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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.
Structural features of mammalian gonadotropins. There are two species for which both pituitary and placental gonadotropins are readily available, humans and horses. The human gonadotropins are better characterized than equine gonadotropins. Nevertheless, the latter are very interesting because they provide exceptions to some of the general structure-function principles derived from studies on human and other mammalian gonadotropins. For example, separate genes encode the hLH beta and hCG beta subunits while a single gene encodes eLH beta and eCG beta. Thus, eCG and eLH differ only in their oligosaccharide moieties and eLH is the only LH tha...
Primary structure of stallion seminal plasma protein HSP-7, a zona-pellucida-binding protein of the spermadhesin family. The primary-structure of HSP-7, a 14-kDa protein isolated from stallion seminal plasma, has been determined, HSP-7 belongs to the spermadhesin protein family, shares 98% sequence identity with the boar seminal plasma protein AWN, and, like its boar homolog, displays zona-pellucida-binding activity. Despite these conserved structural and functional features, the equine and porcine spermadhesins differ in their topography on spermatozoa.
Fibronectin concentrations correlate with ovarian follicular size and estradiol values in equine follicular fluid. The amounts of total protein, albumin, fibronectin, alpha 2-macroglobulin (alpha 2-M), immunoglobulin G, ceruloplasmin and antithrombin were determined in fluids collected from 53 preovulatory equine follicles and compared with the contents of estradiol-17 beta, progesterone and androstenedione, with follicle size and the amounts of the equivalent proteins in normal equine plasma. The concentration of fibronectin and the fibronectin/albumin ratios increased significantly with follicle size and with follicular estradiol levels. The alpha 2-M levels and alpha 2-M/albumin ratios correlated with f...
[Observations of Setaria equina (Nematoda: Setariidae) with the optical microscope and scanning electron microscope]. Adults of S. equina (Spirurida, Setariidae), 1 male and 2 females, collected from vaginal sac of stallion, were studied by soanning electron microscopy (SEM). The amphids, cephalic and cervical papillae, peribuccal ring, fine transverse bands and bosses of the cuticle, as well as caudal papillae were visualized clearly at this examination. The results of the present survey contribute towards the identification of S. equina, improve the definition of the characters which are demonstrated by common light microscopy and give the exact number of male caudal papillae including the lateral cloacal r...
Measurement of cardiac output by transoesophageal Doppler echocardiography in anaesthetized horses: comparison with thermodilution. In order to determine if transoesophageal Doppler echocardiography could be used to estimate cardiac output in anaesthetized horses, we have compared the technique with estimations of cardiac output by thermodilution in eight healthy adult thoroughbreds. Measurements of aortic blood flow velocity were made by high pulse repetition frequency (HPRF) and continuous wave (CW) Doppler echocardiography from a 3.5-MHz transoesophageal probe. Cardiac output was increased during the study by administration of dobutamine, providing a range of cardiac output measurements by thermodilution from 15.0 to 64...
Trophectoderm projections: a potential means for locomotion, attachment and implantation of bovine, equine and human blastocysts. The behaviour of bovine, equine and human blastocysts was studied in vitro by time-lapse videomicrography and computer imaging. This study revealed that cytoplasmic extensions of the trophectoderm ['trophectoderm projections' (TEP)] were expressed by embryos of all three species, prior to or during zona escape. Bovine and human blastocysts escaped their zonae with a combination of blastocoele expansion, collapse and re-expansion coupled with the penetration of the zona pellucida by TEP. In equine embryos, after several cycles of blastocoele expansion and collapse, trophectoderm ruptured the zo...
Separation of equine IgG subclasses (IgGa, IgGb and IgG(T)) using their differential binding characteristics for staphylococcal protein A and streptococcal protein G. Equine IgG possesses four well-defined subisotypes, designated IgGa, IgGb, IgGc and IgG(T) on the basis of their increasing anodal mobility in electrophoresis. However, the preparation of IgGa and IgGb reference proteins has not previously been reported. Certain bacterial cell wall proteins, termed protein A and protein G, have been used for purification of IgG subisotypes from the serum of domestic animals which, combined with other techniques utilising differences in the physico-chemical properties of the proteins, has allowed the purification of Ig isotypes. This paper describes purificatio...
