Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Horses
"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
Regional brain blood flow and O2 delivery during severe exertion in the pony. Regional distribution of brain blood flow (radionuclide labelled 15 microns diameter microspheres) and O2 supply were studied in 11 healthy adult grade ponies at rest and during severe exercise (SE) performed on a treadmill (heart rate = 220 +/- 4 beats X min-1; VO2 = 126 +/- 9 ml X min-1 X kg-1). During SE, the mean aortic pressure increased to 169 +/- 4 mm Hg and the pHa, PaCO2 and PaO2 were 7.213 +/- 0.010, 30 +/- 1 mm Hg and 85 +/- 4 mm Hg, respectively. The hemoglobin concentration increased by 59.6% with SE. Whereas blood flow increased in the cerebellar gray matter (96%), pons (39.5%) a...
Phenylbutazone and oxyphenbutazone distribution into tissue fluids in the horse. The clinically recommended dose rate of phenylbutazone (4.4 mg/kg) was administered intravenously as a single dose to five Welsh Mountain ponies. Distribution of phenylbutazone and its active metabolite oxyphenbutazone into body fluids was studied by measuring concentrations in plasma, tissue-cage fluid, peritoneal fluid and acute inflammatory exudate harvested from a polyester sponge model of inflammation. The ready penetration of phenylbutazone into inflammatory exudate was demonstrated by the relatively high mean value for Cmax of 12.4 micrograms/ml occurring at a time of 4.6 h and a mean A...
Chronic granulomatous bowel disease in three sibling horses. Chronic granulomatous bowel disease was diagnosed in 3 sibling Standardbred horses. Clinical signs included weight loss, loose feces, and decreased appetite in the terminal stage of the disease. Abnormal laboratory findings included hypoproteinemia and low xylose absorption. Necropsy revealed granulomatous inflammation of the intestines, mesenteric lymph nodes, and liver. Eosinophilic infiltration of the granulomatous lesions was a prominent finding in one horse. A causative agent was not detected by special histochemical staining or bacteriologic culturing.
Prevalence of carpal fractures in thoroughbred and standardbred racehorses. The prevalence of carpal fractures was determined for 211 thoroughbred and 75 standardbred racehorses. Statistically significant differences were found in the location of fractures between the 2 breeds. In the thoroughbred and standardbred groups, total fractures (460) were distributed nearly equally between the left (224) and right (236) carpi. The most common site of fracture in the thoroughbred group was the distal aspect of the radiocarpal bone (112), whereas the most common site of fracture in standardbred horses was the proximal surface of the third carpal bone (61). Slab fractures were ...
Interpretation of laryngeal function tests in the horse. Idiopathic left-sided laryngeal paralysis was present in 14 of 169 horses on a thoroughbred horse farm (8.3 per cent). In nine animals, it was evident only after exercise and arytenoid abduction and adduction were normal at rest. Asynchronous movement of the arytenoid cartilages was observed in 94 horses at rest (55.6 per cent), 86 of which were considered to be normal after exercise. Conversely, synchronous movement of the arytenoids was noted when at rest in six of the 14 animals diagnosed as having laryngeal hemiplegia after exercise. An abnormal inspiratory noise during exercise was detect...
Effects of urea and guanidine hydrochloride on the activity and dynamical structure of equine liver alcohol dehydrogenase. The inactivation of equine liver alcohol dehydrogenase by guanidine hydrochloride and urea has been studied by monitoring the intrinsic tryptophan fluorescence and phosphorescence emission. The use of triplet-state lifetimes to probe the flexibility of protein structure at the site of tryptophan-314 reveals a distinct behavior between the two denaturants. At predenaturational concentrations, the loss of enzyme activity in guanidine hydrochloride is associated with a loosening of intramolecular interactions resulting in a greater fluidity of the interior region of the macromolecule. In contrast...
Single photon absorptiometry for the measurement of bone mineral content in horses. A safe, non-invasive method for the accurate measurement of bone mineral content in the third metacarpal bone of the horse is described. The technique involves scanning the bone with a single photon beam from an Americium-241 source. Data were obtained from the excised metacarpal bones from both forelimbs of 50 normal and seven lame horses. Measurements were made in vivo on eight normal and seven lame horses and on one experimental horse with osteopenia induced by partial weightlessness in a flotation tank. In the normal horses bone mineral content altered with age, particularly in the first s...
