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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.
Peculiarities of vitamin D and of the calcium and phosphate homeostatic system in horses. The aim of the present study was to investigate the importance of putative regulatory factors of the calcium (Ca) and inorganic phosphate (P(i)) homeostatic system in the horse. The concentrations of Ca, P(i), vitamin D metabolites, parathyroid hormone (PTH), the activity of the alkaline phosphatase (AP) and the concentration and binding properties of vitamin D binding protein (DBP) were measured in the plasma. In addition, the ability of the renal cortex to hydroxylate calcidiol into 24,25(OH)2D3 and 1,25(OH)2D3 was evaluated in vitro. The plasma concentration of Ca (3.2 +/- 0.15 mmol.L-1, N ...
The effect of propanediol on the morphology of fresh and frozen equine embryos. Seventeen horse embryos recovered on the sixth day after spontaneous ovulation were; 1) washed in PBS (n = 6), 2) treated with 1.5 M 1-2 propanediol (n = 6) or, 3) frozen and thawed using 1.5 M propanediol as the cryoprotectant (n = 5). After treatment, the embryos were incubated for 6 h in medium before they were fixed, serially sectioned and examined microscopically to count the total numbers of interphase, mitotic and pycnotic nuclei. Significant differences were measured only in the mean proportions of pycnotic cells (+/- s.d.), both between the control (9.2 +/- 7.3%) and frozen-thawed emb...
Distribution of putative primordial germ cells in equine embryos. Eighteen equine embryos, 3 each on Days 20, 22, 24, 26, 28 and 30 post ovulation, were collected transcervically by uterine lavage, fixed in 4% paraformaldehyde and embedded in paraffin wax. Ten micron serial sections were stained to determine alkaline phosphatase (AP) activity in the cells. Positive cells were counted and their approximate location determined. The cells were approximately 8 microm in diameter and the entire cell, except the nucleus, stained strongly with many small round areas of intense staining in the cytoplasm. The cells varied from round to elongated in shape and pseudopo...
Comparison of different methods for the recovery of horse oocytes. The object of this study was to compare 4 different methods of oocyte recovery from mares; 1) transvaginal follicle aspiration in vivo; 2) follicle aspiration in vitro; 3) oocyte recovery by isolation of follicles in vitro and 4) follicle scraping in vitro. Oocyte recovery was highest after follicle scraping (71.1%) and follicle isolation and rupture (61.3%). Follicle aspiration in vitro and in vivo yielded oocytes on 31.2% and 19.3% of occasions, respectively. The output of different types of cumulus-oocyte-complexes was different among the methods; the portion of compact cumulus-oocyte-compl...
Parentage testing of Day 10 equine embryos by amplified PCR analysis of microsatellites. Paternity analysis was performed on the DNA of 21 equine embryos collected nonsurgically 10 days after ovulation from known mares, but involving 3 possible sires. After extraction, the DNA of each embryo was typed by radioactive PCR amplification using 10 characterised microsatellites; HMS 1, 2, 5, 6, 7 and 8 (Guérin et al. 1994) and HTG 3, 4, 6 and 10 (Marklund et al. 1994). The 21 dams and 3 sires were genotyped using DNA extracted from blood and amplified by PCR. After electrophoresis and autoradiography of the PCR products of the embryo and parents, the alleles of the embryo were compared...
Activation of extracellular matrix metalloproteinases in equine laminitis. Samples of connective tissue obtained from the hoof of six laminitic and eight non-laminitic adult horses were analysed zymographically to investigate whether connective tissue matrix metalloproteinases are activated or induced during laminitis. The activity or matrix metalloproteinases was substantially greater in the tissues from the laminitic horses than in the tissues from the non-laminitic horses. A comparison of the collagenolytic activity in the laminitic and control tissues showed that collagenolytic activities corresponding to the 92 kDa (P < 0.001), 72 kDa (P < 0.01) and 66 kDa (P < ...
Lectin-staining pattern in extratesticular rete testis and ductuli efferentes of prepubertal and adult horses. This study was undertaken to determine the lectin affinity of the extratesticular rete testis and ductuli efferentes epithelial cells in adult and prepubertal horses, using ten different lectin horseradish peroxidase conjugates: Con-A, LCA, WGA, GSA-II, SBA, PNA, RCA-I, DBA, UEA-I, and LTA. In some cases, treatments with sialidase and KOH preceded the lectin staining. In sexually mature and immature horses the results showed the presence of different kinds of sialoglycoconjugates with the terminal sialic acid linked to D-GalNAc and beta-D-Gal residues in the rete testis. In the apical surface ...
