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.
Marlin DJ, Roberts CA, Schroter RC, Lekeux P.The respiratory stimulant lobeline has been used in equine clinical practice to increase inspiratory and expiratory airflow rates at rest in order to facilitate investigation of both lower and upper airway function. Some of the responses to lobeline in the pony have been reported, but the detailed time course, effect of dose, possible side effects and reproducibility associated with lobeline administration have not been described in the horse. Respiratory airflow rates and oesophageal pressure were measured with a Fleisch No. 5 pneumotachometer and lightweight facemask and a microtip pressure ...
Smith KC, Whitwell KE, Mumford JA, Hannant D, Blunden AS, Tearle JP.The V592 strain of equid herpesvirus-1 (EHV-1), which was originally isolated from a fetus during an abortion epizootic, has proved to be of low virulence in infection studies. Five Welsh Mountain pony mares and one foal were challenged intranasally or by aerosol with this isolate, and monitored clinically and virologically. All six animals shed virus in nasopharyngeal mucus, and viraemia was recorded from day 7 post-infection (PI). Pathological investigations revealed mild rhinitis and bronchiolitis in the mares, with viral antigen expression in degenerating epithelial cells of the nasal muco...
Yates P, Mumford JA.To investigate the level of cross-protection induced by equine influenza H3N8 vaccines derived from different lineages, two studies have been carried out with ponies vaccinated with 'American-like' and 'European-like' vaccines and experimentally challenged with a European-like strain. The results demonstrated that equine influenza vaccines clearly protect against challenge with homologous virus if serum antibody titres are sufficiently high. On the other hand, protection is incomplete even when animals vaccinated with heterologous strains have comparative antibody levels. Nevertheless, the pro...
Ohnuma K, Yokoo M, Ito K, Nambo Y, Miyake YI, Komatsu M, Takahashi J.Early pregnancy factor (EPF) is an immunosuppressive protein detected in the early pregnancy serum. We have already reported that we developed the rosette inhibition test for mare EPF and detected EPF in thoroughbreds. The aim of this study was to determine whether or not our method could be used clinically. Methods: The rosette inhibition test for equine EPF was carried out on serum from six nonpregnant and six pregnant Shetland ponies, a female and a male Chinese pony, and four nonpregnant and 13 pregnant thoroughbred mares. In the thoroughbreds sera were collected during the pregnancy perio...
Peltier MR, Robinson G, Sharp DC.The effects of melatonin implant treatment over a four week period on LH, estradiol (E2) and progesterone (P4) secretion during the breeding season were studied in ovary-intact and ovariectomized pony mares. Mares with melatonin implants had significantly higher daytime melatonin concentrations than mares with sharm implants (P = 0.0065). In ovariectomized mares, LH secretion did not differ between mares with melatonin and sham implants. In ovary-intact mares, melatonin implants altered the pattern of LH secretion (P = 0.0023) in such a way that an increase in LH secretion was observed during ...
Peltier MR, Robinson G, Sharp DC.The effects of melatonin implant treatment over a 4 wk period at the summer solstice on the transition into and out of the following anovulatory season were evaluated in ovary-intact and ovariectomized mares. Melatonin implants tended to delay the timing of the final ovulation of the breeding season (P = 0.0797) in the ovary-intact mares. Although the decline in LH secretion associated with the end of the breeding season was parallel between treatments and ovarian statuses, the rate of LH secretion, as expressed by its mathematical accumulation, was lower in ovariectomized, melatonin-treated m...
Gastal MO, Gastal EL, Torres CA, Ginther OJ.The effects of oxytocin, prostaglandin F2 alpha (PGF2 alpha), and clenbuterol on uterine contractility and tone during anestrus and diestrus, and during mobility and postfixation of the embryonic vesicle were studied in 51 pony mares. Contractility was assessed by scoring real-time ultrasound images, and tone was assessed by transrectal digital compression. Scoring was done by an operator who had no knowledge of treatment assignments. In anovulatory mares primed with progesterone for 16 d, oxytocin did not significantly alter contractility but did stimulate an increase in tone, whereas clenbut...