Iopamidol myelography in the horse. The use of the non-ionic, water-soluble contrast agent iopamidol for myelography in seven horses is described. Contrast columns of diagnostic quality were produced in all seven cases and the procedure did not invoke any adverse reactions in the five cases which were recovered from general anaesthesia. It is concluded that iopamidol is a safe and effective contrast agent for myelography in the horse.
Crystalline composition of equine urinary calculi. X-ray diffraction crystallography was used to determine the crystalline composition of 18 equine urinary calculi, including stones originating in the kidney, bladder and urethra. Calcium carbonate in the form of calcite was found to be the major component in all calculi examined. Other components commonly found included weddellite and substituted vaterite. Urine deposits from a number of normal horses were also examined. The significance of these findings, as well as those from a number of previous reports, are discussed in relation to the possible aetiology of urolithiasis in the horse.
Type II renal tubular acidosis in a mare. Persistent, severe metabolic acidosis complicated the operative and postoperative period in a 4-year-old mare with colic. On the basis of clinical and laboratory findings, a renal tubular disorder was diagnosed. Renal tubular acidosis is rare in horses. In the only report found on the subject, type I renal tubular acidosis was described in 2 horses. Bicarbonate titration studies in our case helped document type II renal tubular acidosis in this mare.
Gentamicin tissue concentrations in equine small intestine and large colon. Gentamicin sulfate (2.2 mg/kg of body weight, IV) was given to anesthetized horses. Jejunal and large colon tissue samples (1 g), serum, and urine were collected over a 4-hour period. Maximum gentamicin concentrations in serum (10.06 +/- 2.85 micrograms/ml) occurred at 0.25 hours after injection. Maximum gentamicin concentrations in the large colon (4.13 +/- 1.80 micrograms/ml) and jejunum (2.26 +/- 1.35 micrograms/ml) occurred in horses at 0.5 and 0.33 hours, respectively. Tissue concentrations decreased in parallel with serum concentrations and were still detectable at the end of the 4-hour ...
Ground reaction force patterns of Dutch Warmblood horses at normal walk. The ground reaction force patterns from 20 clinically sound Dutch Warmblood horses (Group A) were recorded at the normal walk. The data from four to 10 stance phases of each limb were computer averaged after normalisation to the animal's body mass and to the stance time. This analysis method allowed comparison of data from left and right fore- and hindlimbs within and between horses. The left-to-right symmetry in the reaction force peaks of contralateral limbs of one horse exceeded 90 per cent. The time in the stance phase at which the peaks occur were even more symmetrically distributed. A ch...
Equine pythiosis in Costa Rica: report of 39 cases. Thirty-nine pythiosis equine cases, were studied at the Veterinary Medicine School of the National University of Costa Rica, between 1981 and 1984. Lesions were located in different parts of their anatomy: anterior and posterior extremities, abdomen, thorax, breast and mammary gland, and were characterized by their tumoral appearance with necrotic tissue in which yellow-white coral-like necrotic masses, called kunker or leeches were shown. Splendore-Hoeppli like phenomenon and eosinophilic inflammatory reaction around the hyphae, was microscopically observed. Pythium sp. (Hyphomyces destruens)...
Induction of ovulation in anestrous mares with pulsatile administration of gonadotropin-releasing hormone. Four seasonally anestrous mares (Standardbred), housed under a nonstimulatory photoperiod of 8 hours light:16 hours dark, were administered gonadotropin-releasing hormone (GnRH) in a pulsatile pattern (50 or 250 micrograms of GnRH/hour) for 8 to 18 days during February and March 1985. Treatment with GnRH, irrespective of dose or month, induced an increase in serum luteinizing hormone from a mean pretreatment value typical of anestrus (0.58 +/- 0.02 ng/ml +/- SE) to 10.84 +/- 1.27 ng/ml on day 8 of GnRH treatment. Ovulation in the 4 mares occurred 8.8 +/- 0.7 days after the initiation of pulsat...
Isolation and characterization of latherin, a surface-active protein from horse sweat. A protein, latherin, with unusual surface activity was isolated from horse sweat by gel filtration and ion-exchange chromatography. The protein has a Stokes radius, determined by gel filtration, of 2.47 nm, and in the ultracentrifuge sediments as a single species with S20,W 2.05 S, indicating an Mr of 24,400. On SDS/polyacrylamide-gel electrophoresis the molecule behaves as a single peptide chain of apparent Mr 20,000. Latherin contains a high proportion of hydrophobic amino acids (37.2%), and the leucine content (24.5%) is exceptionally high. The unusual composition of the protein may account...
