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.
Experimental Leptospira interrogans serovar Kennewicki infection of horses. Little information is available about experimental induction of leptospirosis in horses. Objective: Determine serologic, hematologic responses of horses to Leptospira interrogans serovar Kennewicki infection. Methods: Four adult horses seronegative for leptospirosis. Methods: Experimental and observational study. Horses were challenged with an equine isolate of L. interrogans serovar Kennewicki at 2 different doses and different inoculation sites. After challenge, the horses were monitored for 60 days. Blood, urine, and aqueous humor samples were collected at intervals until euthanasia 60 days...
Evaluation of 30- and 25-diopter intraocular lens implants in equine eyes after surgical extraction of the lens. To determine appropriate intraocular lens (IOL) implant strength to approximate emmetropia in horses. Methods: 16 enucleated globes and 4 adult horses. Methods: Lens diameter of 10 enucleated globes was measured. Results were used to determine the appropriate-sized IOL implant for insertion in 6 enucleated globes and 4 eyes of adult horses. Streak retinoscopy and ocular ultrasonography were performed before and after insertion of 30-diopter (D) IOL implants (enucleated globes) and insertion of 25-D IOL implants (adult horses). Results: In enucleated globes, mean +/- SD lens diameter was 20.14 ...
Pharmacokinetics and pharmacodynamics of dexamethasone after oral administration in apparently healthy horses. To assess pharmacokinetic and pharmacodynamic properties of dexamethasone administered PO as a solution or powder, compared with properties of dexamethasone solution administered IV, in apparently healthy horses. Methods: 6 adult horses. Methods: Serum cortisol concentration for each horse was determined before each treatment (baseline values). Dexamethasone (0.05 mg/kg) was administered PO (in solution or powdered form) or IV (solution) to horses from which feed had or had not been withheld (unfed and fed horses, respectively). Each horse received all 6 treatments in random order at 2-week in...
Evaluation of neutralization patterns of the five unique Argentine equine arteritis virus field strains reported. Equine viral arteritis (EVA) is a contagious viral disease that frequently causes mild or subclinical infections in adult horses. Only one EAV serotype has been described. However, there are differences in antigenicity, pathogenicity and neutralization characteristics of virus field strains. The interaction of two viral proteins, GP5 and M, is critical for infectivity and amino acid changes in the GP5 sequences have an effect on the neutralizing phenotype, regardless the effects of other viral proteins. The objective of the present study was to evaluate the neutralization phenotypes of the 5 u...
In vitro biomechanical comparison of a modified 5.5 mm locking compression plate fixation with a 5.5 mm locking compression plate fixation of osteotomized equine third metacarpal bones. To compare number of cycles to failure for palmarodorsal 4-point bending of a modified 5.5 mm broad locking compression plate (M5.5-LCP) fixation with a 5.5 mm broad LCP (5.5-LCP) fixation used to repair osteotomized equine third metacarpal (MC3) bones. Methods: In vitro biomechanical testing. Methods: Adult equine cadaveric MC3 bones (n=6 pairs). Methods: An 8-hole, M5.5-LCP, obtained by having a 1.0 mm thickness removed from the bone contact portion of the 5.5-LCP, was applied to the dorsal surface of 1 randomly selected MC3 from each pair, and an 8-hole, 5.5-LCP was applied dorsally to the ...
Topographic comparative study of paranasal sinuses in adult horses by computed tomography, sinuscopy, and sectional anatomy. Clinical and radiographic investigations of paranasal sinuses in horses are difficult due to the complex anatomy of these regions, the lack of patognomonic symptoms, and the low sensitivity of conventional diagnostic techniques. The aim of this study was to produce an anatomical atlas to support computed tomography (CT) and sinuscopy of the paranasal sinuses of the adult horse. Transverse, sagittal, and dorsal CT images were acquired, and sinuscopy with both rigid and flexible endoscopes was performed. The heads were frozen and sectioned using a band saw, with the cuts aligned as close as poss...
Distribution of voriconazole in seven body fluids of adult horses after repeated oral dosing. The purpose of this study was to assess safety and alterations in body fluid concentrations of voriconazole in normal horses on days 7 and 14 following once daily dose of 4 mg/kg of voriconazole orally for 14 days. Body fluid drug concentrations were determined by the use of high performance liquid chromatography (HPLC). On day 7, mean voriconazole concentrations of plasma, peritoneal, synovial and cerebrospinal fluids, aqueous humor, epithelial lining fluid (ELF), and urine were 1.47 +/- 0.63, 0.61 +/- 0.22, 0.70 +/- 0.20, 0.62 +/- 0.26, 0.55 +/- 0.32, 79.45 +/- 69.4, and 1.83 +/- 0.44 microg...
