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.
Brockschmidt LD, Loch WE, Sikes JD.An experiment was conducted to test the effect of repeated transcervical (non-surgical) uterine flushing and a prostaglandin analogue (PG) on the estrous cycle of pony mares. Uteri in group A were trancervically flushed for embryos 7 to 9 days post ovulation. In addition, group B mares were given 5 ml of PG by intramuscular injection on the day of flushing. Group C served as controls and were not flushed or given PG but were allowed to cycle normally. All mares (except controls) were bred A.I. every other day during estrus. There was no effect on embryo recovery rate from repeated flushing or ...
Davies JV, Gerring EL.Small intestinal ischaemia is a cause of pain in man and horses. Occlusion of the vascular supply to Thiry loops in experimental ponies caused severe discomfort and loss of motility within a few minutes but these effects could not be reproduced by a similar procedure in intact gut preparations. However, embolisation of the mural vascular network produced ischaemia of the small intestine of anaesthetised ponies which led to a cessation of motility in the affected segments, though unaffected segments became hypermotile with a characteristic motility pattern. These results suggest the need for re...
Skarda RT, Muir WW, Ibrahim AI.The CSF concentrations of mepivacaine in 10 Standardbred horses and of procaine in 10 Holstein cows given the drugs by thoracolumbar subarachnoid injection were determined. Mepivacaine hydrochloride was injected into the horses (502 +/- 60.5 kg) at an average dosage of 30 mg (1.5 ml of 20 mg/ml solution). Analgesia was produced 7.5 +/- 4.3 minutes after injection, extended between spinal cord segments T13 and L3 on both sides of the spinal column, and lasted 47 +/- 18.7 minutes at the T18 dermatome. Procaine hydrochloride was injected into cows (614 +/- 51.5 kg) at a dosage ranging between 75 ...
Leaper DJ, Foster ME, Brennan SS, Davies PW.Magnetic fields have been considered for treating many ailments over man's history. There have been many anecdotal unsupported claims for successful treatment of soft tissue injury although reports have been more substantive in the orthopaedic field. The widespread clinical and veterinary use of a light self-adhesive magnetic foil in Europe prompted this trial of experimental wound healing. One hundred and sixty Sprague-Dawley rats had a linear 2.5 cm incision or a circular 1 cm skin defect made over the mid-dorsal spine. Equal numbers were randomised to receive either a magnetic foil or a dum...
Sullins KE, Stashak TS, Mero KN.Arteriovenous (ischemic strangulation obstruction, ISO) or venous (hemorrhagic strangulation obstruction, HSO) occlusions were created in the jejunum of 5 anesthetized horses and were left in situ for 1-, 2-, or 3-hour intervals. Segments were evaluated grossly for color, thickness, and motility. The horses were euthanatized, and the degree of mucosal slough, edema, congestion, and hemorrhage was determined histologically. Segments subjected to ISO became dark, but did not contain edema or hemorrhage. Segments subjected to HSO were characterized by progressive congestion, edema, and hemorrhage...
Mirbahar KB, McDonell WN, Bignell W, Eyre P.Pulmonary function tests were performed in seven conscious, standing horses. Changes in pulmonary mechanics and ventilation volumes were measured after inhalation challenge with saline (baseline), histamine (1% w/v solution for 5 min) and carbachol (0.5% w/v solution for 3 min). Comparisons between baseline and posthistamine values revealed a significant (P less than 0.05) increase in nonelastic work of breathing (Wb), maximum change in transpulmonary pressure (max delta Ppl), and pulmonary resistance (RL), while dynamic compliance (Cdyn) decreased (P less than 0.05). Tripelennamine completely...
