Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Animal Studies
Animal studies involving horses encompass a range of research focused on understanding equine biology, behavior, and health. These studies often investigate various aspects of horse physiology, genetics, nutrition, and disease pathology. Researchers utilize animal studies to explore the effects of different treatments, management practices, and environmental factors on horse welfare and performance. The findings from such studies contribute to the development of improved care strategies and health interventions. This page gathers peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of animal studies conducted on horses, providing insights into their application in advancing equine science.
[The effect of a single dose of dexamethasone on the production of superoxide anion and on the chemotaxis of blood polynuclear neutrophils in the horse]. Chemotaxis and superoxide anion production of neutrophils in healthy horses were investigated before and 8 h after, a single injection of dexamethasone at a dose of 0.045 mg/kg. Chemotaxis was studied by the technique of migration under agarose and superoxyde production was measured by ferricytochrome c reduction. Superoxide anion production was not changed, but the chemotactic index, with zymosan activated horse serum, was increased. The FMLP chemoattractant effect, at 10(-4) M, was slightly enhanced.
Survival of day-4 embryos from young, normal mares and aged, subfertile mares after transfer to normal recipient mares. The estimated embryonic loss rate between Days 4 and 14 after ovulation for young, normal mares (9%) was significantly lower (P less than 0.01) than the estimated embryonic loss rate for aged subfertile mares (62%). Fertilization rates, which were based on the recovery of embryos at Day 4 after ovulation, were 96% and 81% (P less than 0.1) for normal and subfertile mares, respectively. Day-4 embryos were collected from the oviducts of normal and subfertile donors mares. These embryos were transferred to the uteri of synchronized, normal recipient mares to test the hypothesis that the high inci...
A comparative study on acetyl-CoA synthesising enzymes in spinal cord from cows, horses and pigs. 1. Comparative data are presented of the activities of pyruvate dehydrogenase complex and acetyl-CoA synthetase and of the acetate content in homogenates from ventral grey matter in spinal cord from cows and two non-ruminant species, pigs and horses. The methods used in the study are evaluated and discussed. 2. The total pyruvate dehydrogenase complex activity was 24.9-29.9 mU/mg protein and did not differ between the species. The part of the complex that was in active form at the sampling occasion was 60, 85 and 95% in cows, pigs and horses, respectively. 3. Acetyl-CoA synthetase activity dif...
Alterations in the cell cycle characteristics of granulosa cells during the periovulatory period: evidence of ovarian and oviductal influences. Granulosa cells at different stages of differentiation were collected from ovarian follicles and oviducts during the periovulatory period, and their nuclear DNA content was monitored by flow cytometry to establish their cell cycle characteristics (G0 + G1, S, G2 + M). The proportion of cells in the three phases of the cell cycle varied in characteristics patterns depending upon the time they were collected, before or following ovulation. Granulosa (cumulus) cells recovered from ovulated oocytes were mitotically inactive as shown by the large proportion of cells with a 2C amount of DNA and the ...
Comparison of sensory nerve conduction velocities in horses versus ponies. Normal sensory nerve conduction velocity (SNCV) values in 8 ponies and 8 horses were compared by use of a percutaneous signal-averaging technique. Nerve fibers evaluated included those in the medial and lateral palmar and plantar digital nerves. Mean SNCV values were significantly slower (P less than 0.0002) for horses, compared with those values for ponies. Animal height and nerve segment length were inversely related to SNCV consistently. The SNCV values were affected by surface skin temperature by a factor of approximately 1.2 m/s change for 1 degree C change in temperatures from 35 C. The ...
Evolution of tooth structure in the Equoidea. During the evolution of the Equoidea, the histological structures of the teeth have become more complex as the molars have become hypsodont in form. The straight Hunter-Schreger bands of Hiracotherium have evolved into a more complex pattern in Equus. The enamel prisms changed from an arched form (about 5μm in diameter) with an alternating pattern in Hiracotherium to an oval form (about 2 μm width) arranged in straight rows in Equus. In Equus the rows of prisms are separated by interprismatic sheets. This pattern may have increased the architectural strength of the enamel, and is related to ...
