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Topic:Veterinary Research
Veterinary research in horses encompasses the study of diseases, health management, and medical treatments specific to equine species. This field investigates various aspects of horse health, including infectious diseases, metabolic disorders, and musculoskeletal conditions. Researchers focus on understanding the pathophysiology of equine ailments, developing diagnostic tools, and evaluating therapeutic interventions. The study of horse health also involves examining preventive measures such as vaccination protocols and nutritional management to promote overall well-being. This page collects peer-reviewed research studies and scholarly articles that explore the diverse areas of veterinary science related to horses, providing insights into disease mechanisms, treatment strategies, and advancements in equine healthcare.
Post-transfusion survival of 50Cr-labeled erythrocytes in neonatal foals. Erythrocytes transfused allogeneically into mature horses have a short survival (less than 4 days) compared with an expected erythrocyte life span of 140-150 days. Yet, foals undergo transfusions for neonatal isoerythrolysis successfully. The authors have determined the survival of transfused erythrocytes in neonatal foals, using the stable isotope, 50Cr, to label the erythrocytes. Normal foals underwent transfusions with labeled erythrocytes from three sources: their own erythrocytes (autologous), the erythrocytes of their dam, and the erythrocytes of an unrelated castrated male. After transf...
Pharmacokinetics of phenobarbital in horses after single and repeated oral administration of the drug. Six healthy mature horses were orally administered a single dose of phenobarbital (26 mg/kg of body weight), then multiple doses (13 mg/kg) orally for 42 consecutive days. Seventeen venous blood samples were collected from each horse after the single dose study and again after the last dose on day 42. Plasma phenobarbital concentration was determined by use of a fluorescence assay validated for horses. Additional blood samples (n = 11) were collected on days 8 and 25 to determine peak and trough concentrations, as well as total body clearance. Phenobarbital disposition followed a one-compartme...
Selective measurement of lipoprotein lipase and hepatic triglyceride lipase in heparinized plasma from horses. Affinity chromatography on heparin sepharose was used to identify 2 lipolytic enzymes in heparinized plasma from horses. One enzyme was typical of hepatic triglyceride lipase (HTGL), because it was resistant to inactivation by high concentrations of NaCl, and it did not require the addition of serum for activity. The other enzyme was identified as lipoprotein lipase (LPL), because of its inactivation at NaCl concentrations in excess of 0.2M, and its dependency on addition of serum as a source of apolipoprotein C-II activator. The enzymes were purified by 347-(HTGL) and 442- (LPL) fold, with yi...
[The characteristics of the helminth community in the Turkmen kulan (Equus hemionus)]. The helminth fauna of 24 kulans from Askaniya-Nova and Badkhyz was studied. 42 species of helminths were found, 34 of which belong to strongylids. The helminth species composition of kulan is similar to that of other species of horses. This is a result of an intensive parasite exchange in the historical past when numerous populations of different Equidae species made long seasonal migrations over steppe inter-river lands of Asia and grazed for some time on common pastures.
Detection of diuretics in horse urine by GC/MS. The use of diuretics in horses subject to doping control is prohibited. Thus, a sensitive screening procedure is required to identify the chemically different diuretics. We communicate here a method to detect three commonly employed acidic diuretics: bumetanide, ethacrynic acid, and furosemide. A liquid-liquid extraction on Extrelut 3 was performed at weak acidic and basic conditions using ethyl acetate as organic solvent. For analysis by GC, the diuretics were methylated on-column in the presence of MSTFA/TMAH, avoiding the commonly employed highly toxic derivatizing agent methyl iodide. For ...
Pathological aspects of Australian Stringhalt. Nine horses with clinical signs of Australian Stringhalt were killed and tissues collected for a detailed pathological study. Lesions were limited to peripheral nerves and muscles. The most severely affected nerves were the superficial and deep peroneal, distal tibial, plantar digital, volar and recurrent laryngeal nerve with changes characterised by a selective loss of large diameter myelinated fibres with various degrees of demyelination, fibrosis, Schwann cell proliferation and onion-bulb formation. A routine evaluation of the brain and spinal cord by light microscopy failed to reveal any c...
Horner’s syndrome in ten horses. Ten cases of equine Horner's syndrome were reviewed. None of the clinical signs in this series were transient (<48 hours). Sweating and ptosis were consistently observed by the attending clinician in over half of the affected horses. Enophthalmos and prolapse of the third eyelid were not reported consistently. The average duration of the clinical signs was 4.94 months and ranged from 14 days to 15 months. Eight of the ten horses developed associated complications, some of which affected performance. Airway obstruction and impedance of passage of a fiberoptic endoscope due to nasal mucosal e...