Mollett TA, Elmore RG, Blanchard TL, Berg JN.This study was conducted to determine if Escherichia coli endotoxin was absorbed from the equine uterus and if exogenous progesterone and estrogen affected the absorption of intrauterine endotoxin. Six mature anestrous pony mares were used in three consecutive crossover experiments (Periods) with a 14 day recovery between each period. Mares were randomly assigned to one of two treatment groups (three mares per group) and received an intrauterine infusion of either saline or endotoxin. Treatment groups were reversed and readministered after 14 days completing a crossover design (Period 1). Duri...
van den Hoven R, Wensing T, Breukink HJ, Meijer AE, Kruip TA.The distribution of type-I and type-II fibers in 9 different parts of the musculi triceps brachii, longissimus dorsi, gluteus medius, and biceps femoris was studied to determine whether biopsies from these muscles give reliable information. All 4 investigated muscles were not homogeneous in their fiber-type distribution. Large differences existed among different muscle parts. The percentage of type-I fibers increased toward the deeper and cranial parts of the muscles. In the same zone of the gluteus muscle, differences of 30% were found for type-I fibers. Therefore, results obtained by biopsie...
Timoney PJ, O'Reilly PJ, McArdle JF, Ward J, Harrington AM.Contagious equine metritis (CEM) was reproduced in 3 of 4 donkey mares with an Irish streptomycin-resistant strain of Haemophilus equigenitalis isolated from an experimental case of the disease in a pony mare. Although some variability in clinical response occurred, there was no evidence that semen enhanced the clinical severity of the infection. Variable amounts of vaginal discharge and associated inflammatory changes of the vagina and/or cervix, similar to those seen in the horse, were observed. All the affected donkeys made spontaneous clinical recoveries and so far as could be detected, su...
Derksen FJ, Scott D, Robinson NE, Slocombe RF, Armstrong PJ.Pulmonary function and airway reactivity to IV histamine were measured in a group of ponies with a history of recurrent airway obstruction (heaves) and their age-, weight-, and gender-matched controls. Ponies were studied during a period of clinical remission (period A), after exposure to a barn environment (period B), and twice during a 2-week recovery phase (periods C and D). At periods A, C, and D, PaO2, dynamic compliance (Cdyn), pulmonary resistance, tidal volume, respiratory frequency, and the log dose of histamine required to reduce Cdyn to 65% of base-line value (log ED65Cdyn) of princ...
Kizaki T, Mizuno Y, Takasawa T, Shiokawa H.Analysis of the quantitative precipitin reaction of acylphosphatase from porcine skeletal muscle with rabbit antiserum indicated the presence of at least two antigenic determinants on the porcine enzyme molecule. Immunological cross-reactivities of acylphosphatases from equine and rabbit skeletal muscles were examined. In double immunodiffusion with the antiserum, the precipitin lines of the porcine and equine enzymes completely fused, while the rabbit enzyme gave no precipitin line. The reaction between the 125I-labeled porcine enzyme and its antibody was inhibited to the same extent by the p...
Bousfield GR, Liu WK, Ward DN.LH hybrids were prepared by combining eLH alpha and eLH beta with the corresponding subunits of oLH, pLH and hCG. Recombinants were isolated by gel filtration and assessed by SDS-polyacrylamide gel electrophoresis under both dissociating and non-dissociating conditions. All combinations of subunits produced hybrid LH molecules. Hybrids prepared by combining eLH beta with oLH alpha, pLH alpha or hCG alpha were very inactive in rat radioligand and Leydig cell in vitro bioassays. Hybrids prepared with eLH alpha were very active in both assays. The greatest potentiating activity was observed when ...
Soma LR, Sams R, Duer W, Tobin T, Woodward C, McDonald J.The plasma and serum concentrations of phenylbutazone (PBZ) and oxyphenbutazone were measured in 158 Thoroughbred horses after various doses of PBZ wer given. All horses were competing or training at racetracks in various parts of the country. All horses used in the study had not been given PBZ 24 hours before they were placed on a specific dosage schedule. Samples were collected 24 hours after the last PBZ administration. Four grams of PBZ were given daily by stomach tube, paste, or tablet for 3 days. On day 4, 24 hours before sample collection, an IV dose of 2 g of PBZ was given, regardless ...
