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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.
Effect of diethylcarbamazine on Strongylus vulgaris infection in ponies. Shetland ponies (n = 4) were given diethylcarbamazine orally at a dose level of 22 mg/kg/day for 1 week before they were inoculated with 800 third-stage larvae of Strongylus vulgaris. Treatment was continued for 86 (1 pony) or 200 days (3 ponies) after the inoculation. As compared with the changes seen in a similarly inoculated group of ponies (group 2) which were not treated, diethylcarbamazine did not prevent the clinical or pathologic changes due to the migrating larvae. Fewer adult parasites were recovered at necropsy from treated ponies than from nontreated (group 2) ponies, even when tre...
Prostaglandins in stallion semen. The purpose of the experiment was to obtain preparatory information about the presence of prostaglandins in semen collected from various types of horses after different periods of sexual rest. Semen was collected with an artificial vagina. Prostaglandin-like activity was estimated by the bioassay procedure described by Vane (1). Results are expressed in ng/ml PGE(2) of seminal plasma. The total concentration of prostaglandins in the full ejaculate averaged 43.73 +/- 4.93 ng/ml of plasma while the total amount of prostaglandins in the ejaculate was 1076 ng. Taking into consideration the period ...
Hemolytic anemia in horses after the ingestion of red maple leaves. Signs of acute hemolytic anemia developed in 4 adult horses from 2 Georgia farms 3 to 4 days after the ingestion of wilted leaves from cut red maple trees (Acer rubrum). Clinical findings included weakness, polypnea, tachycardia, depression, icterus, cyanosis, and brownish discoloration of the blood and urine. Blood changes included methemoglobinemia, free plasma hemoglobin, decreased pcv, and Heinz bodies in erythrocytes. These findings plus hemoglobinuria suggested intravascular hemolysis. Three of the 4 horses diet 5 to 7 days after ingestion of the leaves. Gross pathologic changes included...
Pedal bone rotation as a prognostic sign in laminitis of horses. We reviewed 91 cases of laminitis in horses admitted to the Michigan State University Veterinary Clinical Center between Jan 1, 1973 and Dec. 30, 1978. From information in the case records and from the results of a telephone questionnaire, cases were classified into 4 categories on the basis of return to athletic function. The degree of pedal bone rotation was inversely correlated with return to athletic performance. Horses with less than 5.5 degrees rotation returned to former athletic function, whereas horses with more than 11.5 degrees rotation lost their use as performance animals. Ponies ...
Effect of stress on steroid hormone levels in racehorses. Cortisol and testosterone were measured by radioimmunoassay in plasma samples from race horses. None of 6 stressed male horses had low cortisol levels but testosterone levels (0.81 +/- 0.15 nmol/l) were significantly lower than in healthy horses (1.86 +/- 0.31 nmol/l). The conclusion was made that adrenocortical insufficiency is not a common association of stress in race horses. The reduction in testosterone levels is probably a nonspecific response similar to that seen in other species.
Capsular serotypes of Rhodococcus equi. One hundred strains of Rhodococcus equi from various animal species and sources in Australia were examined for capsular serotype. Eighty-four of the strains fell into the existing 7 serotypes, and just under half of the strains belonged to serotype 1. Isolates from the intestines and faeces of horses, cattle, pigs and other species, and from soil, were found to belong to the same serotypes as those recovered from the lungs of foals with R. equi pneumonia. There was no clear relationships between capsular serotype and source of origin of the isolates.
Acid-base and electrolyte alterations in horses with exertional rhabdomyolysis. In examination of the acid-base and electrolyte status of 7 horses with acute exertional rhabdomyolysis, the most consistent abnormality was hypochloremia. Metabolic acidosis was not evident in any of the horses. Therefore, the use of sodium bicarbonate in treatment of such disorders may not be indicated in all cases.
Osseous cyst-like lesions of the medial femoral condyle in the horse. Osseous cyst-like lesions of the medial femoral condyle were found in 32 horses admitted to the University of Pennsylvania between 1971 and 1978. Sex or breed predilection was not found. In 12 horses, osseous cysts were found in both hindlimbs. Of the 25 horses on which follow-up information was obtained, 16 became sound and useful between 4 months and 1 year after diagnosis. Horses that became lame before 3 years of age had a better chance for later soundness. Horses that became sound had significantly smaller cysts than those that remained lame.
Leukotriene generation by eosinophils. Horse eosinophils purified to greater than 98% generated slow reacting substance (SRS) when incubated with the calcium ionophore A23187. On a per cell basis, eosinophils generated four to five times the SRS produced by similarly treated horse neutrophils. Eosinophil SRS production was inhibited by 5,8,11,14-eicosatetraynoic acid and augmented by indomethacin and arachidonic acid, suggesting that it was a product(s) of the lipoxygenase pathway of arachidonic acid metabolism. Compounds with SRS activity were purified by high-pressure liquid chromatography (HPLC) and identified by ultraviolet spe...
Systemic d-phenylalanine and d-leucine for effective treatment of pain in the horse. This study showed that subcutaneous injection of a solution of D-amino acids produced effective analgesia in horses. It is postulated that systemic D-phenylalanine and D-leucine may become one of the safe, effective and nonaddictive drugs for acute and chronic pain treatment. These D-amino acids cause analgesia by presumably preserving brain endorphins. They may bind reversibly to enkephalinases and prevent enzymatic degradation of enkephalins.
