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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.
Contribution of delta bilirubin to the interpretation of hyperbilirubinemia in the horse – a pilot study. A study was conducted to examine the relationship of delta bilirubin to traditional bilirubin fractions to determine if delta bilirubin might assist in differentiating causes of hyperbilirubinemia in the horse. A recently introduced thin-film method was used for delta bilirubin determination. Thin-film and the traditional diazo methods were used for determining total, unconjugated, and conjugated bilirubin fractions. Sera from 38 healthy and 85 sick horses were examined.Thin-film serum delta bilirubin determination does not appear to assist in differentiating causes of unconjugated hyperbiliru...
Left cranial vena cava in a horse. A complete left cranial vena cava (LCVC) was found in a normal horse. The LCVC was well developed, but there was a complete absence of the right cranial vena cava. The azygous vein was normally distributed on the right side of the thoracic vertebral bodies but passed ventral to the aortic arch to empty into the cranial vena cava on the left close to the origin of the aortic arch. The LCVC passed over the dorsal aspect of the left atrium to reach the coronary sulcus on the caudal aspect of the heart. The LCVC opened into the right atrium via a 5 cm diameter orifice (orifice of coronary sinus). ...
Arthrographic observations of the equine distal interphalangeal joint (Articulationes interphalangeae distalis manus) and navicular bursa (Bursa podotrochlearis). Twenty cadaver limbs of adult horses were examined by arthrographic examination of the distal interphalangeal joint. The joint capsule and space is described. Comparison is made with existing descriptions.
Maternal and umbilical venous plasma lipid concentrations at delivery in the mare. The concentrations and fatty acid composition of the plasma free fatty acid, triacylglycerol and phospholipid fractions were determined in maternal and umbilical cord vein blood samples taken at delivery from 17 mares. Maternal and umbilical vein plasma free fatty acid concentrations were of a similar order and a positive correlation was found between the two levels suggesting that the equine placenta is permeable to fatty acid. Substantial amounts of the essential fatty acids and their longer chain derivatives were seen in both umbilical vein plasma free fatty acid and phospholipid fractions ...
Duodenal glands of the pony (Equus caballus). The ultrastructure and histochemistry of the duodenal glands of the pony (Equus caballus) was examined in four horses. Unlike that of most species except for the rabbit, the submucous glands of the horse contain two distinct cell types, serous and mucous. These cells are described.
Muscle disorders in the horse: a retrospective study. Case records of horses with muscle disorders presenting to the Veterinary Medical Teaching Hospital of the University of California, Davis, over a nine year period were evaluated. The objectives of the review were to identify the common myogenic muscle problems and their clinical features. Muscle disease of idiopathic aetiology following exercise was by far the most common condition noted. Other causes of myogenic muscle disorders included congenital, infectious, immune-mediated and nutritional factors.
Equine herpesvirus 1 sequence near the left terminus codes for two open reading frames. We have previously reported the sequence of the equine herpesvirus one genomic termini that are homologous to the genomic termini of other herpesviruses. In this paper, we present the nucleotide sequence adjacent to the left terminus sequence (map units 0.0087 to 0.0237). This sequence codes for two open reading frames (ORF) which are homologous to ORF2 and ORF3 of the varicella-zoster virus genome and are located at colinear positions. The L region sequence presented here also contains a segment that is involved in the generation of the genome of EHV-1 DI particles through recombination with ...
Common white facial markings in bay and chestnut Arabian horses and their hybrids. Common white facial and leg markings have a multifactorial mode of inheritance in Equus caballus. Evidence for the complexity of the genetic component is the observation that chestnut (e/e) horses have more extensive white markings than do bay (E/-) horses. Computerized records obtained from the Arabian Horse Registry of America, Inc., were used to determine if heterozygous (E/e) bay horses have more extensive white facial markings than do homozygous (E/E) bay horses. Thirty-five sire families were analyzed. Each sire family consists of a sire, his foals, and the dams of those foals. The facia...
A comparison of techniques to enhance the evaluation of equine laryngeal function. This study was designed to define a simple, unequivocal test for the evaluation of laryngeal function and the diagnosis of idiopathic laryngeal hemiplegia (ILH). ILH is a disorder that results from left recurrent laryngeal neuropathy and in which there is no movement of the left arytenoid cartilage and vocal fold. Laryngeal function was evaluated in seven horses using four techniques designed to stimulate laryngeal movements:-nasal occlusion, exercise, swallowing and administration of a respiratory stimulant. In addition, the effects of sedation and twitching on the endoscopic examination were...