Jeffcott LB, McCartney RN.A simple non-invasive method is described for calculating the transverse apparent velocity of sound of horse bone. This was achieved, both in vivo and at post mortem examination using the metacarpal bone and its covering soft tissue. On 34 post mortem specimens (ie, 68 limbs) from horses older than one year an average measurement of 2802 +/- 37 (1sd) m/sec was obtained. There were changes noted according to age and at different sites on the shaft of the metacarpus. The highest readings were obtained in the proximal shaft where the cortex was thickest. The velocity values gradually decreased to...
Borgsteede FH.A comparison was made of the efficacy of Ivermectin administered as an injection and as a paste. Fourteen horses which were naturally infected with small strongyles were divided into three groups. Animals of group 1 received an injection of 5 ml Ivermectin, equivalent to 500 kg bodyweight, horses of group 2 received one injector with Ivermectin as a paste (for 500 kg body weight), a third group remained untreated as a control. Faecal examinations and larval cultures on the day of treatment and 14, 28 and 42 days later showed that both injection and paste had a 100 percent efficacy against matu...
Németh F, Dik KJ.A sagittal fracture of the navicular bone in five horses was treated by means of lag screw. Intra-operative radiographic monitoring and a specially developed guide apparatus was necessary to implant the screw precisely along the transverse axis of the navicular bone. Internal fixation resulted in progressive radiographic narrowing of the fracture zone. In all five patients the fracture healed (bony union) without superfluous callus formation.
Collier MA, Brighton CT, Norrdin R, Twardock AR, Rendano VT.The effect of a 20-microA direct-current implantable bone growth stimulator (BGS) on bone production with a "gap healing" model in the horse was evaluated. The right and left 4th metatarsal bones (Mt-4) were used in 7 adult horses to create the "gap healing" model. A 4-mm section of the Mt-4 bone was resected bilaterally in each horse. The BGS was surgically placed into the 7 left Mt-4 defects. The 7 right Mt-4 defects served as controls. Six horses survived the 16-week experimental period. Signs of pain, decreased range of limb motion, or lameness was not observed in any animal during the 16 ...
Collier MA, Kallfelz FA, Rendano VT, Krook LP, Schryver HF.The use of capacitively coupled low-voltage signals for stimulation of osteogenesis has been reported in a variety of animal models. Electrically induced osteogenesis was investigated with a capacitively coupled electric field on a radius (distal-lateral orientation) osteotomy model, in conjunction with internal fixation and postoperative loading. Twelve adult horses of either sex were allotted to 2 groups of 6; 1 group was given electrical stimulation and the other served as controls. A low-voltage high-frequency capacitively coupled electrical signal was locally and continuously applied to t...
Turek JJ, Templeton CB, Bottoms GD, Fessler JF.Endotoxic shock was induced in 5 ponies by intraperitoneal injections of 20, 40, 60, 80, and 80 micrograms of Escherichia coli endotoxin (LPS)/kg of body weight at 0, 6, 12, 18, and 24 hours, respectively. At 24 hours, the ponies also were given 20 micrograms of LPS/kg via catheter in the left ventricle of the heart. A 2nd group of 4 ponies was given 1.1 mg of flunixin meglumine (FM)/kg, IV, at 6, 12, 18, and 24 hours just before the corresponding LPS injection. Two hours after the 24-hour LPS injection, the ponies in both groups were anesthetized, the lungs were perfused with fixative, and po...
Diesing L, Steuber S, Ahmed JS.Using luminol-dependent chemiluminescence (LCL), the specificity of antibodies to variable antigen type (VAT)-populations of Trypanosoma evansi was studied in four infected ponies. Trypanosomes of each wave of parasitemia were isolated and multiplied in irradiated mice. Their opsonization by serum collected during the infection was investigated with LCL and results for isolated VAT-populations are shown in the paper. Antibodies specific to each VAT-population were first found three days after the maximum of a parasitemic wave. There was no cross reactivity between different VAT-populations. LC...
