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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.
Muscle thickness and neuron density in the caecum of horses with chronic recurrent caecal impaction. In this study, the hypothesis that caecal smooth muscle layers would be thinner and the linear neuron density of myenteric plexus greater was tested in normal horses compared to those with chronic recurrent caecal impaction. Four normal horses and 18 horses with chronic recurrent caecal impaction were subjected to euthanasia and 7 tissue samples were collected from each horse at different regions of the caecum (apex, dorsal body, cranial base, dorsal base, caudal base, caudal body, ventral body). Twelve horses with chronic recurrent caecal impaction were treated surgically. Only one tissue sam...
Antigenic and molecular analyses reveal that the equine rotavirus strain H-1 is closely related to porcine, but not equine, rotaviruses: interspecies transmission from pigs to horses? We have sequenced the genes encoding the inner capsid protein VP6 and the outer capsid glycoprotein VP7 of the subgroup (SG) I equine rotavirus strain H-1 (P9[7], G5). The VP6 and VP7 proteins of the equine rotavirus strain H-1 shared a high degree of sequence and deduced amino acid identity with SG I porcine strains and serotype G5 porcine strains, respectively. Previous sequence analyses of the genes encoding the outer capsid spike protein VP4 and the nonstructural proteins NSP1 and NSP4 of equine H-1 strain also revealed a high degree of sequence and deduced amino acid homology with the pro...
Nucleotide and deduced amino acid sequence of equine retinal and pineal gland phosducin. To determine the full-length complementary DNA (cDNA) sequence of equine retinal and pineal gland phosducin (PHD) and to clone these sequences. Methods: Samples of equine retinal RNA. Methods: A primer set was designed for use in identifying a fragment of the equine PHD nucleotide sequence, derived from retinal RNA samples, and subsequently for use to deduce specific primers for additional examination. The full-length cDNA was determined by the method of rapid amplification of cDNA ends (RACE). For full-length cDNA, newly designed primers were used. Nucleotide sequences were analyzed by use of...
Comparative studies in the promoter and exon 1 regions of tumour suppressor p53 in several mammalian species: absence of mutations in a panel of spontaneous domestic animal tumours. Tumour suppressor p53 is critical in a broad panel of tumour types in human, mouse and other mammals. Regions of the promoter and exon 1 play an important role in expression of p53. In the present study, the DNA sequences of promoter and exon 1 regions of four domestic animal species (dog, cat, horse and cattle) are determined and compared with experimental rodents (mouse, rat and hamster) and man. A broad panel of tumour types have been investigated for mutations in this regulatory area in 90 canine, 136 feline, 25 equine and 10 bovine patients. No mutation was detected in any of the tumours ...
A random amplified polymorphic DNA polymerase chain reaction technique that differentiates between Neospora species. Neospora caninum is a recently described coccidial parasite that was first isolated from a dog in 1988 and has subsequently been shown to infect a wide range of mammals. Neospora hughesi, a new species of this genus, has recently been isolated from the spinal cord of horses showing clinical signs of equine protozoal myeloencephalitis. The random amplified polymorphic DNA polymerase chain reaction technique is capable of differentiating between N. caninum and N. hughesi.
Evaluation of a polyvalent enzyme-linked immunosorbent assay incorporating a recombinant p44 antigen for diagnosis of granulocytic ehrlichiosis in dogs and horses. To develop and evaluate a polyvalent ELISA incorporating a highly specific recombinant antigen (p44) for diagnosis of granulocytic ehrlichiosis in dogs and horses. Methods: 32 dogs and 43 horses. Methods: Results of the ELISA were compared with results of indirect fluorescent antibody (IFA) staining and western immunoblotting incorporating whole-cell antigen. Results: For the canine and equine samples, percentages of samples with positive IFA staining, western immunoblotting, and ELISA results were similar. For 29 (91 %) canine samples and 30 (70%) equine samples, results of IFA staining, west...
Aggregation behavior and electrophoretic mobility of red blood cells in various mammalian species. Differences of red blood cell (RBC) aggregation among various mammalian species has been previously reported for whole blood, for RBC in autologous plasma, and for washed RBC re-suspended in polymer solutions. The latter observation implies the role of cellular factors, yet comparative studies of such factors are relatively limited. The present study thus investigated RBC aggregation and RBC electrophoretic mobility (EPM) for guinea pigs, rabbits, rats, humans and horses; RBC were re-suspended in isotonic 500 kDa dextran solutions for the EPM and aggregation measurements, with aggregation stud...
