Topic:Adult Horses
Adult horses encompass a category of equines that have reached maturity, typically considered to be around five years of age and older. This stage of life is characterized by full physical development and the potential for peak performance in various activities such as riding, racing, and work. Adult horses require specific nutritional, health, and management practices to maintain optimal condition and performance. The study of adult horses covers a range of topics, including physiology, behavior, and the impact of environmental factors on their well-being. This page compiles peer-reviewed research studies and scholarly articles that explore the physiology, health management, and performance aspects of adult horses.
Soft tissue emergency in adult horses. Equine practitioners are frequently called to attend to soft tissue injuries. The majority of these cases are routine and straightforward; however, a certain percentage may present as a life-threatening situation with potentially serious complications. Client communication, adequate preparation, patient stabilization, accurate injury assessment and appropriate wound preparation are key factors to expedite recovery and achieve a favorable outcome. Understanding the limitations of field therapy and deciding when to transport the case to a clinic or referral center plays an important role in the ...
Insulin-like growth factor II in the horse: determination of a cDNA nucleotide sequence and expression in fetal and adult tissue. Horse cDNA for insulin-like growth factor II (IGF II) has been isolated. cDNA was synthesized from bulk mRNA and subsequently PCR-amplified and sequenced. Like its human counterpart, the mature horse IGF II peptide contains 67 amino acids with only two substitutions, isoleucine instead of valine in position 35 and asparagine instead of serine in position 36. The nucleotide homology was 92.1% between horse and human and 87.8% between horse and mouse. The isolated cDNA hybridized to multiple transcripts in fetal and adult tissues, thus confirming earlier reports on developmental expression of th...
Resistance of castrated male horses to attempted establishment of the carrier state with equine arteritis virus. Twelve geldings all became infected when inoculated intranasally with the KY-84 strain of equine arteritis virus (EAV), a strain previously shown to be capable of establishing the carrier state in the stallion. With the exception of one animal that showed no effects other than pyrexia, all of the geldings developed clinical signs characteristic of equine viral arteritis (EVA). The geldings were febrile for varying periods within the range of 2-10 days after inoculation. Viraemia occurred from day 2 onwards, for periods varying from 9 to at least 19 days. Nasal shedding of virus began 2-4 days ...
Distribution of equid herpesvirus-1 (EHV-1) in the respiratory tract of ponies: implications for vaccination strategies. Twelve adult ponies and 2 conventional foals were exposed to 10(6.6) TCID50 of Equid herpesvirus-1 (EHV-1), strain Ab4 and samples of respiratory tract tissues were recovered. Infectious virus in tissue homogenates was detected using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry of paraffin sections. The results illustrated the rapid dissemination of EHV-1 throughout the respiratory tract, with early replication in the lungs one day after exposure. Endothelial cell infection was prominent in all areas of the nasopharyn...
A study of the biomechanical properties of the adult equine linea alba: relationship of tissue bite size and suture material to breaking strength. The purposes of this study were to mechanically determine the optimal tissue bite size and to evaluate seven suture materials at their largest commercially available size for breaking strength and stiffness using cadaveric adult equine linea alba. Soft tissues were removed from the abdominal fascia of 16 adult horses. Individual test sections were created from the entire linea alba and labeled (1 through 6) starting at the umbilicus and extending craniad. A single biomechanical test was performed on each test section. Tissue bite size (3, 6, 9, 12, 15, 18, and 21 mm) significantly altered brea...
In vitro mechanical properties of the accessory ligament of the deep digital flexor tendon in horses in relation to age. The material properties of the accessory ligament of the deep digital flexor tendon (AL) of 21 forelimbs from horses between ages one day and 15 years were determined. The force (634-11416 N), failure stress (45-138 N/mm2), failure strain (7-24%) and tangent modulus (33-1639 MPa) are presented in relation to age. Tangent modulus did not indicate changes in elasticity due to age. The results demonstrate that complete ligament failures (CLF) of ALs of older horses (mean 7835 N) occur at lower forces than ALs of young adult horses (mean 8894 N). Sudden decreases, 'dips', in the force-time curves ...
Effect of phenylephrine on hemodynamics and splenic dimensions in horses. Pharmacologically induced splenic contraction might be useful during certain medical or surgical procedures in horses. The effects of phenylephrine, an alpha 1-adrenergic receptor agonist, on hemodynamic function and splenic dimensions were examined in 6 healthy adult horses. Phenylephrine infusion (1, 3, or 6 micrograms/kg of body weight/min for 15 minutes) resulted in a dose-related increase in mean pulmonary artery pressure; right atrial pressure; systolic, mean, and diastolic arterial pressures; and packed cell volume (P = 0.0001). Concurrent decreases in heart rate and specific cardiac ou...