Merkies K, Buhr MM.Spermatozoal function is affected by the ability to regulate intracellular calcium concentrations ([Ca2+]i), and may be influenced by epididymal maturation as well as environmental components. Regulation of [Ca2+]i in ejaculated and epididymal stallion spermatozoa was monitored over time in various media. Spermatozoa from each of 5 pony stallions (3 ejaculate samples and 1 caput and cauda sample) were labeled with the fluorescent calcium indicator probe Indo-1 in a calcium-free modified Tyrode's buffer. Fluorescent emissions were monitored by a dual wavelength spectrofluorometer over 5 h. Calc...
Gastal EL, Gastal MO, Nogueira GP, Bergfelt DR, Ginther OJ.The effect of altered LH concentrations on the deviation in growth rates between the 2 largest follicles was studied in pony mares. The progestational phase was shortened by administration of PGF2alpha on Day 10 (Day 0=ovulation; n=9) or lengthened by daily administration of 100 mg of progesterone on Days 10 to 30 (n=11; controls, n=10). All follicles > or = 5 mm were ablated on Day 10 in all groups to initiate a new follicular wave. The interovulatory interval was not altered by the PGF2alpha treatment despite a 4-day earlier decrease in progesterone concentrations. Time required for growt...
Goodrich LR, Moll HD, Crisman MV, Lessard P, Bigbie RB.To evaluate healing of pinch-grafted wounds on the distal aspect of the limbs of ponies bandaged with equine amnion or a standard nonadherent wound dressing material. Methods: 6 ponies. Methods: A 2.5x2.5-cm full-thickness section of skin was removed from the dorsal aspect of each limb at the midpoint of the metacarpus or metatarsus. Six days later, wounds were grafted with partial-thickness pinch grafts. Half the wounds were bandaged with amnion, and the other half were bandaged with a nonadherent dressing. Bandages were changed every 3 days until wound healing was complete. At each bandage c...
van der Kolk JH, Wensing T.The urinary corticoid:creatinine (c:c) ratio was determined in ten pony mares suffering from hyperlipoproteinaemia. The mean (+/- sd) urinary c:c ratio of these ten ponies (47 +/- 31 x 10(-6)) was not significantly different from that of twelve pony mares with a pituitary pars intermedia adenoma (31 +/- 18 x 10(-6). The correlation between the urinary concentration of corticoids and plasma total lipids, and the correlation between the urinary c:c ratio and plasma total lipids in ponies with hyperlipoproteinaemia were not significant (P > 0.05; r = 0.53 and r = 0.008, respectively). Preliminary...
Baudena MA, Chapman MR, French DD, Klei TR.Cyathostome development and survival on pasture in subtropical climates of the US have yet to be completely defined and available data on seasonal transmission are minimal. In an attempt to study this phenomenon, a group of pony mares and their foals was maintained on a naturally contaminated pasture in southern Louisiana. Fecal egg counts (FEC) and numbers of infective third stage larvae (L3) kg(-1) dry herbage were recorded biweekly during two time periods, from January 1986 through December 1988, and September 1996 through October 1997. A FEC rise occurred during the late summer-early autum...
Ros A.A case of a cystic calculus in a pony mare is described. In this case an urethro-sphincterostomy accomplished removal of a 362 g calculus with dimensions of 9 x 7 cm without any complications after surgery.
Back W, Schamhardt HC, Van Weeren PR, Barneveld A.The trot at 3 m/s of 24 Shetland foals ('ponies') and 24 Dutch Warmblood foals ('horses') was recorded at age 4 months on a treadmill using a modified CODA-3 apparatus to characterise equine locomotion at young age. Locomotor variables of the ponies were qualitatively and, after scaling, quantitatively compared with those of horses. Ponies made shorter strides than horses, evidenced by a shorter stance and swing duration, although their relative stance durations were similar. Neither linear nor dynamic scaling procedures could completely compensate for differences in height at the withers comp...
Katz LM, Bayly WM, Hines MT, Sides RH.Horses exercising at > or = approximately 90% VO2max develop arterial hypoxaemia with concurrent hypercapnoea, whereas ponies exercising at comparative levels become hypocapnoeic and maintain arterial oxygen tensions close to resting values. We sought to investigate the possibility that these differences relate to the ventilatory responses of these animals to exercise. Six Thoroughbred horses weighing mean +/- s.e. 501 +/- 27 kg and 5 ponies weighing mean +/- s.e. 164 +/- 18 kg exercised for 2 min on a 10% slope at speeds calculated to require 60% VO2max and for at least 1 min at speeds cal...
