Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:In Vivo
In vivo studies involving horses refer to research conducted within living organisms to understand various biological processes, disease mechanisms, and therapeutic interventions in equine species. These studies provide insights into the physiological and pathological responses of horses under natural conditions. In vivo research encompasses a range of investigations, including pharmacokinetics, disease modeling, and the evaluation of treatment efficacy. It often involves the use of controlled environments to simulate real-life scenarios while observing the effects of specific variables on equine health. This page gathers peer-reviewed research articles and scholarly studies that explore the methodologies, findings, and implications of in vivo research in horses, contributing to the advancement of equine science and veterinary medicine.
Aversive conditioning of periodic spontaneous erection adversely affects sexual behavior and semen in stallions. Periodic spontaneous erection and penile movements known as masturbation (SEAM) occur normally at approximately 90 min intervals in awake equids. SEAM in horses has traditionally been misunderstood by many horsemen as aberrant behavior that should be eliminated. Accordingly, it is not uncommon for trainers of performance stallions or managers of breeding stallions to punish SEAM in an attempt to eliminate the behavior. Previous clinical observations and preliminary unsystematic trials had suggested that attempts to stop stallion SEAM may lead to an increase rather than a decrease in SEAM, and ...
Reticulocyte changes after experimental anemia and erythropoietin treatment of horses. Availability of recombinant human erythropoietin (EPO) has facilitated use to enhance red blood cell production, and therefore aerobic performance, in human and equine athletes. Recombinant human EPO promotes growth and differentiation of equine erythroid precursor cells, but in some horses repeat administration induces immune interference with endogenous EPO resulting in fatal anemia. Although blood reticulocyte parameters acquire unique changes in humans treated with EPO, with manual enumeration methods, horses were not considered to release reticulocytes from the bone marrow into circulatio...
Equine FISH mapping of 36 genes known to locate on human chromosome ends. The INRA and the CHORI-241 horse BAC libraries were screened by hybridization with DNA probes and/or directly by PCR with primers designed in consensus sequences of genes localized at the end of each human chromosome. BAC clones were retrieved and 36 could be FISH mapped after the expected gene was confirmed in each BAC by sequencing. Our results show that 16 BACs can be considered to be at telomeric or centromeric positions in the horse and 15 were found at the boundary of actually defined conserved segments even-though often located within conserved syntenic fragments between horse and human...
Structure of equine 2′-5’oligoadenylate synthetase (OAS) gene family and FISH mapping of OAS genes to ECA8p15–>p14 and BTA17q24–>q25. Mammalian 2'-5' oligoadenylate (2-5A) synthetases are important mediators of the antiviral activity of interferons. Both human and mouse 2-5A synthetase gene families encode four forms of enzymes: small, medium, large and ubiquitin-like. In this study, the structures of four equine OAS genes were determined using DNA sequences derived from fifteen cDNA and four BAC clones. Composition of the equine OAS gene family is more similar to that of the human OAS family than the mouse Oas family. Two OAS-containing bovine BAC clones were identified in GenBank. Both equine and bovine BAC clones were phy...
The use of impulse oscillometry for separate analysis of inspiratory and expiratory impedance parameters in horses: effects of sedation with xylazine. To improve the outcome of parameters measured by the impulse oscillometry system (IOS) in horses by separate assessment of inspiratory and expiratory impedance spectra in the frequency range between 1 and 10 Hz. As basis for further studies, the influence of sedation with xylazine on respiratory impedance was also investigated. Methods: (i) The respiratory impedance of 11 horses was measured using IOS before and 6 min after sedation (xylazine; 0.6 mg/kg b.w.). (ii) The time course of impedance parameters in a period of 24 min after administration of xylazine was evaluated in 12 horses at regul...
The use of a systemic prime/mucosal boost strategy with an equine influenza ISCOM vaccine to induce protective immunity in horses. In horses, natural infection confers long lasting protective immunity characterised by mucosal IgA and humoral IgGa and IgGb responses. In order to investigate the potential of locally administered vaccine to induce a protective IgA response, responses generated by vaccination with an immunostimulating complex (ISCOM)-based vaccine for equine influenza (EQUIP F) containing A/eq/Newmarket/77 (H7N7), A/eq/Borlänge/91 (H3N8) and A/eq/Kentucky/98 (H3N8) using a systemic prime/mucosal boost strategy were studied. Seven ponies in the vaccine group received EQUIP F vaccine intranasally 6 weeks after...
