Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
Babesia bovis merozoites invade human, ovine, equine, porcine and caprine erythrocytes by a sialic acid-dependent mechanism followed by developmental arrest after a single round of cell fission. Babesia bovis infections have only been observed in bovine species in contrast to Babesia divergens that also can infect humans, sheep and rodents. Using an in vitro assay that assesses invasion of erythrocytes by free merozoites after a 1-h incubation period, it was shown that specificity is not determined by host-specific interactions associated with invasion. Human erythrocytes were invaded more efficiently than bovine erythrocytes whereas erythrocytes of sheep, pigs and horses were invaded only slightly less efficiently. In contrast, goat erythrocytes were refractory to efficient invasion....
Ca2+ ATPase in Dutch warmblood foals compared with Na+, K+ ATPase: intermuscular differences and the effect of exercise. We studied the effects of exercise without or with a subsequent period on pasture on Ca2+ ATPase concentration in foal skeletal muscle, and compared the results with those previously reported on Na+, K+ ATPase. Ca2+ ATPase was measured in homogenates as Ca2+-dependent steady-state phosphorylation from [gamma-32P]ATP. From day 7 after birth, 24 foals were divided into three groups: (i) staying in a box stall (Box); (ii) staying in a box stall with an exercise programme of an increasing number of sprints per day (Exercise); and (iii) staying on pasture (Pasture). Half of the foals (12 with four ...
Use of the impulse oscillometry system for testing pulmonary function during methacholine bronchoprovocation in horses. To compare sensitivity of the impulse oscillometry system (IOS) with that of the conventional reference technique (CRT; ie, esophageal balloon method) for pulmonary function testing in horses. Methods: 10 horses (4 healthy; 6 with recurrent airway obstruction [heaves] in remission). Methods: Healthy horses (group-A horses) and heaves-affected horses (group-B horses) were housed in a controlled environment. At each step of a methacholine bronchoprovocation test, threshold concentration (TC(2SD); results in a 2-fold increase in SD of a value) and sensitivity index (SI) were determined for respir...
Do Thoroughbred and Standardbred horses have similar increases in pulmonary vascular pressures during exertion? To test the hypothesis that the pulmonary vascular pressures of Thoroughbred and Standardbred horses behave similarly during exertion. Measurements were made on 5 Thoroughbred and 5 Standardbred horses on a treadmill at rest and during 3-minute exercise intervals at speeds predicted to produce 75%, 90%, and 100% maximal heart rate. Left forelimb acceleration, heart rate, esophageal pressure, and pulmonary artery pressure were measured continuously. Pulmonary capillary and wedge pressures were measured during intermittent occlusion of the pulmonary artery. Breathing rate and gait frequency were...
Characterization and comparison of the responses of equine digital arteries and veins to endothelin-1. To compare the responses of equine digital arteries (EDAs) and equine digital veins (EDVs) to endothelin-1 (ET-1) and determine the role of the endothelium and type of receptors involved in the modulation and mediation of those responses, respectively. Methods: 5 to 9 palmar digital vessels/experiment from 28 healthy horses. Methods: Rings of dissected vessels were mounted under tension between force transducer wires in organ baths containing Krebs-Henseleit solution at 30 degrees C. Responses of EDAs and EDVs (with intact [+e] or denuded [-e] endothelium) to cumulative concentrations of ET-1 ...
Assessment of the accuracy of computed tomography for measurement of normal equine pituitary glands. To describe the anatomic features of the pituitary gland region in horses via computed tomography (CT) and determine the accuracy of CT for estimating normal equine pituitary gland dimensions. Methods: 25 adult horses with no clinical signs of pituitary disease. Methods: Transverse CT images and gross transverse tissue sections were compared in 2 horses. Contrast-enhanced CT of the pituitary gland region was performed postmortem in 23 horses with 4 slice thickness and interval settings (10-mm contiguous or overlapping slices and 4-mm contiguous or overlapping slices). Gross and CT estimates of...
Hormonal mechanism of follicle deviation as indicated by major versus minor follicular waves during the transition into the anovulatory season in mares. Follicle growth and circulating hormone concentrations were compared between an interovulatory interval and the first 60 days of the anovulatory season in pony mares. Daily observations were made from November of three groups: (i) ablation of follicles of >/=6 mm in diameter at day 10 after an ovulation that initiated an interovulatory interval, as determined retrospectively (ovulatory group, n=8), (ii) ablation at day 10 after the last ovulation of the year (anovulatory-10 group, n=6); and (iii) ablation at day 60 after the last ovulation of the year (anovulatory-60 group, n=6). Follicular...
