Omneity® Pellets
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Topic:Equine Health
Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
Chondrosarcoma in the radius of a horse. An aged Thoroughbred stallion was examined because of progressive lameness, carpal swelling, and weight loss. Radiography revealed a destructive lesion in the caudomedial, distal portion of the radius. Chondrosarcoma was diagnosed by tumor-core biopsy. Gross and histologic evaluation of the neoplasm after necropsy revealed a locally invasive chondrosarcoma at the distal end of the radius that infiltrated the radiocarpal joint capsule and invaded the carpal bones. The malignant nature of this tumor was evident by its invasiveness and histologic features of cell pleomorphism and presence of mito...
Equine adenovirus 1 isolated from cauda equina neuritis. Equine adenovirus 1 was recovered after four to six passages from two out of three cases of cauda equina neuritis (CEN) using kidney monolayers. Similar treatment of lumbo-sacral spinal cord from six normal horses did not yield adenovirus. All three cases of CEN had antibodies to the neuritogenic myelin protein P2 while immunofluorescence demonstrated that autologous IgG bound to the myelin of affected nerves. Adenovirus was not detected in neural tissue by immunofluorescence.
Partial amino-acid sequence and cysteine reactivities of cytosolic aspartate aminotransferase from horse heart. Cytosolic aspartate aminotransferase (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1) from horse heart has five cysteine residues, two of which can be titrated with 5,5'-dithiobis(2-nitrobenzoid acid) in the native enzyme with no impairment of catalytic activity. The rate of modification is unaffected by the presence of substrates. Reaction with N-ethylmaleimide leads to loss of catalytic activity, the rate of inactivation being increased by the presence of substrates. Peptides containing 361 amino-acid residues (about 88% of the total number in the protein) have been isolated and ali...
Antigenic variation during persistent infection by equine infectious anemia virus, a retrovirus. The recurrent nature of equine infectious anemia has been attributed to relatively rapid antigenic variations in equine infectious anemia virus (EIAV) during persistent infection under selective immune pressures. This model was tested by serological and biochemical analysis of virus isolates recovered from separate febrile episodes in two experimentally infected ponies. Neutralization assays employing immune sera from the experimentally infected ponies demonstrated that distinct antigenic strains of virus predominate during sequential febrile episodes in a single pony. Analysis of the test str...
Haematological and biochemical values in horses naturally infected with Strongylus vulgaris. The concentrations of serum proteins (beta 1, beta 2, gamma, alpha 1, alpha 2 globulins and albumin) and absolute numbers of eosinophils, neutrophils and lymphocytes were examined in 64 naturally infected horses and ponies in which the number of larvae of Strongylus vulgaris in the cranial mesenteric artery and the severity of the lesion of verminous arteritis could be determined. The horses were grouped according to the number of larvae found and the severity of the arteritis. The results demonstrated that, although some significant deviation from a random distribution occurred in certain of ...
Acute diarrhea in horses of the Potomac River area: examination for clostridial toxins. Fecal specimens from horses in Montgomery County, Md, and in Fairfax and Loudoun counties, Va, were examined for Clostridium perfringens type A enterotoxin and for C difficile cytotoxin (92 and 108 specimens, respectively). The toxins were found in feces from horses that had experienced an acute diarrhea syndrome and from clinically normal horses. The toxins did not appear to be primary determinants of the diarrhea syndrome, although they may have contributed to the spectrum of clinical entities observed.
The regulatory peptide system of the large bowel in equine grass sickness. In recent years, distinct changes in regulatory peptides have been found in a number of gastrointestinal diseases. Grass sickness is a fatal disease of horses for which the etiology has yet to be fully ascertained. In this study, the peptide-containing nerves and ganglionic and mucosal endocrine cells of the ileum, colon and rectum were investigated in horses with sub-acute or chronic grass sickness and compared with normal controls using immunocytochemistry, at both the light and electron microscopical levels, and radioimmunoassay. A substantial loss of both peptide-containing cells and nerve...