DiPietro JA, Todd KS, Lock TF, Reuter-Dallman V.Fifty horses from a herd known to have benzimidazole-resistant small strongyles were treated with febantel (6 mg/kg), combinations of febantel (6 mg/kg) and piperazine citrate (25 or 55 mg base/kg), thiabendazole (44 mg/kg), or placebo (0.6 ml of water/kg). Pretreatment and 7-day posttreatment fecal examinations were done. Fecal cultures, strongyle egg per gram (epg) counts, sugar flotation fecal examinations, and in vitro testing for benzimidazole resistance were performed. Results of fecal examinations before treatment were similar in all horses, and results of testing were positive for benz...
Sullins KE, Stashak TS, Mero KN.In 6 horses, 2 types of ischemic lesions were created in small intestinal segments by selective ligation of vessels and intestinal wall for 1, 2, or 3 hours. After confirming the ischemia by IV injection of sodium fluorescein, the ligatures were released. Five minutes later, the fluorescent patterns were documented photographically. Observed patterns ranged from normal (identical to that observed in unaffected bowel) to a patchy distribution of non-fluorescence (indicating incomplete perfusion). None of the experimental segments was normal when reevaluated 1 month later. The typical appearance...
Draeger J, Köhler L, Winter R.The larger the corneal graft, the more difficult is the excision of the button and especially suturing of the graft. The instruments and microsurgical unit are adapted to size and dimensions of animal surgery. The mathematical correlation between the diameter of the graft, the thickness of the cornea, and the length of the wound edges and suturing material can be calculated.
Becker M.During the last 10 years 268 laparotomies by a midline incision were performed. A high incidence of seromas, fistulas caused by suturing material and wound ruptures were observed. After finding only a small number of publications in the veterinary medicine about wound healing disturbances an analysis of the human medical literature was done. This induced the change of our surgical procedure and suturing technique: The midline incision and surgical management during the laparotomies in 14 horses suffering from colic were performed by a minimized trauma. The abdominal wall was closed layer by la...
Aguado LI, Ojeda SR.During the days preceding the first ovulation the ovary of the rat exhibits a remarkable increase in estradiol (E2) and progesterone (P) release in response to gonadotropins. No such increase is observed in the case of androgens (A, testosterone + dihydrotestosterone). The present experiments were undertaken to examine the possibility of reproducing these developmental events by stimulating the ovary with a gonadotropin that has substantial FSH-like activity. In vivo administration of pregnant mare serum gonadotropin (PMSG) to juvenile 29-day-old rats greatly increased the in vitro E2 and A re...
Lindberg R, Karlsson L.The jejunal mucosa of 4 cases of equine granulomatous enteritis and 2 control horses was investigated by light microscopy and by scanning and transmission electron microscopy. Attention was focused upon changes in mucosal topography and enterocyte morphology in the inflamed mucosa. Structural changes ranged in severity from only a slight thickening and shortening of villi to the appearance of a virtually flat mucosa, upon which crypts opened directly or through shallow cavities encircled by collars of epithelial cells. Between these extremes, the mucosa showed a variety of patterns, all charac...
Baggot JD, Love DN, Rose RJ, Raus R.The serum concentrations of the aminoglycosides neomycin, kanamycin and streptomycin were determined after intravenous (iv) and intramuscular (im) administration. These values were then related to the minimum inhibitory concentrations (MIC) of a number of equine pathogenic bacteria to determine the duration of therapeutic serum concentrations of the aminoglycosides in the horse. Pharmacokinetic analysis of the data using neomycin as the example revealed a mean (+/- sd) peak serum concentration of 23.2 +/- 10.2 micrograms/ml present at 30 mins, and at 8 h the serum concentration was 2.8 +/- 0.8...
Martens JG, Stephens KA, Kerchner LJ, Heck FC, Martens RJ.Plasma fibronectin concentrations were measured in clinically healthy mares and their neonatal foals, using a modified human fibronectin competitive enzyme-linked immunosorbent assay. Ranges of plasma fibronectin were established in clinically healthy horses, and the assay was reliable and reproducible. Plasma fibronectin concentrations were similar in mares and foals, both before and after colostrum ingestion.