Alterations in equine guttural pouch morphology with head position: observations using a new technique for producing accurate casts. An improved technique for preparing casts of the equine guttural pouch is described. The new technique is simplified and inexpensive in comparison to previous techniques and produces highly accurate anatomic models which are both durable and flexible. Methods: Silicone rubber bathtub caulk was injected into the guttural pouches of horse cadavers. The silicone was allowed to cure overnight, and casts were removed by dissection. The new technique was then used to evaluate changes in the shape of the guttural pouch with changes in head position. Results: With flexion of the atlanto-occipital join...
Measurement of extravascular lung water by the double indicator dilution method using heat and sodium in horses under general anesthesia. Rapid infusion is believed to be harmful to the lung, however, the pathological status of pulmonary edema resulting from excessive fluid therapy in horses has not been clarified because the quantitative diagnosis of pulmonary edema is impossible. To evaluate the precision of the double indicator dilution method using heat and sodium in horses, which allows the quantitative diagnosis of pulmonary edema, we compared extravascular lung water volume measured using a lung water computer based on the theory of the double indicator dilution method with that determined by the direct method. The value ...
[The effect of the season and sexual stress on the concentration of testosterone and estradiol-17beta in the seminal plasma of stallions]. Semen from three stallions was collected weekly for six months (December through May) to determine semen parameters and hormones (testosterone and estradiol-17 beta) in seminal plasma. Once a month three ejaculates were collected at intervals of one hour and examined accordingly. Testosterone and estradiol-17 beta were also determined in peripheral blood plasma (V. jugularis) collected twice a week. Semen parameters (volume, gel-free volume and sperm concentration) were clearly influenced by season. The testosterone concentration in peripheral blood plasma was lowest during December whereas in...
Collagen fiber organization is related to mechanical properties and remodeling in equine bone. A comparison of two methods. We studied birefringence as an indicator of collagen fiber orientation in the diaphysis of the equine third metacarpal bone. We had previously shown that tissue from the lateral cortex of this bone is stronger monotonically, but less fatigue resistant, than tissue from the medial and dorsal regions. To learn whether collagen fiber orientation might play a role in this regional specialization, we tested three hypotheses using the same specimens: (1) collagen fiber orientation is regionally dependent; (2) remodeling changes collagen fiber orientation; (3) longitudinal collagen fibers correlate p...
The structure of the keratan sulphate chains attached to fibromodulin isolated from articular cartilage. Fibromodulin has been isolated from bovine and equine articular cartilage and the attached keratan sulphate chains subjected to digestion by keratanase II. The oligosaccharides generated have been reduced and subsequently isolated by strong anion-exchange chromatography. Their structures have been determined by high-field 1H-NMR spectroscopy and high-pH anion-exchange chromatography. Both alpha(2-6)- and alpha(2-3)-linked N-acetylneuraminic acid have been found in the capping oligosaccharides, and, fucose which is alpha(1-3)-linked to N-acetylglucosamine has been found as a branch in both repe...
Analysis of the long terminal repeat from a cytopathic strain of equine infectious anemia virus. Sequential passage of the tissue culture-adapted prototype strain of EIAV in fetal donkey dermal (FDD) cell cultures generated a virus stock which exhibits cytopathic effects in FDD cell cultures. In this study, the effects of the long terminal repeat (LTR) region on virus replication and cytopathogenicity were examined. The FDD-adapted virus LTR was found to contain a number of base pair mutations and a large insertion within the U3 region in comparison with the previously characterized LTR, lambda12. Transient gene expression studies showed that basal promoter activity, in FDD cell cultures,...
Use of diagnostic ultrasonography in horses with signs of acute abdominal pain. To evaluate the use of abdominal ultrasonography as a diagnostic tool in horses with signs of colic. Methods: Prospective study. Methods: 226 horses with signs of acute abdominal pain were compared to 20 clinical normal horses. Methods: The following were performed in horses with signs of colic: physical examination, CBC, abdominal fluid analysis, placement of a nasogastric tube to obtain gastric reflux, abdominal palpation per rectum, and ultrasonography of the abdomen. Results of ultrasonography were compared with the surgical, necropsy, or medical findings. Results: Ultrasonography of horse...
