Ponies are members of the Equidae family and share many physiological and anatomical characteristics, yet they are distinguished by several key differences. Ponies are generally smaller in stature, with a height at the withers of 14.2 hands (58 inches) or less, while horses exceed this height. In addition to size, ponies often exhibit a stockier build, thicker manes, tails, and coats, and a greater bone density compared to horses. These differences can influence their suitability for various tasks and environments. This topic encompasses a collection of peer-reviewed research studies and scholarly articles that explore the genetic, phenotypic, and behavioral distinctions between ponies and horses, as well as their implications for breeding, management, and performance in equine disciplines.
Spurlock GH, Spurlock SL.A 3-year-old Welsh pony mare was referred for evaluation of right hind limb lameness. The lameness developed 4 months after the pony had been captured by use of a projectile dart syringe to administer a tranquilizer. The lameness was attributable to a projectile dart foreign body. The dart was removed after induction of local anesthesia, and the lameness improved. The use of projected syringes has inherent risk, and clients should be advised before they are used.
Riemersma DJ, Schamhardt HC, Hartman W, Lammertink JL.Loads on the suspensory ligament, deep digital flexor tendon, superficial digital flexor tendon, and long digital extensor tendon of the equine hind limb were determined in ponies by use of implanted strain gauges consisting of silicone rubber tubes filled with mercury. Recordings were made simultaneously with force plate measurements and high-speed film recordings while the ponies were walking. The relationship between strain gauge signals and tendon loads was obtained from tension-strain tests performed after death of the ponies. The suspensory ligament and the 2 digital flexor tendons were ...
Boudreaux MK, Wagner-Mann C, Purohit R, Hankes G, Spano J, Pablo L, Lee S, Conti J.Platelet isolation techniques and platelet function were evaluated in 35 adult ponies. Platelet recovery from whole blood was consistent and the preparation of platelet rich plasma was facilitated by an enhanced erythrocyte sedimentation rate. All platelet samples aggregated in response to 10 microM ADP. However, concentrations of ADP as high as 100 microM did not elicit significant 14C-serotonin release. Collagen induced irreversible platelet aggregation and 14C-serotonin release in all samples. The threshold dose for collagen in most ponies was 1.5 micrograms. Arachidonic acid (500 microM) f...
Riemersma DJ, van den Bogert AJ, Schamhardt HC, Hartman W.Strains of the suspensory ligament and deep digital flexor, superficial digital flexor, and long digital extensor tendons in the equine (pony) hind limb were recorded in vivo, using implanted strain gauges consisting of silicone rubber tubes filled with mercury. The relationship between strain gauge signals and tendon strains was obtained from tension-strain tests performed on isolated tendons after death of the ponies. During normal walking, maximal tendon strain (elongation over initial length, relative to the length of the structures at first ground contact) was 3.1% in the suspensory ligam...
Shirer HW, Erichsen DF, Orr JA.Previous reports indicate that intravenous infusion of HCl can alter breathing and blood pressure even if reductions in systemic arterial pH are prevented. To extend these findings, as well as to determine whether other acids elicit comparable results, this report compares the cardiopulmonary response between right atrial infusion of lactic acid and HCl in awake ponies. Lactic acid, infused at a dose of 1.5 mmol/kg over 18 min, lowered systemic and pulmonary arterial pH 0.062 and 0.092 U, respectively, and increased pulmonary arterial pressure (delta Ppa, 4 mmHg), heart rate (HR, 4/min), and t...
Wilson DV, Suslak L, Soma LR.Cardiovascular effects and pulmonary gas exchange were compared during conventional mechanical ventilation (CMV) and interrupted high-frequency, positive-pressure ventilation (IHFPPV) in 6 anesthetized ponies in dorsal recumbency. When the peak airway pressure (Paw) was held constant at control values attained during CMV (18 to 20 cm of H2O), and the ventilator frequency of IHFPPV was varied over the range, 2.5 to 12.5 Hz, significant (P less than 0.05) changes from control values were observed only in the ratio of dead-space volume to tidal volume (VD/VT) and in the respiratory minute volume ...