Muscle fibre type composition in untrained and endurance-trained Andalusian and Arab horses. Muscle biopsies were taken from the middle gluteal muscle of 68 stallions (52 Andalusian [AN] and 16 Arab [AR]) ranging from six to 12 years of age. Seventeen AN horses and eight AR horses were untrained, while the remainder underwent active endurance training for 6 months. Fifteen AN horses were moderately endurance-trained while the other 20 AN horses and eight AR horses were strongly endurance-trained. Percentages of type I and type II fibres were similar in all groups (P greater than 0.05). The group of horses with the hardest training had a higher percentage of type IIA fibres (AN P less ...
Lobeline-induced hyperpnea in equids. Comparison with rebreathing bag and exercise. In order to facilitate lung auscultation, a transitory hyperpnea may be obtained by lobeline administration, use of a rebreathing bag or exercise. The effect of these three methods on the pulmonary function were studied and compared in 5 healthy ponies. Respiratory airflow and tidal volume were measured with a pneumotachograph Nr. 5 and pleural pressure with the esophageal balloon catheter technique. Pulmonary function values were measured before, during and after the hyperpnea induced by (i) lobeline, (ii) rebreathing and (iii) exercise. Lobeline administration induced an hyperpnea due to bot...
Comparative properties of three functionally different but structurally related serpin variants from horse plasma. Three structurally related but functionally different serpins from horse plasma were isolated and characterized. In spite of their identical N-terminal sequences, which show some similarity to that of human alpha 1-proteinase inhibitor, the reactive-centre loops of each of these proteins show extensive variation. Only inhibitor I, with a P1 methionine residue, resembles human alpha 1-PI with regard to (a) similarity of amino acid sequence in the vicinity of the reactive-site peptide bond, (b) broad inhibitory specificity, (c) sensitivity to oxidative inactivation and (d) high rate of reactivit...
Arytenoid cartilage movement in resting and exercising horses. Endoscopic examinations of the larynx were recorded on 49 horses at rest and while exercising on a 5% inclined high-speed treadmill for 8 minutes at a maximum speed of 8.5 m/sec. Subjective laryngeal function scores at rest and while exercising were based on the degree and synchrony of arytenoid abduction. Arytenoid abduction was expressed as a left:right ratio of rima glottidis measurements. Horses with arytenoid cartilage asynchrony at rest (grade 2) could not be distinguished from normal horses (grade 1) when exercising because full abduction was maintained throughout the exercise period. F...
In vitro development of day-2 equine embryos co-cultured with oviductal explants or trophoblastic vesicles. This study compared the in vitro development of Day-2 equine embryos co-cultured with either trophoblastic vesicles or oviductal explants. Embryos were collected surgically from the oviducts of pony mares 2 d after ovulation and assessed for stage of development. Culture medium was Ham's F12 and Dulbecco's Modified Eagle's Medium (50:50 v/v) in a humidified atmosphere of 5% CO(2) in air at 38.5 degrees C with either trophoblastic vesicles or oviductal explants. The quality score of embryos was assessed daily. After 4 d in culture, embryos were stained (Hoechst 33342) and evaluated with epifluo...
Characterization and mapping of melatonin receptors in the brain of three mammalian species: rabbit, horse and sheep. A comparative in vitro binding study. Melatonin receptors were characterized in the brains of three mammals (rabbit, horse and sheep) by an in vitro binding technique, using 2-[125I]iodomelatonin as labelled ligand. Although binding sites for melatonin have been described recently in several vertebrate species (including the sheep), the rabbit and the horse have not been the subject of investigation so far. Apart from characterization, the present report describes receptor distribution in a number of brain regions, thus allowing for direct interspecies comparison under the same methodological conditions. 2-[125I]iodomelatonin labe...
