Topic:Pony
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.
Dose-response of ponies to parenteral Escherichia coli endotoxin. The response of the pony to increasing doses of Escherichia coli endotoxin was evaluated using intravenous and intraperitoneal administration models. Marked changes were seen in all parameters measured following endotoxin administration. Leukopenia (neutropenia, lymphopenia) and thrombocytopenia were not dose-dependent. Similarly, elevated plasma fibrinogen and altered glucose concentrations (hyperglycemia and hypoglycemia), pyrexia and increased lactate/pyruvate ratios were apparent at all endotoxin doses but were not dose related. The widely used packed cell volume and capillary refill time,...
A technique for catheterisation of the coronary sinus in adult ponies (Equus caballus). Long-term catheterisation of the coronary sinus using a specially designed catheter was accomplished in 6 ponies via a right lateral thoracotomy. The catheter comprised a 10 to 12 cm long stiff segment (Teflon) joined to a 100 cm length of pliable medical grade (vinyl) tubing. Catheters were kept functional up to 10 weeks postoperatively. Location of the catheter tip was verified by determining the oxygen tension of anaerobically withdrawn blood samples. Normal values of oxygen tension of the coronary sinus blood in ponies were similar to those reported for the dog, whereas oxygen content was ...
Prevention of endotoxin-induced arterial hypoxaemia and lactic acidosis with flunixin meglumine in the conscious pony. Bacterial endotoxin injected intravenously into conscious ponies produced alterations in cardiopulmonary and gastrointestinal function. Specifically, tachypnoea, dyspnoea, hypoxaemia, colic, lactic acidosis and diarrhoea resulted from administration of 10 micrograms/kg Escherichia coli endotoxin. Pretreatment of the ponies with a potent prostaglandin synthetase inhibitor, flunixin meglumine, prevented these ill effects of endotoxin.
Variations of plasma enzymes in the pony and the dog after carbon tetrachloride administration. Adult female dogs or pony mares were subjected to a nonlethal dose of CCl4 (0.5 ml/kg of body weight). Amounts of several plasma enzymes thought to be indicative of hepatic disease were monitored. Plasma enzymes alanine aminotransferase, aspartate aminotransferase (AST), alkaline phosphatase (ALP), arginase, gamma-glutamyltransferase (GGT), and iditol dehydrogenase (ID), as well as total plasma bilirubin, were determined in these animals before and after the administration of the CCl4. In the dog, GGT was not significantly increased, whereas ALP values were increased during days 1 to 6. In the...
GnRH localization in the equine brain and infundibulum: an immunohistochemical study. Immunohistochemical localization of the decapeptide gonadotropin releasing hormone (GnRH) in neural structures in the pony brain and infundibulum (INF) was conducted at the light-microscopic level. This procedure utilized an antiserum generated against GnRH conjugated to bovine serum albumin. In the rostral INF, GnRH was distributed mainly in the external layer, with greatest concentrations adjacent to the long capillary loops of the hypophyseal portal system. The intermediate portion of the INF contained the hormone throughout the external layer, especially in the dorsolateral regions just ve...
Technique for reversible vagal blockade in the standing conscious pony. A surgical technique is described for preparation of chronic cervical vagal loops in ponies. Vagal blockade was induced by circulating methanol (-2 C) through coils which enclosed the loops. Vagal blockade increased tidal volume, heart rate, and systemic blood pressure and decreased respiratory rate. Atropine, given at a dose of 0.04 mg/kg IV, increased heart rate and systemic pressure but did not alter respiratory variables, indicating that vagal cooling caused both afferent and efferent blockade. The effects of vagal blockade were rapidly reversed when refrigerated coils were removed.
Vaginal pH during estrus in mares. Vaginal hydrogen ion concentration of Saddlebred mares was measured throughout the behavioral estrous period. The mean pH on the day of ovulation was significantly (P = <.01) lower than on all other tested days of estrus. Follicular development and vaginal pH values in pony mares at time of slaughter were highly correlated. A significant decrease in vaginal pH values, determined through a series of carefully monitored measurements during estrus, was found to be characteristic and indicative of ovulation.
Complement requirement for virus neutralization by antibody and reduced serum complement levels associated with experimental equine herpesvirus 1 infection. Pony foals, negative for detectable serum-neutralizing antibody to equine herpesvirus 1 by the standard tube-culture virus neutralization test, were experimentally infected with equine herpesvirus 1. Complement-requiring (CR) and non-complement-requiring (NCR) serum-neutralizing antibodies were evaluated in preinfection and postinfection sera by means of a complement-enhanced plaque reduction assay. Low levels of CR antibodies were found in the preinfection sera of only group II ponies. Upon infection, CR antibodies were detected by day 2 postinfection and reached peak titers between 7 and 14 ...
