hardware was measured during each step of insertion with ...