Full-thickness skin grafting to cover equine wounds caused by laceration or tumor resection. To describe and evaluate full-thickness skin grafting of equine wounds. Methods: Case series. Methods: Adult horses (n=6). Methods: A full-thickness graft was harvested from the pectoral region with the horse anesthetized or standing and sedated after local anesthetic infiltration. Grafts were attached to the cutaneous margin of the wound with staples and/or sutures if the horse was anesthetized or if the recipient site was desensitized. Cyanoacrylate glue was used to attach the grafts to the cutaneous margin of the wound of 3 horses. Medical records were reviewed for history, physical examina...
Physical and clinicopathologic findings in foals derived by use of somatic cell nuclear transfer: 14 cases (2004-2008). To describe the health status of foals derived by use of somatic cell nuclear transfer (NT) at a university laboratory. Methods: Retrospective case series. Methods: 14 live-born NT-derived foals. Methods: Medical records from 2004 through 2008 were evaluated to identify all pregnancies resulting in live-born NT-derived foals. Information obtained included gestation length, birth weight, foaling complications, gross abnormalities of the fetal membranes, appearance of the umbilicus, mentation of the foal, limb deformities, and any other abnormalities detected in the neonatal period. Clinicopatho...
Morphometry and abnormalities of the feet of Kaimanawa feral horses in New Zealand. The present study investigated the foot health of the Kaimanawa feral horse population and tested the hypotheses that horses would have a large range of foot morphology and that the incidence of foot abnormality would be significantly high. Methods: Abnormality was defined as a variation from what the two veterinarian assessors considered as optimal morphology and which was considered to impact negatively on the structure and/or function of the foot. Fifteen morphometric variables were measured on four calibrated photographic views of all four feet of 20 adult Kaimanawa feral horses. Four morp...
Evaluation of a new enzyme-linked immunosorbent assay to detect keratan sulfate in equine serum. This study aimed to evaluate a system that identifies cartilage turn over and/or degradation through measurement of a new keratan sulfate (KS) epitope concentration in equine sera. Blood samples were collected from 30 horses, 1 (n = 15) and 2 year-olds (n = 15). Serum samples were analyzed for an epitope of keratan sulfate by 1/20/5D4 (KS5D4) and new epitopes of keratan sulfate using high sensitive keratan sulfate (HSKS), measured by two respective enzyme-linked immunosorbant assays (ELISAs). There was no correlation in serum concentration of KS evaluated using 5D4 and HSKS. Age had no signifi...
Clinical aspects of multinodular pulmonary fibrosis in two warmblood horses. Two warmblood horses with a history of chronic weight loss and inappetence were referred to the Faculty of Veterinary Medicine, Ludwig-Maximilians University of Munich, Germany, for further examination. The clinical signs in horse 1 were fever, tachycardia and tachypnoea, and chronic ulcerative keratopathy of both eyes. Horse 2 had severe oral ulcerations and was coughing during feeding. In both horses, increased bronchovesicular sounds were heard during auscultation of the lungs. Laboratory findings included mild anaemia, lymphopenia and hypoalbuminaemia. Radiographic examination of the thora...
Analgesic efficacy of intra-articular morphine in experimentally induced radiocarpal synovitis in horses. To compare the analgesic effect of intra-articular (IA) and intravenous (IV) morphine in horses with experimentally induced synovitis. Methods: Eight adult horses. Methods: Randomized, observer blinded, double dummy trial with sequential crossover design. Methods: Radiocarpal synovitis was induced by IA injection of lipopolysaccharide on two occasions separated by a 3-week washout period. In one study period horses received treatment IA; morphine IA (0.05 mg kg(-1)) plus saline IV and in the other study period they received treatment IV; saline IA plus morphine IV (0.05 mg kg(-1)). Lameness an...
Pharmacokinetics of intra-articular morphine in horses with lipopolysaccharide-induced synovitis. To describe the pharmacokinetics of intra-articularly (IA) administered morphine. Methods: Experimental randomized, cross-over study. Methods: Eight adult healthy mixed breed horses aged 6.5 +/- 2.3 (mean +/- SD) years and weighing 535 +/- 86 kg. Methods: Unilateral radiocarpal synovitis was induced by IA injection of 3 microg lipopolysaccharide (LPS) on two occasions (right and left radiocarpal joint, respectively) separated by a 3-week wash-out period. Treatments were administered 4 hours post-LPS-injection: Treatment IA; preservative free morphine IA (0.05 mg kg(-1)) plus saline intravenous...