Miller CB, Wilson DA, Keegan KG, Kreeger JM, Adelstein EH, Ganjam VK.To determine if there is a difference in in vitro growth of fibroblasts isolated from the trunk and distal aspect of the limb of horses and ponies. To determine the effects of a corticosteroid and monokine on in vitro growth of fibroblasts isolated from the trunk and distal aspect of the limb of horses and ponies. Methods: Growth of fibroblasts from tissues harvested from the trunk and limb were compared from horse and pony samples grown in control media and control media with triamcinolone or monokine added. Methods: Dermal and subcutaneous tissue from 22 horses and 17 ponies of various ages ...
Chang YF, Novosol V, McDonough SP, Chang CF, Jacobson RH, Divers T, Quimby FW, Shin S, Lein DH.Seven specific-pathogen-free (SPF) ponies, 1-5 years old, were exposed to Borrelia burgdorferi-infected adult ticks while being treated with dexamethasone over 5 consecutive days. One SPF pony (pony No. 178) was first exposed to laboratory-reared nymphs without B. burgdorferi infection and 3 weeks later was exposed to B. burgdorferi-infected adult ticks with concurrent dexamethasone treatment for 5 consecutive days. Four uninfected ponies treated with dexamethasone, exposed to laboratory-reared ticks without B. burgdorferi infection served as uninfected controls. Clinical signs, bacteriologic ...
Cullen CL, Grahn BH.The study reports on the diagnosis and treatment of a severe case of corneal ulceration and anterior uveitis in a 1-year-old Norwegian fjord pony, which did not respond to initial […]
Chang YF, McDonough SP, Chang CF, Shin KS, Yen W, Divers T.A pony was vaccinated with recombinant OspA vaccine (rOspA) and then exposed 3 months later to Borrelia burgdorferi-infected ticks (Ixodes scapularis) collected in Westchester County, N.Y. At 2 weeks after tick exposure, the pony developed a high fever (105 degrees F). Buffy coat smears showed that 20% of neutrophils contained ehrlichial inclusion bodies (morulae). Flunixin Meglumine (1 g daily) was given for 2 days, and the body temperature returned to normal. PCR for ehrlichial DNA was performed on blood samples for 10 consecutive days beginning when the pony was first febrile. This pony was...
Robinson SJ, Neal H, Allen WR.Equine embryos enter the uterus 144-156 h after ovulation, before which time the passage of embryos through the oviduct is halted in the region of the ampullary-isthmic junction. It is thought that further onward movement of embryos to the uterus is facilitated by secretion of prostaglandin E2 (PGE2) by the embryos, which relaxes the smooth muscle of the isthmus. In the present study, the effect of a single local application of PGE2 on oviductal transport was examined in 22 Thoroughbred and Pony mares that were inseminated on alternate days during oestrus. On day 4 after ovulation, the ipsilat...
Blanchard T, Varner D, Johnson L, Roser J, Hill J, Miller C.The scrota of three Pony stallions and one miniature horse were insulated for 36 h. Plasma testosterone concentrations decreased gradually and were significantly (P < 0.05) lower than pretreatment values at 16, 24, 30, 38 and 44 h after onset of scrotal insulation. Plasma LH and oestradiol concentrations were significantly (P < 0.05) decreased 18 h, and 24 and 26 h, after onset of scrotal insulation, respectively. Plasma FSH concentrations were significantly (P < 0.05) decreased 4 days after the insulation was removed. Decreases in the potential daily sperm output per Pony for early p...
Guillaume D, Duchamp G, Nagy P, Palmer E.Classical photostimulation of winter anoestrous mares consists of a light treatment with 14.5-16.0 h white light (100 lux), starting near the time of the winter solstice and ending around the time of the summer solstice. Cyclicity is obtained typically after about 70 days of treatment. The aim of the present study was to establish the minimum number of days of treatment, the lowest light intensity and the duration of light required per day to advance the onset of ovarian activity in winter anoestrous mares. In Expt 1 it was demonstrated that a 35 day exposure to a photoperiod (14.5 h light: 9....
