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.
Vascular response of the equine radius to cerclage devices. The arterial blood supply to the diaphysis of the radius, and the vascular reaction when three cerclage devices (cerclage wire, Parham-Martin band, and a partially contacting band) were applied 2 cm apart, were studied in six adult ponies. The opposite radial diaphysis served as the control. Ponies were euthanatized at weeks 4 and 8. A centrifugal blood flow pattern was demonstrated by microangiography. Larger numbers of medullary arteries exist in equine than in canine and human long bones. Changes in centrifugal blood supply were not identified beneath any of the cerclage devices.
A survey of whole blood selenium concentrations of horses in Maryland. We surveyed the whole blood selenium status of a randomly sampled population of horses from 4 contiguous counties in northern Maryland. Two hundred and two horses from 74 farms were sampled. Whole blood selenium levels greater than or equal to 0.100 parts per million (ppm) were considered adequate; blood levels less than 0.100 ppm were considered marginal or deficient. The average blood selenium concentration of the horses sampled was 0.137 ppm, with a standard deviation of 0.041 ppm. Blood selenium concentrations ranged from 0.050-0.266 ppm. Thirty-eight of 202 horses (18.8%) had a selenium l...
Haemodynamic effects of small volume hypertonic saline in experimentally induced haemorrhagic shock. A comparison of the haemodynamic benefits of small volume hypertonic saline (2,400 mOsm/litre) versus isotonic saline (300 mOsm/litre) was conducted in 12 adult horses using a haemorrhagic shock model. The horses were anaesthetised and intravascular catheters placed for the measurement of haemodynamic data. Mean systemic arterial pressure was then reduced to 50 to 60 mmHg by controlled haemorrhage and maintained at that level for 40 mins. Cardiac output, stroke volume, mean systemic arterial pressure, plasma volume and urine production decreased significantly following blood loss. Hypertonic o...
Isolation of Gardnerella vaginalis from the reproductive tract of four mares. A gram-variable pleomorphic bacillus was isolated from the reproductive tracts of 4 mares during routine prebreeding soundness examinations. Using a commercial bacterial identification system, these organisms were identified as Streptococcus acidominimus. However, colonial and Gram-staining characteristics did not support this identification. Subsequent testing indicated the organism was similar to Gardnerella vaginalis. Additional growth and biochemical analysis performed in our laboratory and at the Michigan Department of Public Health and by the Center for Disease Control, Atlanta, Georgia,...
Seasonally inhibited development of cyathostomine nematodes in Shetland ponies in The Netherlands. Two groups of three yearling Shetland ponies were used in 1988 to study the epidemiological significance of inhibited development of the Cyathostomine nematodes. In Group 1, acquisition of infections was prevented throughout the grazing season whereas in Group 2 strongylid infections were acquired from the beginning of July until the end of September. Worm counts showed that the Cyathostomine nematode populations of Group 1 ponies mainly consisted of adult worms and those of Group 2 ponies of inhibited early third stage larvae (L3). These results indicate that a large proportion of Cyathostomi...
Serum proteins in guinea-pigs and horses infected with Trypanosoma evansi (Steel, 1885). The serum protein pattern in guinea-pigs infected with T. evansi was analysed and compared with those found in horses with either a natural or experimental infection. In both species, a highly significant decrease in albumin levels and an increase in gamma-globulins were seen, leading to a very low albumin/globulin ratio. No significant differences in total protein levels between healthy and infected animals were registered. Likewise, alpha-globulins were not significantly affected. A decrease in beta-globulins was observed in one horse and in guinea-pigs with experimental infection, while in ...
Antigenic assay for protein C determination in horses. An antigenic assay was developed for determination of protein C in horses. Protein C, a natural, vitamin K-dependent anticoagulant component in blood, was isolated from equine plasma, a specific antibody was produced in goats, and a rocket electroimmunophoresis assay was established. Tests were performed to verify the identity of the isolated protein C and to determine the purity of the antibody. Protein C antigen was measured in plasma from 34 clinically normal horses, and values were compared with amidolytic function values. The mean (+/- SD) values for the 2 test methods were similar (antig...
