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.
Influence of morphine sulfate on the halothane sparing effect of xylazine hydrochloride in horses. To quantitate the dose and time-related effects of morphine sulfate on the anesthetic sparing effect of xylazine hydrochloride in halothane-anesthetized horses and determine the associated plasma xylazine and morphine concentration-time profiles. Methods: 6 healthy adult horses. Methods: Horses were anesthetized 3 times to determine the minimum alveolar concentration (MAC) of halothane in O2 and characterize the anesthetic sparing effect (ie, decrease in MAC of halothane) by xylazine (0.5 mg/kg, i.v.) administration followed immediately by i.v. administration of saline (0.9% NaCI) solution, lo...
Sepsis in adults and foals. Sepsis develops in horses when the host response to the invading pathogens is not properly balanced according to the severity of the insult. Several clinical conditions frequently encountered in equine practice may be associated with the development of sepsis and have the potential to progress to more severe forms, such as severe sepsis, MODS, and septic shock. Consequently, it is important for equine practitioners to be aware of the manifestations,pathophysiology, and treatment of sepsis. Although enormous progress has been made in recent years in our understanding of the pathophysiology of s...
Inotropes and vasopressors in adults and foals. Successful treatment with inotropes and vasopressors depends on an understanding of the interplay of flow, pressure, and resistance in the cardiovascular system and an appreciation of the pathophysiologic mechanisms leading to inadequate tissue perfusion. Any treatment strategy is necessarily a compromise between the requirements of different vascular beds.Furthermore. the underlying hemodynamic derangements can change rapidly. Therefore. inotropes and vasopressors should be titrated to measures of improved hemodynamic status, and the treatments should be frequently reviewed.
Effect of topical application of diclofenac liposomal suspension on experimentally induced subcutaneous inflammation in horses. To determine whether 1% diclofenac liposomal suspension (DLS) ointment would be absorbed transdermally and attenuate experimentally induced subcutaneous inflammation in horses. Methods: 7 healthy adult horses. Methods: Inflammation was produced by injecting 1% sterile carrageenan into subcutaneously implanted tissue cages 8 hours before (time -8) and at the time of application of test ointment. A crossover design was used. Horses received 1 of 2 treatments (topically administered control or DLS ointments) during 48 hours of carrageenan-induced subcutaneous inflammation. A single application of...
Assessment of the effects of age and joint disease on hydroxyproline and glycosaminoglycan concentrations in synovial fluid from the metacarpophalangeal joint of horses. To assess the effects of age and joint disease on hydroxyproline and glycosaminoglycan (GAG) concentrations in synovial fluid from the metacarpophalangeal joint of horses and evaluate the association of those concentrations with severity of osteoarthritis and general matrix metalloproteinase (MMP) activity. Methods: Synovial fluid was collected from the metacarpophalangeal joints of foals at birth (n = 10), 5-month-old foals (10), 11-month-old foals (5), and adult horses (73). Methods: Hydroxyproline and GAG concentrations were determined in synovial fluid samples. The severity of osteoarthrit...
Cholinergic, nitrergic and peptidergic (Substance P- and CGRP-utilizing) innervation of the horse intestine. A histochemical and immunohistochemical study. The small and large intestine of adult horses were histochemically and immunohistochemically investigated in order to evidence components of the intramural nervous system. The general structural organization of the intramural nervous system was examined by using Nissl-thionin staining as well as the anti-neurofilament 200 (NF200) immunoreaction, which demonstrated the presence of neurons in the submucous as well as myenteric plexuses. The additional presence of subserosal ganglia was shown in the large intestine. Acetylcholinesterase (AChEase) activity was observed in both the submucous and my...
Immunogenecity of synthetic peptides representing linear B-cell epitopes of VapA of Rhodococcus equi. Amino acid 65-78 of membrane protein VapA of the facultative intracellular Rhodococcus equi contained an immunodominant N-terminal B-cell epitope (N15Y peptide). Safety and immunogenecity of a synthetic peptide consisting of the amino acid 65-78 of VapA (peptide N15Y) were evaluated first in mice and in healthy adult horses. A single dose of a peptide-VapA vaccine induced and only in presence of adjuvant, specific IgG antibodies in sera of mice. After challenge with virulent R. equi 3 weeks after immunization, tissue clearance was more delayed in immunized mice than in control mice. An antibod...