Histopathologic evidence of reperfusion injury in the large colon of horses after low-flow ischemia. Effects of low-flow ischemia and reperfusion of the large colon on mucosal architecture were determined in horses. Twenty-four adult horses were randomly allocated to 3 groups: sham-operated (n = 6), 6 hours of ischemia (n = 9), and 3 hours of ischemia and 3 hours of reperfusion (n = 9). Low-flow ischemia was induced in horses of groups 2 and 3 by reducing colonic arterial blood flow to 20% of baseline values. Systemic hemodynamic and metabolic variables were maintained constant and in a normal physiologic range. Full-thickness biopsy specimens were obtained from the left ventral colon for his...
Acute effects of perineural administration of sodium hyaluronate on palmar digital neurectomy sites in horses. Biaxial palmar digital neurectomy of all limbs was performed on 6 mixed-breed castrated adult male horses, using a standard guillotine method. Using a Teflon catheter, 20 mg (2 ml) of sodium hyaluronate (group 1), 2 ml of phosphate-buffered saline solution (group 2), or catheter placement with no infusion (group 3) was applied to 4 (group 1) or 2 (groups 2 and 3) of 8 incisions/horse. Treatments were administered after closure of the neurectomy incision, and the catheter was removed. Horses were evaluated daily for 1 week, then weekly over a 9-week period for evidence of lameness, swelling, an...
Neutrophil accumulation in the large colon of horses during low-flow ischemia and reperfusion. Histomorphologic/morphometric evaluation, leukocyte scintigraphy, and myeloperoxidase activity were used to determine whether neutrophils accumulate in the large colon of horses during low-flow ischemia and reperfusion. Twenty-four adult horses were assigned to 1 of 3 groups: group 1, sham-operated (n = 6); group 2, 6 hours of ischemia (n = 9); and group 3, 3 hours of ischemia and 3 hours of reperfusion (n = 9). Low-flow ischemia of the large colon was induced in horses of groups 2 and 3 by reducing colonic arterial blood flow to 20% of baseline. Radiolabeled (99mTc) autogenous neutrophils wer...
Characterization of the hemodynamic and metabolic alterations in the large colon of horses during low-flow ischemia and reperfusion. Effects of low-flow ischemia and reperfusion of the large colon on systemic and colonic hemodynamic and metabolic variables were determined in horses. Twenty-four adult horses were randomly allocated to 3 groups: sham-operated (n = 6), 6 hours of ischemia (n = 9), and 3 hours of ischemia and 3 hours of reperfusion (n = 9). Low-flow ischemia was induced in groups 2 and 3 by reducing colonic arterial blood flow to 20% of baseline. Heart rate, arterial blood pressures, cardiac index, pulmonary artery pressure, right atrial pressure, and colonic blood flow were monitored. Arterial, mixed-venous, a...
Neurological manifestation of cholesterinic granulomas in three horses. Cholesterinic granulomas have been previously reported as an incidental post mortem in horses. Three adult horses with diencephalic dysfunction due to cholesterinic granulomas are described. All the horses exhibited profound depression, somnolence and reluctance to move. One horse experienced generalised seizures. Cerebrosinal fluid was xanthochromic with an elevated total protein in two of the cases evaluated. The large cholesterinic granulomas caused expansion of the lateral ventricle and secondary hydrocephalus due to the build up of cerebrospinal fluid behind the mass. Cholesterinic granul...
Alpha tocopherol concentrations in clinically normal adult horses. Evaluation of the vitamin E status of horses is difficult because
plasma or serum alpha tocopherol (aT) concentrations are often
low, <5 Wml, a level which is considered to be deficient in man
(Traber et al. 1987). Calculation of serum aT per lipids, as has
been used for human values, does not reduce the variability of
plasma aT measurements in horses (Craig et al. 1989), perhaps
because the range of lipids is small.
The vitamin E status of people at risk for vitamin E
deficiency has been assessed by assaying aT concentrations in
adipose tissue (Kayden et al. 1983). As in other specie...
Equine motor neuron disease: findings in 28 horses and proposal of a pathophysiological mechanism for the disease. Over a three and one-half year period, 28 adult horses were diagnosed with equine motor neuron disease (EMND). The most commonly identified environmental risk factors for a horse having EMND were absence of grazing for more than a year and provision of poor quality hay. Quarter Horses were 5.4 times more at risk than other breeds but this was thought to be an epiphenomenon related to the frequency of Quarter Horses at boarding stables. Weight loss, excessive recumbency and/or trembling were the first signs noted. Other clinical diagnostic signs included: constant shifting of the weight in the ...