Greaves HE, Porter MB, Sharp DC.Long-term ovariectomized Pony mares were treated with oestradiol (0.2-5.0 mg; i.m.) at 12 h intervals for 10 days. Blood samples were collected by jugular venepuncture three times a day throughout the experiment and additional blood samples were collected at 15 min intervals for 12 h on days 0 and 10 (sampling periods 1 and 2, respectively). There were significant effects of oestradiol treatment (P < 0.05) and oestradiol treatment x day (P < 0.0001) on the mean LH concentrations each day. Regression analysis of LH time trends each day indicates that there is heterogeneity (P < 0.001) ...
Forhead AJ, Broughton Pipkin F, Taylor PM, Baker K, Balouzet V, Giussani DA, Fowden AL.Blood pressure, heart rate and the plasma concentrations of cortisol and components of the renin-angiotensin system were measured in chronically catheterized Pony mares (n=15) and their fetuses during the second half of gestation (day 153-336 of gestation; term is normally between day 320 and day 340 of gestation). Fetal blood pressure increased towards term with the prepartum surge in plasma cortisol concentration, and there was a correlation between fetal blood pressure and both gestational age (r = 0.88, P < 0.0005) and plasma cortisol concentration (r = 0.88, P < 0.0005). Plasma concentrat...
McKelvie J, Foster AP, Cunningham FM, Hamblin AS.Circulating lymphocyte numbers are elevated in horses with the allergic skin disease sweet itch and skin lesions are typified by an infiltrate of eosinophils and mononuclear cells, the latter of which have not been fully characterised. The aim of the present study was to characterise the lymphocyte subpopulations in the circulation and skin of ponies with sweet itch by flow cytometry and a newly developed modified alkaline phosphatase immunohistochemical technique. Sweet itch ponies were found to have significantly greater numbers of circulating CD5+ and CD4+ T-lymphocytes than normal animals....
Bedford SJ, McDonnell SM.To evaluate the effects of trimethoprim-sulfamethoxazole and pyrimethamine treatment on various measures of reproductive function in healthy pony stallions. Methods: Randomized complete block study. Methods: 12 healthy, mature pony stallions. Methods: Stallions were assigned to treatment and control groups balanced for age and various characteristics of reproductive function. The treated group received trimethoprim-sulfamethoxazole and pyrimethamine for 90 days during summer and fall; the control group was not treated. Semen characteristics, sexual behavior, testicular volume, and sperm produc...
Li F, Leroux C, Craigo JK, Cook SJ, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) is genetically one of the simplest lentiviruses in that the viral genome encodes only three accessory genes, tat, rev, and S2. Although serological analyses demonstrate the expression of the S2 protein in persistently infected horses, the role of this viral gene remains undefined. We recently reported that the S2 gene is not essential for EIAV replication in primary equine macrophages, as EIAV mutants lacking the S2 gene replicate to levels similar to those of the parental virus (F. Li, B. A. Puffer, and R. C. Montelaro, J. Virol. 72:8344-8348, 1998). We n...
Smiet E, Haritova A, Heil BA, Fink-Gremmels J, Wijnberg ID.To compare the pharmacokinetics of the fourth generation cephalosporin, cefquinome, in neonatal foals, 6-week-old foals and mature New Forest ponies in order to recommend appropriate dosage regimens for use of this drug. Methods: Cefquinome was administered i.v. at 1 mg/kg bwt twice a day (q. 12 h), 1 mg/kg bwt 3 times a day (q. 8 h) or 4.5 mg/kg bwt q. 12 h to each age group (n = 6). Plasma cefquinome concentrations were analysed using high-performance liquid chromatography combined with electrospray tandem mass spectrometry. Results: Both foal age groups had comparable pharmacokinetic data e...
MacFarlane PD, Mosing M.This case series is the first report of the use of CPAP (continuous positive airway pressure) ventilation in adult horses. Two horses and 3 ponies anesthetized for orthopedic procedures in lateral recumbency received 10 cm H(2)O CPAP. During anesthesia, arterial oxygen partial pressure tended to increase and arterial carbon dioxide pressure tended to increase despite increased minute ventilation index. The measured cardiovascular parameters were within physiologic limits. Cette série de cas est le premier rapport sur l’utilisation de la ventilation spontanée en pression positive continue ...
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...