Scott JS, Garon H, Broadstone RV, Derksen FJ, Robinson NE.We examined the response of five ponies with recurrent airway obstruction (principals) and five age- and gender-matched controls to the aerosol alpha-adrenergic agonist phenylephrine after blockade with propranolol and atropine. Measurements were made with principal ponies in clinical remission (period A) and during acute airway obstruction (period B). The blockade had no effect on base-line pulmonary mechanics in control ponies during periods A and B or in the principal ponies during period A. However, in the principal ponies during period B, blockade increased dynamic compliance (Cdyn) and d...
Goodson J, Tyznik WJ, Cline JH, Dehority BA.Microbial numbers, pH, fluid volume, and turnover rate in the pony cecum were measured during an abrupt change from an all-forage to an all-concentrate diet, both fed at maintenance energy levels. Concentrate feeding resulted in increased (P less than 0.01) numbers of total viable anaerobic bacteria. The numbers of organisms growing on selective starch medium increased (P less than 0.01) when concentrate was fed, while numbers on xylan and pectin media decreased (P less than 0.025). Seven days after the diet change to concentrate, the number of bacteria growing on lactate medium increased (P l...
Art T, Lekeux P.The exercise-induced changes in the equine breathing pattern were studied by analyzing tidal breathing flow-volume loops recorded in ten ponies both at rest and during a standardized exercise. Airflow, tidal volume, esophageal pressure and mask pressure were simultaneously recorded before, during and after a treadmill exercise. From the collected data, respiratory frequency and total pulmonary resistance were calculated, tidal breathing flow-volume loops were retraced using a computerized method and loop indices were measured for each period of the experimental protocol. For each pony, results...
Stick JA, Arden WA, Chou CC, Parks AH, Wagner MA, Johnston CC.Using isolated autoperfused intestinal segments, the effects of flunixin meglumine administration on systemic arterial blood pressure, jejunal blood flow, vascular resistance, motility, arteriovenous oxygen difference, and oxygen consumption were determined in 10 anesthetized ponies ventilated with a mixture of halothane and oxygen. Saline solution or flunixin meglumine (1.1 mg/kg of body weight) was infused as a single bolus into the left jugular vein. By 10 minutes, flunixin meglumine increased systemic arterial blood pressure and increased intestinal vascular resistance. The jejunal blood f...
Davis JL, Manohar M.Large increases in systemic and pulmonary arterial pressures of exercising healthy ponies have been observed. Because exercise causes a considerable increase in PCV of ponies, we examined the effect of splenectomy on exercise-induced changes in systemic and pulmonary pressures. These pressures (taken with catheter-tip micromanometers) and indicator dilution cardiac output were determined on 9 healthy ponies that had undergone splenectomy 4 to 9 weeks before the study. Data obtained at rest and during submaximal (10.5 to 11.0 mph) and maximal (14 to 15 mph) exercise from these ponies were compa...
Eysker M, Boersema JH, Kooyman FN, Berghen P.To determine resistance of small strongyles to albendazole, 3 female ponies (group 1) were grazed on a pasture from May to November 1985 and were treated with 7.5 mg of albendazole/kg of body weight, PO, 2 days before turnout in May and again in June and in July. Three other female ponies (group 2) grazed on a similar pasture from May to July, were treated with 7.5 mg of albendazole/kg, and were removed to another pasture until November. In December, ponies from both groups were treated with 7.5 mg of albendazole/kg, and 8 days later, they were euthanatized and necropsied for a critical test. ...
Art T, Serteyn D, Lekeux P.Pleural, tracheal, pharyngeal and mask pressures as well as airflow and tidal volume of five ponies on a treadmill (incline 8.3 degrees) were recorded simultaneously while resting, walking, trotting slowly, trotting fast, after standing for 30 secs and 5 mins after the end of the exercise. The curves obtained were used to calculate total pulmonary resistance (RL), lower airway resistance (RLA) and upper airway resistance (RUA). The latter was also divided into nasal resistance (Rnas) and laryngeal plus extrathoracic tracheal resistance (Retr + lar). Furthermore, the inspiratory and expiratory ...
Morris DD, Messick J, Whitlock RH, Palmer J, Ward MV, Feldman BF.Hemostatic function was determined in 10 ponies at various times after inoculation with Ehrlichia risticii to determine whether equine ehrlichial colitis (EEC) caused changes in the hemostatic system and to determine the prognostic value of hemostatic function tests during EEC. Mean platelet count; plasma fibrinogen, fibronectin, factor VIII: coagulant, alpha 2-antiplasmin, and plasminogen values; and serum concentrations of fibrin/fibrinogen degradation products changed significantly (P less than 0.05) from base line (day 0, before inoculation) during 18 days after inoculation with E risticii...
