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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.
Hormonal changes in the immature rat after administration of pregnant mare serum gonadotrophin: influence of body weight. We have shown previously that pregnant mare serum gonadotrophin (PMSG) induces ovulation only in rats weighing over 60 g on the day of injection. The under-60 g rats do not ovulate although they secrete a preovulatory surge of a pleiomorphic form of LH. Presumably this pleiomorph is inactive. Comparisons were made of plasma hormone concentrations in rats treated with PMSG that weighed over and under 60 g. The measurements were made on samples taken between 13.00 and 22.00 h on the day of the expected preovulatory LH surge. Prolactin and corticosterone levels were lower in the lighter group com...
Follicle stimulating hormone, luteinising hormone and progesterone concentrations in the blood of thoroughbred mares exhibiting single and twin ovulations. The concentrations of follicle stimulating hormone, luteinising hormone and progesterone were measured in serial blood samples taken throughout one or more oestrous cycles from 12 Thoroughbred mares, some of which exhibited single and others twin ovulations. The resulting profiles clearly demonstrated that no simple relationship exists between circulating gonadotrophin levels and subsequent ovulation rate in the mare. However, plasma progesterone concentrations during dioestrus are, as expected, higher following twin than single ovulations. The findings suggest that the underlying cause of twi...
Nitrogen partitioning along the equine digestive tract. Twelve adult horses were fed a corn-oats-timothy hay diet containing 2.87% nitrogen (N) for 4 wk and were then killed. Fresh digesta samples were immediately harvested from the stomach, duodenum, jejunum, ileum, cecum, large colon, small colon, rectum and feces. Total N content of the digesta (on a dry matter basis) increased from the stomach (2.74%) to the duodenum (5.58%; P less than .01), decreased in the cecum (3.10%, P less than .01), remained constant through the large intestine and decreased in the feces (2.10%; P less than .01). High-speed centrifugation of wet digesta and low-speed ce...
Induction of male sex behavior in pony mares with testosterone propionate. Two pony mares were administered 150 mg of testosterone propionate every other day for 20 days (ten injections) and every ten days there-after. An additional two mares and one stallion were not treated and served as controls. Testosterone propionate was dissolved in absolute ethanol and administered subcutaneously. Sex behavior tests were conducted 26 and 40 days after the first injection. Control mares exhibited very little male sex behavior. Both testosterone propionatetreated mares, however, exhibited mounting, sniffing, flehmen, biting and vocalization behavior in the presence of an estrou...
Release of 3H2O from 1 beta,2 beta[3H]androstenedione by equine granulosa cells. Granulosa cells were harvested from mares at various stages of the oestrous cycle and incubated in Krebs-Ringer bicarbonate buffer with 1 beta,2 beta[3H]androstenedione as substrate. The release of 3H2O expressed as CPM/h/mg protein varied from 44000 to 768000 in follicles from 7 mares. The release of 3H2O was not significantly altered by luteinizing hormone, follicle stimulating hormone or pregnant mare's serum gonadotrophin. There was a significant negative correlation between the release of 3H2O and the concentration of progesterone in the follicular fluid. Based on the assumption that the ...
Palatal myositis in horses with dorsal displacement of the soft palate. The histologic and histochemical features of palatine muscles from 53 horses were studied; 25 of the horses were racehorses that had upper airway obstruction associated with dorsal displacement of the soft palate and 28 of the horses did not have any respiratory disorders and served as controls. Pathologic features observed included myonecrosis, phagocytosis, mononuclear cell infiltration of perimysial connective tissue, alkaline phosphatase-positive myofibers, and myofibers with cytoarchitectural changes that included irregular staining of the intermyofibrillar sarcoplasm and sarcoplasmic mas...
Spermatogenesis, testicular composition and the concentration of testosterone in the equine testis as influenced by season. The influence of season on spermatogenesis, testicular composition and the concentration of testosterone in the equine testis was evaluated using testes from 45 stallions. Testes were obtained through a commercial abbatoir during September, December-January, March and July. The weights of the testes, the tunica albuginea and testicular parenchyma and the proportion of the testicular parenchyma occupied by seminiferous tubules or interstitial tissue were similar during each season. How ever, diameter of the seminiferous tubules was greater in July than during other months of the study. In addit...
Review of pulsing electromagnetic field therapy and its possible application to horses. The relevant literature on electrostimulation in general, and pulsing electromagnetic fields in particular, is reviewed. DC current influences cell behaviour by affecting transmembrane ion transport, which is often under enzymatic control. Pulsing electromagnetic fields influence cell functions through adsorption of ions or dipole formation at the cell membrane. Invasive and non-invasive DC current stimulation is compared to pulsing electromagnetic fields. The mode of application of pulsing electromagnetic fields to the equine limb and suggested treatment times are briefly discussed. Two case ...
