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.
Comparison of antibody and cell-mediated immune responses in horses following feeding of a novel dietary antigen, ovalbumin, and rotavirus. Adult ponies which were fed ovalbumin (OVA) daily for 2 weeks had significantly greater serum anti-OVA IgG (P = 0.001) and antigen specific lymphocyte responses (P = 0.031) after intramuscular injection with OVA given with saponin than control ponies which had not been fed the antigen. This suggests that, despite the lack of evidence of B- or T-cell activation in peripheral blood during the period of OVA feeding, the animals were primed for an active secondary immune response. Adult ponies were challenged with equine rotavirus, strain H-2, but no statistically significant differences were foun...
Microvascular permeability changes in ischemia/reperfusion injury in the ascending colon of horses. The normal microvascular permeability of the ascending colon in horses and the microvascular permeability of that segment after ischemia and reperfusion were investigated. Microvascular permeability was estimated by the ratio of lymphatic protein to plasma protein concentration (Cl/Cp) at high lymph flow rates in 8 adult horses in 2 equal groups: normal and ischemic (2-hour period). Lymphatic flow rates and lymph and plasma protein concentrations were determined. Intestinal biopsy specimens were obtained at the end of each experiment. Flow independent values were selected and compared by one-w...
Conservative management of fourth tarsal bone fracture in a draft horse. A fourth tarsal bone fracture was treated conservatively in an adult draft horse. Seven months after the injury, the horse had no evidence of lameness and was able to compete in athletic events. It has been suggested that conservative management of these fractures be considered for brood animals or animals used for less strenuous activities. The outcome of this case suggests that fourth tarsal bone fractures can be successfully treated in athletic animals with conservative management.
Effects of ketamine infusion on halothane minimal alveolar concentration in horses. Eight adult horses were used in a study to determine ketamine's ability to reduce halothane requirement. To obtain steady-state plasma concentrations of 0.5, 1.0, 2.0, 4.0, and 8.0 micrograms/ml, loading doses and constant infusions for ketamine were calculated for each horse on the basis of data from other studies in which the pharmacokinetic properties of ketamine were investigated. Blood samples for determination of plasma ketamine concentrations were collected periodically during each experiment. Plasma ketamine concentrations were determined by capillary gas chromatography/mass spectromet...
Arteriovenous differences for glutamine in the equine gastrointestinal tract. Glutamine has been shown to be an important metabolic substrate of enterocytes in many animals, including cats, dogs, hamsters, human beings, monkeys, rabbits, rats, and sheep. To determine whether glutamine is important in the metabolism of cells of the equine gastrointestinal tract, we examined transintestinal differences in glutamine concentrations in the arterial and venous circulation, and measured activity of the major glutamine catabolizing enzyme, glutaminase. Arteriovenous differences provide an index of the amount of a given substrate removed by the tissue across which the measuremen...
An arthroscopic biopsy procedure for obtaining osteochondral samples from the equine midcarpal joint. An in vivo biopsy technique was developed to harvest cylindrical osteochondral core samples (2 mm diameter x 2 mm depth) from the articular surfaces of radial carpal bones in adult horses for use in osteoarthritis drug kinetic studies. A 25 degree arthroscope was introduced into the midcarpal joint through the dorsolateral surface, and a custom-built motorized core drill was introduced through the dorsomedial surface to create the osteochondral core samples. A total of 24 core samples were sequentially harvested in vivo, and 16 at postmortem, from eight horses on four different occasions withi...
Antemortem diagnosis of cholangiocellular carcinoma in a horse. A 10-year-old Tennessee Walking Horse gelding was admitted to the veterinary teaching hospital for evaluation of intermittent fever, lethargy, and anorexia. Initial laboratory analyses revealed anemia and hyperfibrinogenemia. Abdominocentesis and thoracentesis yielded fluid samples with high nucleated cell counts and total protein concentrations. The tentative diagnosis was nonseptic peritonitis. The horse did not improve after 4 days of antimicrobial treatment, and pitting edema of the ventral midline developed. Thoracic radiography and ultrasonography revealed consolidation of the ventral as...