Sharif MB, Fitak RR, Wallner B, Orozco-terWengel P, Frewin S, Fremaux M, Mohandesan E.New Zealand has the fourth largest feral horse population in the world. The Kaimanawas (KHs) are feral horses descended from various domestic horse breeds released into the Kaimanawa ranges in the 19th and 20th centuries. Over time, the population size has fluctuated dramatically due to hunting, large-scale farming and forestry. Currently, the herd is managed by an annual round-up, limiting the number to 300 individuals to protect the native ecosystem. Here, we genotyped 96 KHs for uniparental markers (mitochondrial DNA, Y-chromosome) and assessed their genetic similarity with respect to other...
Lees P, May SA, Hoeijmakers M, Coert A, Rens PV.The pharmacodynamics and enantioselective pharmacokinetics of vedaprofen were studied in six ponies in a two period cross-over study, in which a mild acute inflammatory reaction was induced by carrageenan soaked sponges implanted subcutaneously in the neck. Vedaprofen, administered intravenously at a dosage of 1 mg/kg, produced significant and prolonged inhibition of ex vivo serum thromboxane B2 (TXB2) synthesis and short-lived inhibition of exudate prostaglandin E2 (PGE2) and TXB2 synthesis. Vedaprofen also partially inhibited oedematous swelling and leucocyte infiltration into exudate. Vedap...
Griffin PG, Ginther OJ.Transrectal ultrasonography was used to quantitate uterine contractile activity during the estrous cycle and early pregnancy in pony mares (nonbred, n = 9; pregnant, n = 16). Continuous 1-min scans of longitudinal sections of the uterine body were videotaped, and uterine activity scores (1=minimal activity, 5=maximal activity) were assigned to each tape segment. There was a tendency (P<0.06) for a main effect of reproductive status (nonbred versus pregnant), a main effect of day (P<0.0001), and a reproductive status by day interaction (P<0.006). Uterine activity scores were higher (P&...
Pan LG, Forster HV, Bisgard GE, Dorsey SM, Busch MA.We assessed the relationship of ventilation (VE) to cardiodynamic variables and CO2 transport in seven normal ponies during treadmill exercise. At 1.8, 3, and 6 mph, respectively, VE increased from 15 l/min at rest to 43, 51, and 86 l/min by 1 min and 48, 68, and 125 l/min by 8 min. In three ponies at the same work loads, cardiac output (Qc) increased from approximately 12 l/min at rest to 19.7, 28.1, and 40.3 l/min between 30-60 s (P less than 0.05) and then decreased by about 20% to a steady state by 3-4 min. Heart rate (HR) shows a similar biphasic response during exercise. Mean right ventr...
Dunnett M, Harris RC, Sewell DA.Taurine (TAU) is found in large but variable amounts in the skeletal muscles of many species. It has been reported that slow twitch muscles in the rat exhibit higher TAU levels than fast twitch muscles. Variation in muscle taurine content may be attributable to differences in the fibre type composition of different muscles. TAU content (mmol kg-1 dry muscle) and percentage type-1, type-2A, and type-2B fibre section area (f.s.a.) were measured in muscle samples taken from up to six sites in the middle gluteal muscle of four horses and one pony at post mortem and in biopsy samples taken from twe...
Loretti AP, Colodel EM, Gimeno EJ, Driemeier D.This study reports a neurological disease unrecognised until now in ponies in southern Brazil. Objective: Epidemiological data strongly suggests that the ingestion of Sida carpinifolia is involved in the aetiology. We tested the hypothesis that it is an acquired lyosomal storage disease. Methods: Following the death of 3 ponies, all ponies from the premises were closely monitored; epidemiological data and clinical findings carefully recorded. Fragments of several organs, including CNS, were fixed in neutral formalin and embedded in paraffin-wax. Sections were stained with haematoxylin and eosi...
Robinson C, Heather Z, Slater J, Potts N, Steward KF, Maskell DJ, Fontaine MC, Lee JJ, Smith K, Waller AS.Strangles, caused by Streptococcus equi subspecies equi (S. equi) is one of the most frequently diagnosed infectious diseases of horses and there remains a significant need to develop new preventative vaccines. We generated a live vaccine strain of S. equi containing deletions in six genes: sagA, hasA, aroB, pyrC, seM and recA, which was administered to nine Welsh mountain ponies via the intramuscular route. Four vaccinated ponies developed adverse reactions following the first vaccination from which the live vaccine strain was isolated. Two of these ponies were withdrawn from the study and se...
