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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.
Anthelmintic resistance. In populations of livestock in which anthelmintics have become the only means of control, individual worms in some species of helminths evade the effects of specific anthelmintics. If these resistant individuals are selected (by removing the susceptible individuals in the population) then the resistant worm population on individual farms becomes dominant in both numbers and effect. This selection of anthelmintic resistant populations is most often reported in equids and small ruminants (the hosts in which anthelmintics are used most frequently). There is little evidence of anthelmintic resista...
Ultrastructure of epididymal epithelium in Equus caballus. The ultrastructure of the epithelial lining of the ductuli efferents and the ductus epididymis in the horse (Equus caballus) is described. Several types of cells can be distinguished: ciliated and non-ciliated cells make up the epithelium of the ductuli efferents, whereas principal, apical and basal cells are found in the ductus epididymis. The observations are compared with those made in other species, in particular in the donkey (Equus asinus), and the possible functional roles of the different cell types are discussed.
Purification and characterization of insulin and the C-peptide of proinsulin from Przewalski’s horse, zebra, rhino, and tapir (Perissodactyla). Within the order Perissodactyla, the primary structure of insulin has been strongly conserved. Insulin from Przewalski's horse and the mountain zebra (suborder Hippomorpha) is the same as that from the domestic horse and differs from insulin from the white rhinoceros and mountain tapir (suborder Ceratomorpha) by a single substitution (Gly-->Ser) at position 9 in the A-chain. A second molecular form of Przewalski's horse insulin isolated in this study was shown to represent the gamma-ethyl ester of the Glu17 residue of the A-chain. This component was probably formed during the extraction of ...
Trypanosomiasis of domestic animals in China. Trypanosomiasis caused by Trypanosoma evansi (surra) is a problem of great economic importance in livestock in China because it affects important working animals: buffaloes in the south and east, and horses and cattle in the north and west. In addition, buffaloes are an important source of meat and leather for the Chinese population. In the north and west, T. evansi is found mainly in camels, whereas in the east, the south and the southwest, it is primarily buffaloes, cattle and horses that are affected by this parasitic flagellate. Although trypanosomiasis is one of the most important parasit...
Comparative study of the stability of the folding intermediates of the calcium-binding lysozymes. Unfolding profiles of two calcium-binding lysozymes, equine milk lysozyme and pigeon egg-white lysozyme, were obtained by circular dichroism and proton NMR measurements. Equine lysozyme unfolds through a stable molten globule intermediate. The molten globule of equine lysozyme was characterized as more ordered than that of bovine alpha-lactalbumin. On the other hand, pigeon lysozyme unfolds by a two-state mechanism and the intermediate could not be observed in guanidine or thermal unfolding, the same as with conventional non-calcium-binding lysozymes. Thus, from the point of view of the unfold...
Effects of intraarticular corticosteroid and sodium hyaluronate injections on synovial fluid production and synovial fluid content of sodium hyaluronate and proteoglycans in normal equine joints. Hyaluronate and cartilage proteoglycan fragments in synovial fluid from normal equine joints were determined after repeated intraarticular injections of beta-methasone, methylprednisolone, hyaluronate, saline and a combination of beta-methasone + hyaluronate and methylprednisolone + hyaluronate. The experimental intraarticular treatments were given at the beginning of the study and after one and two weeks. Synovial samples were obtained at the onset of the study and after 1, 2, 3, 4, 6, and 8 weeks. The synovial volume was determined and showed no significant changes after the repeated arthroc...
Clearance of infused triglyceride by resting horses. 1. Clearance of infused lipid was observed in six mature resting horses, 2 to 6 hr after receiving a meal of alfalfa hay. 2. Intralipid, a 10% triglyceride emulsion, was infused at a rate of 0.2 ml/kg into the jugular vein. 3. Blood samples were obtained for 80 min post-infusion and assayed for plasma triglyceride concentration. 4. Clearance rate of the infused lipid was very slow (mean t1/2 = 269 min). 5. The clearance rate of the infused lipid in these horses was much slower than has been observed in other species. 6. The slow clearance of infused triglyceride in horses may suggest an inabil...