Some factors affecting isolation of Clostridium tetani from human and animal stools. Clostridium tetani was isolated from human and animal stools at the following rates [95% confidence interval (CI)]: Human, 0% (1.5-0); horse, 1% (5-0); cow in cowshed, 4% (10-1); cow in pasture, 8.3% (17-1), calf in pasture, 0% (7-0); dog, 2% (11-0) and sheep in pasture, 25% (44-14). Quantification of C. tetani in 16 animal stools positive for the bacillus was impossible in most cases, as the number of tetanus bacilli present was not large enough for this purpose. Contaminating anaerobic and facultative anaerobic bacteria in human and animal stools, i.e., C. perfringens and Streptococcus sp., ...
Biphasic disruption of fasting equine gut motility by dopamine–a preliminary study. Dopamine was infused intravenously (1, 5 and 10 micrograms/kg/min) for 60 min in three fasted ponies. A dose-dependent increase in heart rate occurred that was rapid in onset and termination at the start and end of the infusions, respectively. Dose-dependent changes in gastric and small intestinal motility were observed. An initial marked inhibition of gastric contraction amplitude was followed by a secondary prolonged period of activity. At the same time the small intestine showed a prolonged period of irregular activity (phase II) and a marked increase in the interval between successive phas...
Communications and boundaries of the middle carpal and carpometacarpal joints in horses. To study communications and boundaries of the middle carpal and carpometacarpal joints of the horse, 50 forelimbs were obtained from fresh cadaver specimens. Blue latex solution (20 +/- 2.5 ml) was injected into the middle carpal joint, and the specimens were frozen in extension. Frozen specimens were cut into 1-cm sagittal sections from the middle of the radius to the middle of the metacarpus. The communications between the middle carpal and carpometacarpal joints and the presence, length, and position of the distopalmar outpouchings of the carpometacarpal joint were recorded. The middle carp...
Effectiveness of an ivermectin liquid formulation given by nasogastric tube against strongyles in horses. Twenty horses were treated with ivermectin either by nasogastric tube with a liquid formulation for sheep or per os with a paste formulation for horses at a dosage of 200 mug/kg of body weight. Fecal samples were collected from these horses and from ten untreated horses at the time of treatment and every 2 wk thereafter for up to 10 wk. The samples were examined for nematode eggs using the Cornell-McMaster dilution and the Cornell-Wisconsin Double Centrifugation procedures.There were no signs of toxicosis in horses treated with ivermectin. Strongyle eggs were found in the feces of all horses b...
Mitochondrial size and shape in equine skeletal muscle: a three-dimensional reconstruction study. Individual mitochondria were reconstructed from ultrathin serial sections of selected muscle fibers in the M. semitendinosus of a horse, over a length of nearly two sarcomeres. Mitochondria were found to be highly variable, with size and complexity of single mitochondria increasing with the fractional part of a fiber occupied by mitochondria. In fibers with a mitochondrial volume density of less than 4%, corresponding to the mitochondrial content of fast-twitch glycolytic fibers, mitochondria were generally rather simple cylindrical shapes, oriented parallel to the myofibrils. In fibers with a...
The nutritional status of pregnant and non-pregnant mares grazing South East Queensland pastures. It has been reported that the increasing nutritional demands from mid to late pregnancy of grazing mares may not be met when these stages of gestation coincide with pastures being affected by frost. It was established in this study that grass/legume pastures could support the nutritional requirements of brood mares by providing digestible energy intakes of 68.0 and 91.7 MJ/day and digestible nitrogen intake of 91.2 and 138 g/day during mid and late pregnancy, respectively.
Biotransformation of 1-dehydrotestosterone in the equine male castrate: identification of the neutral unconjugated and glucuronic acid conjugated metabolites in horse urine. The in vivo biotransformation of (1,2(n)-3H)1-dehydrotestosterone was studied in three equine male castrates and a number of neutral metabolites were identified in the urinary unconjugated and glucuronic acid conjugate fractions by gas chromatography/mass spectrometry. The metabolites were extracted from aliquots of the 0-24 h urine samples by Amberlite XAD-2 and separated into combined unconjugated plus glucuronic acid conjugated and sulphoconjugated fractions by Sephadex LH-20 column chromatography. After enzymatic hydrolysis of the glucuronides, the crude neutral unconjugated steroids plus ...