Hypovolemic hyponatremia and signs of neurologic disease associated with diarrhea in a foal. Hypovolemic hyponatremia attributable to severe fluid and electrolyte alterations was diagnosed in a foal with diarrhea. Subsequent consumption of water resulted in rapid reduction of serum sodium concentration and serum osmolar depression. Clinical signs of neurologic disease developed including blindness, loss of menace response, and seizures. Treatment of this condition with IV administered fluids included hypertonic saline solution (7.2%; 2 ml/kg of body weight), and frequent monitoring of serum electrolyte concentrations and osmolality resulted in gradual correction of the fluid and elect...
Growth hormone in mares and stallions: pulsatile secretion, response to growth hormone-releasing hormone, and effects of exercise, sexual stimulation, and pharmacological agents. Short-term patterns of growth hormone (GH) secretion and factors affecting it were studied in mares and stallions. In Exp. 1, hourly blood samples were collected from three mares and three stallions in summer and winter. Although GH concentrations varied in a pulsatile manner in all horses, there was no effect of sex or season (P greater than .1) on plasma GH concentrations and no indication of a diurnal pattern of GH secretion. In Exp. 2, 10-min blood samples were drawn for 8 h from 12 mares; after 6 h, porcine GH-releasing hormone (GHRH) was administered i.v. at 0, 45, 90, or 180 micrograms/...
Prevalence of benzimidazole-resistance in equine cyathostome populations in south east England. In order to study the prevalence of benzimidazole-resistance in equine cyathostomes, 30 stables in south east England were selected according to strict criteria but with minimum bias to provide three matched groups of 100 horses. One group was treated with fenbendazole, one with pyrantel embonate and the third was left untreated. The overall efficacies of fenbendazole and pyrantel embonate, as judged by the faecal egg-count reduction test, were 56.3 and 95.8 per cent, respectively. The numbers of horses at individual stables were too small to draw conclusions at each stable, but whereas effica...
Immune responses of pony foals during repeated infections of Strongylus vulgaris and regular ivermectin treatments. Ten helminth-free pony foals divided into three groups were used in this study. Eight foals were each experimentally infected per os with 50 Strongylus vulgaris infective larvae weekly for 4 weeks, at which time one foal died of acute verminous arteritis. The remaining seven foals subsequently received 50 S. vulgaris infective larvae every 2 weeks for an additional 20 weeks. Four of the infected foals remained untreated (Group 1) and three of the infected foals were given ivermectin at 8, 16 and 24 weeks post initial infection (Group 2). Two foals served as controls (Group 3). Foals in Group 1...
Normal and abnormal sexual behavior. This article includes a brief description of the reproductive patterns and specific behaviors comprising courtship and copulation in equids. The author then focuses on breeding behavior of the domestic stallion. Descriptions of normal breeding behavior under a variety of domestic management systems, comments on sexual behavior of donkeys and exotic equids, and the most common types and treatments of sexual behavior dysfunction are included.
Lincomycin-induced severe colitis in ponies: association with Clostridium cadaveris. Four groups of two ponies, free of fecal Salmonella and Clostridium cadaveris, were treated as follows: Group A, control group; B, single nasogastrically administered dose of lincomycin (25 mg/kg) followed 48 h later by 3 L of C. cadaveris (10(9) organisms/mL); C, the same dose of lincomycin as group B; D, the same dose of C. cadaveris as group B on each of three occasions at 12 h intervals. Groups A and D remained healthy, but groups B and C developed severe colitis 48-56 h (B) or 72 h (C) after administration of lincomycin. Three ponies were euthanized and one in group B died. Clostridium ca...
Bioavailability of two ibuprofen oral paste formulations in fed or nonfed ponies. The bioavailability and pharmacokinetics of ibuprofen, a nonsteroidal antiinflammatory drug, was studied in healthy Shetland ponies. Ibuprofen was administered IV, as a suspension, and as a solid solution oral paste to ponies from which food was withheld. The suspension paste was also administered to ponies that received hay and water ad libitum. Both formulations had an absolute bioavailability of about 80%. Bioavailability was not influenced by feeding.
Incidence of sarcocysts in skeletal muscles of horses. The incidence of sarcocysts was examined in postural, propulsive and respiratory muscles from 74 horses ranging in age from mid-gestation to 14 years post-natal. Cryostat sections were stained for myosin adenosine triphosphatase (ATPase) at pH 9.5 and the type of muscle fibre containing sarcocysts was identified. Sarcocysts were found in muscles from three animals, all aged 1 year or more. Counts showed that they displayed no preference for any particular muscle. However, fibres with a high activity for myosin ATPase were preferentially colonized. Transverse sectional profiles of sarcocysts sh...