Changes in fluid composition on the serosal surface of jejunum and small colon subjected to venous strangulation obstruction in ponies. In 6 anesthetized ponies, 3 segments of jejunum and 3 segments of small colon were isolated from the peritoneal cavity in plastic bags filled with Hanks' balanced salt solution. One jejunal and 1 small colon segment were subjected to venous strangulation obstruction for 3 hours (VSO-3), venous strangulation obstruction for 6 hours (VSO-6), or a 6-hour sham procedure to control for changes induced by isolation in a plastic bag. Additional segments of jejunum and colon that were not placed in bags served as controls for histologic examination and collagenase measurements. Samples of fluid surrou...
Uterine tear without a corresponding placental lesion in a mare. A 3-cm full-thickness tear near the tip of the previously gravid uterine horn of a 12-year-old Thoroughbred mare was diagnosed at surgery. The mare had delivered a foal with veterinary assistance 2 days prior to surgery. The mare subsequently developed muscle tremors, anorexia, and signs of depression. Physical examination revealed pyrexia, extended capillary refill time, muscle fasciculations, and fewer-than-normal borborygmi. Abnormalities of the uterus or vagina were not detected by palpation per rectum or per vagina. The chorioallantois underlying the area of the tear was intact. We propos...
[Effect of a paramunity inducer on the incidence of diseases and the plasma cortisol content in Thoroughbred foals before and after weaning]. The effect of the prophylactic application of the paramunity inducer Baypamun on the incidence of diseases among foals (n = 63) in four Thoroughbred studs was evaluated. In a blind study, 38 of the foals received 2 ml of Baypamun intramuscularly while 25 of the foals received a placebo at six and four days before weaning and on the fifth day post-weaning. During the observation period of three weeks, beginning with the first and ending ten days after the last application, 7.9% of the foals treated with Baypamun (3 out of 38) suffered from respiratory infections compared to 24% of the foals tre...
Antibody responses of Japanese horses to influenza viruses in the past few years. A total of 305 horse sera collected in the Hidaka district of Hokkaido in the years 1988-90 were tested for the presence of hemagglutination-inhibition (HI) antibodies to A/equine/Newmarket/1/77 (H7N7), A/equine/Tokyo/2/71 (H3N8) and A/equine/Kentucky/1/81 (H3N8, Kentucky) strains of equine influenza (EI) virus. Antibodies to the 3 strains were detected in hardly of the 45 sera from 2-years-old horses which were collected before vaccination. Many of the 51 horses, after vaccination with inactivated EI virus, had HI antibodies to the 3 strains in 37 to 88 per cent. However, the number of positi...
Characteristics of Escherichia coli isolated from septic foals. Fifteen Escherichia coli isolates from the blood and tissue of foals with septicemia were compared with 15 from the feces of clinically normal horses. Comparisons were made with respect to survival in normal equine serum, production of aerobactin, and production of hemolysin. Isolates from the blood and tissues of septic foals were more likely to be resistant to equine serum than were isolates from feces of clinically normal horses. There were minimal differences between the isolates with respect to aerobactin and hemolysin production, almost all being nonhemolytic and aerobactin negative. Ser...
Hoary alyssum (Berteroa incana) toxicity in a herd of broodmare horses. A herd of pregnant horses exposed to hoary alyssum through ingested hay developed acute and severe gastrointestinal toxicity accompanied by intravascular hemolysis. Postmortem lesions were consistent with these signs. Three horses had late-term abortions.