Bacterial meningitis and brain abscesses secondary to infectious disease processes involving the head in horses: seven cases (1980-2001). To determine clinical features of horses with bacterial meningitis or brain abscesses secondary to infectious disease processes involving the head. Methods: Retrospective study. Methods: 7 adult horses. Methods: Medical records of Tufts University, the University of Pennsylvania, and the Livestock Disease Diagnostic Center (Lexington, Ky) were reviewed to identify adult (> 12 months old) horses in which a postmortem diagnosis of bacterial meningitis or brain abscess had been made. Horses were included in the study if an intracranial infection was confirmed, the horse had a primary infectious d...
Electromyographic activity of the longissimus dorsi muscles in horses during trotting on a treadmill. To use electromyography (EMG) to measure physiologic activity of the longissimus dorsi muscles of horses during trotting on a treadmill. Methods: 15 adult horses (5 to 20 years old that weighed 450 to 700 kg) that did not have clinical signs of back pain. Methods: Data were recorded for each horse during trotting on a treadmill at speeds of 2.6 to 4.4 m/s. Surface electromyography was recorded bilaterally from the longissimus dorsi muscles at the levels of T12, T16, and L3. Results: In each motion cycle, 2 EMG maxima were found at the end of the diagonal stance phases. The EMG activity peaked ...
Concentrations of gentamicin in serum and bronchial lavage fluid after once-daily aerosol administration to horses for seven days. To assess gentamicin concentrations in serum and bronchial lavage fluid (BLF) of horses during a 24-hour period after once-daily aerosol administration of gentamicin (GAER) for 7 days and the pattern and degree of bronchial tree inflammation associated with repeated GAER. Methods: 13 healthy adult horses (9 geldings and 4 mares). Methods: The treatment group comprised 8 horses, and 5 horses were untreated control animals. Gentamicin (20 mL of gentamicin [50 mg/mL]) was administered via aerosol once daily for 7 days. Samples of serum and BLF were obtained from all horses before GAER and 0.5, 4,...
Effects of insulin-like growth factor-II on the mitogenic and metabolic activities of equine articular cartilage with and without interleukin 1-beta. To investigate the effects of insulin-like growth factor-II (IGF-II) on DNA and glycosaminoglycan (GAG) synthesis and the expression of matrix-related genes in equine articular cartilage explants and chondrocytes, respectively, with and without interleukin 1-beta (IL1-beta). Methods: Articular cartilage from 12 adult horses. Methods: Articular cartilage was incubated in standard media with and without equine IL1-beta (10 ng/mL) containing various concentrations of IGF-II for 72 hours. Synthesis of DNA and GAG was determined by incorporation of thymidine labeled with radioactive hydrogen (3H) a...
Effects of infusion of adenosine triphosphate-magnesium chloride on cardiopulmonary and clinicopathologic variables, cytokine activity, and endothelin concentration in horses administered a low dose of endotoxin. To evaluate systemic effects of i.v. infusion of ATP-MgCl2 subsequent to infusion of a low dose of endotoxin in horses. Methods: 12 adult horses. Methods: Horses were administered endotoxin (lipopolysaccharide [LPS]) or saline (0.9% NaCl) solution i.v., during a 30-minute period. Immediately thereafter, horses in each group were infused i.v. with ATP-MgCl2 or saline solution. Two weeks later, horses were administered the opposite solution (LPS or saline solution), but it was followed by the same infusion as 2 weeks previously (ie, ATP-MgCl2 or saline solution). Cardiopulmonary and clinicopatho...
Repair of extensive articular cartilage defects in horses by autologous chondrocyte transplantation. Damaged adult articular cartilage has very limited capacity to heal. Autologous chondrocyte transplantation (ACT) has been used clinically and studied in experimental animals in an attempt to provide biologically based cartilage regeneration. This study evaluated cartilage repair following ACT in a large animal model over a period of 2 years. Articular cartilage defects (10 mm in diameter, full-thickness) were created in the minor load-bearing area on the lateral talus of tibiotarsal joints of eight adult horses. In each animal, the right joint was repaired using autologous chondrocytes inject...
Effect of radiosynovectomy with holmium-166 ferric hydroxide macroaggregate on adult equine cartilage. To analyze the effect of radiosynovectomy with holmium-166 ferric hydroxide macroaggregate (166Ho-FHMA) on articular cartilage in 6 adult horses. Methods: Arthritic changes and mechanical properties of articular cartilage were evaluated with arthroscopy and postmortem microscopic analyses. Glycosaminoglycan content was measured by safranin-O staining combined with digital densitometry, uronic acid analyses, and dimethylene blue binding assay. 35S-sulfate labeling and autoradiography were used to localize proteoglycan synthesis and to characterize proteoglycan structures using SDS-agarose gel e...