Vitamin A nutrition of the equine: growth, serum biochemistry and hematology. Four diets were fed to pony fillies for 40 weeks. One group received a basal diet low in carotene, designated mildly deficient. Other groups were fed basal diet plus vitamin A propionate equivalent to 12 (control), 1,200 (mildly intoxicated) or 12,000 (severely intoxicated) microgram retinol/kg body weight/day. The mildly deficient group exhibited impairment of growth and hematopoiesis with decreased serum concentrations of iron, albumin and cholesterol prior to depletion of liver vitamin A. Growth was depressed in mildly intoxicated and severely intoxicated fillies. The latter became debilita...
Experimentally induced arthritis of the equine carpus: histologic and histochemical changes in the articular cartilage. Arthritis was experimentally induced in the intercarpal joints of a series of mature ponies by the intraarticular injections of 400 microgram of the polyene antibiotic filipin in 1 ml of dimethyl sulfoxide. Twelve consecutive weekly injections were administered and the ponies were euthanatized 4 weeks after the last injection of filipin was made. The ponies were exercised for 1 hour each day throughout the experiment. Articular cartilage specimens from 4 sites in each intercarpal joint were examined histologically and histo-chemically. For the histochemical examination, safranin O-fast green, ...
A preliminary report on an attempt to modify behavior of untamed ponies by acupuncture. A preliminary study using various acupuncture techniques to modify behavior of untamed ponies was attempted. In five of the seven tested parameters, the animals's behavioral responses were unaffected by acupuncture treatments. However, substantial improvement of general behavior of the nervous ponies was observed in animals treated with jaw and scutiform points. The results are not conclusive and further testing of acupuncture as a mean of modifying animal behavior is desirable.
Copper metabolism and requirement in mature ponies. The effects of copper intake on stable copper and 64Cu metabolism and on the excretory pathways of absorbed copper were examined in ponies. Bile and feces collected from two bile duct-cannulated ponies following an intravenous dose of 64Cu showed that bile was the main route of endogenous copper excretion. Stable copper and 64Cu metabolism were examined in three intact ponies fed dietary copper to provide 5.6, 16.6 and 25.7 mg Cu/100 kg body weight/day. The amount of copper excreted in urine was not influenced by dietary treatment. Stable copper absorption and 64Cu retention significantly incr...
[A serological study of the contagious equine metritis: comparison between indirect immunofluorescence, slow agglutination and complement fixation techniques (author’s transl)]. Serological response of pony mares to contagious equine metritis is studied comparing three techniques: slow agglutination, complement fixation and indirect immunofluorescence. Sera were taken from pony mares vaccinated with a heat inactivated suspension of Haemophilus equigenitalis, from experimentally-infected pony mares and from healthy horses. All three reactions detected antibodies in vaccinated and infected animals. The highest titers are observed with vaccinated mares. Titers are low in infected animals. Antibodies detected by indirect immunofluorescence appeared sooner and persisted lo...
Ultrastructural observations in ponies after treatment with monensin. Ultrastructural studies were made of myocardium, diaphragm, appendicular muscle, liver, and kidney of 3 ponies acutely poisoned with a single oral dose of monensin (4 mg/kg of body weight). These ponies developed severe signs of toxicosis and were killed 28 to 72 hours after treatment. Severe mitochondrial damage (swelling) and lipoidosis in myocardial tissues were observed in 2 of the 3 ponies; similar, but less severe, changes were observed in the 3rd pony. The hepatocytes of the 3 ponies were characterized by increased amounts of smooth endoplasmic reticulum, large numbers of lipid droplets...
Influence of dietary molybdenum on copper metabolism in ponies. The effects of molybdenum ingestion on copper metabolism were investigated in bile duct-cannulated ponies fed diets containing 1.01, 27.4 and 107.3 ppm molybdenum. Copper metabolism was assessed by examination of 64Cu and stable copper excretion in feces, bile and urine. The addition of molybdenum to the diet decreased copper absorption and retention as a consequence of increased excretion of dietary copper in feces and increased excretion of absorbed copper in bile. Only 5% or less of the absorbed copper was excreted in urine regardless of dietary treatment. Biliary molybdenum excretion was o...
Regional pulmonary perfusion in horses: a comparison between anaesthetised and conscious standing animals. The regional perfusion to the lungs of 14 ponies was studied using radioactively labelled microspheres injected intravenously. It was found that within half an hour of induction of anaesthesia the perfusion to the dependent lung had decreased significantly from the values in the standing animal. When anaesthesia was maintained for more than two and a half hours, however, the lung perfusions were not significantly different from the standing values when the animals were lying in lateral or supine recumbency.
Contagious equine metritis: effect of vaccination on control of the disease. Pony mares were vaccinated with killed contagious equine metritis (CEM) bacteria by IV, subcutaneous, and intrauterine (IU) routes (or a combination of these routes). The serum agglutinating antibody titer varied from 1:64 to 1:1,024 after vaccination. In pony mares challenge exposed with 96-hour-old culture of CEM bacteria given by IU route, there were clinical signs of CEM, but these signs were less severe in vaccinated mares than in nonvaccinated mares. The bacterium was isolated for the exudate and from uterine samples collected from the mares after challenge exposure. A low titer of IU an...