Effect of hypertonic vs isotonic saline solution on responses to sublethal Escherichia coli endotoxemia in horses. Cardiovascular responses to sublethal endotoxin infusion (Escherichia coli, 50 micrograms/ml in lactated Ringer solution at 100 ml/h until pulmonary arterial pressure increased by 10 mm of Hg) were measured 2 times in 5 standing horses. In a 2-period crossover experimental design, horses were either administered hypertonic (2,400 mosm/kg of body weight, IV) or isotonic (300 mosm/kg, IV) NaCl solution after endotoxin challenges. Each solution was administered at a dose of 5 ml/kg (infusion rate, 80 ml/min). Complete data sets (mean arterial, central venous, and pulmonary arterial pressures, pul...
Neuroaxonal dystrophy associated with vitamin E deficiency in two Haflinger horses. Neuroaxonal dystrophy and minimal diffuse degenerative myelopathy was diagnosed in two female full sibling, 1- and 2-year-old, Haflinger horses. Both animals developed slowly progressive ataxia from the age of 4 months. Clinical signs, which were more prominent in the hind legs, included hypermetria and dysmetria. Histological examination revealed neuroaxonal dystrophy characterized by spheroid formation, vacuolation, astrogliosis and lipofuscin pigment deposition in macrophages and neuronal perikarya. These changes were restricted to the gracilis and cuneate nuclei, nucleus of the solitary tr...
Overo lethal white foal syndrome: equine model of aganglionic megacolon (Hirschsprung disease). The lethal white foal syndrome (LWFS) is a congenital abnormality of overo spotted horses which is a model for human aganglionic megacolon or Hirschsprung disease. Foals with LWFS have an all white, or nearly all white, coat. They also present clinically with an intestinal obstruction that proves fatal within the first few days of life. The LWFS involves both melanocytes and intestinal ganglion cells, and appears to result from a genetic defect involving neural crest cells. This report describes pathologic studies of two recent cases of LWFS. Two different hypothetical models of inheritance of...
The inheritance of the leopard complex of spotting patterns in horses. The leopard complex of white spotting patterns in horses consists of the leopard, few-spot leopard, blanket, blanket with spots, varnish roan (or marble), snowflake, frosted, speckled, and mottled patterns. Horses with any of these patterns can produce the other patterns when mated to nonpatterned horses. Twenty-two horses of the Welsh Pony, Noriker, Appaloosa, and Pony of the Americas breeds produced 270 foals in a distribution consistent with a single dominant allele being responsible for the patterns. The symbol for this dominant allele, Lp, is retained from previous work on the leopard pat...
Effects of allopurinol on endotoxin-induced increase in serum xanthine oxidase in the horse. Using a modified bovine milk enzyme kinetic assay, xanthine oxidase activity of serum collected from 34 adult, healthy horses of both sexes was determined. Enzyme activity varied from 0 to 126 mU litre-1 with a mean of 44.95 +/- 21.05 mU litre-1. The optimal pH and temperature for maximal activity were 7.8 and 28 degrees C, respectively. Freezing the serum for four days at -70 degrees C did not destroy the enzyme activity. Various doses (25, 50 and 75 micrograms kg-1, intraperitoneally) of endotoxin (lipopolysaccharide D1 Escherichia coli O26:B6) previously known to have caused moderate to sev...
Uterine contractile activity in mares during the estrous cycle and early pregnancy. Transrectal ultrasonography was used to quantitate uterine contractile activity during the estrous cycle and early pregnancy in pony mares (nonbred, n = 9; pregnant, n = 16). Continuous 1-min scans of longitudinal sections of the uterine body were videotaped, and uterine activity scores (1=minimal activity, 5=maximal activity) were assigned to each tape segment. There was a tendency (P<0.06) for a main effect of reproductive status (nonbred versus pregnant), a main effect of day (P<0.0001), and a reproductive status by day interaction (P<0.006). Uterine activity scores were higher (P&...