Solter PF, Farner S.The purpose of this study was to compare 2 different nonradioactive assay methods with a conventional radioimmunoassay (RIA) measuring the concentration of serum thyroxine (T4) in horses. Serum was obtained from 85 adult standardbred horses. The T4 concentration of each sample was analyzed by RIA, chemiluminescent enzyme immunoassay (CEI), and homogeneous enzyme immunoassay (HEI). The correlation between the HEI method and RIA method was significantly greater (r = 0.89) than the correlation between the CEI and the reference method (r = 0.53). In addition, the precision of the HEI method was si...
Knickelbein KE, Lassaline ME, Kim S, Thomasy SM.The iridocorneal angle (ICA) is the major pathway of aqueous humour outflow from the anterior chamber of the eye. Ultrasound biomicroscopy (UBM) has been utilised to characterise the morphology of this drainage pathway in numerous species. UBM may allow for early recognition of aqueous humour outflow obstructions in horses, allowing for earlier recognition of risk for glaucoma, a vision-threatening and painful disease. UBM morphology of the normal equine ICA has yet to be described. Objective: To determine the ultrasonographic morphology of the equine ICA by UBM in standing sedated horses. Met...
Magilton JH, Swift CS, Ghoshal NG.The heads of 5 ponies were embalmed and the vessels were double injected with latex. Dissection of these specimens revealed venous pathways (1) from the nasal area to the cavernous sinus and (2) from the parietofrontal region to the ventral petrosal sinus. Thermistors were chronically implanted near the orbital emissary veins of 3 additional ponies. Hot and cold packs were applied alternately to the parietofrontal regions. The temperature near the orbital emissary veins increased during the 5 trials with cold application and decreased during the 5 trials with hot application. The authors were ...
Schmotzer WB, Hultgren BD, Huber MJ, Watrous BJ, Riebold TW, Wagner PC, Shires GM.The efficacy of eliminating parotid salivary secretions by retrograde infusion of 10% formalin, 2% chlorhexidine, or 2% or 3% silver nitrate solutions was evaluated in 10 horses. Solutions were kept within the parotid salivary gland for 90 seconds after infusion through parotid duct cannulae and then allowed to drain freely. Severed parotid ducts and surgical incisions were left to heal by second intention. All agents eliminated glandular secretions. There was less necrosis and suppurative inflammation after formalin infusion than after chlorhexidine and silver nitrate. Silver nitrate (2% and ...
Rabbogliatti V, De Zani D, Zani DD, Di Cesare F, Brioschi FA, Gioeni D, Crivellari B, Ravasio G.To compare the peribulbar injectate distribution and probability of regional anaesthesia of four peribulbar anaesthetic techniques in equine cadavers. Methods: Prospective experimental cadaver study. Methods: A total of 12 isolated equine cadaver heads and 24 eyes. Methods: The 24 orbits underwent one of four injection techniques (six orbits each) with a mixture (1:4) of contrast medium and saline (CM): 20 mL ventrolateral peribulbar injection (V-20), 20 mL dorsolateral peribulbar injection (D-20), combined ventrolateral and dorsolateral peribulbar injections 10 mL each (VD-20) or 20 mL each (...
Bedford SJ, Hinrichs K.It has recently been reported that large insemination volumes might affect fertility of mares. The results from these studies are confounded by other factors, however, such as inadequate number of spermatozoa in the inseminate. We conducted a study to test whether volume alone affects fertility when sufficient numbers of spermatozoa are present. Semen from one stallion was collected, extended at 50 x 10(6) spermatozoa/ml, and stored in a commercial semen cooling device for 18 to 30 h before insemination. Ten pony mares were assigned during estrus in random pairs to be bred every other day with...
Giguère S, Prescott JF.The remarkable ability of the horse and other animals to prevent infection by most bacterial pathogens encountered is the result of a complex set of distinct but overlapping defense mechanisms. This article summarizes the current state of knowledge on innate and adaptive immunity to bacterial pathogens and reviews various ways in which some bacteria have evolved in order to evade components of the host response.