Cushing’s disease: a new approach to therapy in equine and canine patients. Forty-one cases of Cushing's Disease affecting both equine and canine patients were treated with an identical mixture of two homeopathically prepared remedies (ACTH 30c and Quercus robur 30c), and the clinical improvements seen in the cases assessed. Homeopathy has been described as a medicine that can only be prescribed on the basis of individual symptoms shown, fitting the remedy to the patient, not the disease. The aim of this study was to define whether a standardised approach, using homeopathically prepared remedies, was a valid system of therapy for this disease, and if so, whether resul...
Comparison of radiography and scintigraphy in the diagnosis of dental disorders in the horse. Scintigraphy, with 99mTechnetium methylenediphosphonate (99mTc-MDP) and 99mTc-labelled leucocytes, was compared to radiography in the diagnosis of dental disease in the horse in a prospective case-controlled study, comprising 30 horses with clinical signs of dental disease and 30 control horses. In each case, right and left lateral, ventral and dorsal soft tissue and bone phase scintigraphic images were obtained after i.v. injection of 1 GBq/100 kg bwt 99mTc-MDP, using a gamma camera. The same views were acquired in 10 horses with clinical signs of dental disease and 12 control horses after in...
Repeatability of diagnostic ultrasonography in the assessment of the equine superficial digital flexor tendon. A quantitative investigation of the variation that can occur during the course of ultrasonography of the equine superficial digital flexor tendons (SDFT) was undertaken. The aim of this investigation was to use an objective measure, namely the measurement of CSA, to quantify the variability occurring during the course of the ultrasonographic assessment of the equine SDFT. The effects of 3 variables on the CSA measurements were determined. 1) Image acquisition operator (IAc): two different operators undertaking the ultrasonographic examination; 2) image analysis operator (IAn): two different op...
Comparative responses of bronchial rings to mediators of airway hyperreactivity in healthy horses and those affected with summer pasture-associated obstructive pulmonary disease. To compare responses of bronchial rings obtained from healthy horses and horses affected with summer pasture-associated obstructive pulmonary disease (SPAOPD) to selected mediators of airway hyperreactivity in vitro. Methods: Bronchial rings from 6 healthy horses and 6 horses affected with SPAOPD. Methods: Bronchial rings obtained from each group of horses were mounted in organ baths and attached to force transducers interfaced with a polygraph. After applying 2g of tension, each ring was allowed to equilibrate for 45 minutes in Tyrode's solution at 37 C. Cumulative concentration-response rela...
Assessment of stallion spermatozoa viability by flow cytometry and light microscope analysis. Viability of spermatozoa can be assessed by numerous methods, but many are slow and poorly repeatable, and subjectively assess only 100 to 200 spermatozoa per ejaculate. We collected two ejaculates from each of 4 stallions, and extended them to 50x10(6) sperm/mL in a nonfat dried milk solids glucose extender (EZ Mixin). Half the ejaculate was freeze-killed by immersing in liquid nitrogen for 10 min. Aliquots using appropriate volumes of live and freeze-killed spermatozoa provided the following ratios of live:dead spermatozoa: 100:0, 75:25, 50:50, 25:75, 0:100. We determined the viability of ea...
Cytogenetics of donkey chromosomes: nomenclature proposal based on GTG-banded chromosomes and depiction of NORs and telomeric sites. With the expansion of comparative genome analysis across different mammals, there is an increasing need to have well-defined banded karyotypes for the species chosen for investigation. In this context, the steadily growing gene mapping data in the donkey urgently require a framework whereby alignment/comparison of genetic information can be readily made with equids and other mammalian species. Hence a GTG-banded karyotype of the donkey (Equus asinus; EAS) is presented, along with schematic drawings and nomenclature of the banded chromosomes. In addition, the most characteristic features of ind...
Effect of extensive ileal resection with a large resulting mesenteric defect and stapled ileal stump in horses with a jejunocaecostomy: a comparison with other anastomotic techniques. Extensive resection of the ileum of the horse, using automated stapling equipment followed by a stapled jejunocaecostomy, without closure of the mesenteric defect, was evaluated prospectively as a surgical treatment for lesions involving the distal small intestine. Of 153 horses treated surgically for colic, 10 horses with strangulating lesions involving the distal ileum were treated by extensive resection and jejunocaecal anastomosis leaving a residual mesenteric defect. These were compared with 12 horses with jejunoileal lesions treated by jejunocaecal anastomosis with closure of the mesente...
The interaction of ferrocytochrome c with long-chain fatty acids and their CoA and carnitine esters. Non-covalent modification of cytochrome c may have implications for electron transport and energy metabolism. We examined the interaction of various fatty acids (FAs), their coenzyme A and carnitine esters, and fatty alcohols with horse heart ferrocytochrome c. A comparison of FAs indicated a minimum chain length of 14 carbons was required for significant effect on the ferroheme chromophore and major changes in electronic spectra. Coenzyme A and carnitine esters interacted less strongly than FAs whereas long-chain alcohols did not interact with the protein. We found a single, saturable FA bind...