Giant cell tumor of soft parts in six horses. Giant cell tumor of soft parts was diagnosed in 6 horses 3 to 12 years old (mean, 6.8 +/- 3.5 years): 3 Quarter Horse geldings, 2 Standardbred mares, and 1 Standardbred stallion. The neoplasms developed as raised, solitary masses, approximately 1 to 4 cm in diameter, which were firmly attached to subcutaneous tissue of the neck (1 horse), shoulder (1 horse), thigh (2 horses), or stifle (2 horses). Excision was followed by local recurrence in 3 horses within 1 to 1 1/2 months. The neoplasms were firm and cut with resistance. On cut surface, they were white, with mottled red hemorrhagic areas.
Standard antisera produced in ponies for the identification of bovine mycoplasmas: comparative growth-inhibition results from six laboratories. Antisera to 10 mycoplasma species of bovine origin were produced in 10 ponies and were distributed for evaluation in growth-inhibition tests at 6 laboratories in Australia, England, Denmark, France, and the United States. Except for a few failures with some antigens produced at the 6 laboratories, the antisera induced large zones of growth inhibition in homologous, but not heterologous, systems. These antisera may be useful as standard reagents for the identification of the bovine mycoplasmas.
Observational study of “urine testing” in the horse and donkey stallion. Although "urine testing" is said to enable the male equid to assess the sexual status of the mare, there are no reports in the literature of any detailed study of this behavioural response of the stallion. Behavioural response to conspecific urine was studied in two horse stallions and one donkey stallion. The relevant nasopalatine anatomy is described. Events observed during urine testing included head, neck, lip, jaw, tongue movements, penile changes and nasal secretion. Nasal endoscopy indicated that the source of part of the nasal secretion was the secretory glands of the vomeronasal organ...
Use of an autogenous cancellous bone graft in the treatment of subchondral bone cysts in the medial femoral condyle of the horse. The clinical features, diagnosis and radiological findings of eight cases of a subchondral bone cyst involving the medial condyle of the femur are described. Surgical treatment, which comprised performing an arthrotomy of the femorotibial joint, curetting and packing the cystic cavity with an autogenous cancellous bone graft, is described.
Leptospiral infection in aborted equine foetuses. During an investigation of equine abortion, leptospiral infection was demonstrated in nine out of 22 foetuses examined by immunofluorescence and culture. Strains belonging to four serogroups (Australis, Pomona, Hebdomadis and Icterohaemorrhagiae) were isolated. The age of leptospira infected foetuses ranged from six months to term.
Glutathione peroxidase activity in the blood of healthy horses given different selenium supplementation. Glutathione peroxidase (GSH-px) activity in the blood is correlated to the amount of selenium which was given to the horse. Currently recommended doses of selenium seem to be sufficient in order to prevent selenium deficiency. The blood GSH-px in foals reflects the amount of selenium given to the mare during pregnancy.
Volatile fatty acids and the role of the large intestine in the control of feed intake in ponies. The roles of volatile fatty acids (VFA) and of the large intestine in the control of feeding in ponies were investigated. Ponies with cecal fistulas were adapted to ad libitum access to pelleted feed. Treatment solutions were given as a bolus 15 min before the animals were allowed free access to feed after a 4-h fast. Each dose of VFA solution was tested in a crossover design with a water control. When the ponies were permitted to eat after the treatments, the latency to eat, first meal size, and duration and first intermeal interval were recorded. Feed intakes were measured at 3 and 18 h afte...
Experimental production of neonatal isoerythrolysis in the foal. Serological evidence with or without clinical signs of neonatal isoerythrolysis was experimentally produced in 6 of 8 foals born to mares allo-immunized with washed erythrocytes from the stallion. Blood group antigens were determined in all mares, stallions and foals, and the incompatible antigenic factor(s) responsible for the disease were defined. In 5 of 8 foals born to alloimmunized mares, a single antigenic factor difference accounted for the erythrocyte incompatibility between mare and foal. The erythrocyte antigen suspected as the most responsible for isoerythrolysis observed was A1. Ag...
High-performance liquid affinity chromatography on silica-bound alcohol dehydrogenase. Horse liver alcohol dehydrogenase was immobilized on glycerylpropyl-silica (10 micron, 1000-A pores) activated with 2,2,2-trifluoroethanesulfonyl chloride (tresyl chloride). The coupling and activity yield was almost 100%. The coenzyme-binding sites were equivalent and virtually unaffected by the immobilization process, as judged from Scatchard plots and active-site titrations. The silica-bound enzyme, packed in steel columns, was integrated with HPLC equipment and then successfully used for chromatography of adenine nucleosides, adenine nucleotides, and triazine dyes. Dissociation constants w...