Evaluation of a veterinary glucometer for use in horses. Glucose assessment and regulation are important factors in the treatment of hospitalized horses and foals. Objective: The purpose of this study was to compare glucose measurement by a veterinary glucometer, adjusted by code for use in horses and foals, to a reference chemistry analyzer. It was hypothesized that the veterinary glucometer and reference analyzer would yield similar results and that interpretation of glucose values obtained from a veterinary glucometer would result in clinically appropriate decisions. Methods: Fifty blood samples from adult horses and 50 blood samples from neonata...
Long-term outcome after arthroscopic debridement of distal phalanx extensor process fragmentation in 13 horses. To report long-term outcome after arthroscopic removal of fragmentation of the extensor process of the distal phalanx in horses. Methods: Case series. Methods: Adult horses (n=13). Methods: Medical records (2003-2004) of horses that had arthroscopic debridement of fragmentation of the extensor process of the distal phalanx were reviewed. Inclusion criteria included: lameness localized to the foot, fragmentation of the extensor process of the distal phalanx debrided arthroscopically, and a follow-up period of > or = 4 years. Results: Of the 13 horses, lameness was resolved in 11 (85%) initia...
Comparison of the morphology of the limbs of juvenile and adult horses (Equus caballus) and their implications on the locomotor biomechanics. We analyzed the morphology and the walk-trot and trot-gallop transition velocities of nine juvenile horses and compared them with their mothers. We also compared the relative stride length and the duty factor of the juveniles with respect to adults at three equivalent trotting speeds (Froude numbers 0.5, 0.75, and 1.0), to determine dynamic similarity. Juveniles had a negative allometry in their leg bones, mainly because of little size changes of the distal portions. The negative allometry of extremities allows juveniles to increase stride length without increasing step frequency, which can be...
Effects of domperidone on digital laminar microvascular blood flow in clinically normal adult horses. To determine effects of domperidone and acepromazine maleate on microvascular blood flow in digital laminae of clinically normal adult horses. Methods: 8 clinically normal adult horses (4 mares and 4 geldings). Methods: In a 4-period crossover study, domperidone was administered PO at 1.1 mg/ kg and 5.5 mg/kg and IV at 0.2 mg/kg; acepromazine was administered IV at 0.04 mg/kg. The washout period between treatments was 1 week. A 3-minute measurement of laminar microvascular blood flow (LMBF) was obtained with laser Doppler flowmetry. Baseline measurements were obtained at -2, -1, and 0 hours pr...
Enteral fluid therapy in 108 horses with large colon impactions and dorsal displacements. To assess the effect of enteral fluid therapy (EFT) in horses with colic, 78 adult horses with colon impactions and 30 with left dorsal colon displacements received an isotonic electrolyte solution via a nasogastric tube at a rate of 8 to 10 l every two hours until resolution of clinical signs. Clinical progression was monitored closely, and plasma biochemistry was evaluated before, during and after treatment. Volume of fluids, time to resolution, and outcome were also recorded. EFT was well tolerated by 102 of 108 horses and was an effective method to resolve 99 per cent of colon impactions a...
Identification of immunologically relevant genes in mare and foal dendritic cells responding to infection by Rhodococcus equi. Rhodococcus equi is a facultative intracellular bacterial pathogen of horses; infected foals develop pyogranulomatous pneumonia, however adult horses are largely unaffected. R. equi infects and proliferates within host macrophages and dendritic cells (DCs). DCs initiate the appropriate adaptive immune response, thereby playing a critical role in determining the outcome of infection. Our aim was to identify genes that are differentially expressed in R. equi infected monocyte-derived DCs (mdDCs). Peripheral blood monocytes from mares and foals were used to derive mdDCs by culturing with recombin...
Adult equine bone marrow stromal cells produce a cartilage-like ECM mechanically superior to animal-matched adult chondrocytes. Our objective was to evaluate the age-dependent mechanical phenotype of bone marrow stromal cell- (BMSC-) and chondrocyte-produced cartilage-like neo-tissue and to elucidate the matrix-associated mechanisms which generate this phenotype. Cells from both immature (2-4 month-old foals) and skeletally-mature (2-5 year-old adults) mixed-breed horses were isolated from animal-matched bone marrow and cartilage tissue, encapsulated in self-assembling-peptide hydrogels, and cultured with and without TGF-beta1 supplementation. BMSCs and chondrocytes from both donor ages were encapsulated with high viab...
Fecal egg counts after anthelmintic administration to aged horses and horses with pituitary pars intermedia dysfunction. To determine effects of pituitary pars intermedia dysfunction (Cushing's disease) and age on fecal egg count and time to egg reappearance after anthelmintic treatment in horses residing in similar environments. Methods: Cross-sectional study. Methods: 29 healthy horses (4 to 35 years old) and 13 horses with PPID (13 to 33 years old). Methods: Fecal egg counts were performed by use of a modified Wisconsin flotation method at 2-week intervals before and after ivermectin treatment. Results: Horses with PPID had higher fecal egg counts before and 8, 10, and 12 weeks after ivermectin treatment, com...