Prevalence of Eimeria leuckarti (Flesch, 1883) and intensity of faecal oocyst output in a herd of horses during a summer grazing season. The prevalence of Eimeria leuckarti infection and the intensity of faecal oocyst output were determined in a herd of 14 mares and their foals in northwest Germany using a sedimentation technique at weekly intervals during a summer grazing season from May to September. None of the mares, but all foals shed oocysts on at least one occasion. The patent periods lasted up to 16 weeks. The mean intensity of oocyst output (0.1-33 o.p.g.) was very low. No clinical signs of gastrointestinal disorder were noticed in any of the foals during this study.
Preferred landing sites of Culicoides species (Diptera: Ceratopogonidae) on a horse in Israel and its relevance to summer seasonal recurrent dermatitis (sweet itch). Six hundred and twenty culicoides of five species were collected from a bait horse at Kannot, Israel, between April and September 1986. Seventy-two per cent of the midges were collected from the belly and 27 per cent from the dorsal aspect of the body, ie, the sweet itch summer seasonal recurrent dermatitis (SSRD) zone. Midges were active mainly from half an hour prior to half an hour after sunset. Only Culicoides puncticollis, C imicola and C schultzei group were collected in considerable numbers. While C imicola was present continuously throughout the season, the appearance of the two other ...
Evaluation of a test kit for determination of serum immunoglobulin G concentration in foals. The accuracy of an immunoglobulin (Ig) G test kit for the semiquantitative measurement of IgG concentration was evaluated with serum from 88 foals. Failure of passive transfer (IgG less than 400 mg/dl) was correctly identified in each of 34 samples, and partial failure of passive transfer (400 less than or equal to IgG less than 800 mg/dl) was correctly identified in each of nine samples. Evidence of adequate passive transfer (IgG greater than or equal to 800 mg/dl) was detected in 44 of 45 samples. One sample with 800 mg/dl or more of IgG was incorrectly classified as a partial failure of pas...
Costal vs. crural diaphragmatic blood flow during submaximal and near-maximal exercise in ponies. The present study was carried out 1) to compare blood flow in the costal and crural regions of the equine diaphragm during quiet breathing at rest and during graded exercise and 2) to determine the fraction of cardiac output needed to perfuse the diaphragm during near-maximal exercise. By the use of radionuclide-labeled 15-micron-diam microspheres injected into the left atrium, diaphragmatic and intercostal muscle blood flow was studied in 10 healthy ponies at rest and during three levels of exercise (moderate: 12 mph, heavy: 15 mph, and near-maximal: 19-20 mph) performed on a treadmill. At re...
The role of intestinal microflora in the metabolism of trichothecene mycotoxins. The role of faecal and intestinal microflora on the metabolism of trichothecene mycotoxins was examined in this study. Suspensions of microflora obtained from the faeces of horses, cattle, dogs, rats, swine and chickens were incubated anaerobically with the trichothecene mycotoxin, diacetoxyscirpenol (DAS). Micro-organisms from rats, cattle and swine completely biotransformed DAS, primarily to the deacylated deepoxidation products, deepoxy monoacetoxyscirpenol (DE MAS) and deepoxy scirpentriol (DE SCP). By contrast, faecal microflora from chickens, horses and dogs failed to reduce the epoxide ...
A comparison of three methods of end-to-end anastomosis in the equine small colon. Six animals were used to compare simple interrupted, simple continuous, and stapled techniques for end-to-end rotated small colon anastomoses. Three ponies were evaluated three days after surgery for adhesion formation and luminal diameter at each anastomosis site. Two ponies and one horse were evaluated 14 days after surgery for adhesion formation. All anastomosis sites were examined histologically for alignment of tissue planes, and evidence of inflammation. No single technique was superior in all areas examined. While only three of the nine anastomoses had mild fibrinous adhesions at three ...
Left ventricular oxygen extraction during submaximal and maximal exertion in ponies. 1. Left ventricular (LV) myocardial O2 extraction was studied in five healthy ponies which had catheters implanted in the great cardiac vein and main pulmonary artery 15-30 days before the study. The abdominal aorta was percutaneously catheterized to sample arterial blood. 2. In addition, phasic LV and aortic pressures, LV dP/dtmax and rate-pressure product were also studied; dP/dtmax is the maximal rate of rise of the left ventricular pressure during the isovolumic phase, and is considered an index of myocardial contractility. Measurements were made at rest (control) and during adenosine infu...