Quantitative analysis of long-bone growth in the horse. Long-bone growth at the distal ends of the radial bones, the distal ends of the 3rd metacarpal bones, the distal ends of the 3rd metatarsal bones, and the proximal ends of the proximal phalangeal bones (of thoracic and pelvic limbs) was quantitatively analyzed in 9 Thoroughbred-Quarter Horse foals from birth to 2 years of age. Metal growth markers were surgically implanted in the bones of the animals at 2 to 4 days of age. Radiographs of the bones were made on the day of surgical manipulation, the next day, and then once a week for 8 months, and once a month thereafter for an additional 18 mon...
Lymphocyte alloantigens of the horse. II. Antibodies to ELA antigens produced during equine pregnancy. Evidence is presented for a reproducible maternal immune response to histocompatibility antigens during equine pregnancy. Mares were stimulated as a result of pregnancy to produce cytotoxic antibodies to paternal lymphocyte alloantigens. The majority of these antibodies were directed against antigens of the equine lymphocyte antigen (ELA) system, which is the major histocompatibility complex (MHC) of the horse. In 16 experimental pregnancies produced using 12 mares and 4 stallions which had been typed for ELA antigens, there was correlation between ELA incompatibility between sire and dam and ...
Enzyme-linked immunosorbent assay for detection of equine infectious anemia antibody to purified P26 viral protein. An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection of equine infectious anemia (EIA) antibody in horse sera. Purified P26 viral protein was the antigen; alkaline phosphatase linked to rabbit anti-horse immunoglobulin G was the conjugate. The ELISA detected EIA antibodies in horse sera as early as 11 to 14 days after experimental inoculations. There was full agreement between the results of ELISA and the agar-gel immunodiffusion tests on EIA proficiency test sera. The ELISA readily detected EIA antibody in horse sera that had weak positive reactions on agar-ge...
Management of proximal sesamoid bone fractures in the horse. The case records of 49 horses with proximal sesamoid bone fracture were studied. The population consisted of 20 Thoroughbreds, 20 Standardbreds, 5 Quarter Horses, 2 Arabians, and 2 grade horses. The fractured bones were classified into 5 categories: apical fractures, basilar fractures, abaxial fractures, middle one-third fractures, and bilateral comminuted-distracted fractures. Apical fractures occurred most frequently in the Standardbred, with the prevalence of medial fracture being equal to that of lateral fracture. Basilar fractures occurred predominantly in the Thoroughbred, with the highe...
Amikacin sulfate in mares: pharmacokinetics and body fluid and endometrial concentrations after repeated intramuscular administration. Six mares were given 5 IM injections (at 12-hour intervals between doses) of amikacin sulfate at a dosage of 7 mg/kg of body weight. Serum amikacin concentrations were measured serially throughout the study; synovial, peritoneal, endometrial, and urine concentrations were determined after the last injection. Amikacin concentrations of the CSF were measured serially in 3 of the 6 mares; 1 of the 3 mares had septic meningitis. Mean serum amikacin concentrations peaked at 1 to 2 hours after IM injection. The highest mean serum concentration was 19.2 micrograms/ml (1.5 hours after the 5th injectio...
Illness in horses following spraying with amitraz. Sickness occurred in 3 of 4 horses within 24 h of being sprayed with an 0.025% w/v aqueous suspension of amitraz. The latter consisted of a portion of an amitraz aqueous suspension made up some 3 weeks previously, to which some freshly prepared spray fluid had been added. It seemed likely that the amitraz in the older solution had broken down to the highly toxic N-3, 5- dimethylphenyl N-methyl formamadine derivative and that this was in fact the main cause of the untoward effects observed. The horses displayed typical clinical signs of tranquillisation, depression, ataxia, muscular incoordinat...
Topographic distribution of pulmonary ventilation and perfusion in the horse. The regional distribution of ventilation to perfusion ratios (VA/Q) in the lungs of 8 healthy standing Thoroughbred geldings (4.4 +/- 1.5 years, 465.7 +/- 46.6 kg) was studied, using steady-state inhalation and IV infusion of the radioactive gas krypton-81m. The VA/Q was uniformly distributed within a vertical lung strip centered over the 9th rib on the right side. Ventilation per unit of alveolar volume (V/VA) assessed from the clearance of inhaled radioactive gas in 5 horses increased from 0.49 +/- 0.13 (arbitrary units) in nondependent lung zones to 1.45 +/- 0.16 in dependent lung zones. Se...