Evaluation of an in-shoe pressure measurement system in horses. To develop an objective, accurate method for quantifying forelimb ground reaction forces in horses by adapting a human in-shoe pressure measurement system and determine the reliability of the system for shod and unshod horses. Methods: 6 adult Thoroughbreds. Methods: Horses were instrumented with a human in-shoe pressure measurement system and evaluated at a trot (3 m/s) on a motorized treadmill. Maximum force, stance time, and peak contact area were evaluated for shod and unshod horses. Three trials were performed for shod and unshod horses, and differences in the measured values were examine...
Morphological and functional changes of stallion spermatozoa after cryopreservation during breeding and non-breeding season. The study compared quality and freezability of stallion semen during breeding and non-breeding seasons. Ejaculates were collected twice per week from four stallions during May (n = 24) and December (n = 24). The semen was mixed with skim milk extender, centrifuged and resuspended in fresh extender. Aliquots of this sperm suspension were separated from extender and diluted in TALP medium for sperm evaluation or with cryoextender (type "Gent" or a combination of Triladyl and skim milk). Samples of 0.5ml were cryopreserved in straws using a programmed freezer. Parameters of sperm quality were eva...
Geophagia in horses: a short note on 13 cases. Recorded in several species including humans, geophagia or soil eating has been observed in both wild and domesticated horses and has generally been regarded as an indication of nutritional deficiency or "boredom". Studies of soils consumed by different species have led to several theories as to the identity of soil constituents that stimulate geophagia. In this study, geochemical analysis of 13 equine geophagic sites from different parts of Australia was undertaken. Significantly larger concentrations of iron and copper were found in soil samples from geophagic sites when compared to paired c...
Pharmacokinetics of gentamicin in mares in late pregnancy and early lactation. The disposition of drugs may differ between pregnant and nonpregnant animals, necessitating a change in dosage. We hypothesized that volume of distribution or clearance may be different for aminoglycoside antibiotics in pregnant mares vs. nonpregnant lactating mares. To examine this hypothesis, we administered gentamicin sulfate to seven Thoroughbred and Quarterhorse mares on two occasions, followed by plasma drug gentamicin assay and pharmacokinetic analysis. The first dose was administered 1-4 weeks before parturition (mean weight 578 kg) and the second dose was administered in the period 1-...
Equine muscular dystrophy with myotonia. To describe a case of equine muscular dystrophy with myotonia. Methods: A 5-year-old horse presented with hypertrophy and delayed relaxation of the muscles of the hindlimbs from age 2 months. Testicular atrophy developed from 2 years of age. Action and percussion myotonia was associated with weakness in these muscles, and EMG showed diffuse myotonic discharges and myopathic features. Biopsy of the gluteal muscle showed adipose and connective tissue infiltration, marked variation in muscle fibre size, and moth-eaten, ring and whorled fibres. Results: Injection of apamin, a peptide blocker of ca...
Heterologous expression of lacticin 3147 in Enterococcus faecalis: comparison of biological activity with cytolysin. Lacticin 3147 is a broad-spectrum, two-component, lanthionine-containing bacteriocin produced by Lactococcus lactis DPC3147 which has widespread food and biomedical applications as a natural antimicrobial. Other two-component lantibiotics described to date include cytolysin and staphylococcin C55. Interestingly, cytolysin, produced by Enterococcus faecalis, has an associated haemolytic activity. The objective of this study was to compare the biological activity of lacticin 3147 with cytolysin. The lacticin 3147-encoding determinants were heterologously expressed in Ent. faecalis FA2-2, a plasm...
Pharmacokinetics of metronidazole in horses after intravenous, rectal and oral administration. Metronidazole pharmacokinetics in horses was studied after intravenous (i.v.), rectal (p.r.) and oral (p.o.) administration at 20 mg/kg using a triple crossover study design. Metronidazole mean+/-SD half-life was 196+/-39, 212+/-30 and 240+/-65 min after i.v., p.r. and p.o. administration, respectively. The metronidazole clearance was 2.8 (mL/min/kg) and the volume of distribution at steady state was 0.68 L/kg. The pharmacokinetic parameters calculated for metronidazole after administration of the drug by the various routes showed that bioavailability (74+/-18 vs. 30+/-9%) and maximum serum co...