[Various aspects of lactate production and disappearance in trotters during exertion]. Venous lactate concentrations were determined in standard-bred trotters following exercise of varying intensity to obtain a useful parameter in determining the working capacity of horses. After standard exercise, well-trained horses produced less lactate than did inadequately trained horses. During the post-exercise resting period, lactate disappeared faster from the blood in well-trained horses and young lightly trained horses than it did in poorly trained horses. Steady-state training resulted in lower lactate levels than those recorded after racing, whereas interval training resulted in the...
A retrospective clinical study of osteochondrosis dissecans in 21 horses. Osteochondrosis dissecans was diagnosed clinically and radiographically in 31 joints of 21 horses. The horses ranged in age from 8 months to 5 years at the time of presentation. The usual age of onset of clinical signs was 18 to 24 months. Presenting complaints included joint effusion and lameness of either gradual or sudden onset. In Thoroughbred horses, the stifle joint was the most common site of lesions and in Standardbred horses lesions occurred more commonly in the hock. In 16 of the 21 horses, the contralateral joint was radiographed and 9 of these horses had bilateral lesions. Thorough...
Identification of 3 beta-hydroxy-5,7-pregnadien-20-one and 3 beta-hydroxy-5,7-androstadien-17-one as endogenous steroids in the fetal horse gonad. The 5,7-dienes, 3 beta-hydroxy-5,7-pregnadien-20-one and 3 beta-hydroxy-5,7-androstadien-17-one were extracted from fetal horse gonads and purified by solvent partition, thin-layer chromatography and high performance liquid chromatography. The isolated steroids were identified by comparison with the synthetic steroids using ultraviolet and mass spectroscopy and by gas chromatography-mass spectroscopy. The identification of these compounds as endogenous steroids, together with the data on their biosynthesis reported previously, support the proposal that in the fetal horse gonad there is a 5,7-d...
Comparison of pyrimidine 5’nucleotidase activity in erythrocytes of sheep, dogs, cats, horses, calves, and Mongolian gerbils. Pyrimidine 5'nucleotidase (P5N) activities of erythrocytes for Mongolian gerbils, cats, dogs, sheep, horses, and calves were measured, using a radiometric technique with [14C]cytidine monophosphate as the substrate. Erythrocytes of gerbils had the highest activity [1,177.1 +/- 133.6 mU/g of hemoglobin (Hb)]. Feline erythrocytes had 327.4 +/- 204.4 mU/g of Hb. Canine erythrocytes had 148.0 +/- 19.8 mU/g of Hb. Ovine erythrocytes (44.3 +/- 20.9 mU/g of Hb), equine erythrocytes (30.0 +/- 15.9 mU/g of Hb), and bovine erythrocytes (14.1 +/- 6.9) had relatively low P5N activity. The P5N activity was...
Distribution of blood flow during moderate and strenuous exercise in ponies (Equus caballus). Blood flow to the brain, heart, kidneys, diaphragm, and skeletal muscles was studied at rest and during graded treadmill exercise, using radionuclide-labeled microspheres (15 microns diameter), in 11 healthy adult ponies. Hemodynamic changes brought about by exercise included marked increases in cardiac output, mean aortic pressure, left ventricular end-diastolic pressure, and right ventricular systolic and end-diastolic pressures. Blood flow to the brain stem and cerebral hemispheres was unchanged during both moderate exercise (heart rate = 154 +/- 3 beats/min) and severe exercise (heart rate...
Alternate grazing of horses and sheep as control for gastro-intestinal helminthiasis in horses. Gastro-intestinal helminth infections of a group of three yearling mare Shetland ponies, which were set-stocked on a small pasture from February until September, were compared with those of a similar group of ponies, which grazed a similar pasture from February to July and subsequently was removed to a pasture which had been grazed by sheep from April to July. In addition both groups were treated with cambendazole when the latter group was removed to the sheep pasture. Pasture larval counts and worm counts demonstrated that the group grazed after the sheep acquired considerably smaller burdens...
Lactation in the horse: milk composition and intake by foals. Milk samples averaging 500 ml were collected weekly from 10 to 54 days postpartum from five lactating mares. Samples were obtained by hand milking after oxytocin administration and while the foal nursed. Dry matter, protein and gross energy were higher in samples obtained at 10 and 17 days postpartum than those obtained during the midlactation period of 24-54 days. Midlactation samples averaged 10.5% dry matter, 1.29% fat, 1.93% protein, 6.91% sugar and 50.6 kcal/100 g. Protein comprised 22% of milk energy. Milk intake was estimated in five foals from deuterium oxide (D2O) turnover to be 16, 1...