Bioavailability of oral penicillins in the horse: a comparison of pivampicillin and amoxicillin. The pharmacokinetics of ampicillin and amoxicillin following intravenous administration at a dose rate of 15 and 10 mg/kg respectively were studied in four healthy adult horses. Pharmacokinetics of pivampicillin and amoxicillin were studied after oral administration to four healthy adult horses. Pivampicillin, a prodrug of ampicillin, was administered orally to starved and fed horses at a dose rate of 19.9 mg/kg, which is equivalent on a molecular basis to 15 mg/kg ampicillin. Amoxicillin was administered orally to starved horses only, at a dose rate of 20 mg/kg. Ampicillin and amoxicillin con...
The effect of CO2 laser neurectomy on neuroma formation and axonal regeneration. In an attempt to prevent neuroma formation and digital reinnervation after sharp palmar digital neurectomy in 10 adult horses with navicular disease, 18,426 W/cm2 of CO2 laser energy was applied to the proximal nerve stump. Clinical follow-up was 4 to 23 months. In two horses, palmar digital nerve biopsies were taken at month 4 (four nerves) and month 7 (two nerves). Nine horses were sound immediately and at all follow-up examinations. None had clinical evidence of painful neuroma or digital reinnervation. Histologically, there was minimal scar tissue at the surgical site; axonal sprouts were ...
Histochemical study on the gland of pelvis renalis in the horse. The glands of pelvis renalis in adult and fetal horses were examined by histochemically. The glandular terminal was divided into two types, intraepithelial gland (IE) and extraepithelial gland (EE) by their locations and histochemical characters. Both glands were composed of mucous cells. The former lay in the transitional epithelium and were stained reddish with galactose oxidase-Schiff (GOS) and mild oxidation-Schiff (MOS), bluish purple with periodic acid-cold thionine Schiff-NaOH-PAS (PCP). The latter distributed in the lamina propria, but was not discovered in the fetus. They were stained...
[Typical presentation of the common tendon sheath of the M. flexor hallucis longus and the M. tibialis caudalis in the horse]. The possibilities for imaging soft tissue structures, especially fluid-filled cavities such as articulations, bursae or tendon sheaths, have been improved markedly by sonography in recent years. Ultrasonic examinations were performed on the common tendon sheath of the musculus flexor hallucis longus and the musculus tibialis caudalis, from the medioplantar aspect of the tarsus, in 12 sound adult draft- and warm blood horses, and in 5 animals with a distended common sheath. The diagnostic precision of the sonographic examination of the tendon sheath is excellent and is superior to conventional ...
Effect of a histamine H2 type receptor antagonist (WY 45, 727) on the healing of gastric ulcers in ponies. Using video gastroscopy, the efficacy of a Histamine-H2 type receptor antagonist (WY 45, 727) was investigated in young ponies with spontaneous and experimentally induced gastric ulcers. Oral administration of WY 45, 727 at 2 mg/kg and 10 mg/kg of body weight every 12 hours for 14 days resulted in complete healing of spontaneous gastric ulcers in the non-glandular portion of the stomach in 2/5 (40%) and 3/4 (75%) of the ponies, respectively, compared (P < 0.05) to 0/5 (0%) placebo-treated ponies. After intramuscular administration of flunixin meglumine at 1.5 mg/kg body weight every 8 hours fo...
Effects of general anesthesia on myoelectric activity of the intestine in horses. Myoelectric activity was monitored from the terminal ileum, cecum, and colonic pelvic flexure by use of AgpAgCl bipolar electrodes in 4 adult horses before, during, and after general anesthesia. Horses were anesthetized by way of 3 commonly used regimens, including xylazine (1.1 mg/kg of body weight) and ketamine hydrochloride (2.2 mg/kg); thiopental sodium (7.7 mg/kg), followed by halothane vaporized in oxygen; and thiopental sodium (2.5 g) in guaifenesin (100 mg/ml) solution given to effect, followed by halothane in oxygen. All 3 anesthetic regimens decreased intestinal spike-burst activity ...
Computer-based collection and analysis of myoelectric activity of the intestine in horses. Extracellular myoelectric activity from the terminal ileum, cecum, and colonic pelvic flexure was assessed in 4 adult horses. The collection and analysis of myoelectric data involved the development and use of a computer-based system. After collection, the myoelectric signal was digitally filtered to enhance the activity of interest. The smoothed signal was then processed by use of computer programs designed to identify and count spike-burst activity and estimate burst duration. The intense phases of myoelectric complexes also were identified. The propagation of myoelectric spike-burst activit...