Cardiovascular responses to exogenous platelet-activating factor (PAF) in anesthetized ponies, and the effects of a PAF antagonist, WEB 2086. The effects of exogenous platelet-activating factor (PAF) were determined in anesthetized ponies. Administration of PAF induced a decrease in cardiac index that resulted in systemic hypotension. This was followed by tachycardia, hypertension, and a return of cardiac index to baseline. Pulmonary arterial pressure increased markedly because of pulmonary vasoconstriction. Exogenous PAF also caused leukopenia and thrombocytopenia. The specific PAF receptor antagonist (WEB 2086) blocked all PAF-induced changes. Flunixin meglumine, a cyclooxygenase inhibitor, abolished the pulmonary hypertension and...
Effect of hypercapnia on the arrhythmogenic dose of epinephrine in horses anesthetized with guaifenesin, thiamylal sodium, and halothane. The effect of hypercapnia on the arrhythmogenic dose of epinephrine (ADE) was investigated in 14 horses. Anesthesia was induced with guaifenesin and thiamylal sodium and was maintained at an endtidal halothane concentration between 0.86 and 0.92%. Base-apex ECG, cardiac output, and facial artery blood pressure were measured and recorded. The ADE was determined at normocapnia (arterial partial pressure of carbon dioxide [PaCO2] = 35 to 45 mm of Hg), at hypercapnia (PaCO2 = 70 to 80 mm of Hg), and after return to normocapnia. Epinephrine was infused at arithmetically spaced increasing rates (ini...
Chronic selenosis in horses fed locally produced alfalfa hay. Chronic selenosis (alkali disease) was diagnosed in horses of western Iowa, a region associated with marginal to adequate soil selenium. Two locally produced alfalfa hays (Medicago sativa L) were identified as the primary source. Difficulty in selecting diagnostic specimens to evaluate potential chronic selenosis cases is complicated by the wide range of tissue concentrations reported in previous cases, conflicting correlation of sample selenium concentrations in the literature, and different recommendations on specimen selection and diagnostic value. These problems arise form the similarity i...
Free radical oxidation products in plasma and synovial fluid of horses with synovial inflammation. Free radical oxidation products, namely conjugated dienes, ultraviolet fluorescence (excitation 325 nm, emission 395 nm) and visible fluorescence (excitation 360 nm, emission 460 nm) were measured in equine synovial fluid exposed to free radicals in vitro and in the plasma and synovial fluids of horses with synovial effusions. The synovial effusions were induced by intra-articularly administered carrageenin (0.3 ml, 1%), which rarely resulted in clinical lameness. The free radicals were generated in vitro by mixtures of iron and ethylene diamine tetra acetate (Fe/EDTA) or mixtures of hypoxanth...
Bilateral optic disc colobomas and microphthalmos in a thoroughbred horse. A thoroughbred colt had bilateral but unequal microphthalmos together with microcornea, abnormalities of the iris and lens and posterior segment colobomas. The case is compared with other reports of microphthalmos and coloboma in horses.
Intratumoral chemotherapy with cisplatin in oily emulsion in horses. Twenty horses with 30 lesions were studied to evaluate the effects of intratumoral chemotherapy with cisplatin in sesame oil on equine sarcoids (n = 19), squamous cell carcinomas (n = 7), and squamous cell papillomas (n = 4). Treatment consisted of 4 sessions of intratumoral cisplatin chemotherapy at 2-week intervals. A controlled-release formulation of cisplatin in sesame oil was used to limit drug egress from the injection site. Mean dosage per session was 0.97 (+/- 0.17, SEM) mg of cisplatin/cm3 of tumor tissue treated for tumor volumes ranging from 10 to 20 cm3. Dosage tended to be slightl...
Choledocholithiasis attributable to a foreign body in a horse. Cholelithiasis is the most common cause of biliary obstruction in horses. Proposed mechanisms include ascariasis, biliary stasis, ascending biliary infection, and changes in bile composition. In this horse, a foreign body acted as the nidus for bile-salt deposition and ascending cholangitis. Clinical signs (intermittent abdominal pain, icterus, and pyrexia) in conjunction with high serum activity of enzymes indicative of obstructive biliary disease led to a tentative diagnosis of cholelithiasis. Ultrasonography was used to confirm the diagnosis. Postmortem examination revealed a 7-cm wooden st...