Turnover of carbon isotopes in tail hair and breath CO2 of horses fed an isotopically varied diet. Temporal stable isotope records derived from animal tissues are increasingly studied to determine dietary and climatic histories. Despite this, the turnover times governing rates of isotope equilibration in specific tissues following a dietary isotope change are poorly known. The dietary isotope changes recorded in the hair and blood bicarbonate of two adult horses in this study are found to be successfully described by a model having three exponential isotope pools. For horse tail hair, the carbon isotope response observed following a dietary change from a C3 to a C4 grass was consistent with...
Effects of injection of botulinum toxin type B into the external anal sphincter on anal pressure of horses. To determine effects on anal pressure of horses after local injection of the external anal sphincter with Clostridium botulinum toxin type B. Methods: 11 healthy adult horses. Methods: Peak and resting anal sphincter pressures were measured with a custom-made rectal probe that was connected to a pressure transducer. Pressures were measured before treatment and after injection with botulinum toxin type B (BTB) or saline (0.9% NaCl) solution. Dose titration with 500, 1,000, 1,500, and 2,500 U of BTB was completed. Physical changes, behavior, and anal pressure were recorded for each horse. Result...
Idiopathic granulomatous pneumonia in seven horses. The history, clinical signs and pathological findings in seven adult horses with histologically confirmed idiopathic granulomatous disease, primarily of the lungs, are reviewed. They ranged in age from eight to 21 years, five were geldings and two were females, they belonged to five breeds and there were no seasonal or geographical associations. The primary clinical signs were chronic weight loss, exercise intolerance and respiratory distress which did not respond to conventional treatment. The most consistent physical findings were depression, anorexia, tachycardia, tachypnoea and adventitiou...
Hypomagnesemia in hospitalized horses. This study was initiated to identify the signalment and clinical variables potentially associated with hypomagnesemia in horses evaluated at the North Carolina State University, College of Veterinary Medicine (NCSU-CVM) veterinary teaching hospital between January 1999 and May 2001. A nested case reference study (nested case-control study) was conducted to examine the potential relationship between hypomagnesemia and signalment, serum chemistry panel analyses, number of hospitalization days, discharge status, and diagnosis. A series of independent and multivariable logistic regression models w...
Bone gentamicin concentration after intra-articular injection or regional intravenous perfusion in the horse. To compare intra-articular (IA) and bone gentamicin concentrations achieved after intra-articular administration or regional intravenous perfusion (RIP). Methods: Experimental study. Methods: Twelve healthy adult horses. Methods: Horses were assigned to 2 treatment groups (n = 6/group): Group 1, 1 g gentamicin administered simultaneously in both left and right metacarpophalangeal joints and group 2, 1 g gentamicin administered simultaneously in both left and right lateral palmar veins. Serum, synovial fluid, and bone biopsy specimens were collected. Gentamicin concentrations were determined by...
Pharmacokinetics and plasma concentrations of acetylsalicylic acid after intravenous, rectal, and intragastric administration to horses. Six healthy adult horses (5 mares and 1 stallion) were given a single dose of acetylsalicylic acid (ASA), 20 mg/kg of body weight, by intravenous (IV), rectal, and intragastric (IG) routes. Serial blood samples were collected via jugular venipuncture over a 36-h period, and plasma ASA and salicylic acid (SA) concentrations were determined by high-performance liquid chromatography. After IV administration, the mean elimination rate constant of ASA (+/- the standard error of the mean) was 1.32 +/- 0.09 h(-1), the mean elimination half-life was 0.53 +/- 0.04 h, the area under the plasma concentra...
Detection of lameness and determination of the affected forelimb in horses by use of continuous wavelet transformation and neural network classification of kinematic data. To investigate continuous wavelet transformation and neural network classification of gait data for detecting forelimb lameness in horses. Methods: 12 adult horses with mild forelimb lameness. Methods: Position of the head and right forelimb foot, metacarpophalangeal (ie, fetlock), carpal, and elbow joints was determined by use of kinematic analysis before and after palmar digital nerve blocks. We obtained 8 recordings from horses without lameness, 8 with right forelimb lameness, and 8 with left forelimb lameness. Vertical and horizontal position of the head and vertical position of the foot, ...
Assessment of the accuracy of computed tomography for measurement of normal equine pituitary glands. To describe the anatomic features of the pituitary gland region in horses via computed tomography (CT) and determine the accuracy of CT for estimating normal equine pituitary gland dimensions. Methods: 25 adult horses with no clinical signs of pituitary disease. Methods: Transverse CT images and gross transverse tissue sections were compared in 2 horses. Contrast-enhanced CT of the pituitary gland region was performed postmortem in 23 horses with 4 slice thickness and interval settings (10-mm contiguous or overlapping slices and 4-mm contiguous or overlapping slices). Gross and CT estimates of...