Homburg-van den Broek FT, Rutgers LJ.It was found that wound infections may be considerably reduced when castration is carried out under strictly aseptic conditions. In this clinical review, healing of the wound following castration with and without closure of the scrotal wounds is compared. All castrations were performed under similar aseptic conditions, general anaesthesia having been produced in the recumbent stallion. The results do not show that there is a significant difference in the appearance of wound infections in scrotal wounds which are closed and those which are left completely open. On the basis of both papers and t...
Nourian AR, Mills PC, Pollitt CC.Intraosseous (i.o.) infusion of the distal phalanx (IOIDP) as a delivery route targeting hoof lamellar tissue of standing, conscious horses was evaluated. Following sedation and regional nerve blockade in six Standardbred horses, a microdialysis (MD) probe was implanted into the hoof lamellar tissue of one forelimb. A purpose designed cannulated bone screw was introduced into the body of the distal phalanx, approximately 6 cm from the MD probe. Gentamicin solution (25 mg/mL) was infused at 20 microL/min through the bone screw for 2 h without the application of a tourniquet. MD and blood sample...
Pilsworth RC.Pelvic fracture is a relatively common spontaneous fracture in thoroughbred racehorses. Its diagnosis can be difficult, and radiography in the acute phase carries the risks associated with anaesthesia and recumbency. This paper describes the use of a hand-held probe for point counting after the injection of technetium-99m in the investigation of four cases of pelvic fracture. The level of increased uptake of radioactivity was lower (40 to 61 per cent increase) than for distal limb bone fractures.
Tranchina MM, Scott DW, McDonough SP.Summary A small population of resident T lymphocytes is present in the healthy human and murine epidermis. However, resident epidermal lymphocytes have not been reported in normal skin of the horse. Skin biopsy specimens from the normal skin of 27 horses were examined histologically and immunohistochemically for the presence of lymphocytes, CD3+ cells and BLA.36+ cells in epidermis and adnexal epithelia. All examinations were negative. It appears that lymphocytes occur rarely, if at all, in the epidermis and adnexal epithelia of normal horse skin. Hence, the presence of lymphocytes in these st...
Divers TJ, Mongodin EF, Miller CB, Belgrave RL, Gardner RB, Fraser CM, Schutzer SE.Antemortem diagnosis of neuroborreliosis in horses has been hindered by both the low sensitivity of PCR testing for in CSF and the low specificity of serum:CSF ELISA ratios used to determine intrathecal antibody production against the bacterium. PCR testing of the CSF of an adult horse with acute neurologic disease for the flagellin gene was negative. However, we enriched DNA through nucleic acid hybrid capture, followed by next-generation sequencing, and identified in the CSF of the horse, confirming a diagnosis of neuroborreliosis.
Theoret CL, Grahn BH, Fretz PB.Atresia of the nasal punctum is the most common congenital anomaly for the equine nasolacrimal system. Nasomaxillary dysplasia has not been previously documented in foals, is of unknown etiology, and appears to be a rare condition. Conjunctivomaxillary sinostomy was successful in resolving the epiphora.
Lyons ET, Drudge JH, Tolliver SC.Critical tests were conducted in 14 naturally infected equids (13 horses and 1 pony) to evaluate the antiparasitic activity of haloxon. Single doses were administered by stomach tube to 3 horses and 1 pony (60 mg/kg of body weight), by addition to the feed of 3 horses (60 mg/kg), and intraorally by powder gun to 7 horses (65 mg/kg). Haloxon was efficacious (99% to 100%) against infections of Parascaris equorum, Oxyuris equi (mature and immature), and Strongylus vulgaris at both dosage levels. Probstmayria vivipara parasites were removed in 1 horse treated at 60 mg/kg by stomach tube and S equi...