French DD, Klei TR, Taylor HW, Chapman MR, Wright FR.The efficacy of ivermectin in oral paste formulation at a dosage of 200 micrograms/kg of body weight was tested against naturally acquired larval and adult stages of Parascaris equorum, in a controlled study. Twenty infected pony foals 18 to 27 weeks of age were randomly allocated to 2 groups of 10 each and were placed in dry lots. Foals in 1 group were given ivermectin on day 0. Necropsies and parasite recoveries from small intestines and lung tissues were performed on 5 foals in each group at 2 weeks after treatment (WAT) and on the remaining foals at 5 WAT. Ivermectin was 100% effective aga...
Derksen FJ, Robinson NE, Scott JS, Stick JA.Ponies with recurrent airway obstruction (principal ponies) and their controls were given aerosolized Micropolyspora faeni antigen via endotracheal tube during a period when the principal ponies were in disease remission. In both groups of ponies, we performed bronchoalveolar lavage (BAL) and measured pulmonary function at base line, and 5 hours after aerosol administration of 30 ml of 0.9% NaCl solution or 30 ml of 1% w/v particulate M faeni antigen in 0.9% NaCl solution. In both groups of ponies, aerosolized M faeni antigen increased WBC count, neutrophil numbers, and albumin concentration i...
Freeman DE, Gentile DG, Richardson DW, Fetrow JP, Tulleners EP, Orsini JA, Cimprich R.Strangulation obstruction was induced in anesthetized ponies for periods of 2 and 3 hours by clamping 45-cm segments of jejunum and associated veins (venous strangulation obstruction) and arteries and veins (arterial and venous strangulation obstruction). Four segments were studied in each of 7 ponies allowed to survive 12 hours, 2 segments in a pony that was allowed to survive 1 hour, and 1 segment in each of 10 ponies allowed to survive 42 days after the strangulation periods ended. Fifteen minutes after the periods of strangulation obstruction ended, the viability of test segments was asses...
Freeman DE, Cimprich RE, Richardson DW, Gentile DG, Orsini JA, Tulleners EP, Fetrow JP.Strangulation obstruction was induced in anesthetized ponies for periods of 2 and 3 hours by clamping 45-cm segments of jejunum and their veins only (venous strangulation obstruction, VSO) and arteries and veins (arterial and venous strangulation obstruction, AVSO). These types of strangulation obstruction were studied in 4 segments in each of 4 ponies allowed to survive 12 hours (group 1) and in a single segment in each of 10 ponies allowed to survive 42 days (group 2) after the strangulation period ended. On visual inspection, segments subjected to VSO had hemorrhage and edema in the bowel w...
Schneider RK, Meyer DJ, Embertson RM, Gentile DG, Buergelt CD.Peritoneal lavage was performed on ponies to determine the effect on peritoneal surfaces. Lavage solution (20 L) was introduced into each pony's peritoneal cavity through catheters placed in the paralumbar fossa, and the solution was removed by drainage from the ventral portion of the abdomen. Six ponies each were lavaged with sterile saline (0.9% NaCl) solution, sterile saline solution containing 5 X 10(6) U of potassium penicillin and 3 g of neomycin or povidone-iodine diluted to 3% by volume with sterile saline solution, and 3 ponies were lavaged with povidone-iodine diluted to 10% with ste...
Scott JS, Broadstone RV, Derksen FJ, Robinson NE.Ponies with recurrent airway obstruction have hyperresponsive airways during acute disease exacerbations but not during clinical remission. We examined the effect of beta-adrenergic blockade with propranolol on airway responsiveness to aerosol histamine in six ponies with recurrent airway obstruction and six age- and gender-matched controls. Measurements were made with principal ponies in clinical remission (period A) and during an acute period of airway obstruction (period B). beta-Adrenergic blockade did not change airway responsiveness, dynamic compliance (Cdyn), or pulmonary resistance (RL...
Watney GC, Hall LW, Jordan C, Nolan AM.The effects of xylazine (an alpha 2-adrenoceptor agonist) and acepromazine (an alpha-adrenoceptor antagonist) on bronchomotor tone were investigated in seven anaesthetised, apnoeic ponies using a computer aided forced oscillation technique, which separates changes in bronchial calibre from changes in lung volume. Both agents produced bronchodilatation and a decrease in lung volume.