Heart rate and behavioural responses of crib-biting horses to two acute stressors. The heart rate and behaviour of 14 adult saddle horses, eight crib-biters and six normal controls, were investigated. Initially, the relationship between crib-biting and heart rate was investigated while the horses were undisturbed. The horses were tested when restrained with a lip twitch, and assessed when they were exposed suddenly to the rapid inflation of a balloon. The heart rate of the crib-biters during crib-biting was lower than during other behaviours. The crib-biters had a higher overall mean heart rate (P<0.05) suggesting that they may have had a higher basal sympathetic activity...
Isolation and characterization of an equine foamy virus. Foamy viruses (FVs) are complex retroviruses which have been isolated from different animal species including nonhuman primates, cattle, and cats. Here, we report the isolation and characterization of a new FV isolated from blood samples of horses. Similar to other FVs, the equine foamy virus (EFV) exhibits a highly characteristic ultrastructure and induces syncytium formation and subsequent cell lysis on a large number of cell lines. Molecular cloning of EFV reveals that the general organization is that of other known FVs, whereas sequence similarity with its bovine FV counterpart is only 40%...
Absence of selective brain cooling in free-ranging zebras in their natural habitat. We used implanted miniature data loggers to measure brain and arterial blood temperatures in three free-ranging zebras (Equus burchelli) in their natural habitat, every 5 min for 9 days. The animals experienced globe temperatures exceeding 40 C, and radiant heat load of about 1000 W m-2. Arterial blood exhibited a moderate amplitude (1.7 C) nychthemeral rhythm, with an acrophase at 19.00 h and a nadir late in the morning, at 10.00 h. Brain temperature consistently exceeded blood temperature, on average by 0.2-0.4 C, and changes in brain temperature closely tracked changes in blood temperature....
Phylogenetic analysis of partial mitochondrial cytochrome oxidase c subunit I and large ribosomal RNA sequences and nuclear internal transcribed spacer I sequences from species of Cyathostominae and Strongylinae (Nematoda, Order Strongylida), parasites of the horse. Three nucleotide data sets, one nuclear (ITS-2) and two mitochondrial (COI and l-rRNA), have been investigated in order to determine relationships among species of Strongylinae and Cyathostominae, intestinal parasites of the horse. The data exhibited a strong mutational bias towards A and T and in the COI gene, silent sites appeared to saturate rapidly partly due to this substitution bias. Thus, the COI gene was found to be less phylogenetically informative than the l-rRNA and ITS-2 genes. Combined analysis of the l-rRNA and ITS-2 genes supported a monophyletic clade of the cyathostomes with T...
Rodeo related large animal injury: is protective head-gear warranted? To compare rodeo associated large animal injuries to large animal associated trauma from other aetiologies in order to determine whether mandatory protective head-gear during rodeo is warranted. Retrospective analysis related to injury involving large animal admissions between 1 January 1990 and 31 December 1995. The setting is at the University of New Mexico Health Science Center, a level 1 trauma centre. All patients admitted with Injury Severity Scores of 1 or higher following large animal associated injuries. There were 140 admissions for which mechanism of injury was known. Thirty-nine oc...
Race-start characteristics and risk of catastrophic musculoskeletal injury in Thoroughbred racehorses. To identify race-start characteristics associated with catastrophic musculoskeletal (MS) injury in Thoroughbred racehorses at 2 racetracks in Florida during 1995 through 1998. Methods: Matched case-control study. Methods: 97 Thoroughbreds (case horses) that incurred a catastrophic MS injury during racing and 388 Thoroughbreds (control horses) randomly selected from noninjured participants and matched on the basis of racetrack and year. Methods: Incidence of MS injury was calculated for all race meets at 2 racetracks in Florida from 1995 through 1998. Race-start characteristics were compared am...
Faecal excretion profile of moxidectin and ivermectin after oral administration in horses. A study was undertaken to evaluate and compare faecal excretion of moxidectin and ivermectin in horses after oral administration of commercially available preparations. Ten clinically healthy adult horses, weighing 390-446 kg body weight (b.w.), were allocated to two experimental groups. Group I was treated with an oral gel formulation of moxidectin at the manufacturer's recommended therapeutic dose of 0.4 mg/kg b.w. Group II was treated with an oral paste formulation of ivermectin at the recommended dose of 0.2 mg/kg b.w. Faecal samples were collected at different times between 1 and 75 days ...
Non-invasive assessment of equine bone: an update. This paper summarizes traditional and current methods of non-invasive assessment of bone in the horse. The description and potential clinical utility of two non-invasive technologies with major development in the last decade are presented, namely, (1) serum biochemical markers for bone turnover and (2) quantitative ultrasound. Serum biochemical markers of bone formation valid in horses are osteocalcin, carboxy-terminal peptide of type I procollagen and bone-specific alkaline phosphatase. The cross-linked carboxy-terminal telopeptide of type 1 collagen c-telopeptides of type I collagen and tota...