Cogley TP, Cogley MC.A synthetic alpha-2 adrenergic agonist, detomidine hydrochloride, was used in the study of in vivo activity of Gasterophilus intestinalis (Diptera: Gasterophilidae) during migration in the tongue of the horse. Use of the drug allowed the investigator to manipulate the tongue and closely observe the movement patterns and tissue disturbance caused by burrowing first-stage larvae. Detomidine hydrochloride should be utilized in studies of drug efficacy and larval biology, whenever possible, to avoid the need to sacrifice the horse.
Puppione DL, Della Donna L, Bassilian S, Souda P, MacDonald MH, Whitelegge JP.As a continuation of our proteogenomic studies of equine apolipoproteins, we have obtained molecular masses for several of the apolipoproteins associated with the HDL in horse cerebrospinal fluid (CSF). Using electrospray-ionization mass spectrometry (ESI-MS), we report on values for apolipoproteins, A-I and A-II, as well as acylated apoA-I. In comparison with our previously published data on equine plasma apolipoproteins, there appears to be a higher percentage of acylated apoA-I in the CSF than in plasma. As was the case in plasma, apoA-II circulates as a homodimer. These studies also reveal...
Doležal P, Doležalová J, Morávková T, Stupka R.In 2018, more than 50 cases of horse death by equine atypical myopathy (AM) were reported in the Czech Republic. This disease is often associated with the toxin hypoglycine A (HGA), which is found in several maple plant materials. To monitor this toxin in products of these trees that grow in or around horse pastures, a rapid and inexpensive analytical method that can provide the required accuracy is needed. Until now, maple samples have been prepared for gas chromatography using time-consuming methods, with preparation processes taking longer than 1 h. In this work, a shorter method (25 mi...
Davison KL, Rowe LD, Witzel DD.To measure absorption of monensin or its metabolites and its elimination from the body, [14C]monensin sodium was given orally (1 mg/kg body wt) to two bile-fistulated ponies and iv (8.7 mg) to one bile-fistulated pony. For one orally-dosed pony, 4.7% of the 14C was eliminated in bile, 52% in feces, .7% in urine and 33% remained in the gastrointestinal (GI) tract after 3 d. Total 14C recovery was 90%. For the other orally-dosed pony, 18.3% of the 14C was eliminated in bile, 69% in feces, 1.7% in urine and 7% remained in the GI tract after 4 d. Total 14C recovery was 98%. For the iv-dosed pony, ...
Oldenkamp EP.A suspension based on the antibiotic, natamycin, was applied by sponging to 83 horses of various breeds and ages with signs of clinical ringworm. A number of different causative agents were involved of which Trichophyton equinum was the most common. Treatment successfully eliminated the disease within 4 weeks. After treatment the recovered animals did not show any evidence of re-infection for up to 6 months. The mycological clearance rate was 97 per cent and apart from the efficacy against ringworm, the preparation had the advantage of being non-irritant and odourless. It was also useful for t...
Kay AD, Lavoie JP.A technique was developed for recording urethral pressure profiles (UPP) in mares. Profiles were obtained from 12 clinically normal mares and from 3 mares with urinary incontinence. Variables measured on the profile included intravesicular pressure and maximal urethral closure pressure. The mean maximal urethral closure pressure of the incontinent mares was significantly less (P less than or equal to 0.001) than that of the normal mares. The technique is simple and reliable for objectively evaluating urethral pressures in mares.
Michell AR, Taylor EA.In the presence of vanadate, the optimum pH of renal (Na+, K+)-ATPase in rats is reduced and lies in the range of intracellular pH. This explains the difference in optimum pH observed with ATP extracted from equine muscle. Removal of vanadate from such ATP (with noradrenaline) raises the optimum to the accepted range obtained with synthetic ATP. Changes in the sensitivity of the enzyme to potassium concentration contribute to the alterations in optimum pH. The optimum pH of Mg-ATPase is unaffected by vanadate. Since vanadate may be an intracellular regulator of (Na+, K+)-ATPase changes of opti...
Coffman JR, Johnson JH, Tritschler LG, Garner HE, Scrutchfield WL.Fourteen horses (7 treated with orgotein and 7 treated with a placebo) with navicular disease were studied on a double blind basis. All 14 horses had clinical and radiographic evidence of navicular disease. Orgotein and the placebo were administered by juxtabursal injection. Of the 7 orgotein-treated horses, 3 responded but none of the 7 placebo-treated horses responded. The difference was statistically significant (P less than 0.05).