Taylor FG, Mair TS, Brown PJ.Equine steatitis is a rare condition which is usually reported in foals. A case of generalised steatitis in an adult pony mare is described and compared with steatitis in other species. It is concluded that the condition resembled that recorded in foals but that its aetiopathogenesis remains obscure.
McNeill-Wiest DR, Thompson DL, Wiest JJ.Twelve long-term ovariectomized (OVX) pony mares were used to determine the effects of dexamethasone (DEX) or progesterone (PR) on concentrations of follicle stimulating hormone (FSH) and luteinizing hormone (LH) in daily blood samples and after administration of gonadotropin releasing hormone (GnRH). All mares were subsequently administered dihydrotestosterone (DHT) to determine if DEX or PR treatment altered the FSH or LH response to this androgen. Daily blood sampling was started on day 1. After a pretreatment injection of GnRH on day 5, four mares were administered DEX at 125 micrograms/kg...
Ball BA, Shin SJ, Patten VH, Garcia MC, Woods GL.Pony mares which were detected pregnant by transrectal ultrasonography received a single intrauterine infusion of either sterile saline (control, n = 12 mares) or 10(6)Candida parapsilosis (treated, n = 12 mares) between Days 11 to 14 postovulation. Subsequent embryonic loss was studied by daily ultrasonography of the mare's uterus, by serum progesterone levels, by endometrial swabs for cytologic and microbiologic examination and by endometrial biopsies that were taken after embryonic loss was detected. Significantly fewer (P<0.01) embryonic losses occurred in control than in treated mares (4 ...
Anderson WI, Picut CA, Georgi ME.Heavy renal infection in a pony with Klosiella equi resulted in moderate diffuse tubular nephrosis and tubular rupture. Multifocal non-suppurative interstitial nephritis was associated with ruptured tubules. Ultrastructural examination of sporoblasts demonstrated both the presence of a bilaminated membrane encasing organisms and nuclear budding. Endogenous corticosteroid production probably led to the development of an immune-compromized state and subsequent extensive parasitic replication.
Bessent C, Ginther OJ.The caracteristics of early intrauterine mobility of the conceptus were compared between ponies (n = 9) and donkeys (n = 9). The extensive mobility of the early conceptus, previously reported for ponies and horses, was found in donkeys as well. There were no significant differences between donkeys and ponies in the characteristics or patterns of mobility. However, the mean day of fixation was approximately one day later (P<0.05) in donkeys (Day 15.6 +/- 0.3) than in ponies (Day 14.7 +/- 0.2).
Shappell KK, Stick JA, Derksen FJ, Scott EA.Between 1981 and 1986, permanent tracheostomy was performed in 46 ponies and 1 adult Quarter Horse. Tracheostomies of 19 ponies and the horse were examined in June 1986 and evaluated for vertical length of stomal orifice (mean = 25.0 +/- 4.7 mm in the ponies and 55 mm in the horse), degree of tracheal obstruction (0/20), regrowth and apposition of epidermis (3/20), and whether or not stomal airflow occurred with nasal occlusion (20/20). In addition, the animals were evaluated to determine whether dyspnea developed during exercise. Records of 27 ponies were evaluated. Six of the 27 were not dys...
Stolk PW, Firth EC.Intra-osseous pressure was measured in the third metatarsal bone of 8 pony foals at the age of 1, 3, 6 and 26 weeks of age, and on one occasion in the third metatarsal bone of 5 ponies aged 1-5 years; the animals were under general anesthesia and in lateral recumbency. Saphenous venous pressure and lateral superficial plantar metatarsal arterial pressure were also monitored throughout the procedure. There were no statistically significant changes in the epiphyseal, diaphyseal, venous or arterial pressures with increasing age of the foals. There was no statistically significant difference betwe...
Sojka JE, Adams SB, Lamar CH, Eller LL.Effect of butorphanol, pentazocine, meperidine, and metoclopramide on jejunal and pelvic flexure myoelectric and mechanical activity in 4 female ponies was investigated. The agent to be tested or saline solution was administered IV at the start of a 6-hour recording trial. In the jejunum, duration between activity fronts of regular spiking activity, defined as the length of the migrating myoelectric complex (MMC), was measured. The average duration of the MMC during control trials was 150 +/- 46 minutes. The average duration of the MMC after meperidine, butorphanol, pentazocine, and metoclopra...