Evaluation of diffusion of triamcinolone acetonide from the distal interphalangeal joint into the navicular bursa in horses. To determine whether triamcinolone acetonide diffuses from the distal interphalangeal joint (DIPJ) to the navicular bursa, diffusion is direct or systemic, and addition of sodium hyaluronan has an effect on diffusion in horses. Methods: 11 adult horses without forelimb lameness. Methods: 1 randomly chosen forelimb DIPJ of each horse received an injection of 10 mg of triamcinolone acetonide plus 20 mg of sodium hyaluronan (group 1), and the contralateral forelimb DIPJ received an injection of 10 mg of triamcinolone acetonide plus 2 mL of lactated Ringer's solution (group 2). Synovial fluid samp...
Effects of top-dress formulations of suxibuzone and phenylbutazone on development of gastric ulcers in horses. Eighteen mature, healthy horses were divided into three groups (six per group) receiving either no treatment, 15 consecutive days of phenylbutazone (PBZ), or 15 consecutive days of suxibuzone (SBZ) at recommended label doses. Horses underwent endoscopy before and after the treatment period and were assigned gastric ulcer scores. Gastric ulcer number and severity scores were similar across treatment groups. These findings suggest that when administered at the recommended label dose for 15 days, neither PBZ nor SBZ causes an increase in the number or severity of gastric ulcers over what would be...
Preliminary molecular analysis of Clostridium difficile isolates from healthy horses in northern Italy. Clostridium difficile, associated with a wide spectrum of diseases in humans, as well as in several animal species, is an important cause of colitis in adult horses and foals. The aim of this study was to investigate by toxin gene profile and PCR-ribotyping the molecular characteristics of 14 C. difficile strains isolated from 42 faeces of healthy horses. Both toxin genes, tcdA and tcdB, were present in only 1 isolate (7.1%). Six isolates (42.9%) demonstrated tcdA-/tcdB+ genotype, and seven isolates (50.0%) were tcdA-/tcdB-. All strains were binary toxin genes negative (cdtA-/cdtB-). The PCR-p...
Comparison of serum iohexol clearance and plasma creatinine clearance in clinically normal horses. Objective-To determine whether a limited sampling time method based on serum iohexol clearance (Cl(iohexol)) would yield estimates of glomerular filtration rate (GFR) in clinically normal horses similar to those for plasma creatinine clearance (Cl(creatinine)). Animals-10 clinically normal adult horses. Procedures-A bolus of iohexol (150 mg/kg) was administered IV, and serum samples were obtained 5, 20, 40, 60, 120, 240, and 360 minutes after injection. Urinary clearance of exogenous creatinine was measured during three 20-minute periods. The GFR determined by use of serum Cl(iohexol) and plas...
The effect of age on the immune response of horses to vaccination. Few studies have investigated immunosenescence in the horse, but it is accepted that the primary and secondary (anamnestic) immune responses may differ between aged and younger horses. The aim of the present study was to determine whether aged horses have a protective immune response post-vaccination. Thirty-four aged healthy horses (> or =20 years) and 29 younger adult horses (4-12 years) of various breeds were vaccinated with commercially produced killed rabies and influenza vaccines. Rabies serum neutralizing antibody titres and equine influenza virus specific antibody subclasses (immunoglo...
Effect of topical 1% tropicamide on Schirmer tear test results in clinically normal horses. To observe the effect of topical 1% tropicamide on equine tear production as measured by Schirmer I tear test. Methods: Fourteen adult horses received one drop of 1% tropicamide ophthalmic solution in one eye and the opposite eye served as the control. The tear production in both eyes was tested at 1, 2, 4, 6, and 24 h after 1% tropicamide administration. Results: Measurements made 1 h after treatment revealed a significant reduction in Schirmer tear test values in tropicamide treated eyes (P = 0.002). The observed decrease in tear production was maintained up to 4 h after treatment (P = 0.002...
Equine protozoal myeloencephalitis caused by Neospora hughesi in an adult horse in Saskatchewan. A protozoal parasite identified as Neospora hughesi was found in inflammatory lesions in the central nervous system of a Canadian-born adult horse presented with neurological signs. This is believed to be the first case of equine protozoal myeloencephalitis (EPM) caused by Neospora hughesi in a horse outside of the United States. Un parasite protozoaire identifié comme a été trouvé dans les lésions inflammatoires du système nerveux central d’un cheval adulte né au Canada présentant des signes neurologiques. On croit qu’il s’agit du premier cas d’encéphalomyélite protozoai...