EGF receptor-binding activity in the urine of normal horses and horses affected by chronic laminitis. A heterologous radioreceptor binding assay (RRA) has been developed capable of detecting nanogram amounts of epidermal growth factor (EGF) receptor-binding activity in equine urine. The binding parameters of [125I]mEGF (murine EGF) to EGF receptors on equine plasma membranes are in good agreement with values from other EGF-RRA systems. The dissociation constant estimated from equilibrium methods (KD = 4 X 10(-10) M) is in reasonable agreement with that determined from the rate constants (KD = 6 X 10(-10) M) and is in good agreement with values determined in other species. The assay is specific...
The effects of phenylbutazone on the morphology and prostaglandin concentrations of the pyloric mucosa of the equine stomach. Phenylbutazone, a nonsteroidal anti-inflammatory drug known to produce gastric ulcers, was administered intravenously (13.46 mg/kg body weight) daily to 12 horses. Horses were euthanatized daily after 24, 48, 72, and 96 hours following the initial injection. Eight untreated horses served as controls. Small multifocal pyloric erosions were seen after 24 hours and then progressed in severity over time. The erosions were characterized by sloughing of the surface epithelium, subepithelial bleb formation, necrosis of the lamina propria, degeneration of the walls of subsurface capillaries, and micro...
Characterisation of Chlamydia psittaci isolated from a horse. This paper describes the isolation and characterisation of a strain of Chlamydia psittaci obtained from a nasal swab taken from a horse with serous nasal discharge. Initial isolation was achieved in cycloheximide-treated McCoy cell monolayers. Chlamydial inclusions stained by immunofluorescence either with a rabbit antiserum raised against C. psittaci or with a monoclonal antibody directed against the genus-specific lipopolysaccharide antigen were single and compact. They did not stain with iodine or with a monoclonal antibody reactive against Chlamydia trachomatis. The agent was re-isolated i...
Specific immunotherapy in the treatment of Culicoides hypersensitive horses: a double-blind study. Fourteen privately owned horses completed a six month, controlled, double-blind trial to assess the efficacy of immunotherapy using an aqueous extract of whole, unfed Culicoides variipennis in the treatment of Culicoides hypersensitivity. Selected horses had a history of a seasonal, pruritic dermatitis, clinical signs and distribution compatible with Culicoides hypersensitivity, failed to improve in response to ivermectin therapy, and reacted to several dilutions of Culicoides extracts without significant reactivity to other possible allergens including insects, moulds and feeds. One horse fro...
Equine synovial tendon sheaths and bursae: an histological and scanning electron microscopical study. The structure of equine synovial tendon sheaths and bursae has been examined by light and scanning electron microscopy. Tissue samples were obtained from horses of various types and ages with no clinical evidence of sheath or bursal disorders. The interior of both structures was lined by a cellular layer superimposed on a vascular zone supported by a fibrous layer. The pattern of cell distribution of the lining varied from site to site within the same structure depending on the nature of the underlying tissue and on the amount of movement to which the structure was subjected. The cellular laye...
Partial pressures of oxygen and carbon dioxide, pH, and concentrations of bicarbonate, lactate, and glucose in pleural fluid from horses. Samples of pleural fluid from 20 horses with effusive pleural diseases of various causes were evaluated; samples from 19 horses were used for the study. There were differences for pH (P = 0.001) and partial pressure of oxygen (PO2) between arterial blood and nonseptic pleural fluid (P = 0.0491), but there were no differences for pH, PO2, partial pressure of carbon dioxide (PCO2), and concentrations of bicarbonate (HCO3-), lactate, and glucose between venous blood and nonseptic pleural fluid. Paired comparisons of venous blood and nonseptic pleural fluid from the same horse indicated no differe...
Endoscopy of the digital flexor tendon sheath in horses. An arthroscopic procedure for examination of the digital flexor tendons and tendon sheath was developed in 16 equine limbs and 12 horses. Distension of the tendon sheath and insertion of the arthroscope was accomplished through a cul-de-sac on the palmar or plantar surface of the tendon sheath 1 to 2 cm palmar or plantar to the digital neurovascular structures and between the annular ligament and proximal digital annular ligament. A single arthroscope entry point allowed examination of all regions of the tendon sheath cavity and most surfaces of the digital flexor tendons within the sheath. Di...