Correlation of performance with endoscopic and radiographic assessment of epiglottic hypoplasia in racehorses with epiglottic entrapment corrected by use of contact neodymium:yttrium aluminum garnet laser. Epiglottic entrapment in 35 Thoroughbred and 44 Standardbred horses was corrected transendoscopically by use of a neodymium:yttrium aluminum garnet laser. Before surgery, the entrapped epiglottis was classified as hypoplastic or normal in each horse on the basis of endoscopic appearance alone. Using a digitizer, thyroepiglottic length was determined from lateral-view laryngeal radiographs. For 78 racehorses, earnings (less than $5,000 or greater than $5,000) were compared before and after surgery. Earnings category and racing performance after surgery were tested for association with endoscopi...
Oral associated bacterial infection in horses: studies on the normal anaerobic flora from the pharyngeal tonsillar surface and its association with lower respiratory tract and paraoral infections. Two hundred and seventy bacterial isolates were obtained from the pharyngeal tonsillar surface of 12 normal horses and 98 obligatory anaerobic bacteria were characterised. Of these, 57 isolates belonging to 7 genera (Peptostreptococcus (1); Eubacterium (9); Clostridium (6); Veillonella (6); Megasphera (1); Bacteroides (28); Fusobacterium (6)) were identified, and 16 of these were identified to species level (P. anaerobius (1); E. fossor (9); C. villosum (1); B. fragilis (1); B. tectum (2); B. heparinolyticus (2)). Three hundred and twenty isolates were obtained from 23 samples from horses with...
[Papillomatosis of cattle and its relationship to equine sarcoid]. The aetiology and the pathogenesis of equine sarcoids are described. Aspects of therapy are discussed.
[Blood serum level of primary bile acids in cattle, horses, swine and dogs]. The levels of the two primary bile acids, cholic acid (CA) and chenodeoxycholic acid (CDCA), were determined by radioimmunoassay in cattle, horse, pig and dog serum. The mean serum cholic acid (SCA) and deoxycholic acid (SCDCA) levels of cows varied with their reproductive status, being 7.8 (+/- 3.3) and 1.5 (+/- 1.0) mumol/l in dry cows, 17.8 (+/- 6.9) and 2.3 (+/- 1.0) mumol/l in freshly calved dams, and 15.8 (+/- 5.7) and 2.3 (+/- 0.8) mumol/l, respectively, in lactating cows. The SCA level found in the immediate prepartal period and also on the day of calving corresponded to those found du...
Use of a computerized system for evaluation of equine spermatozoal motility. Three ejaculates from each of 3 stallions were used to evaluate a computerized system (Hamilton-Thorn motility analyzer; HTMA) for measuring equine spermatozoal motility. Variance components (ejaculate-within-stallion, chamber-within-ejaculate, and microscopic field-within-chamber) were determined for each stallion after diluting ejaculates to 25 x 10(6) spermatozoa/ml with a skim milk-glucose seminal extender. The HTMA was compared with frame-by-frame playback videomicrography (VIDEO) for determining: percentage of spermatozoal motility and spermatozoal number in microscopic fields; curviline...
Comparison of ivermectin, oxibendazole, and pyrantel pamoate in suppressing fecal egg output in horses. Thirty resident horses at a boarding stable in Alberta were used to evaluate the relative efficacies of ivermectin, oxibendazole, and pyrantel pamoate in reducing fecal egg output in adult horses under routine management conditions during spring and early summer, and to more clearly define the duration of suppression of fecal egg production following anthelmintic treatment. Horses were blocked according to pretreatment egg counts and randomly assigned to one of three treatments: pyrantel pamoate at 6.6 mg/kg body weight; oxibendazole at 10 mg/kg body weight; or ivermectin at 200 mug/kg body we...
Different combinations of regulatory elements may explain why placenta-specific expression of the glycoprotein hormone alpha-subunit gene occurs only in primates and horses. Expression of the glycoprotein hormone alpha-subunit gene occurs in the pituitary of all mammals but in placenta of only primates and horses. In humans, two different elements, termed upstream regulatory element (URE) and cAMP response element (CRE), are required for placenta-specific expression of the alpha-subunit gene. The URE binds a protein unique to placenta whereas the CRE binds a ubiquitous protein. Comparative analysis of the promoter-regulatory region of the alpha-subunit gene from a number of mammals indicates that a functional URE has been retained and suggests the potential for pl...