Studies related to the metabolism of anabolic steroids in the horse: the phase I and phase II biotransformation of 19-nortestosterone in the equine castrate. The metabolism of 19-nor[4-14C]testosterone has been studied in the equine castrate. Following XAD-2 extraction of aliquots of the 0-24 h urine samples, the glucuronic acid and sulphate conjugates were separated by Sephadex LH-20 column chromatography. After hydrolysis of the conjugates, the neutral phase I metabolites of 19-nortestosterone were extracted, purified and identified by g.l.c.-mass spectrometry. In phase I metabolism stereospecificity was observed in the reduction of the A-ring with the formation of the 5 alpha, 3 beta-isomers of estranediol. Epimerization at C-17 and hydroxylatio...
Identification of swainsonine as a probable contributory mycotoxin in moldy forage mycotoxicoses. When infested with the fungus Rhizoctonia leguminicola, certain forages, e.g., red clover hay, can cause a "slobber syndrome" of varying severity when consumed by ruminants. The causative agent has been presumed to be slaframine [(1S,6S,8aS)-1-acetoxy-6-aminooctahydroindolizine], which is produced by R. leguminicola. In one serious outbreak of the slobber syndrome in horses, the red clover forage involved was carefully examined and found to contain R. leguminicola and slaframine. An identical hay sample is shown here by ion-exchange chromatographic and gas chromatographic-mass spectrometric an...
Subluxation of the carpus in thirteen horses. The records of 13 horses of various breeds with subluxation of the radiocarpal, intercarpal or carpometacarpal joint, or combinations of these were reviewed. Subluxation was most common at the carpometacarpal joint (n = 10) and concomitant fractures of individual carpal bones or metacarpus II and IV were seen (n = 12).Treatment comprised of immobilization in a full leg plaster cast for from four to 18 weeks. Three animals were euthanized, two because of cast complications and one because of a request by the owner. The remaining ten were saved to function as breeding animals.
Heparin anticoagulant therapy in equine colic. In horses with large bowel disease, those with circulating endotoxins but no evidence of altered hemostasis had a good prognosis for survival. Those with circulating endotoxins and evidence of altered hemostasis (fibrin degradation products) had a poor prognosis. Portal vein infusion of endotoxins over 24 hours caused hoof discomfort, evidenced by shifting of weight and standing with all 4 feet together, and a decreased hoof temperature. Clinical signs appeared within 30 minutes of initiation of infusion and subsided within 4 hours despite continued infusion. Long-term heparin therapy results ...
Prevalence of Onchocerca cervicalis in equids in the Gulf Coast region. Microfilariae of Onchocerca cervicalis were detected in midventral skin biopsy samples in 64 of 84 (76%) mixed-breed ponies greater than 2 years old from the Gulf Coast area and in 42 of 51 (82.4%) horses from Louisiana breeding herds. The number of microfilariae per 8 mm of biopsied skin (ponies) ranged from 1 to 21,570. The number of microfilariae per 6 mm of biopsied skin (horses) ranged from 8 to 55,600.
Genomic alterations associated with persistent infections by equine infectious anaemia virus, a retrovirus. The unique periodic nature of equine infectious anaemia (EIA) is believed to result from the ability of the infecting virus. EIAV, to undergo relatively rapid antigenic variations which circumvent host immune responses resulting in distinct virus populations in sequential clinical episodes in the persistently infected horse. This model was examined by oligonucleotide mapping comparisons of the RNA genomes of selected isolates of EIAV. Variations in oligonucleotide maps could be reproducibly demonstrated (i) after adaptation of the laboratory strain of EIAV to replication in a pony, (ii) after ...
Research needs on internal parasites of horses. The importance of the horse industry to the economy of the United States and the impact of parasitic infections on the industry are well documented. However, contemporary research activity on internal parasites of horses has not kept pace with growth of the horse population. Parasitic infections are a major facet of enteritis and colic in horses. Parasites are also associated with poor growth and development, respiratory tract disease, dermatitis, and CNS lesions. Babesia infections remain a threat to horses imported from some regions of the world. Most research activity has dealt with the dev...