Fine structural and histochemical study of equine Paneth cells. Ultrastructure, lysozyme and glycoconjugate activity in duodenal Paneth cells were observed concurrently in the horse. Paneth cells were seen to uniformly line the base of the equine intestinal glands. The round secretory granules have centrally located electron densities with peripherally located electron lucent halos. Histochemically, the peripheral halo layer was positively stained for carbohydrates by the periodic acid-thiocarbohydrazide-silver protein-physical development (PA-TCH-SP-PD) method and the entire granules reacted positively to the WGA. The central core area reacted with anti-l...
[Activities of the enzymes LDH, gamma-GT, GOT, GPT and lactoperoxidase in the milk of breeding mares during the course of lactation]. Milk samples were collected from 44 mares (trotters, warm blood horses, quarter horses) during lactation between the 1st and 90th day p.p. at 20 defined days. The activity of the enzymes LDH, gamma-GT, GOT, GPT and lactoperoxidase was investigated. The aim of this study was to find out the changes of these parameters during lactation and whether an influence of race, conception, date of foaling, age and number of lactations existed on the enzyme activities in mare's milk. The following results were obtained: In mare's milk the LDH-activity was highest (xg = 629 x 1.5 +/- 1 U/l) on the 1st day ...
Analysis of coagulation proteins as acute-phase reactants in horses with colic. To measure coagulation factor VIII:coagulant (F.VIII:C) and C1-esterase inhibitor (C1-INH), hemostasis-associated acute-phase reactant proteins and coagulation factors VII (F.VII), IX (F.IX), and X (F.X), hemostasis proteins not associated with an acute-phase response, in a select population of horses with colic and hemostasis abnormalities, and presumed to have acute-phase changes. To compare these values and other routine hemostasis test results in the horses with colic with values for a population of healthy horses. To correlate the values of known equine acute-phase reactants, F.VIII:C and...
[Doping of horses]. A survey is given about the situation of "doping" of horses. A definition of the term "doping" is delivered which is up to date and considers the matters of animal welfare. Existing regulations will be discussed in view of recent results of research. Different regulations for horses as well as humans in sports will be compared. Also different attempts of solutions for the regulatory body will be presented, which may change the regulatory significance. Finally a preview about actual questions related to doping is given.
[Intraocular and serum antibody titers to Leptospira in 150 horses with equine recurrent uveitis (ERU) subjected to vitrectomy]. Between February 1993 and July 1997, 150 horses suffering from recurrent uveitis were subjected to parsplana vitrectomy. In these horses, antibody titers to Leptospira serovars were determined in serum samples and in samples from diluted vitreous collected during vitrectomy. Although the vitreous samples were diluted with 250 ml of balanced salt solution, in 86 of the 150 vitreous samples (= 57%) the antibody titers were higher than in the serum samples. Additionally, serum samples from 77 horses suffering from ERU, but which were not subjected to vitrectomy, and serum samples from 97 horses w...
Interindividual variation in total and carrier-mediated lactate influx into red blood cells. To study in standardbred horses interindividual variation in the influx of lactate into red blood cells, venous blood samples were collected from 89 horses from 2 wk to 9 yr of age. For 62 horses, the rate of influx was normally distributed with a mean rate of 4.09 nmol.mg protein-1.min-1 at a lactate concentration of 10 mM, and the respective value for the other 27 horses was 0.58 nmol.mg protein-1.min-1. At 30 mM of lactate, the rates were 8.71 and 1.97 nmol.mg protein-1.min-1, respectively. This bimodal distribution was independent of age. In horses with high transport activity, the monocar...
Adenosine and hypoxanthine transport in horse erythrocytes: evidence for a polymorphism in the transport of hypoxanthine via a sodium-dependent cotransporter. The inward transport of two purines, adenosine and hypoxanthine, at 37 degrees C by horse erythrocytes was compared. No mediated transport of adenosine was detected in horse erythrocytes, nor was saturable, high-affinity binding of the potent facilitated-diffusion inhibitor nitrobenzylthioinosine demonstrable in horse erythrocyte membranes. In contrast, erythrocytes from most horses possessed a saturable sodium-dependent hypoxanthine transporter (apparent K(m), 100 +/- 28 microM; Vmax, 0.20 +/- 0.08 mmol (l cells)-1 h-1; means +/- S.E.M., n = 5). Guanine inhibited hypoxanthine influx (apparent...