Synovial fluid and plasma kinetics of methylprednisolone and methylprednisolone acetate in horses following intra-articular administration of methylprednisolone acetate. Synovial fluid and plasma kinetics of methylprednisolone acetate (MPA) and methylprednisolone (MP) after a single intra-articular administration of MPA at a therapeutic dose (111 mg in toto) was measured in five horses. MPA was detected in synovial fluid for two to six days post injection and MP, which results from synovial MPA hydrolysis, was present in pharmacologically significant concentrations for 4.8 to 39 days, depending on the horse. MPA synovial concentration was maximal (289 +/- 284 micrograms/ml) at the first sampling time (2 h after administration) and MP synovial concentration was...
Vasodilator reserve in respiratory muscles during maximal exertion in ponies. Eight healthy adult grade ponies were studied at rest as well as during maximal exertion carried out with and without adenosine infusion (3 microM X kg-1 X min-1 into the pulmonary artery) on a treadmill to compare levels of blood flow in respiratory muscles with those in other vigorously working muscles and to ascertain whether there remained any unutilized vasodilator reserve in respiratory muscles of maximally exercising ponies. Radionuclide-labeled 15-micron-diam microspheres, injected into the left ventricle, were used to study tissue blood flows. During maximal exertion, there were incre...
Sex variation in the prevalence of exercise-induced pulmonary haemorrhage in racing quarter horses. Post race endoscopy was carried out on 255 two-year-old quarter horses and exercise-induced pulmonary haemorrhage (EIPH) was diagnosed in 166 (65 per cent) of them. Visible epistaxis was seen in a higher proportion of geldings than in either mares or stallions. The prevalence of EIPH was similar in mares (73 per cent) and in geldings (74 per cent). A significantly lower prevalence (49 per cent) was noted in stallions (P less than 0.01). It was concluded that a sex variation in the prevalence of EIPH exists in two-year-old quarter horses.
Isolation of Streptococcus pneumoniae from the respiratory tract of horses. Streptococcus pneumoniae was isolated from nasopharyngeal swabs and tracheal washings taken from Thoroughbred horses in training at three of four separate stables that were sampled during investigations into respiratory disease. The growth of Strep pneumoniae in culture was enhanced by an environment enriched with carbon dioxide. In one stable, five of 15 horses that were sampled repeatedly were found to carry the organism for at least four months. There was an apparent association between lower respiratory tract inflammatory disease and heavy growths (10(6) to 10(8) colony forming units/ml) p...
Ocular angiosarcoma in the horse: morphological and immunohistochemical studies. Angiosarcomas arising in ocular tissues of four aging horses are described. Tumors were locally invasive and eventually metastasized via the mandibular and cervical lymph nodes. Pathologically, the tumors contained well-differentiated regions, in which vascular channels were lined by pleomorphic endothelial cells, as well as poorly-differentiated regions, in which vascular channels were either rudimentary or absent. Red blood cells were scare in vascular structures formed by the tumors. Factor VIII related antigen (VIII:RAg), a blood vascular endothelial marker, was demonstrated by immunohisto...
Comparison of the measurement of plasma testosterone and plasma oestrogens for the diagnosis of cryptorchidism in the horse. The results of performing 1720 blood tests for equine cryptorchidism are described. Using the paired sample human chorionic gonadotrophin (hCG) stimulation test and measuring testosterone, 6.7 per cent of tests did not give a clear result. If only the testosterone concentration in the pre-hCG blood sample was used, this percentage rose to 14 per cent. The paired sample hCG stimulation test was 94.6 per cent accurate. A comparison was made between the paired hCG stimulation test and the measurement of conjugated oestrogen in a single sample. The latter did not give as many doubtfuls but gave fa...
Radioimmunoassay screening for etorphine in racing horses. A commercially available radioimmunoassay kit was used to screen for the presence of etorphine in post-race urines from horses racing in Kentucky. Most horse urines contained small amounts of materials which reacted positively in this immunoassay. These materials are apparently endogenous to the horse and were called apparent etorphine equivalents. The levels of these apparent etorphine equivalents in post-race urines from 70 horses were estimated. Their modal level averaged 0.1 ng/ml, the population distribution was log normal, and individual horses showed levels of up to 0.8 ng/ml.