Equine arch vessel anomaly associated with coarctation of the aorta. Angiography in a 30-year-old man revealed the unique combination of aortic coarctation and an unusual arch anomaly. Proximal to the coarctation, a single arch vessel trifurcated into the brachiocephalic, left common carotid and left subclavian arteries. This anomalous arch vessel is a normal equine variant.
Induction of the acute-phase cytokine, hepatocyte-stimulating factor/interleukin 6, in the circulation of horses treated with endotoxin. Because hepatocyte-stimulating factor/interleukin 6 (IL-6) is the principal inducer of acute-phase protein synthesis in the liver, quantification of its activity in blood provides an early and sensitive assessment of the acute-phase response. Circulating IL-6 activity was monitored in 4 adult horses for 72 hours after IV administration of endotoxin. In 4 experiments performed at weekly intervals and in randomized order, each horse was given endotoxin--1,000 30, 1, and 0 ng/kg of body weight. Plasma IL-6 activity was quantified as the ability to promote growth of the IL-6-dependent B-cell hybri...
Endotoxin-induced production of interleukin 6 by equine peritoneal macrophages in vitro. A study was performed to determine whether equine peritoneal macrophages produce interleukin 6 (IL-6) in vitro in response to endotoxin. Peritoneal fluid was collected from 14 clinically normal adult horses and was used as the source of peritoneal macrophages. Macrophages from each horse were isolated and cultured separately in vitro in the absence or presence of various concentrations (0.5, 5, 500 ng/ml) of endotoxin (lipopolysaccharide from Escherichia coli 055:B5). Culture medium supernatants were collected after 3, 6, 12, and 24 hours' incubation and were frozen at -70 C until assayed for ...
Differentiation of chronic lymphocytic leukemia in the horse. A report of two cases. Chronic lymphocytic leukemia (CLL) was diagnosed in two horses: an 18-year-old Quarter Horse gelding that was examined because of edema of the prepuce and ventral abdomen; and a 20-year-old mixed breed gelding that was referred because of lymphocytosis, ventral edema, and weight loss. The first horse had enlarged peripheral lymph nodes and cool nonpainful pitting edema of the ventral abdomen and prepuce. The second horse had enlarged peripheral lymph nodes, cool nonpainful pitting edema of the ventral thorax and cranial ventral abdomen, and a 3/5 holosystolic heart murmur. The diagnosis of CLL...
Conservative management of uroperitoneum in a gelding. Uroperitoneum as a sequela to urethral calculus in an adult gelding was successfully managed by use of subischial urethrotomy and abdominal drainage. Necrosis of bladder mucosa was seen endoscopically, but a tear or rupture was never identified. Peritonitis developed but was controlled with antibacterial treatment. Although uroperitoneum is usually a sequela to bladder rupture and the ideal treatment is surgical repair, conservative management may be warranted in selected cases.
Microvascular circulation of the descending colon in horses. The microvascular circulation of the descending colon was studied in 5 adult horses, using microangiography and light microscopy combined with gross studies and scanning electron microscopy of vascular replicas. After heparinization, horses were euthanatized, and 3 segments of the descending colon and its mesentery containing 1 vascular arcade were removed from each horse. The fecal balls were gently massaged from the lumen, and the blood was flushed free of the circulation with isotonic NaCl. In 5 segments, the vascular system was injected with a modified radiopaque medium and evaluated radio...
[Scanning electron microscopic findings of the navicular bone and deep flexor tendon in podotrochlosis of horses]. In 25 adult horses the podotrochlea of 49 forelimbs was examined by means of light and electron microscopy in order to correlate clinical and morphological findings. According to the clinical diagnosis the animals were divided into three groups: lameness due to syndrome of podotrochlosis (group 1) or due to tendopathy (group 2) and horses without lameness (group 3). The most striking pathological findings of the navicular bone and the opposite surface of the deep flexor tendon were found in horses with podotrochlosis, consisting of loss of cartilage and tendon matrix with denudation of collage...