Diagnostic and operative arthroscopy of the coxofemoral joint in horses. Arthroscopic examination of the hip joint was performed in mature and juvenile horses, using a lateral approach and standard or long instruments depending on body weight. Nine hip joints were examined in three cadavers and four anesthetized horses. The lateral, cranial, and caudal regions of the femoral head and acetabulum were accessible, and, after distraction of the limb, the ligament of the head of the femur and the acetabular notch were also visible. In small horses, the medial regions of the hip joint were visible but were inaccessible in larger horses. Iatrogenic injury to the sciatic n...
Review of 40 cases of lung abscesses in foals and adult horses. A retrospective study of 40 horses with primary lung abscesses without pleuropneumonia showed that lung abscesses occurred predominantly in young horses, usually in foals aged < or = 6 months. Hyperfibrinogenaemia was present in all but 2 horses, and other common clinical and haematological findings were hyperthermia, tachycardia, polypnoea, and neutrophilic leucocytosis. The most common bacterial species isolated from transtracheal aspirates were Streptococcus zooepidemicus (20/34) and Rhodococcus equi (13/34). Most horses (23/27) discharged from the hospital were long term survivors. Of t...
Bilateral diaphragmatic paralysis in a pony. An adult pony had a 1-month history of severe respiratory distress that was resistant to treatment and environmental changes. Results of blood gas analysis were indicative of alveolar hypoventilation. Simultaneous recordings of thoracic and abdominal wall motion by inductance plethysmography, together with complete pulmonary mechanics evaluation that included transdiaphragmatic pressure monitoring, revealed complete passive behavior of the diaphragm during breathing. Because radiography, necropsy, and histologic examination did not reveal any major lesion to explain the clinical and functional...
Substance P and calcitonin gene-related peptide-like immunoreactive nerve fibers in lungs from adult equids. Distribution of pulmonary nerves immunoreactive for either substance P or calcitonin gene-related peptide was determined, using immunohistochemical methods on healthy lungs from adult equids. The overall patterns of distribution of substance P and calcitonin gene-related peptide-like immunoreactivity were similar. Distribution of immunoreactive nerves was not uniform throughout the lungs; nerve fibers immunoreactive for these peptides were more frequently observed near the hilus of the lung than in the caudal lobes or in the periphery of the lung. Nerve fibers immunoreactive for substance P or...
Sensory nerve conduction velocity of the caudal cutaneous sural and medial cutaneous antebrachial nerves of adult horses. Maximal conduction velocities of compound action potentials evoked by stimuli of 2 times threshold in the caudal cutaneous sural (CCSN) and medial cutaneous antebrachial (MCAN) nerves were determined by averaging potentials evoked and recorded through percutaneous needle electrodes. Mean maximal conduction velocities of compound action potentials were: CCSN = 61.3 +/- 2.0 meters/second (m/s) and MCAN = 56.4 +/- 2.8 m/s. To confirm accuracy of our percutaneous recordings, compound action potentials were recorded through bipolar chlorided silver electrodes from the exposed surfaces of fascicles ...
An in vitro biomechanical investigation of an interlocking nail for fixation of diaphyseal tibial fractures in adult horses. The compressive, bending and torsional mechanical properties of osteotomized adult equine tibiae stabilized with an interlocking intramedullary nail (nail-tibia composite) were compared with those of intact tibiae to determine the clinical applicability of the the nail for repair of tibial fractures in adult horses. The mean yield load, failure load, and stiffness for the nail-tibia composites were significantly less (P < .05) than those for the intact tibiae in all loading configurations. The mean compressive yield load for the nail-tibia composites was greater than the compressive load ca...
Changes in concentrations of hormones, metabolites, and amino acids in plasma of adult horses relative to overnight feed deprivation followed by a pellet-hay meal fed at noon. Experiment 1 was conducted to characterize the concentrations of prolactin, growth hormone (GH), cortisol, insulin, glucagon, glucose, nonesterified fatty acids (NEFA), urea N, and 10 indispensable amino acids in the plasma of mares (n = 8) and stallions (n = 8) during the last 4 h of a 19-h period of feed deprivation and for 8 h after a noon meal. Experiment 2 was similar to Exp. 1 except that only stallions (n = 8) were used, and they were either fed (n = 4) or not fed (n = 4) at noon in a 2 x 2 Latin square design conducted over two sampling days 7 d apart. In Exp. 1, increases (P < .01)...