Smith HJ.From 1967--1978 observations were made on the presence of the small equine pinworm, Probstmayria vivipara, in seven experimental ponies. The life cycle of this nematode is unusual in that it is endogenous with development of all stages occurring within the host's digestive tract. Initially, worms were found in the feces of four of seven ponies following treatment with thiabendazole but the infection was later transmitted to all ponies possibly via coprophagy. Still later, based on fecal and postmortem examinations, four of the seven ponies lost their pinworm burdens. At necropsy, the principal...
Ginther OJ, Pinaffi FL, Rodriguez MB, Duarte LF, Beg MA.During the luteolytic period in mares, the peak of 65% of pulses of a PGF2α metabolite (PGFM) and the peak of a pulse of PRL have been reported to occur at the same hour. It is unknown whether the synchrony reflects an effect of PGF2α on PRL or vice versa. Controls, a flunixin meglumine (FM)-treated group (to inhibit PGF2α), and a bromocriptine-treated group (to inhibit PRL), were used at 14 days postovulation in June and in September (n = 6 mares/group/mo). Blood samples were collected hourly from just before treatment (Hour 0) to Hour 10. Concentrations of PGFM in the FM group were lower ...
Scheel J, Duswald KH, Ring J, Seifert J, Scholz S, Brendel W.Eight mongrel dogs received a standard daily i.v. infusion of 20 mg/kg b.w. deaggregated horse-anti-dog-lymphocyte-globulin (ALG) and additional prednisolone (1 mg/kg b.w. daily i.v.) over a maximum period of 82 days following pretreatment with deaggregated normal horse IgG. No sensitization against horse protein was observed during therapy of afterwards as proved by lack of humoral antibodies against horse antigens, maintained lymphopenia, good compatibility, longterm prolongation of xenogeneic skin graft survival (85.6+/-20.6 days, n=8' untreated controls 12.5+/-1.3 days, n=4) and longterm s...
Shand N, Alexander SL, Irvine CH.For aqueous extracts of pituitary glands of oestrous mares, luteinizing hormone (LH) profiles were found to be similar to each other and to earlier work after chromatofocussing (CF) and isoelectricfocussing (IEF). After CF, both LH and follicle-stimulating hormone (FSH) in pituitary extracts focussed in multiple peaks in the acidic range, with 86% of LH and 80% of FSH found between pH 4 and 6. By contrast, in pituitary venous plasma, only 18% of the LH focussed in this range, whereas a significantly greater proportion (P less than 0.01) eluted above pH 7 than occurred in pituitary extracts (37...
Purcell SH, Seidel GE, McCue PM, Squires EL.The aim of this study was to compare the efficacy of three approaches for recovering equine oocytes via transvaginal ultrasound-guided follicular aspiration. Fourteen mares were used as oocyte donors during the spring transition period and physiologic breeding season, and 11 mares were bred for use as oocyte donors during early gestation. In all mares, large (>20 mm) and small (10-20 mm) follicles were aspirated in eight rounds every 10-11 days. In each of the four rounds during the transition period, half the mares received 12.5 mg eFSH once daily for 4 days prior to aspiration. For each of t...
Attenburrow DP, Flack FC, Portergill MJ.The technique of impedance plethysmography is described and its application to observation of lung volume changes in the horse at exercise is discussed. The results from horse at rest show that there is a close relationship between rate of lung volume change (flow rate) and the associated impedance changes during both inspiration and expiration. Impedance changes during exercise were related to inspiration and expiration by observation of associated respiratory sounds. Artefacts related to technical difficulties are also indicated.
Edwards GB, Jones DG.The use of a thermoplastic linear polyester polymer orthopaedic tape in the treatment of six horses, one donkey and a bull with a variety of orthopaedic problems requiring immobilisation of a limb is described.