[Three cases of virus isolation from horse fetuses diagnosed with equine arteritis virus (EAV) abortion from stud farms with different breeds]. Three cases of abortions were diagnosed as caused by Equine Arteritis Virus (EAV) by isolation and typing of this virus from the respective fetuses. All 3 abortions were single cases, one occurring on a stud with Iceland Ponies, one with Warmbloods, one with Lipizzaner horses. On each stud horses of the respective breed were kept exclusively, therefore there existed no epidemiologic link. By means of seroneutralization tests performed on in contact horses it could be shown, that EAV had only been introduced recently into the stud with the Iceland Ponies. An extraneous mare stabled temporarily ...
Binding of estrogen-3-sulfates to stallion plasma and equine serum albumin. The binding of estrone-3-sulfate (E1-3-S) and estradiol-3-sulfate (E2-3-S) to adult stallion plasma was determined and compared with the binding to equine serum albumin (ESA). On the ESA molecule, two binding sites for E1-3-S with an association constant of 1.3 x 10(5) M-1 and several sites of weaker affinity were found; the data for E2-3-S showed the existence of four binding sites of moderate affinity (1 x 10(5) M-1) and several sites of weaker affinity. The removal of albumin from the stallion plasma resulted in the absence of binding of E1-3-S or E2-3-S, whereas the removal of glycoprotein...
Detection of equine immunoglobulin-secreting cells by a plaque assay. A protein A-hemolytic plaque assay was applied to detect immunoglobulin (Ig)-producing cells in horse peripheral blood, using pokeweed mitogen as a B lymphocyte activator. A maximum number of Ig-secreting cells was obtained when horse peripheral blood lymphocytes were cultured in a medium containing horse serum. The number of Ig-secreting cells in young horses (2 years old) was lower than that in adult horses (6 to 23 years old). In addition, the plaque formation was unchanged from blood samples kept at 4 degrees C for 24 hours, while blood samples kept for 72 hours did not yield plaques. Thes...
Standardised imaging technique for guided M-mode and Doppler echocardiography in the horse. Eighteen echocardiographic images useful for diagnostic imaging, M-mode echocardiography, and Doppler echocardiography of the equine heart were standardised by relating the position of the axial beam to various intracardiac landmarks. The transducer orientation required for each image was recorded in 14 adult horses by describing the degree of sector rotation and the orientation of the axial beam relative to the thorax. Repeatable images could be obtained within narrow limits of angulation and rotation for 14 of the 18 standardised images evaluated. Twenty-seven National Hunt horses were subse...
Chronic diarrhoea in adult horses: a review of 51 referred cases. A retrospective analysis of the clinical and laboratory findings from 51 adult horses with chronic diarrhoea revealed that the most common conditions were larval cyathostomiasis (14 cases), idiopathic chronic colitis (nine cases) and alimentary lymphoma (five cases). Five animals had diarrhoea as a result of non-alimentary disease. A diagnosis was reached in 37 cases, but only 15 were made ante mortem. Among the 18 animals (35 per cent) which survived, there were five cases of larval cyathostomiasis, one case of colonic impaction and 12 cases were undiagnosed. The most frequent abnormalities d...
A tracheal tube-in-tube technique for functional separation of the lungs in the horse. The tube-in-tube technique for the functional separation of the lungs in intact anaesthetised adult horses is based on fibre-optic-guided left-sided endobronchial intubation avoiding tracheostomy. It facilitates a valid separation of the two lungs despite variability in bronchial and carinal anatomy. No clinical complications that could be related to its use have been seen.
Histologic features of the carotid artery trifurcation in thoroughbreds. The common, external, and internal carotid and occipital arteries were examined histologically at the trifurcation of the common carotid arteries in 13 Thoroughbred foals (0 to 30 days old) and 64 Thoroughbred adults (2 to 4 years old). Calcification in the media of the common carotid and external carotid arteries was observed in 3 of the 13 foals and in 30 of the 64 adult horses. Calcification resembled that seen in Mönckeberg's arteriosclerosis in human beings, the cause of which is unknown.
Brachygnathia in horses: 20 cases (1979-1989). The medical records of 20 horses admitted to the veterinary medical center with a diagnosis of brachygnathia over a 10-year period (1979 to 1989) were reviewed. The study included 18 foals and 2 adult horses. Males were affected 5.7 times more frequently than females. The amount of disparity between the mandible and premaxilla varied between 0.75 and 3 cm. Sixteen foals were treated surgically with the temporary application of premaxillary tension band devices. Thirteen of the 16 surgical cases were available for follow-up evaluation. All of the surgically treated animals had improved incisive...