Comparative histology of the laminar bone between young calves and foals. Laminar bone or primary plexiform tissue, not Haversian bone, shows an alternative concentric pattern of laminar-bone units or plates around the bone marrow periphery of long bones, although the laminar bone is gradually replaced by osteons during the growth period. One laminar-bone unit is constructed with a hypercalcified line in the center, woven bone on both sides of the line, and lamellar bone with laminated appositional lines. Such a laminar bone showing a homogeneous calcification has been reported in young calves and some young large animals, but it has not been reported in foals altho...
Study of the clinical effects of postoperative parenteral nutrition in 15 horses. Several clinical variables were compared in two groups of 15 horses recovering from resection and anastomosis of a strangulated small intestine; 15 were treated with parenteral nutrition and 15 were starved routinely. There was some evidence that parenteral nutrition had a short-lived adverse effect on both the catheter sites and gastric emptying, but there were no marked adverse clinical effects and no evidence of any improvement in the horses' condition.
Post-entry restriction of retroviral infections. Pathogenic retroviruses have driven the evolution of several dominant-acting mechanisms able to block infection and protect the host. These are exemplified by the mouse gene Fv1, which encodes a Gag-like protein able to protect against murine leukemia virus (MLV) infection. The block is saturable, occurs after reverse transcription and is directed against the viral capsid gene. Several other mammalian species are also able to block MLV infection with the same capsid specificity. A human gene with this activity has been named Ref1. Recently, primates have been shown to restrict a variety of ret...
Determination of reference range values indicative of glucose metabolism and insulin resistance by use of glucose clamp techniques in horses and ponies. To acquire reference range values indicative of glucose metabolism by use of the hyperglycemic clamp technique in healthy horses and evaluate the usefulness of the euglycemic hyperinsulinemic clamp technique in healthy horses and ponies. Methods: Dutch Warmblood horses and 4 Shetland ponies. Methods: The hyperglycemic clamp technique was used for quantification of the sensitivity of beta cells to exogenous glucose infusion in horses. The euglycemic hyperinsulinemic clamp technique was used to determine the sensitivity and responsiveness of tissues to exogenous insulin in horses and ponies. Res...
Comparative pharmacokinetics of diphenhydramine in camels and horses after intravenous administration. The pharmacokinetics of diphenhydramine (DPHM) was compared in camels (n = 8) and horses (n = 6) following intravenous (i.v.) administration of a dose of 0.625 mg/kg body weight. In addition, the metabolism and urinary detection time of DPHM was evaluated in camels. The data obtained (median and range in brackets) in camels and horses, respectively, were as follows. The terminal elimination half lives (h) were 1.58 (1.13-2.58) and 6.11 (4.80-14.1), and the total body clearances (L/h per kg) were 1.42 (1.13-1.74) and 0.79 (0.66-0.90). The volumes of distribution at steady state (L/kg) were 2.38...
Significance of affinity and cooperativity in oxygen binding to hemoglobin of horse fetal and maternal blood. The physiological significance of the position and shape of the oxygen equilibrium curve (OEC) of horse hemoglobin (Hb) is considered from the viewpoint of oxygen (O2) transport efficiency and the effectiveness of the Bohr effect. In horse fetal and maternal bloods, their physiological O2 affinities are nearly optimized with respect to the effectiveness of the Bohr shift occurring at the O2 release site, when it is measured by the change in O2 saturation per unit change in P50. With relatively low cooperativity (n=2.69) of horse Hb under physiological conditions, the effectiveness of the Bohr ...
In vitro comparison of equine cancellous bone graft donor sites and tibial periosteum as sources of viable osteoprogenitors. To compare the osteogenic potential of cancellous bone of conventional graft sites with that of one nonconventional site (fourth coccygeal vertebra) and to investigate the tibial periosteum as a donor site with respect to osteogenic potential. Methods: In vitro osteogenic cell culture system. Methods: Eight adult horses. Methods: Cancellous bone or tibial periosteum was aseptically collected and cut into bone chips or periosteal strips of 1 to 2 mm(3) for primary explant cultures. After 2 weeks, primary tissue cultures that yielded a population of osteogenic cells were counted and subcultured ...