Pierson RE, Sahu SP, Dardiri AH, Wilder FW.Contagious equine metritis was reproduced experimentally in 6 pony mares. The disease was characterized by rapidly developing cervicitis and by varying amounts of exudate. The exudate, apparent as early as 48 hours after inoculation, drained from the cervix as a tenacious, mucopurulent discharge for several days, then rapidly disappeared. In all mares, the clinical disease cleared within several weeks of inoculation, without treatment.
Weitkamp LR, Costello-Leary P, Guttormsen SA.Polymorphism for two autosomal alleles of equine plasminogen, PLG1 and PLG2, was demonstrated in plasma by isoelectric focusing and immunofixation, with a goat anti-human plasminogen antibody. The frequency of PLG2 was 0.16 in 150 Standardbreds, 0.20 in 96 Thoroughbreds, and 0.39 in 32 Shetland ponies. No evidence for linkage of PLG with any of 13 marker loci was found.
Wyn-Jones G, Baker JR.The presenting signs exhibited by a pony with a large diaphragmatic defect of probable developmental origin are described. The results of clinical examination, laparotomy and post mortem examination are presented.
Coignoul FL, Bertram TA, Roth JA, Cheville NF.Neutrophils from 4 pony foals, 3 lactating pony mares, and 3 nonlactating mares were evaluated ultrastructurally and by in vitro function tests. Neutrophils from foals had significantly (P = 0.05) less random migration than neutrophils from mares; values in tests for iodination and Staphylococcus aureus ingestion were also lower with foal neutrophils. Neutrophils from lactating mares had lower responses to iodination, antibody-dependent cell-mediated cytotoxicity, and random migration tests than did neutrophils from nonlactating mares. Ultrastructurally, granule concentration did not differ si...
Ella A, Gomot G, Lévy I, Dominici C, Adriaensen H, Reigner F, Keller M, Guillaume D.Magnetic resonance imaging (MRI) is now widely used in equine veterinary practice. However, the mandatory European legislation regarding horse identification imposes the implantation of a transponder within the fatty tissue of the neck cervical ligament. While performing brain MRI for scientific purposes in ponies, we faced artifacts produced by such transponder and reported here this problem. Indeed, pony mares were anesthetized for 2 hours and placed, bedded on their back, in a 3T MRI scanner. A four-element flexible antenna positioned around the head was used. Three MRI sequences were perfo...
The Journal of heredityJuly 1, 1978
Volume 69, Issue 4 214-216 doi: 10.1093/oxfordjournals.jhered.a108933
Trommershausen-Smith A.Genetic segregation patterns among blood type markers and various phenotypically observed traits were studied in a small herd of ponies. The herd consisted of 10 mares without white spotting and a single stallion with the dominant pattern of tobiano spotting. Comparison of segregation patterns at loci for which the stallion was heterozygous showed tight linkage for the Alb-B and tobiano markers. In 17 cases in which the Alb contribution of the sire could be determined, all 10 foals that inherited AlbB from him were tobiano spotted, and all 7 non-spotted foals inherited his AlbA. The use of the...
Butler CM, Westermann CM, Koeman JP, Sloet van Oldruitenborgh-Oosterbaan MM.Over the last ten years a fatal syndrome associated with immunodeficiency and severe anaemia has been reported in young Fell pony foals in the UK. Affected foals are usually normal at birth but from the age of 2-4 weeks they progressively lose condition and become severely anaemic. Signs of immunodeficiency become apparent at around 3-4 weeks of age. Morbidity is low but mortality is 100% despite intensive treatment. Affected foals die or are euthanized usually before they reach the age of 3 months. A single autosomal recessive gene is suggested to be on the basis of the syndrome. Recently, af...
Magnuson NS, Perryman LE, Mason PH, Marta KM.A microassay requiring as few as 2 X 10(5) cells per assay was developed for systematic analysis of 9 purine enzymes in lymphocytes from equine peripheral blood, spleen, lymph node, thymus and bone marrow. The activities of adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), adenosine kinase (AK), deoxyadenosine kinase (dAK), deoxycytidine kinase (dCK), 5'-nucleotidase (5'-N), AMP deaminase, hypoxanthine-guanine phosphoribosyl transferase (HGPRT or HPRT), and adenine phosphoribosyl transferase (APRT) were measured by this microassay in lymphocytes from peripheral blood from four ...