Biochemical and biomechanical properties of lesion and adjacent articular cartilage after chondral defect repair in an equine model. Chondral defects may lead to degradative changes in the surrounding cartilage, predisposing patients to developing osteoarthritis. Objective: To quantify changes in the biomechanical and biochemical properties of the articular cartilage adjacent to chondral defects after experimental defect repair. Methods: Controlled laboratory study. Methods: Specimens were harvested from tissue within (lesion), immediately adjacent to, and at a distance from (remote area) a full-thickness cartilage defect 8 months after cartilage repair with genetically modified chondrocytes expressing insulin-like growth f...
A non-invasive method of tendon force measurement. The ability to measure the forces exerted in vivo on tendons and, consequently, the forces produced by muscles on tendons, offers a unique opportunity to investigate questions in disciplines as varied as physiology, biomechanics, orthopaedics and neuroscience. Until now, tendon loads could be assessed directly only by means of invasive sensors implanted within or attached to these collagenous structures. This study shows that the forces acting on tendons can be measured, in a non-invasive way, from the analysis of the propagation of an acoustic wave. Using the equine superficial digital flexor...
Alpha-melanocyte stimulating hormone release in response to thyrotropin releasing hormone in healthy horses, horses with pituitary pars intermedia dysfunction and equine pars intermedia explants. Thyrotropin releasing hormone (TRH) stimulates an increase in plasma cortisol in horses with pars intermedia dysfunction (PPID, Cushing's disease). A similar phenomenon is observed in humans with Cushing's disease or Nelson's syndrome. The mechanism of the response in humans is not known, but an alteration in receptor expression, selectivity or responsiveness in abnormal corticotropes has been proposed. Horses with PPID, unlike humans, almost exclusively have adenomas of pars intermedia (PI) rather than pars distalis (PD) origin. Therefore, the mechanism responsible for the TRH response observ...
Differentiating among horse (Equus caballus), donkey (Equus asinus) and their hybrids with combined analysis of nuclear and mitochondrial gene polymorphism. A novel and brief method of differentiating among horse (Equus caballus) and donkey (Equus asinus) and their hybrids (mule, E. asinus x E. caballus and hinny, E. caballus x E. asinus) with combined analysis of nuclear and mitochondrial gene polymorphism (CANMGP) was reported in the present report. A nuclear gene, protamine P1 gene of donkey was sequenced and compared with the known horse sequence from GenBank while a published equid mitochondrial gene, cytochrome b gene of donkey was compared with that of horse. In each of the two genes, a fixed nucleotide substitution within an exon that coul...
Agonist-independent alteration in beta-adrenoceptor-G-protein-adenylate cyclase system in an equine model of recurrent airway obstruction. We examined the inhibitory sympathetic beta-adrenergic mechanisms in peripheral lung, bronchi and trachea of an equine model of recurrent airway obstruction (RAO), to support the hypothesis that the beta-adrenergic receptor dysfunction is not only restricted to cell surface receptor density but rather encompasses a mechanistic defect apart from the receptor, to the intracellular signaling components. The non-asthmatic lung possessed 3.2-fold more beta-adrenergic receptors than bronchi (496 +/- 19.4 vs. 155.1+/- 19.6 fmol/mg protein; P < 0.01) and 6.2-fold higher than in the trachea (79.8 +/...
Immunologic disorders in neonatal foals. Foals live in an environment heavily populated by bacteria, many of which are capable of causing disease. Development of infection,however, is the exception rather than the rule. The ability of the foal to prevent infection by most pathogens is the result of a sophisticated set of defense mechanisms. These defense mechanisms can be divided into adaptive and innate immunity. Innate immunity encompasses defense mechanisms that pre-exist or are rapidly induced within hours of exposure to a pathogen. Conversely, adaptive or acquired immunity represents host defenses mediated by T and B lymphocytes...
In vitro evaluation of the effect of the opioid antagonist N-methylnaltrexone on motility of the equine jejunum and pelvic flexure. Although potent analgesics, opioids decrease intestinal activity, leading to ileus in many species. N-methylnaltrexone (MNTX), an opioid antagonist which does not cross the blood-brain barrier and antagonises the morphine effect on the intestine, directly stimulates motility and restores function without affecting analgesic properties. While its use has been reported in human subjects, there is no information with regard to its usage in the horse. Objective: To determine whether MNTX has an effect on contractile activity of the equine jejunum and pelvic flexure. Methods: Using circular smooth ...
The effects of polyester (terylene) fibre implants on normal equine superficial digital flexor tendon. To determine the effect of polyester (terylene) fibre implants on normal equine superficial digital flexor (SDF) tendon structure. Methods: Normal forelimb SDF tendons (n=24) of 12 horses were divided into unoperated, sham-operated, and implanted (terylene fibre implant) groups. Horses were assessed for lameness and ultrasonographic changes to SDF tendons at intervals up to 48 weeks post-operatively. After euthanasia, SDF tendons were collected for histological and ultrastructural examination. Histological sections were examined for alcian blue staining intensity, cellularity, fibril bundle al...