Characterization of the horse (Equus caballus) IGHA gene. Nucleotide sequences of the immunoglobulin constant heavy chain genes of the horse have been described for IGHM, IGHG and IGHE genes, but not for IGHA. Here, we provide the nucleotide sequence of the genomic IGHA gene of the horse ( Equus caballus), including its secretion region and the transmembrane exon. The equine IGHA gene shows the typical structure of a mammalian IGHA gene, with only three exons, separated by two introns of similar size. The hinge exon is located at the 5' end of the CH2 exon and encodes a hinge region of 11 amino acids, which contains five proline residues. The coding ...
M-mode echocardiographic ratio indices in normal dogs, cats, and horses: a novel quantitative method. A novel method for quantitative echocardiographic interpretations is introduced based on the calculation of ratio indices in which each raw M-mode measurement is divided by the aortic root dimension (Ao). "Aorta-based" indices were calculated with the animal's measured aortic root dimension (Ao(m)) as the length standard. Conversely, "weight-based" indices employed an idealized estimate of aortic dimension (Ao(w)) with a weighted least squares linear regression against the cube root of body weight (Ao(w) = kW(1/3)). Use of these indices circumvented undesirable statistical characteristics inhe...
Equine cyathostome populations: accuracy of species composition estimations. Historically, surveys of equine parasites either are not quantitative in regard to prevalence and intensities of cyathostome species, or if quantitative, are estimates based on the identification of a very small sample of the population. Commonly 100-200 worms are identified. In the current study cyathostomes from 10 ponies were counted and identified to species in subsets of approximately 200 worms each from 5% aliquots of the large intestine contents until all worms in the aliquot were examined. A mean of 10.9+/-4.3 species were identified by examining 200 cyathostomes from each animal. This...
Characterisation of movement pattern and velocities of stallion spermatozoa depending on donor, season and cryopreservation. The aim of the study was to compare different types of movement pattern and velocities of stallion spermatozoa depending on cryopreservation during breeding and non-breeding season. Ejaculates were collected from four stallions during May (n = 24) and December (n = 24). Parameters of sperm movement were evaluated by computer-aided sperm analysis (CASA) system, and included percentages of motile spermatozoa, different patterns of motility, the velocity, linearity (LIN), amplitude of lateral head displacement (ALH) and beat-cross frequency (BCF). In winter the average percentages of motility wer...
Comparison of the caudal lung borders determined by percussion and ultrasonography in horses with recurrent airway obstruction. The aim of the study was to evaluate the diagnostic value of thoracic percussion and ultrasonography with the help of distance measurements and statistical methods in the determination of the caudal lung border in horses with recurrent airway obstruction (RAO). Examinations were performed on 11 healthy, warm-blooded horses of different breeds, age and grade of disease. First, the caudal lung border was determined by the traditional indirect percussion method in the 10th, 12th, 14th and 16th intercostal spaces at the end of inspiration and expiration on both sides of the thorax. To apply standa...
Differences in polymorphonucleocyte function and local inflammatory response between horses and ponies. Wound healing proceeds faster in ponies than in horses and complications during healing, such as wound infection, occur less frequently in ponies. Earlier studies suggested that this difference might be related to differences in the initial post traumatic inflammatory response. Objective: That polymorphonuclear leucocyte (PMN) function and profiles of humoral factors in local inflammatory processes are different in horses and ponies. Methods: PMNs were isolated from venous blood of horses and ponies. Chemotaxis and reactive oxygen species (ROS) production was determined. Tissue cages were impl...
Effects of oat processing on the glycaemic and insulin responses in horses. This study was conducted to evaluate the effects of different oat processing techniques on the plasma glucose and insulin response in horses. In a cross-over design, six horses (ages 4-15 years, mean body weight+/-SD: 450+/-37 kg) were fed in random order: untreated oats, finely ground, steam-flaked and popped oats. The total oat intake varied between 1.05-1.5 kg/day, and the amount of diet was adjusted to a starch content of 630 g starch per day and horse (1.2-1.5 g starch/kg BW/day). During the stabilization period of 10 days, horses additionally received 6 kg grass hay. Following this adapt...
Studies on feed digestibilities in captive Asian elephants (Elephas maximus). In order to test the suitability of the horse as a nutritional model for elephants, digestibility studies were performed with six captive Asian elephants on six different dietary regimes, using the double marker method with acid detergent lignin as an internal and chromium oxide as an external digestibility marker. Elephants resembled horses in the way dietary supplements and dietary crude fibre content influenced digestibility, in calcium absorption parameters and in faecal volatile fatty acid composition. However, the absolute digestibility coefficients achieved for all nutrients are distinc...