Serum hepatitis in two brood mares. Two adult Quarter Horse mares from the same farm developed signs of hepatic disease approximately 2 months after parturition. Both mares had received tetanus antitoxin at the time of foaling. One mare developed subcutaneous edema of the distal aspect of all 4 limbs, photodermatitis involving unpigmented areas of skin, and high serum activities of liver-specific enzymes. The other mare had signs of acute hepatic failure, including icterus, hepatic encephalopathy, and high serum activities of liver-specific enzymes, and died. The second mare had signs typical of serum hepatitis (Theiler's diseas...
Use of the serum neutralisation test for equine viral arteritis with different virus strains. Serum cross neutralisation tests were conducted with a recent American isolate (84KY-A1) and a European isolate, (Wroclaw-2) and compared with the prototype and modified viruses of the Bucyrus strain of equine arteritis virus by using virus specific immune horse sera. The modified Bucyrus strain was neutralised and showed high neutralisation titres with all the immune sera. The prototype Bucyrus strain was also substantially neutralised, followed by the 84KY-A1 strain. As a result of the tests with the modified Bucyrus strain as the antigen, 20 seropositive horses were discovered among home-br...
Torsion in quadrupeds and its impact on mammalian joints. Congenital and acquired torsion occur in the limbs of domestic animals. Congenital abnormalities are of clinical significance in foals; they are also seen in calves whose dams have ingested certain toxic plants that contain teratogenic agents. Acquired torsional deformities are most common in foals, but are also observed in adult horses, dogs, and llamas. Acquired rotational deformities are almost always associated with angular limb deformities. The clinical consequence of torsional deformities is the early development of degenerative joint disease.
Nerve supply of the proximal sesamoid bone in the horse. In chronical proximal sesamoid bone lameness it is difficult to localise the exact site of pain. A specific diagnostic analgesia is not available because of a deficiency of detailed information about the nerve supply to the proximal sesamoid bones and surrounding area. A macroscopic study of the nerve distribution to the proximal sesamoid bones of 10 foals and 5 adult horses revealed that these bones are innervated by two branches, in this study called the medial and lateral sesamoidean nerve, respectively, originating from the medial and lateral palmar nerve. Histology of the left forelimbs o...
[Case report of a complex odontoma in a horse–clinical picture, radiography, ultrasonography and computed tomography]. The clinical signs, diagnosis and pathology of an adult horse with a complex odontoma are described. Computer tomography was shown to be a new diagnostic technique with outstanding potential in the investigation of diseases of the equine head.
Evaluation of laser Doppler flowmetry for measuring coronary band and laminar microcirculatory blood flow in clinically normal horses. Once daily for 3 days, laser Doppler flowmetry was used in 5 healthy, nonsedated adult horses to evaluate coronary band and laminar microcirculatory blood flow (MBF) in both forelimbs. The coronary band had significantly (P < 0.05) higher MBF than did the laminae on the days evaluated. Significant variation in MBF was not found over the 3-day measurement period in any one site. Significant (P < 0.05) variation was found in coronary band MBF among horses. This variation was not observed in laminar MBF. On occlusion of the digital arteries at the level of the fetlock, marked decrease in coronary...
Early insulin response to an intravenous glucose tolerance test in horses. Plasma insulin concentration of many species has a characteristic early or acute-phase response in the minutes after IV administration of glucose. However, the plasma insulin response of horses soon after the IV administration of glucose has not been examined, whereas the more prolonged response has been evaluated. We examined the plasma insulin and glucose concentration responses of adult mares during the 30 minutes after rapid IV administration of glucose (0.33 g/kg of body weight). Plasma glucose concentration peaked at 664 +/- 54 mg/dl within 1 minute of cessation of glucose administration...
Morphological, histochemical, and myosin isoform analysis of the diaphragm of adult horses, Equus caballus. The horse provides an interesting model for study of the structure and function of the mammalian diaphragm. Multiple regions of diaphragm from seven adult horses were prepared for histochemistry, immunocytochemistry, myosin heavy chain electrophoresis, and native myosin electrophoresis. Two additional adults were dissected to demonstrate myofiber and central tendon morphology and stained for acetylcholinesterase to demonstrate motor endplates. All regions of the adult diaphragm were histochemically characterized by a preponderance of type I fibers with some type IIa fibers. Type IIb fibers wer...
Serological and microbiological findings on 3 farms with equine leptospiral abortions. Blood and urine samples from horses on 3 central Kentucky horse farms with prior histories of leptospiral abortions were analysed. Blood samples were obtained from all available horses on each farm and tested for antibodies to 6 leptospira serovars. Urine samples were collected from non-gravid mares with serum antibody titres > or = 1:800 and examined for leptospires by dark-field microscopy, fluorescent antibody testing and culture. Adult horses had the greatest serological evidence of exposure to leptospira, followed by yearlings, then foals. Of horses with anti-leptospiral antibodies, 76...