Kuemmerle JM, Fürst AE.To report open reduction and joint stabilization using a prosthetic capsule technique for treatment of a craniodorsal coxofemoral luxation in a lightweight pony. Methods: Clinical report. Methods: Pony stallion (8 years old, 113 kg). Methods: A craniodorsal approach to the coxofemoral joint was performed under general anesthesia. After open reduction, a prosthetic capsule technique was used. Four 3.5 mm self-tapping cortical anchor screws were implanted: 2 screws were inserted above the cranial aspect of the dorsal acetabular rim, and 2 screws were inserted into the femoral neck. Subsequently,...
Rouse BT, Ditchfield WJ.Nasal secretions and serum were collected from ponies in order to determine the types of immunoglobulins responsible for antibody activity against Myxovirus influenzae A-equi 2. Using specific antisera to remove each immunoglobulin, the antiviral activity of serum was shown to be a property of IgG globulin, whereas in nasal secretions activity was found in both IgG and IgG(T) globulins. However in secretions the predominant activity was attributed to IgG(T) globulin. Because of its sensitivity to 2 mercaptoethanol, early serum antibody was assumed to belong to the IgM class of immunoglobulins....
Duncan JL, Reid JF.In a controlled trial in naturally-infected young ponies, oxfendazole administered orally at dose-rates of 10 mg per kg and 50 mg per kg resulted in complete elimination of Trichostrongylus axei, Parascaris equorum, Oxyuris equi and adult Strongylus vulgaris. Also, all migrating Strongylus edentatus larvae recovered from the subperitoneal tissues of the flank were found to be dead. Minimum efficiencies of 99.8 per cent and 99.1 per cent were obtained against adult small strongyles (Trichonema spp) and 97.6 per cent and 100 per cent of developing small strongyle larvae at dose-rates of 10 mg pe...
Vigani A, Shih A, Queiroz P, Pariaut R, Gabrielli A, Thuramalla N, Bandt C.New volumetric variables of preload, such as total end-diastolic volume index (TEDVI) and active circulation volume index (ACVI) and central blood volume index (CBVI), may represent good indicators of preload and predictors of fluid responsiveness. During acute changes of intravascular volume these variables would allow a more accurate intervention. Objective: The aim of the present study was to investigate the changes in TEDVI, ACVI, CBVI in a juvenile model of hemorrhagic shock and resuscitation. Methods: Twelve anaesthetized ponies (3-8 months of age) were studied at normovolaemia (BASE), a...
van Doorn DA, Schaafstra FJ, Wouterse H, Everts H, Estepa JC, Aguilera-Tejero E, Beynen AC.This study addresses the question of whether feeding rations rich in P for a period of up to 42 d induces a positive P balance in adult ponies. Biochemical bone markers and parathyroid hormone (PTH; intact as well as whole PTH) were measured to obtain clues as to the effect of P loading on bone metabolism. The experiment had a Latin square design. Each feeding period lasted 42 d, and there were 2 balance trials (ECP1 and ECP2) within each feeding period. Each balance trial lasted 10 d (ECP1: d 11 to 21; ECP2: d 33 to 42). Six ponies aged 2.5 to 7 yr were fed a control diet that provided P and ...
Watson ED, Thomassen R, Nikolakopoulos E.During spring transition, when estrus may be exhibited for prolonged periods, it is important for veterinarians and stud farm personnel to be able to predict whether a large follicle will ovulate or regress. It is thought that the presence of ultrasonically detectable uterine edema indicates that a follicle will ovulate, however, there is little evidence to support this. In the present study, 16 mares were regularly examined by transrectal ultrasonography to follow growth and regression of follicles from seasonal anestrus in February until second ovulation. Blood samples were collected daily f...