Scanning electron microscopy of the equine oviduct and observations on ciliary currents in vitro at day 2 after ovulation. There are considerable differences between mammalian species in the distribution and activity of ciliated cells within the oviduct, and limited information is available concerning either the distribution or activity of cilia within the equine oviduct. Patterns of ciliary activity were characterized in the ampulla and isthmus of oviducts recovered at 2 d after ovulation from 10 mares, and scanning electron microscopy was used to examine regional differences in the distribution of cilia in oviducts from 3 of these mares. Based upon the motility of 15 microm latex microspheres, ciliary activity w...
Evaluation of pulse oximetry in anaesthetised foals using multiple combinations of transducer type and transducer attachment site. A commercially available pulse oximeter was evaluated in anaesthetised foals to determine its accuracy for estimating arterial haemoglobin saturation (SaO2). Five different transducer/transducer attachment site (TTAS) combinations were evaluated; 1-3) a fingertip transmission transducer attached to the foal's ear, lip and tongue, 4) an adhesive transmission transducer positioned on the foal's ear and 5) a forehead reflectance transducer placed on the ventral aspect of the foal's tail-base. Eight normal, Quarter Horse foals (age 5-10 days) were studied while under general anaesthesia. Alteratio...
Immunohistochemical examination of light-chain expression (lambda/kappa ratio) in canine, feline, equine, bovine and porcine plasma cells. Five species of domestic animals were examined immunohistochemically and the light-chain ratios of the immunoglobulins produced by plasma cells analysed. Forty dogs, 11 cats, 10 horses, 11 cattle and 14 pigs were tested using the sequential indirect immunoperoxidase and immunophosphatase methods. Tissues from the tonsils, spleen and cervical lymph nodes were analysed. It could be seen that the lambda/kappa ratio in dogs, cats, horses and cattle is largely dominated by the lambda chains (lambda/kappa ratio in dogs: 91/9%, in cats; 92/8%; in horses: 96/4%; in cattle: 91/9%). A more or less balan...
Factors related to the time of fixation of the conceptus in mares. The temporal relationships among day of conceptus fixation (cessation of mobility), conceptus diameter, uterine tone, uterine contractility, and myometrial and endometrial thickness of the middle and caudal segments of the uterine horns were assessed in 13 pony mares with fixation in the caudal segment of a uterine horn. The mean day of fixation (14.9 +/- 0.3) was established by 2-h mobility trials. Uterine tone increased (P < 0.0001) gradually over Days 11 to 21, whereas uterine contractility decreased (P < 0.0001) between Days 14 and 18. The diameter of the spherical embryonic vesicle ...
Study of the haemolytic process and receptors of thermostable direct haemolysin from Vibrio parahaemolyticus. The haemolytic action of 125I-labelled thermostable direct haemolysin from Vibrio parahaemolyticus was studied on human and equine erythrocytes. In the first step, the haemolysin bound to the membranes of both erythrocyte species. This binding seemed temperature-independent. Then, for human erythrocytes, haemolysin produced cell disruption, and haemoglobin was released. Following this step, haemolysin was also released in a temperature-dependent manner. In contrast, equine erythrocytes were not disrupted, and no release of haemolysin occurred. The receptors of labelled haemolysin were analysed...
The complete mitochondrial DNA (mtDNA) of the donkey and mtDNA comparisons among four closely related mammalian species-pairs. The nucleotide sequence of the complete mitochondrial genome of the donkey, Equus asinus, was determined. The length of the molecule is 16,670 bp. The length, however, is not absolute due to pronounced heteroplasmy caused by variable numbers of two types of repetitive motifs in the control region. The sequence of the repeats is (a) 5'-CACACCCA and (b) 5'-TGCGCGCA, respectively. The order of (a) and (b) can be expressed as {n[2(a)+(b)]+m(a)}. In 32 different clones analyzed the number of n and m ranged from 0 to 9 and 1 to 7. The two rRNA genes, the 13 peptide-coding genes, and the 22 tRNA gene...