Methemoglobinemia and eccentrocytosis in equine erythrocyte flavin adenine dinucleotide deficiency. This report describes erythrocyte biochemical findings in an adult Spanish mustang mare that exhibited persistent methemoglobinemia, eccentrocytosis, and pyknocytosis that were not related to the consumption or administration of an exogenous oxidant. The methemoglobinemia was attributed to a deficiency in cytochrome-b5 reductase (Cb5R) activity, and the eccentrocytes and pyknocytes were attributed to a marked deficiency in reduced nicotinamide adenine dinucleotide phosphate-dependent glutathione reductase (GR) activity that resulted in decreased reduced glutathione concentration within erythro...
Effects of acetylcysteine and migration of resident eosinophils in an in vitro model of mucosal injury and restitution in equine right dorsal colon. To evaluate the in vitro protective effects of acetylcysteine and response of resident mucosal eosinophils in oxidant-induced injury to tissues of right dorsal colon of horses. Methods: 9 adult horses. Methods: Gastrointestinal mucosa was damaged in vitro with 3 mM hypochlorous acid (HOCl), with and without prior exposure to 6mM acetylcysteine. Control tissues were not exposed to HOCl or acetylcysteine. Control and damaged tissues were incubated in Krebs-Ringer-bicarbonate solution and tissue resistance measured during 240 minutes. Tissue permeability to radiolabeled mannitol was also used to ...
An in vivo equine forelimb model for short-term recording of peak isometric force in the superficial and deep digital flexor muscles. To develop and test an experimental model for in vivo short-term recording of peak isometric forces of the digital flexor muscles in the forelimb of adult horses. Methods: In vivo experimental study. Methods: Four healthy, anesthetized, adult Thoroughbred horses (3 to 7 years old; 527 +/- 87 kg) Methods: In dorsal recumbency, ulnar and median nerves were exposed and instrumented with insulated bipolar cuff stimulation electrodes for later connection to an electrical stimulator. In left lateral recumbency, a biplanar fixator was applied to the right humerus and a custom-made, rigid, aluminum fr...
In vitro comparison of equine cancellous bone graft donor sites and tibial periosteum as sources of viable osteoprogenitors. To compare the osteogenic potential of cancellous bone of conventional graft sites with that of one nonconventional site (fourth coccygeal vertebra) and to investigate the tibial periosteum as a donor site with respect to osteogenic potential. Methods: In vitro osteogenic cell culture system. Methods: Eight adult horses. Methods: Cancellous bone or tibial periosteum was aseptically collected and cut into bone chips or periosteal strips of 1 to 2 mm(3) for primary explant cultures. After 2 weeks, primary tissue cultures that yielded a population of osteogenic cells were counted and subcultured ...
Fetal development of the segment-specific papillary body in the equine hoof. Fetal development of the unique papillary body and its localized peculiarities in the equine hoof are described based on the study of 51 fetuses, nine newborn foals, and five adult horses. The shape and dimensions of the dermal papillae and lamellae have a formative influence on the structure and physical quality of the corneous hoof capsule with its horn tubules and lamellae. The size and arrangement of these horn structures determine the mechanical quality of hoof horn. Proper horn quality is a prerequisite for the various functions of the hoof capsule, such as protecting the living dermis s...
An evaluation of diagnostic data in comparison to the results of liver biopsies in mature horses. The diagnostic value of several investigative procedures commonly used during the evaluation of suspected equine hepatopathy cases has not been specifically quantified in previous studies. Objective: No noninvasive procedures would clearly discriminate between horses with and without significant liver disease. Methods: Histopathology of biopsy samples was used as the 'gold standard' technique for definitive diagnosis of the presence or absence of significant liver disease. Clinical, ultrasonographic and clinicopathological data obtained during the investigation of 82 suspected cases of hepatop...
Preliminary evaluation of a behaviour-based system for assessment of post-operative pain in horses following arthroscopic surgery. To develop a method for objective assessment of equine post-operative pain. Methods: Prospective nonblinded clinical study. Methods: Twelve adult horses: Group 1 (G1, n = 6), admitted for arthroscopy (under general anaesthesia, with multimodal analgesia); Group 2 (G2, n = 6), 'pain free' controls. Methods: Horses were filmed continuously (CVI, time-lapse video recorder) over 72 hours, from 24 hours pre-surgery (PS) to 48 hours post-recovery (PR) (G1), and over 24 hours (G2). Activity budgets were determined from 24 to 0 hours PS, 0-24 and 24-48 hours PR (G1) and for 24 hours (G2). Using direct...