Hinojosa AM, Bloeser JR, Thomson SR, Watson ED.Relatively little is known about endocrine control of reproduction in the stallion, but gonadotropins are thought to be central in regulating spermatogenesis and libido. The ability to effectively antagonise GnRH, and thereby gonadotropins, is therefore important both in further investigations of hormonal control of reproduction in stallions, and for clinical applications. In the present study four pony stallions were treated with a potent GnRH antagonist, Antarelix. Their libido, seminal parameters, and hormonal profiles were compared with those recorded before administration of the antagonis...
Suwannachot P, Verkleij CB, Kocsis S, Enzerink E, Everts ME.We determined the effects of food supply and low-intensity training on growth, serum thyroid hormone levels and the Na(+),K(+)-pump concentration in equine skeletal muscle. Twenty-two Shetland ponies were subjected to two different feeding regimes for 2(1/2) years (11 ponies per group): food restriction (body condition score kept at 2) or ad libitum fed (body condition score kept at 8). Five ponies in each group underwent low-intensity training. Gluteus medius muscle and serum samples were obtained in April 1998. Subsequently, all ponies were fed ad libitum and the training programme was stopp...
Hahn CN, Mayhew IG, Washbourne JR.Lateral thoracic nerve reflex latencies values were measured in ponies using a simple, non-invasive technique. The reflex was elicited using an external triggering hammer attached to an electrodiagnostic unit. The resulting evoked, compound muscle action potentials were recorded with electrodes, which were placed over the 6th ribs or 11th rib level with the axilla. Two superimposed repeats of 4 signal-averaged sweeps of 50 or 100 milliseconds were recorded and the estimated reflex pathway was measured for each subject in order to calculate the reflex latencies and latency velocities. Mean left...
Marrable AW, Flood PF.A sequence of ten known-age embryos recovered from Dartmoor Ponies during the first 4 months of gestation is described. Changes in size, shape and vascularity of the conceptus are recorded, as well as the growth and decline of the yolk-sac and the succeeding establishment of the allantochorion. The progress of equine somatogenesis is compared with that of the pig which it lags on average of about 4 days. Some quantitative data are presented.
Finco DR, Groves C.Free-flow and stop-flow procedures conducted on 2 female and 2 testosterone-treated castrated male ponies indicated that [14C]inulin and exogenous creatinine clearance values were the same. These results indicated that creatinine was neither reabsorbed nor secreted by the renal tubules and that exogenous creatinine clearance was an accurate method for determining glomerular filtration rate. As in other species which have been studied, endogenous creatinine clearance probably underestimated glomerular filtration rate because of the presence of noncreatinine chromogens in plasma.
Putt W, Fisher RA.In this paper we describe seven enzymes, NP, GOTM, PGM2, alpha FUC, PEP A, ADA and MPI which are found in the white cells of horses, including 39 British crossbred ponies and 16 crossbred horses, 30 Mongolian ponies and 10 Icelandic ponies. Two of these enzymes--alpha FUC and MPI--were polymorphic in all the populations of horses studied and could prove useful as additional markers in the paternity testing of horses. PEP A and GOTM were also polymorphic in two of the populations studied and could be used as further markers in these populations.
Weiss DJ, Evanson OA, Wells RE.To determine whether synthetic peptides containing the arginine-glycine-aspartate (RGD) sequence inhibit equine platelet function. Methods: For in vitro studies of blood, 3 healthy Thoroughbreds; for in vivo and ex vivo studies of administration of RGD-containing peptides, 4 young adult pony mares. Methods: Blood was incubated with and without addition of aspirin or RGD-containing peptides (RGDS, RPR 110885) and platelet aggregation responses and platelet adhesion to subendothelial collagen were determined. RPR 110885 was administered IV, and platelet function was evaluated. Platelet aggregati...
Traub-Dargatz JL, Schultheiss PC, Kiper ML, Stashak TS, Wrigley R, Schlipf J, Applehans FM.Fibrosis of the small intestine led to recurrent colic and weight loss in 2 ponies and 5 horses. There was a reduction in the length of the small intestine to one-half normal in horses 4 to 7. Histologic examination revealed substantial small intestinal submucosal fibrosis and arteriole sclerosis. The cause was not determined, but an environmental factor was suspected because 3 horses were from the same farm and the other animals were from within a 10-mile radius of the farm. The submucosal fibrosis appeared to be secondary to sclerosis of arterioles in the submucosa and mesentery, with low bl...