Duke T, Cruz AM, Cruz JI, Howden KJ.To compare the cardiopulmonary effects of the head-down position, with or without capnoperitoneum, in halothane-anesthetized horses. Methods: Prospective randomized study. Methods: Five ponies (four mares, one stallion; bodyweight 302 ± 38.4 kg [mean ± SD]) were used. Methods: The ponies were anesthetized with xylazine, guiafenesin, ketamine, and maintained with halothane/oxygen and lungs were ventilated to 40 ± 2 mm Hg (5.3 ± 0.3 kPa) end-tidal CO tension. After baseline cardiopulmonary measurements, ponies were kept in horizontal position for 30 minutes, then tilted head-down 30° to the...
Peltier MR, Robinson G, Sharp DC.The effects of melatonin implant treatment over a 4 wk period at the summer solstice on the transition into and out of the following anovulatory season were evaluated in ovary-intact and ovariectomized mares. Melatonin implants tended to delay the timing of the final ovulation of the breeding season (P = 0.0797) in the ovary-intact mares. Although the decline in LH secretion associated with the end of the breeding season was parallel between treatments and ovarian statuses, the rate of LH secretion, as expressed by its mathematical accumulation, was lower in ovariectomized, melatonin-treated m...
Drudge JH, Lyons ET, Tolliver SC, Swerczek TW.Oxibendazole (OBZ; 10 mg/kg of body weight) was administered to ponies at 8-week intervals to control strongylosis in a breeding band of Shetland-type ponies (n = 29 to 50) from October 1978 through September 1984. A similar use of cambendazole (CBZ; 20 mg/kg of body weight) in this band of ponies during the preceding 4-year period resulted in the survival of a CBZ-resistant population (S) of small strongyles. Effectiveness of OBZ treatments was monitored by pre- and posttreatment counts of the number of strongyle eggs per gram of feces (epg) and of the number of strongyle larvae per gram of f...
Sleutjens J, Serra Bragança FM, van Empelen MW, Ten Have RE, de Zwaan J, Roelfsema E, Oosterlinck M, Back W.Obesity and hyperinsulinaemia are frequently encountered in the equine population and risk factors for the development of laminitis. There are many options for hoof support that claim a beneficial effect, but often the scientific evidence is scarce. Objective: To quantify the effect of frog-supportive shoes on hoof kinetics in normal and obese ponies. Methods: Controlled in vivo trial. Methods: Ten Shetland mares (n = 10) with a normal (n = 5) or obese (n = 5) body condition were led over a dynamically calibrated pressure plate before (T0), immediately after (T1) and 72 h (T2) after ap...
Haluska GJ, Currie WB.Concentrations of plasma progesterone were similar to values reported in the literature except that a significant decrease in progesterone during the last day, but before parturition, was detected by systematic, high-intensity blood sampling. Mean concentrations of oestradiol-17 beta increased sharply and significantly, plateaued for 132.8 +/- 1.5 days (mean +/- s.e.m., N = 9), then declined sharply in each mare. There was obvious variation between the mares in when these increases and decreases in oestradiol-17 beta occurred, with the events being related closely to ambient photoperiod condit...
Ringger NC, Pearson EG, Gronwall R, Kohlepp SJ.Five healthy Equidae (4 horses and one pony) were given a single i.v. dose of ceftriaxone (50 mg/kg bwt) to determine the pharmacokinetics and concentration in cerebrospinal fluid (CSF). Blood was drawn from an i.v. jugular catheter and CSF from a pre-placed, intrathecal catheter. Serum and CSF concentrations were determined by high performance liquid chromatography. The mean serum concentration of ceftriaxone was 144.7 micrograms/ml 15 min after injection and declined to 0.3 microgram/ml 10 h after injection. The elimination rate constant (lambda 2) was 0.63 +/- s.e. 0.23/h, the elimination h...
Sugiyama A, Takeuchi T, Morita T, Matsuu A, Kanda T, Shimada A, Amaya T, Hikasa Y.A 15-year-old, neutered-male pony presented with a history of weight loss during 4 months. Clinical evaluation revealed severe bradycardia and complete atrioventricular block. At necropsy, a lobulated mass in the anterior mediastinum and moderate enlargement of the superficial cervical lymph nodes were observed. The vagus nerve and the brachiocephalic trunk were embedded in this anterior mediastinal tumor. Histologically, the mass was composed of sheets of neoplastic lymphoid cells expressing CD3, with a low mitotic rate. To the best of our knowledge, this is the first reported case of mediast...