In vitro propagation of Theileria annulata infected schizonts in different media supplemented with heterologous sera. Efficacy of medium RPMI-1640 (supplied by Gibco USA, Centron and Hi-media) supplemented with horse, donkey, sheep and goat sera was evaluated for in vitro propagation of Theileria annulata (Hisar) infected bovine mononuclear cells. The results were compared with the growth rate in RPMI-1640 supplemented with foetal bovine serum (Gibco). RPMI-1640 (Gibco) proved to be the best medium for in vitro cultivation of the parasite infected cells. Foetal bovine serum could be easily, safely and reliably substituted with goat and sheep sera in the growth medium. Horse and donkey sera also gave comparabl...
Effect of a set stabled environmental control on pulmonary function and airway reactivity of COPD affected horses. The aim of this study was to evaluate the respiratory function of horses affected with chronic obstructive pulmonary disease (COPD) when maintained in a barn on wood shavings and fed grass silage for a period of 6 weeks. The mechanics of breathing, blood gas analysis and bronchial reactivity were examined on five horses with COPD at the end of the environment-controlled period (Period B) and the results compared with values obtained after 2 months at pasture (Period A) and after the onset of clinical signs of acute crisis (Period C). The results showed that clinical and functional parameters w...
Pharmacokinetics of cefepime and comparison with those of ceftiofur in horses. To determine pharmacokinetics of i.v., i.m., and oral administration of cefepime in horses and to compare pharmacokinetics of i.m. administration of cefepime with those of ceftiofur sodium. Methods: 6 clinically normal adult horses. Methods: Horses received 3 doses of cefepime (11 mg/kg of body weight, PO; 2.2 mg/kg, i.v.; and 2.2 mg/kg, i.m.) and 1 dose of ceftiofur (2.2 mg/kg, i.m.). Two horses also received L-arginine, p.o. and i.v., at doses identical to those contained in the cefepime dihydrochloride-L-arginine preparations previously administered. Blood samples were collected for 24 hour...
An aspartic proteinase expressed in the equine placenta. This manuscript describes the cloning of a novel aspartic proteinase expressed in the placenta of the horse (order Perrisodactyla). Evidence for similar genes in the cat (Carnivora) and ruminants (Artiodactyla), indicates that these molecules have been conserved within widely divergent species with distinct types of placentation. Since ePAG is produced by the outer cell layer (trophoblast) of the placenta, it can tentatively be grouped with the pregnancy-associated glycoproteins (PAG) of cattle, sheep, and pig. The high sequence identity that ePAG shares with pepsinogens as well as the PAG, in...
Serum copper and ceruloplasmin activity at the early growing stage in foals. Serum concentrations of copper (Cu), zinc (Zn), manganese (Mn), calcium (Ca) and inorganic phosphorus (P), as well as antigenic ceruloplasmin (Cp) and oxidase activity as a functional index for copper metabolism, were measured in 10 foals (5 males and 5 females) and their dams. Samples were harvested from the foals within 1 wk after birth and monthly from 1 to 17 mo of age. Samples were collected from their dams in the perinatal period (monthly from 2 mo before delivery to 5 mo postpartum). Serum oxidase activity, antigenic Cp and Cu in foals were extremely low at 1 wk. Serum Cp had the lowest...
Isolation of Actinobacillus equuli from the oral cavity of healthy horses and comparison of isolates by restriction enzyme digestion and pulsed-field gel electrophoresis. Swab samples were collected from the oral cavity of 174 horses in 10 farms and cultured selectively for Actinobacillus equuli. A. equuli could be isolated from 37% of all samples, varying between 12 and 88% in the different farms. Eight horses were sampled repeatedly for several days, with a variation in isolation frequency between 50 and 88%. Isolates were compared by restriction enzyme digestion and Pulsed-Field Gel Electrophoresis. A high degree of strain variability was found within each horse population as well as some variability over time between strains isolated from the same horse.
Clinical biochemical parameters of the endangered Catalonian donkey breed: normal values and the influence of sex, age, and management practices effect. Twelve clinical biochemical parameters were determined in 97 animals of all age groups and both sexes of the endangered Catalonian donkey breed. Significant sex differences were observed for phospholipid concentration (P<0.01). Evaluating the effect of management practices on the various parameters showed significant differences for total bilirubin (P<0.001) and creatinine (P<0.05) concentrations and gamma-glutamyltransferase (P<0.05) activity. Moreover, it was observed that inorganic phosphorus concentration decreased with age (P<0.001), whereas albumin and triglyceride concent...