Effect of increased inspired CO2 on respiratory dead space in ponies. The objective of the present study was to determine the effect of elevated inspired CO2 on respiratory dead space (VD) of 12 normal, 8 carotid body-denervated (CBD), 7 hilar nerve-denervated (HND), and 6 CBD+HND ponies. The Fowler technique was used to determine VD on a breath-by-breath basis while the ponies breathed room air and inspired CO2 at 3 and 6%. During room air breathing, tidal volume (VT) and VD were greater in HND ponies than in normal and CBD ponies (P less than 0.05), and VT was less and VD/VT was greater after CBD than before CBD. For all groups. VD, VT, and breathing frequency...
Evolution of placenta-specific gene expression: comparison of the equine and human gonadotropin alpha-subunit genes. Primate and equine species are thought to be unique among mammals in synthesizing placental gonadotropin glycoprotein hormones. Human chorionic gonadotropin (CG) and equine pregnant mare's serum gonadotropin (PMSG) are produced in placenta by the specific activation of a glycoprotein hormone alpha-subunit gene and a corresponding beta-subunit gene. The evolutionary mechanisms for the apparently independent acquisition of tissue specificity were investigated by cloning the 5' flanking region of the equine alpha-subunit gene and comparing the DNA elements and trans-acting factors involved in pla...
Serum bile acid composition of the dog, cow, horse and human. The fractionation of serum bile acids was performed in the dog, cow, horse, and human by high performance liquid chromatography equipped with an immobilized 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD) column. There were significant differences in the bile acid compositions, conjugation patterns and quantities of each bile acid among these animals. Cholic acid was the major primary bile acid in the dog and cow, which constituted 62.9% and 83.5%, respectively, whereas chenodeoxycholic acid was the major acid in the horse and human, which constituted 68.4% and 46.3%, respectively. Taurine ...
[The effects of crude drugs using diuretic on horse kidney (Na+ + K+)-adenosine triphosphatase]. In the folk-medicine, several kinds of crude drugs are used as diuretics. Twenty three kinds of diuretic drugs were chosen, and examined for their effects on the horse kidney (Na+ + K+)-adenosine triphosphatase (ATPase), which is an intrinsic enzyme of the plasma membrane and responsible for the active transport of Na+ and K+ across the membrane. Twenty one out of twenty three kinds of ethanol extracts of diuretic drugs inhibited the kidney (Na+ + K+)-ATPase activity. The intensity of the inhibition of these drugs was compared by estimating the amounts of their ethanol extracts which inhibited...
Rat muscle acylphosphatase: purification, amino sequence, and immunological characterization. Acylphosphatase was purified from rat skeletal muscle essentially by gel filtration and high-performance ion-exchange chromatography. The complete amino acid sequence was reconstructed by using the sequence data obtained from tryptic, peptic, and S. aureus V8 protease peptides. The protein consists of 96 amino acid residues and is acetylated at the NH2-terminus. The immunological cross-reactivity of acylphosphatase from rat and horse skeletal muscle was examined by ELISA. The reaction with rabbit antiserum revealed the presence of at least five antigenic sites on rat enzyme, two of which are c...
Beta-subunits of equine chorionic gonadotropin and lutenizing hormone with an identical amino acid sequence have different asparagine-linked oligosaccharide chains. The glycoprotein hormones, equine chorionic gonadotropin (eCG) and lutenizing hormone (eLH), possess a beta-subunit with an identical amino acid sequence. The Asn-linked oligosaccharide chains of eCG beta and eLH beta were quantitatively liberated as tritium-labeled oligosaccharides by hydrazinolysis followed by N-acetylation and NaB3H4-reduction. Paper electrophoresis in combination with sialidase digestion and solvolytic desulfation indicated that eCG beta contained neutral and sialylated oligosaccharides, while eLH beta contained neutral, sialylated, sulfated, and both sialylated and sulfat...
Epidemiologic study of ocular/adnexal squamous cell carcinoma in horses. Proportional hospital accession ratios for equine ocular/adnexal squamous cell carcinoma (SCC) were determined for 14 colleges of veterinary medicine participating in the Veterinary Medical Data Program between January 1978 and December 1986. Comparison of the ratios with their respective geographical, physical data has shown an increased prevalence of SCC with an increase in longitude, altitude, or mean annual solar radiation. In contrast, prevalence of SCC increased with a decrease in latitude. Between January 1978 and December 1988, 147 horses with ocular/adnexal SCC were admitted to the Co...