Okada T, Yuguchi K, Kiso Y, Morikawa Y, Nambo Y, Oikawa M, Sasaki F.The pars intermedia of the pituitary gland, and plasma ACTH and cortisol levels in the pony, which was first diagnosed in Japan as indicating equine Cushing's disease, were examined by immunohistochemistry and radioimmunoassay, respectively. The pars intermedia was greatly enlarged and most of its cells were immunoreactive for antisera to both adenocorticotropic hormone (ACTH) and beta-endorphin (beta-End). The plasma ACTH level was elevated when clinical symptoms appeared. The present results reveal that equine Cushing's disease in this pony was induced by the hypersecretion of ACTH and beta-...
Manohar M.Regional distribution of diaphragmatic blood flow (Q; 15-microns-diam radionuclide-labeled microspheres) was studied in normal (n = 7) and laryngeal hemiplegic (LH; n = 7) ponies to determine whether the added stress of inspiratory resistive breathing during maximal exercise may cause 1) redistribution of diaphragmatic Q and 2) crural diaphragmatic Q to exceed that in maximally exercising normal ponies. LH-induced augmentation of already high exertional work of breathing resulted in diminished locomotor exercise capacity so that maximal exercise in LH ponies occurred at 25 km/h compared with 3...
Kaminski RP, Forster HV, Bisgard GE, Pan LG, Dorsey SM.The objective was to determine the effect of moderate changes in ambient temperature (TA) on breathing and body temperature in ponies chronically exposed to a TA of 21 degrees C in the summer and 5 degrees C in the winter. Normal (n = 6) and chronic carotid body-denervated (n = 6, 1-2 yr) ponies were studied during 1) winter months over 3-4 days at 5 (control TA) and 23 degrees C and 2) summer months over 2-4 days at 21 (control TA), 30, and 12 degrees C. Neither rectal nor arterial temperature changed with any alteration of TA (P greater than 0.10). Skin temperature (Tsk) always changed by 2-...
Boyle MS, Cran DG, Allen WR, Hunter RH.The morphology of the uterotubal junction (UTJ) and caudal isthmus during the peri-ovulatory period, and the distribution of spermatozoa within the region, were studied in 10 Pony mares. The proximal tip of the uterine horn and caudal 1-2 cm of the isthmus were removed during oestrus or shortly after ovulation from animals mated or artificially inseminated within the previous 24 h. The tissues were incised longitudinally and fixed for scanning electron microscopy. Analysis of micrographs showed deep longitudinal and oedematous folds in the preovulatory samples. After ovulation, much of the fol...
Rajabi-Toustani R, Tsogtgerel M, Gao Y, Li C, Sakato M, Haneda S, Cheong SH, Nambo Y.Japanese native horses, which consists of 8 breeds, are threatened with extinction. Embryo transfer (ET) is used to reproduce endangered animals in various mammalian species. We aimed to perform ET using native ponies from Kiso and Hokkaido as donors and recipients, respectively. ET operation included long-distance transport of non-cryopreserved embryos from Nagano Prefecture to Hokkaido. Embryos were transported 1500 km over 9 h in a container maintained at 22°C. After transferring two embryos to two recipients, one mare delivered a healthy live foal. These results demonstrated that reciproc...
Lowry TF, Forster HV, Korducki MJ, Forster AL, Forster MA.To gain insight into central and peripheral contributions to changes in breathing during hypoxia, we compared effects on breathing of reducing inspired PO2 (hypoxic hypoxia) with reducing arterial O2 content (CaO2) through elevation of carboxy-hemoglobin (COHb) (CO hypoxia). Twelve awake ponies were studied during 1 h of breathing room air followed by 6 h when COHb was increased to 25% and CaO2 was decreased by 17%. When COHb was increased, arterial PCO2 (PaCO2) increased gradually to 1.3 Torr above (P < 0.05) control level between 30 and 45 min of CO exposure. Pulmonary ventilation (VE) de...