A comparison of the antinociceptive effects of xylazine, detomidine and romifidine on experimental pain in horses. To study the analgesic potency of the alpha2-agonist romifidine in the horse using both an electrical current and a mechanical pressure model for nociceptive threshold testing. In addition, a comparison was made with doses of detomidine and xylazine that produce equivalent degrees of sedation. Methods: Randomized, placebo-controlled, blinded cross-over study. Methods: Six adult Swiss warmblood horses, one mare and five geldings, weighing from 530 to 650 kg and aged 6-15 years. Methods: Nociceptive thresholds were measured using an electrical stimulus applied to the coronary band and using a pn...
Comparison of opioid and alpha-2 adrenergic receptor binding in horse and dog brain using radioligand autoradiography. To test the hypothesis that the distribution, density, and subtype of opioid and alpha (alpha)-2 adrenergic receptors within the central nervous system (CNS) are significantly different between horse and dog. Methods: Prospective experimental study. Methods: Three dogs (3 years of age) and three horses (2-5 years of age). Animals were opioid- and alpha-2 agonist-free at the time of euthanasia. Methods: Brain tissue was obtained at 126 days post-surgery from dogs and 72 days post-surgery from horses. The brains were removed, sectioned coronally into 1-cm slabs, frozen in methylbutane, which was...
Changes in the EEG during castration in horses and ponies anaesthetized with halothane. To identify changes in the amplitude spectrum of the electroencephalogram (EEG) during a standardized surgical model of nociception in horses. Methods: Thirteen entire male horses and ponies referred to Division of Clinical Veterinary Science, Bristol (n = 9) and Department of Clinical Veterinary Medicine (n = 4) for castration. Methods: Following pre-anaesthetic medication with acepromazine, anaesthesia was induced with guaiphenesin and thiopental and maintained with halothane in oxygen. The EEG was recorded continuously using subcutaneous needle electrodes. Additional monitoring comprised EC...
Seasonal changes in plasma concentrations of cecum-derived amines in clinically normal ponies and ponies predisposed to laminitis. To measure concentrations of amines formed in the cecum of clinically normal ponies, determine amine concentrations in plasma samples collected in spring and winter, and compare concentrations of amines and serotonin in plasma samples obtained from clinically normal ponies and ponies predisposed to laminitis. Methods: Cecal contents obtained from 10 ponies euthanatized at an abattoir and blood samples obtained from 42 adult ponies. Methods: Cecal contents were assayed for amines by high-performance liquid chromatography (HPLC). Blood samples were collected at various times of the year from 20 ...
Macroscopic changes in the distal ends of the third metacarpal and metatarsal bones of Thoroughbred racehorses with condylar fractures. To determine changes in the distal ends of the third metacarpal and metatarsal bones (MCIII and MTIII) of Thoroughbred racehorses that had sustained a catastrophic condylar fracture during high-speed exercise. Methods: Fractured and contralateral MCIIIs and MTIIIs from 11 Thoroughbred racehorses that sustained a displaced condylar fracture during racing, both MCIIIs from 5 Thoroughbred racehorses euthanatized because of a catastrophic injury other than a condylar fracture, and both MCIIIs from 5 horses of other breeds that had not been professionally trained or raced. Methods: Macroscopic obse...
Molecular phylogenetics and diagnosis of soil and clinical isolates of Halicephalobus gingivalis (Nematoda: Cephalobina: Panagrolaimoidea), an opportunistic pathogen of horses. Phylogenetic relationships among six isolates of Halicephalobus gingivalis (Stefanski, 1954), a species with pathogenic potential in horses and humans, were evaluated using DNA sequences from the nuclear large-subunit ribosomal RNA (LSU rDNA) gene. Sequences from nematodes obtained from in vitro cultures (soil or clinical sources), or isolated from infected horse tissues, were compared. Gene sequences from a fatal equine clinical case from southern California and a free-living isolate recovered from southern California soil showed no fixed differences. Sequences from isolates representing two ...
Endocrine responses in mares and geldings with high body condition scores grouped by high vs. low resting leptin concentrations. Previous observations from this laboratory indicated that horses with high BCS could have resting plasma leptin concentrations ranging from low (1 to 5 ng/mL) to very high (10 to 50 ng/mL). To study the possible interactions of leptin secretion with other endocrine systems, BCS and plasma leptin concentrations were measured on 36 mares and 18 geldings. From mares and geldings that had a mean BCS of at least 7.5, five with the lowest (low leptin) and five with the highest (high leptin) leptin concentrations were selected. Jugular blood samples were collected twice daily for 3 d from the 20 sele...