Abnormal conditions of the equine descending (small) colon: 102 cases (1979-1989). The signalment, clinical and laboratory findings of surgical conditions, treatment, and outcome of 102 cases of descending colon disease in horses were reviewed. Abnormal conditions were categorized as enteroliths, impactions, strangulating lipomas, fecaliths, foreign body obstruction, volvulus, nephrosplenic entrapment, and other conditions. Eleven breed categories of horses were seen during this period. Arabians, ponies, and American miniature horses were more predisposed to descending colon disease than other breeds (P less than 0.05). Female horses and animals greater than 15 years old wer...
Mediators of maternal recognition of pregnancy in mammals. No abstract available
Evaluation of stallion semen. This article outlines a basic method for conducting a stallion semen evaluation. After the removal of the gel fraction of the ejaculate, semen gel-free volume is determined, and any abnormality in appearance is noted. Concentration of sperm cells in semen can be determined with the use of either a hemacytometer or spectrophotometer after appropriate dilution of raw semen. The percentage of progressively motile sperm is evaluated promptly after collection of semen with the use of a phase-contrast microscope. The total numbers of sperm and progressively motile sperm in the ejaculate are calculat...
Clinical pharmacokinetics in veterinary medicine. Veterinary and human pharmacology differ principally in the range of species in which drugs are used and studied. In animals, as in humans, an understanding of the dose-effect relationship can be obtained by linking pharmacokinetic behaviour with pharmacodynamic information. Studies of different classes of drugs support the assumption that the range of therapeutic plasma concentrations in animals is generally the same as in humans. The requirement for species differences in dosage or administration rate (dose/dosage interval) may be attributed to variations in pharmacokinetic behaviour or phar...
Breed differences in circulating equine relaxin. Equine relaxin has been previously determined in a small number of pregnant Thoroughbred mares. To better define the normal pregnancy pattern of relaxin, the current study reports on a much larger number of mares. It also was designed to determine if all equids have the same gestational pattern of relaxin secretion. Plasma samples were collected weekly in 24 Standardbred mares, every 7-10 days in 10 pony mares, and daily in late pregnancy from 16 burros. Standardbreds had higher concentrations of relaxin than that reported for Thoroughbreds during most of gestation and did not exhibit the midp...
Hormonal contraception of feral mares with Silastic rods. Homogeneous Silastic rods containing ethinylestradiol (EE) (1.5 or 4 g), estradiol-17 beta (E) (4 g) or progesterone (P) (6 g) were implanted into feral mares (Equus caballus) between 4- and 10-yr-old. Six treatment groups (greater than or equal to 10 mares/group) of non-pregnant mares received 36 g P and 12 g E (P+E), 36 g P and 8 g EE (P+HEE), 1.5 g EE (LEE), 3 g EE (MEE, 8 g EE (HEE) or control-implanted mares (CI). CI received implants containing no steroid. Two groups of pregnant mares received P+HEE or HEE. Stallions were placed with the mares 15 to 26 mo after implanting. Blood was coll...
Epizootiological aspects of type 1 and type 4 equine herpesvirus infections among horse populations. The dissemination of equine herpesvirus types 1 (EHV-1) and 4 (EHV-4) among various horse populations in Japan was investigated through the isolation and typing of virus strains from horses with respiratory diseases. Type specific monoclonal antibody pools were used for the typing of isolates. The 42 strains of EHV-1 and 64 strains of EHV-4 were isolated from 4593 nasal swabs and/or blood plasma samples collected from 3326 horses during a period from 1979 to 1990. All the strains of EHV-1 were isolated from racehorses only and during the winter season exclusively, when the epizootic of respira...
Evaluation of zones of iris hypoplasia in horses and ponies. Mass-like lesions of the iris were evaluated in 15 horses or ponies of various ages and breeds. Breed or gender predilection was not found. These lesions were most often found in blue irides at the 12 o'clock region. Because the lesions transilluminated and changed shape rapidly with changes in pupillary size, they were hypothesized to be zones of iris hypoplasia. Histologic evaluation of one specimen supported this interpretation. The lesions were not associated with any other ocular or systemic abnormality.
Venereal disease. Equine venereal infections of concern in the United States include EHV-3, T. equigenitalis, P. aeruginosa, and K. pneumoniae. Stallions may also harbor EAV in the genital tract and transmit the virus to mares during coitus. With the exception of EHV-3, the stallion generally remains asymptomatic while transmitting infections to mares during breeding. Methods for diagnosis, treatment, and control of these infections are discussed.
Influence of age on fibre type characteristics in the middle gluteal muscle of Andalusian foals. 34 Andalusian foals of both sexes were divided into three age-groups (A = mean age 1 month, B = 7 months, C = 14 months). Samples of the right m. gluteus medius were stained for m-ATPase and NADH-TR in order to determine fibre type composition and size as well as the relative area occupied by each type. Results revealed no statistically significant variation in the proportion of type I fibre among the three age-groups. Significant differences were recorded, however, for type II fibres; an increase in the proportion of IIA fibres was accompanied by a decrease in IIB ones, the difference being m...