Allison CJ.A chronic wasting disease in a 16 month old Welsh pony filly is described. The animal died 26 days after the onset of illness which commenced with a sub-acute colic and was characterised by progressive loss of appetite and weight. Post-mortem examination revealed a total invagination of the caecum into the colon and it seemed logical to assume this invagination occurred at the start of the illness. A review of the literature showed that total caecal invagination produces 2 distinct clincal syndromes. It can occur either as an acute illness characterised by severe colic and death after about 10...
Forster HV, Murphy CL, Brice AG, Pan LG, Lowry TF.The major objective was to determine in ponies whether factors in addition to changes in blood PCO2 contribute to changes in plasma [H+] during submaximal exercise. Measurements were made to establish in vivo plasma [H+] at rest and during submaximal exercise, and CO2 titration of blood was completed for both in vitro and acute in vivo conditions. In 19 ponies arterial plasma [H+] was decreased from rest 4.5 neq/l (P less than 0.05) during the 7th min of treadmill running at 6 mph, 5% grade (P less than 0.5). A 5.6-Torr exercise hypocapnia accounted for approximately 2.9 neq/l of this reduced ...
Dubey JP, Miller S.A 10-year-old pony died 5 days after the onset of a nervous disorder. Necropsy revealed a yellowish area of discoloration (1.5 by 1 cm) in the medulla oblongata. Microscopically, necrosis and nonsuppurative myeloencephalitis were found in the medulla oblongata. Immature and mature meronts (25 by 10 microns) were seen in neural tissue and in capillaries of the brain stem. Organisms were similar structurally to those seen in equine protozoal myeloencephalitis of horses.
Dunkel B, Rickards KJ, Page CP, Cunningham FM.To determine the phosphodiesterase (PDE) isoenzymes in equine platelets and evaluate their influence on platelet adhesion. Methods: Platelets obtained from healthy New Forest Pony geldings that ranged from 12 to 20 years of age (mean +/- SEM, 17.3 +/- 1.1 years). Methods: PDE isoenzyme activity in equine platelets was determined by use of a 2-step radioactive assay. Functional importance of PDE isoenzymes was established by use of selective inhibitors in a colorimetric adhesion assay. Results: PDE1, PDE2, PDE3, and PDE5 and small amounts of PDE4 were found in equine platelets. Inhibition of PD...
Archer RM, Parsons JC, Lindsay WA, Wilson JW, Smith DF.Three pairs of longitudinal enterotomies were performed in the small colon of 10 ponies. Each pair consisted of one enterotomy through the antimesenteric band and one through the sacculation. The ponies were destroyed 96 h after surgery. The enterotomies in the two sites were compared for: speed of surgery, adhesions, bursting wall tension, neovascularisation by micro-angiography, and histological reaction. Enterotomies made through the antimesenteric band were superior because they were quicker to perform, stronger, more accurately apposed, and had less inflammation than those made through th...
Kent JE, Blackmore DJ.The turbidimetric analysis of IgG(T) in the serum of horses is described. Reference values are provided for 'worm-free' ponies (2.6 +/- 0.7 g/litre), stabled Thoroughbreds two years old and over (4.1 +/- 1.3 g/litre), grazing Thoroughbred broodmares (7.1 +/- 2.4 g/litre) and regularly wormed adult and young ponies grazing pasture contaminated with intestinal parasite eggs and larvae.
Aggarwal N, Holmes MA.The aim of this study was to characterise CD4+T-cells in equines, as these cells are pivotal in establishing immune responses or regulating established ones. Peripheral blood mononuclear cells from a pony immunised with ovalbumin were cultured in vitro in the presence of the specific antigen and autologous antigen presenting cells. During the antigen starvation phase, cells were maintained on recombinant equine IL-2. After 35 days of culture, most of the cells were CD4+, CD8-and sIg-. Cells proliferated specifically in the presence of antigen, as tested on day 42 of culture. These cells were a...
Stick JA, Arden WA, Chou CC, Parks AH, Wagner MA, Johnston CC.Using isolated autoperfused intestinal segments, the effects of flunixin meglumine administration on systemic arterial blood pressure, jejunal blood flow, vascular resistance, motility, arteriovenous oxygen difference, and oxygen consumption were determined in 10 anesthetized ponies ventilated with a mixture of halothane and oxygen. Saline solution or flunixin meglumine (1.1 mg/kg of body weight) was infused as a single bolus into the left jugular vein. By 10 minutes, flunixin meglumine increased systemic arterial blood pressure and increased intestinal vascular resistance. The jejunal blood f...