Oligonucleotide probes for DNA fingerprinting in horses. 10 different oligonucleotide probes were evaluated for DNA fingerprinting in horses. Five probes were able to detect polymorphic bands. The probes (GT)(8) , (GTG)(5) and (GGAT)(4) are most informative for individual identification and were used to analyze a population of Hannoveranian horses. The probability that two individuals have the same DNA fingerprint pattern is 1.2 × 10(-8) , 5.2 × 10(-10) and 1.5 × 10(-7) respectively. Using a combination of the three probes, paternity tests were performed with exclusion probabilities between 0.08% and 4%. ZUSAMMENFASSUNG: Oligonukleotide-Sonden fÃ...
Temporary bilateral laryngeal paralysis in a horse associated with general anaesthesia and post anaesthetic myositis. An eight-year-old Highland pony which had previously shown normal laryngeal function, underwent general anaesthesia for surgical treatment of a mandibular sinus. During its recovery from the anaesthesia, the pony suffered great respiratory distress and stridor, due to total bilateral laryngeal paralysis and pulmonary oedema. The animal was immediately given a temporary tracheostomy. Some hours later, postoperative myositis developed; it resolved within two days and the pony's laryngeal function returned to normal during the following year.
Quantification of the locomotion of Dutch Warmblood foals. To get an in-depth insight into the ontogeny of the equine locomotor apparatus, the locomotion of 28 Dutch Warmblood foals was recorded at the walk, trot and canter on a treadmill using a CODA-3 apparatus. A great similarity in joint angle-time diagrams was found, although considerable differences in kinematic gait parameters of individual foals could be detected. These results contribute to an objective comparison of the locomotor performance of foals.
Equine protozoal myeloencephalitis: antigen analysis of cultured Sarcocystis neurona merozoites. Antigens of cultured Sarcocystis neurona merozoites were examined using immunoblot analysis. Blotted proteins were probed with S. cruzi, S. muris, and S. neurona antisera produced in rabbits, S. fayeri (pre- and post-infection) and S. neurona (pre- and post-inoculation) sera produced in horses, immune sera from 7 histologically confirmed cases of equine protozoal myeloencephalitis (EPM), and pre-suckle serum from a newborn foal. Eight proteins, 70, 24, 23.5, 22.5, 13, 11, 10.5, and 10 Kd, were detected only by S. neurona antiserum and/or immune serum from EPM-affected horses. Equine sera were ...
In vivo tendon forces in the forelimb of ponies at the walk, validated by ground reaction force measurements. The load distribution over tendinous structures in the equine forelimb was studied by computing forces from in vivo signals of implanted liquid-metal strain gauges in 5 ponies. For validation, these tendon forces were converted to joint moments, which were summed and compared to the calculated joint moments caused by the ground reaction force. Mean peak forces per kilogram body weight (n = 5) amounted to 5.2 N/kg for the superficial digital flexor tendon, 3.8 N/kg for the deep digital flexor tendon, 7.3 N/kg for the distal accessory (check) ligament and 8.4 N/kg for the third interosseous musc...
The effect of exploratory laparotomy on the serum and peritoneal haptoglobin concentrations of the pony. Serum haptoglobin concentration was used as an indicator of the acute phase response in ponies undergoing exploratory laparotomy. Preoperative, 1 h intraoperative, 3 h, 6 h, 12 h and 24 h postoperative blood samples and 48 h postoperative peritoneal fluid samples were obtained for haptoglobin analysis. A spectrophotometric assay based on cyanmethemoglobin binding capacity (CyanBC) was used to determine haptoglobin concentrations. The preoperative reference range for serum haptoglobin concentrations in these ponies was 25-60 mg CyanBC/dL. Intraoperative and 3 h postoperative blood samples had d...