Effects of external thermal manipulation on laminar temperature and perfusion scintigraphy of the equine digit. To assess the effects of external thermal manipulation on the soft-tissue and vascular perfusion of the equine digit using nuclear scintigraphy and documented tissue temperatures. Methods: Six horses were used in a randomised crossover design. Each horse was treated with external heat (47 degrees C) or external cold (4 degrees C) applied to a digit for 30 minutes. The opposite front foot was untreated and used for control measurements. Nuclear scintigraphy was performed before, during, and after therapy to assess vascular and soft-tissue perfusion to the digit in response to therapy. Dorsal ho...
The development and application of the modern reproductive technologies to horse breeding. Although the horse was probably the first animal to experience and benefit from artificial insemination, it trailed the field somewhat with regard to the application of embryo transfer and other oocyte and embryo-related modern breeding technologies. But with a late run it is now back in mid-field and gaining fast on the other large domestic species in the application of the many technological advances of the past 20 years to sound breeding practice. Improvements in extenders and cryoprotectants have resulted in a veritable upsurge in the transport and insemination of cooled and frozen stallio...
Evaluation of iatrogenic hemarthrosis of the metacarpophalangeal joint as a method of induction of temporary reversible lameness in horses. To determine whether iatrogenic hemarthrosis of the metacarpophalangeal joint could be used as a model for temporary reversible joint pain in horses. Methods: 8 adult horses. Methods: Each horse was evaluated on a treadmill before and after injection of 1 metacarpophalangeal joint with 10 mL of autogenous blood. Horses were evaluated subjectively and objectively by use of a computerized force measurement system at intervals until lameness abated. The mean force difference between injected and noninjected limbs at all time periods after injection was compared with the difference between limbs a...
Use of lithium dilution and pulse contour analysis cardiac output determination in anaesthetized horses: a clinical evaluation. To assess the suitability of a human algorithm for calculation of continuous cardiac output from the arterial pulse waveform, in anaesthetized horses. Methods: Prospective clinical study. Methods: Twenty-four clinical cases undergoing anaesthesia for various conditions. Methods: Cardiac output (Qt), measured by lithium dilution (QtLiDCO), was compared with a preceding, calibrated Qt measured from the pulse waveform (QtPulse). These comparisons were repeated every 20-30 minutes. Positive inotropes or vasopressors were administered when clinically indicated. Cardiac indices from 30.7 to 114.9 mL...
Macroscopical and histopathological changes in regressing primary and recurrent equine sarcoids during active specific bio-immunotherapy. Healing sarcoids were followed in 18 horses which had taken part in previous clinical studies on a total of 29 horses suffering from either primary or recurrent sarcoids, treated with bio-immunotherapy. In the present study, attention was paid to changes observed in these fibroblastic skin tumours during their regression. The tumours were surgically debulked leaving the base in the skin. The horses were immunized according to bio-immunotherapy at 2- to 4-week intervals with an autogenous vaccine made from the excised part of the tumour until the base had visibly regressed. Healing was followed...
Assessment of a platelet function analyser in horses: reference range and influence of a platelet aggregation inhibitor. The objective of this study was to assess whether a new human platelet function analyser (the PFA-100) could be used to evaluate platelet function in horses and detect acetylsalicylic acid (ASA)-induced platelet dysfunctions. Citrated blood samples from 40 healthy horses were processed to obtain reference values for closure time (CT) using cartridges with collagen-ADP (CT-ADP) and collagen-epinephrine (CT-EPI) as platelet agonists. In addition, CT-ADP and CT-EPI were also measured before and 24 h after oral ASA administration in another 12 healthy horses. The sensitivity and specificity of the...
Evaluation of Lactobacillus pentosus WE7 for prevention of diarrhea in neonatal foals. To evaluate the efficacy of Lactobacillus pentosus WE7, an equine-origin organism with potentially beneficial in vitro properties, as a probiotic for prevention of neonatal diarrhea in foals. Methods: Randomized controlled clinical trial. Methods: 153 foals. Methods: Foals were enrolled at 24 to 48 hours of age and randomly assigned to treatment or control groups. The treatment group received approximately 2 x 10(11) CFU of freeze-dried L. pentosus WE7 orally once daily for 7 days, whereas the control group received a placebo. Clinical monitoring was performed for 14 days. Results: Probiotic a...