Equine motor neuron disease is not linked to Cu/Zn superoxide dismutase mutations: sequence analysis of the equine Cu/Zn superoxide dismutase cDNA. The cDNA encoding the equine copper/zinc superoxide dismutase (SOD1) was cloned from leukocyte total RNA from healthy horses and its nucleotide (nt) sequence was determined. We further sequenced the SOD1 gene from 16 horses diagnosed with equine motor neuron disease (EMND) and eight unrelated, clinically normal horses to determine if this disease, similar to amyotrophic lateral sclerosis (ALS) in humans, is linked to SOD1 mutations. The 465-bp SOD1 coding region in the horse encodes 153 amino acid (aa) residues. Equine SOD1 exhibited 81.8 and 79.9% sequence identity to the human homolog at the...
PCR-RFLP analysis of the cytochrome b gene in horse mitochondrial DNA. The mitochondrial DNA sequence of cytochrome b gene in a Thoroughbred horse was determined. By comparing DNA sequences between the Thoroughbred and published sequence data (two horses and one Grevyi zebra), polymerase chain reaction (PCR) primers were designed for amplification of a 590 bp DNA fragment in the cytochrome b gene, and PCR-restriction fragment length polymorphism (RFLP) analysis was studied in 140 horses of six breeds using three restriction enzymes (AciI, BamHI, RsaI). Two morphs were found using each of the three enzymes. By combining three enzymes morphs, the 140 horses examine...
The effect of exercise on diaphragmatic activation in horses. Horses chronically-instrumented with costal diaphragmatic electromyographic electrodes were studied during exercise while unencumbered by a breathing mask. Exercise-associated changes in esophageal (Pes), gastric (Pga) and transdiaphragmatic (Pdi) pressures were measured and related to diaphragmatic electromyographic activity (CS EMG) and to left forelimb impact. In all breaths examined, CS EMG always coincided with decrements in Pes. For all exercise trials, linear increases in CS EMG, Pga and Pdi and linear decreases in Pes, as a function of exercise intensity, always occurred. During all ga...
Peritoneal fluid analysis in peripartum mares. To characterize, in mares, changes in peritoneal fluid that occurred within the first 7 days after routine foaling. Methods: Prospective observational trial. Methods: 15 mares. Methods: Abdominocentesis was performed within 10 days before foaling and again 12 hours, 3 days, and 7 days after each horse foaled. Data recorded for each sample included total nucleated cell count, differential cell count, specific gravity, fibrinogen concentration, and total protein concentration. Smears of each sample were examined by a single clinical pathologist. Results: There were not any significant difference...
Analysis of the equine tumor suppressor gene p53 in the normal horse and in eight cutaneous squamous cell carcinomas. Wild type equine p53 was amplified between exons 2 and 9 by the polymerase chain reaction using primers designed from conserved regions in other species. An 828 base pair region, corresponding to codons 25-313 of human p53, was sequenced in both directions. Human and equine amino acid sequences were 87% homologous in this region and 96% homologous in conserved domains II-V. Of eight equine cutaneous or mucocutaneous squamous cell carcinomas directly sequenced from exons 5-8, two had p53 point mutations resulting in single amino acid substitutions.
Comparative morphology of the pectinate ligaments of domestic mammals, as observed under the dissecting microscope and the scanning electron microscope. The pectinate ligaments of ten horses, two donkeys, five oxen, five sheep, ten goats, five dogs, five cats, thirty pigs and two rabbits were studied under the stereomicroscope and the scanning electron microscope. In the horse and the donkey, the pectinate ligament was very prominent and was characterized by sturdy interconnected strands and relatively small intertrabecular spaces. The pectinate ligaments of ruminants were composed of shorter strands, separated by relatively larger spaces. Fusion between adjacent strands, resulting in the formation of fenestrated sheets, was regularly observed...
Variability of cardiomyocyte DNA content, ploidy level and nuclear number in mammalian hearts. DNA content, ploidy level, cell size and nuclear number were investigated in 54 mammalian hearts from nine species. DNA content was determined biochemically and ploidy level of cells was studied by the means of Feulgen cytophotometry. Nuclear number was calculated by a new method, while cell size was determined by using ocular micrometry. In most mammals diploid cell nuclei predominate. Higher ploidy levels were found in the human and the pig hearts. The total amount of DNA correlated with the myocardial weight. Eight million heart muscle cell nuclei were found in mice (myocardial weight 160 m...