Todhunter RJ, Minor RR, Wootton JA, Krook L, Burton-Wurster N, Lust G.Our aim was to determine if mild to moderate postoperative exercise and intra-articular polysulfated glycosaminoglycan result in improved repair of large, experimentally induced osteochondral defects in a weight-bearing surface of equine joints. Arthroscopic debridement was used to produce full-thickness defects in a weight-bearing area of the radial carpal bones in 18 ponies. The ponies were randomly assigned to two groups balanced for age: nine animals in the exercise and nine in the no exercise group. Six ponies in each group were medicated weekly for 5 weeks with an intra-articular injecti...
Glazier DB, Littledike ET, Evans RD.In 11 crossbred ponies, hyperkalemia was induced by acute intracardiac infusion of a 0.4M solution of potassium chloride. The ECG changes noticed can be assigned to 4 stages: (1) a widening and a lowering of amplitude followed by inversion and final disappearance of the P wave; (2) an increase in the amplitude of the T wave; (3) an increase in the QRS interval, with some irregularity in the ventricular rate; and (4) periods of cardiac arrest that became terminal or were followed by ventricular fibrillation. At plasma potassium values of greater than 7.5 mM/L, the T-wave amplitude and duration ...
Forster HV, Erickson BK, Lowry TF, Pan LG, Korducki MJ, Forster AL.Two questions were addressed in this study: 1) Does respiratory resistive unloading (inspired O2 fraction = 0.21, inspired He fraction = 0.79) elicit a compensatory reduction in stimulation of the diaphragm? 2) Do diaphragm and lung afferents contribute to compensatory responses to unloading? Ten intact (I), five diaphragm-deafferented (DD), four hilar nerve-denervated (HND), and seven DD+HND adult ponies were studied at rest and during mild and moderate treadmill exercise. During steady-state unloading at rest, duration of the diaphragm electromyogram (EMGdi) was less (P < 0.05) than contr...
Hughes JP, Trommershausen-Smith A.Reproductive failure was studied in 12 phenotypically normal mares (9 Arabian, 3 Quarter horses, 1 Appaloosa and 1 pony). Karyotyping was performed using lymphocytes isolated from peripheral blood by density gradient procedures, followed by standard culture methods for karyotyping. Nine mares had karyotypes of 63,XO; 1 had 63,XO/64,XX; 1 had 63,XO/64,XY and 1 had 64,XY. All mares had small, firm ovaries that when removed and examined from 4 mares, lacked germ cells and consisted of undifferentiated ovarian stroma.
Escalona EE, Okell CN, Archer DC.Crib-biting and windsucking (CBWS) behaviour in horses has been associated with increased risk of colic in general, recurrence of colic and specific forms of colic. The aims of the present study were to determine the prevalence of colic within a population of horses that display CBWS behaviour and to identify risk factors for colic. Methods: Owners/carers of horses in the general UK equine population that display CBWS behaviour were invited to participate in a questionnaire-based survey about the management and health of these horses. Data were obtained for a number of variables considered to ...
Gratwick Z, Viljoen A, Page PC, Goddard A, Fosgate GT, Lyle CH.Adverse effects on renal health and haemostasis have been documented in human patients administered hydroxyethyl starches (HESs). Gelatins may represent useful substitutes should similar adverse effects be identified in horses. Objective: To compare the effects of a 4% modified fluid gelatin (MFG) with a 6% (130/0.4) HES on haemodilution, colloid osmotic pressure (COP), haemostasis and renal parameters in healthy ponies. Methods: Randomised crossover experiment. Methods: Three treatments (Treatment A: 10 ml/kg bwt HES; Treatment B: 10 ml/kg bwt MFG; Treatment C: 20 ml/kg bwt MFG) were administ...
Ousey JC, McArthur AJ, Rossdale PD.Metabolic rates, rectal temperatures and respiratory quotients (RQ) were determined during the first 24 h post partum in Thoroughbred and pony foals and in relation to environmental temperature. Both breeds had high metabolic rates (greater than 200 W/m2) during the first hour post partum when they were wet and shivering; by 4 to 24 h values were fairly steady at about 153 and 105 W/m2 for Thoroughbred and pony foals, respectively. At birth, rectal temperature was lower in Thoroughbred foals than in pony foals; values increased during the first hour, and then decreased. At 24 h of age, both br...