Immunologic testing of xeno-derived osteochondral grafts using peripheral blood mononuclear cells from healthy human donors. One means of treating osteoarthritis is with autologous or allogeneic osteochondral grafts. The purpose of this study was to evaluate the innate immunological response in humans toward xeno-derived osteochondral grafts that have been partially or entirely treated by the photooxidation process. Methods: The antigens tested included bovine, porcine, ovine and equine osteochondral samples that have been treated in successive steps of photooxidation. ELISPOT assays were used to evaluate the production of IL-1, IL-4, IL-6, IL-10, IL-12 and TNF-alpha by human monocytes in response to the antigens. R...
Analysis of the strongylid nematodes (Nematoda: Strongylidae) community after deworming of brood horses in Ukraine. Communities of intestinal helminths in horses are commonly studied post mortem. The study objectives were here to examine the species composition of the strongylid community in brood horses in Ukraine after deworming with an aversectin drug Univerm. The site distribution of the strongylid species was analysed according to dynamics of their expulsion in faeces. Forty-four horses of different ages from Poltavska oblast (22 horses), Kyivska oblast (17 horses) and Sumska oblast (5 horses) of Ukraine were included in the study. Horses were treated with Univerm anthelmintic (0.2% aversectin) at a do...
Myosin heavy chain isoforms in equine gluteus medius muscle: comparison of mRNA and protein expression profiles. The major structural protein in skeletal muscle, myosin heavy chain (MyHC), is primarily transcriptionally controlled. We compared the expression of MyHC isoforms on the mRNA and protein level in biopsies from the m. gluteus medius from adult untrained horses. In transverse sections, the majority of fibers showed qualitatively identical mRNA and protein expression patterns. However, coexpression of 2a and 2d/x MyHCs was substantially more common at the protein than at the mRNA level, suggesting a fine-tuning of these two genes in normal muscle not subjected to any training protocol. Because tr...
Temperature changes in dental pulp associated with use of power grinding equipment on equine teeth. To quantify the temperature changes in the dental pulp associated with equine dental procedures using power grinding equipment. Methods: A matrix experimental design with replication on the same sample was followed to allow the following independent variables to be assessed: horse age (young or old), tooth type (premolar or molar), powered grinding instrument (rotating disc or die grinder), grinding time (15 or 20 seconds) and the presence or absence of water coolant. Methods: Sound premolar and molar teeth from a 6-year-old horse and a 15-year-old horse, which had been removed postmortem, wer...
Effect of withholding macromolecules on the duration of intestinal permeability to colostral IgG in foals. To quantify absorption of colostral IgG by healthy neonatal foals and to test the hypothesis that delayed ingestion of macromolecules prolongs the duration of intestinal permeability to immunoglobulins (Ig) in newborn foals. Methods: Thirteen mixed breed foals. Methods: Foals were randomly assigned to two treatment groups, which were fed either a glucose-electrolyte solution or a commercial milk replacer for 12 h after birth, before being fed a known amount of colostral IgG. A control group was fed a known amount of colostral IgG from birth. The efficiency of IgG absorption was calculated foll...
In vivo effect of interleukin-1beta and interleukin-1RA on oocyte cytoplasmic maturation, ovulation, and early embryonic development in the mare. A growing body of evidence suggests that the interleukin-1 system is involved in periovulatory events. Previous work from our lab demonstrated that in the mare, interleukin-1beta (IL-1beta) increases the ovulatory rate of metaphase II oocytes. The present study was conducted to analyze in vivo the effect of IL-1 on oocyte cytoplasmic maturation, ovulation and pregnancy rate. In the present work, IL-1beta (experiment 1, n = 13; experiment 2, n = 25) and interleukin-1RA (IL-1RA; experiment 1, n = 25) were injected intrafollicularly by using the transvaginal ultrasound-guided injection method. In...
A method for deriving displacement data during cyclical movement using an inertial sensor. Biomechanical studies often employ optical motion capture systems for the determination of the position of an object in a room-based coordinate system. This is not ideal for many types of study in locomotion since only a few strides may be collected per ;trial', and outdoor experiments are difficult with some systems. Here, we report and evaluate a novel approach that enables the user to determine linear displacements of a proprietary orientation sensor during cyclical movement. This makes experiments outside the constraints of the laboratory possible, for example to measure mechanical energy ...
A modified surgical technique for repairing third-degree perineal lacerations in mares. A modified surgical technique has been developed for repairing third-degree perineal lacerations in mares. Complications of the currently used methods include rectovaginal fistula formation, urine pooling, complete dehiscence of the repair, constipation, tenesmus and difficulty of performance in the practice. The modified method is simpler and more practical. This method was performed on eight Thoroughbred mares with third-degree perineal lacerations after delivery. The rectovestibular septum was reconstructed by three lines of sutures in a transverse direction in relation to the longitudinal ...