Biological characterization of Rev variation in equine infectious anemia virus. Sequence analysis identified significant variation in the second exon of equine infectious anemia virus (EIAV) rev. Functional analysis indicated that limited amino acid variation in Rev significantly altered the export activity of the protein but did not affect Rev-dependent alternative splicing. EIAV Rev can mediate export through two independent cis-acting Rev-responsive elements (RREs), and differences among Rev variants were more pronounced when both RREs were present. Variation in Rev may be an important mechanism for regulation of virus replication in vivo and may contribute to changes ...
Characterization of a microsatellite in the promoter region of the IGF1 gene in domestic horses and other equids. Insulin-like growth factor 1 (IGF1) regulates growth and metabolic functions in vertebrates. A dinucleotide repeat sequence located at the promoter region of the IGF1 gene has been reported in several vertebrate species and may affect the control of the transcriptional activity of this gene. The genotypes of animals from seven horse breeds were determined in order to study the potential association of allelic forms of this microsatellite with adult body size differences found in domestic horses. Among these breeds, five alleles were found. Breed-specific differences in adult body size could no...
Radiographic appearance of the navicular bone and distal interphalangeal joint and their relationship with ossification of the collateral cartilages of the distal phalanx in Finnhorse cadaver forefeet. Radiographic findings in the navicular bone and distal interphalangeal joint as well as the ossification status of the collateral cartilages of the distal phalanx were evaluated in 100 Finnhorse cadaver forefeet. The most common shapes of the proximal articular margin of the navicular bone were convex and straight. Remodeling of the navicular bone was common, especially on the lateral extremity. No bony fragments were identified at the distal flexor margin even though this area appeared irregular in several feet. Several large, rounded or lollipop-shaped synovial invaginations were identified ...
A prospective clinical trial comparing metrizamide and iohexol for equine myelography. A prospective clinical trial comparing adverse postmyelographic effects and myelographic quality of metrizamide and iohexol was conducted. Using a predetermined, randomized assignment, 24 horses exhibiting neurologic signs were administered either metrizamide (180 mgl/ml) or iohexol (180 mgl/ml) via cerebellomedullary puncture. Each horse was evaluated postmyelographically for adverse effects. Myelographic quality was assessed by a numerical scoring method. Adverse effects were observed more frequently with metrizamide (21) compared with iohexol (6) myelography (p < 0.05). Seizures, intensific...
Cytoplasmic extrusion and the switch from creatine kinase B to M isoform are completed by the commencement of epididymal transport in human and stallion spermatozoa. Although in several species there is a relationship between epididymal sperm transport and fertility, in human in vitro fertilization (IVF), spermatozoa recovered from the caput epididymidis or even the rete testis are fertile. We studied two objective markers of sperm maturity in the sperm of men and stallions: creatine kinase (CK) concentrations, which are a measure of cytoplasmic retention in immature spermatozoa, and the ratio of CK-M and CK-B isoforms (% CK-M/[CK-M + CK-B]), which is proportional to the incidence of mature sperm. The CK markers and the fertilizing function are closely rel...
Free amino acids in milks of human subjects, other primates and non-primates. Preterm and term transitional milks of human subjects and mature milks of human subjects, non-human primates and non-primates were analysed for free amino acids (AA) using precolumn phenylisothiocyanate derivatization and liquid chromatography. Differences in free AA between three types of human milk were small. Milks of pinnipeds (seals and sea lions) contained the highest levels of total free AA (8634-20,862 mumol/l), while the milks of cows and sheep had the lowest levels of total free AA (1061-1357 mumol/l). The milks of human subjects, chimpanzees (Pan troglodytes), gorillas (Gorilla gori...
Gonadal and pituitary responsiveness of stallions is not down-regulated by prolonged pulsatile administration of GnRH. The objective of this study was to determine if prolonged pulsatile administration of homologous gonadotropin-releasing hormone (GnRH) at therapeutic or 5x therapeutic doses would cause down-regulation of the stallion's hypothalamic-pituitary-testicular axis. Fifteen stallions were randomly assigned to three treatment groups (n=5/group) and received a 0.5 ml subcutaneous dose of saline (group 1), 50 microg GnRH (group 2), or 250 microg GnRH (group 3) every 2 hours for 75 days. Weekly evaluations of follicle stimulating hormone, luteinizing hormone, and testosterone and monthly evaluations of d...