Myocardial necrosis secondary to neural lesions in domestic animals. Focal myocardial necrosis secondary to neural lesions was diagnosed in 2 dogs and 1 horse. In each case, the neural lesions were traumatic in origin. Spinal cord injury was evident in 1 dog; brain damage was evident in the other dog and presumably in the horse. Retrospective analysis of necropsy material showed that many species were affected, without apparent age or sex predisposition. Central nervous system injury resulting from trauma, infection or space-occupying lesions was associated with acute myocardial necrosis in all cases. The myocardial necrosis was rarely fatal; however, it did ca...
Ovarian disorders: clinical and morphological observations in 30 mares. A five year prospective study of equine ovarian problems requiring surgical correction was undertaken at the Ontario Veterinary College. Thirty mares were studied, of which 14 had granulosa cell tumors, six were with anovulatory persistent follicular "structures", five had ovarian hemotoma, two presented ovarian hypoplasia and one each of ovarian dysgerminoma, teratoma and abscessation. The clinical signs manifested by the affected animals were varied. The affected ovaries were removed via flank or midline laparotomy or through colpotomy. Their morphology was studied and representative portion...
Immunodeficiency disease in animals. Significant contributions to understanding the role of lymphocyte subpopulations in the immune response and to the characterization of immunodeficiencies in children have been achieved through study of animal models of immunodeficiency. Additional contributions can be made in two important areas. One is through identification of relevant, naturally-occurring models of adenosine deaminase deficiency and purine nucleoside phosphorylase deficiency. The second, and potentially more important contribution, would be the identification of the metabolic basis for existing immune deficiencies. The nece...
Cytogenetic and DNA analyses of equine abortion. Although no major structural or numerical abnormalities were found in the karyotypes of 12 aborted equine fetuses, two unrelated abortuses each carried a large polymorphism for the amount of heterochromatin in chromosome 1. In both karyotypes this chromosome was shown to be larger than its homolog. To determine the nature of the extra DNA in these chromosomes, equine DNA was isolated and characterized by buoyant density analysis. Equine mainband DNA had a buoyant density in neutral CsCl of 1.699 g/cm3, while the highly repetitive (dG+dC)-rich fraction had a buoyant density of 1.715 g/cm3. A ra...
The density profile and cholesterol concentration of serum lipoproteins in domestic and laboratory animals. 1. By means of density gradient ultracentrifugation, the density profile of the serum lipoproteins was studied in 14 species of domestic and laboratory animals: the pig, chicken, rhesus monkey, rabbit, dog, horse, sheep, cat, mouse, goat, cow, guinea-pig, trout and rat. 2. The concentration of cholesterol in whole serum and the lipoprotein fractions of these animal species was also determined. 3. There were large differences in the density profile of the serum lipoproteins among the various animals studied and the results indicate that the density limits employed for human serum lipoproteins a...
Effect of the stage of the oestrous cycle on the follicular population in pony mares. In the middle of the breeding season, 16 pony mares (n = 4 per day) were slaughtered on four different days (days 6, 14, 17 and the preovulatory day) of the oestrous cycle, day 0 being the day of the last ovulation. All the ovaries were examined histologically; the number, size and atresia (defined by granulosa cell pyknosis) of all follicles larger than 1 mm in diameter were studied, using a Kryotome-video recorder-TV system. Follicular distribution of all the sizes studied (1-5 mm, 5-10 mm, greater than 10 mm in diameter) was very similar in the right and left ovaries. However, compared to t...
Further observations on the innervation of the proximal sesamoidean ligament of the horse and ox. A vegetative innervation is described for the first time in this district. On the contrary, the finding of Pacini and pacini-like corpuscles, of Golgi Mazzoni's receptors, of muscle spindles and Golgi's tendon-organs testifies the existence of a sensitive innervation in this anatomical territory. According to Karamanlidis free nervous endings are not present. All the above recorded receptors show the typical structure and can be found isolated, grouped to constitute flower-sprays, organized to form opposito-polar corpuscles or associated to originate pecilomorphic fibers. These two last findin...
Factors affecting testis weight in normal and cryptorchid horses. Testes were collected from normal and cryptorchid horses of a variety of breeds and ages and weighed after dissection from the epididymis. Scrotal testes grow little until the second winter of life and little thereafter, although a nearly mature body weight is reached by the end of the first winter. Scrotal testes in unilateral cryptorchids tend to be larger than those of normal stallions, sometimes exceedingly so, although occasional small scrotal testes are recorded. Inguinal testes show some tendency to grow during the second winter but the data are difficult to analyse beyond that age beca...
Management of slab fractures of the third tarsal bone in 5 horses. Five cases of fracture of the third tarsal bone in racehorses are reported. A method of surgical correction employing a cortical bone screw is described in 2 cases. Healing of the fractures was followed radiographically. Surgical repair permitted both horses to return to competition. The 3 cases treated conservatively suffered a prolonged healing time and excessive new bone formation. They were unable to return to training due to persistent lameness.
A random walk model for the migration of Strongylus vulgaris in the intestinal arteries of the horse. A study of the migration of fourth stage larvae of the parasite Strongylus vulgaris in the intestinal arteries of the horse is presented. It is established, that the larvae migrate along the arteries in almost straight lines. It is suggested that this is primarily due to their ability to sense the curvature of the vessel wall, and not, as might have been expected, because of an ability to sense the direction of blood flow. A larva will sometimes alter its direction of motion when encountering a small off-branching artery. This behaviour suggests, that the migration of S. vulgaris larvae can be...