Influence of season and age on reproductive activity in pony mares on the basis of a slaughterhouse survey. Reproductive tracts were collected monthly over a 3-year period from 1,003 nonpregnant ponies at a slaughtering plant in Wisconsin. Ages of the animals were estimated from tooth replacement and wear. Ovaries were examined for follicular and luteal activity. There were no differences between left and right ovaries in size or occurrence of ovulation. The frequency of multiple ovulations, 10%, was higher than previously reported for ponies. The follicular changes during the ovulatory cycle did not support a two-wave theory of follicular growth. Ovarian activity changed seasonally, a finding simil...
Effects of copper pretreatment upon toxicity of selenium in ponies. Thirty-four adult ponies were used to determine the effects of single oral doses of copper (Cu) supplements (0, 20, and 40 mg of Cu/kg of body weight) on the toxicity of oral doses of selenium (Se) supplements (0, 2, 4, 6, and 8 mg of Se/kg of body weight) administered 24 hours after the copper was given. Signs of Se toxicosis-sweating, diarrhea, tachycardia, tachypnea, mild pyrexia, lethargy, and colic-developed in ponies given 6 and 8 mg of Se/kg of body weight without Cu pretreatment. Two of 4 ponies given 6 mg of Se/kg and both ponies given 8 mg of Se/kg without Cu pretreatment died within...
Lymphocyte responses to virus and mitogen in ponies during experimental infection with equine herpesvirus 1. Six pony foals, experimentally infected with equine herpesvirus 1 (EHV-1), were studied for their lymphocyte responses to EHV-1 and phytohemagglutinin (PHA) stimulations. Lymphocyte blastic transformation in the presence of EHV-1 appeared as early as 2 days after the foals were inoculated, reached a peak in 7 to 10 days, and subsequently decreased. In contrast, the lymphocyte blastic transformation in the presence of PHA increased sharply, reaching a peak in 2 to 3 days, and then decreased to its lowest level in 10 days after which it returned to its near preinoculation level. As for the mecha...
Recovery of peripheral chemoreceptor function after denervation in ponies. Resting ventilation (PaCO2) and ventilatory responses to acute hypoxia and to intravenous NaCN were assessed over a 4-yr period following cutting of the carotid sinus nerves and stripping the adventitia of the aortic arch. The data indicated essentially complete loss of peripheral chemoreceptor function immediately after surgery and hypoventilation during normoxia (delta PaCO2 = +8.7 Torr). There was a time-dependent, partial recovery of peripheral chemoreceptor function between 2 and 22 mo after surgery. Approximately 10% of the ventilatory response to iv NaCN returned, and 30-40% of the norm...
Esophageal and intrapleural pressures in the healthy conscious pony. Pleural and esophageal pressures were compared in 6 standing sedated ponies. Pleural pressure was measured with blunt needles attached to transducers and inserted in the 10th intercostal space level with and 10 and 20 cm above the point of the shoulder. Two balloons (a condom and an esophageal balloon) attached to transducers measured esophageal pressure in the cranial, middle, and caudal portions of the thoracic part of the esophagus. Tidal volume was measured by integrating a flow signal derived from a pneumotachograph attached to an endotracheal tube inserted through a tracheostomy. Frequen...
Equine pelvic flexure impaction. A model used to evaluate motor events and compare drug response. Pelvic flexure fistulas (2.5 cm diameter) were established in eight 160 kg Shetland X ponies. Impaction was induced at the pelvic flexure 25 times in the 8 animals through partial obstruction by a 1 litre rubber rebreathing bag fixed at the fistula site. Blood flow probes were implanted on the dorsal and ventral colic arteries (right colic artery and colic branch of ileocolic artery) in two of the ponies. Intraluminal pressure changes were measured at 8 different locations in the large colon during episodes of colic and following administration of flunixin or xylazine. Episodes of colic charac...
Effect of intraluminal oxygen in intestinal strangulation obstruction in ponies. This study examined the effect of intraluminal oxygen administration on mucosal morphology following intestinal strangulation obstruction (ISO) in anesthetized ponies. The ISO was produced by ligation of the intestinal vasculature in 5 ponies for 50 minutes and 2 ponies for 90 minutes. Two ponies served as controls. Light and scanning electron microscopic examination of intestinal biopsy specimens revealed progressive mucosal degeneration following ISO in nontreated intestines, whereas high magnification scanning electron microscopic examination documented subtle evidence of microvilli disrupt...
Lactic acidosis and arterial hypoxemia during sublethal endotoxemia in conscious ponies. Effects of a sublethal IV dose (10 micrograms/kg of body weight) of Escherichia coli endotoxin were studied in 7 conscious ponies. Arterial blood gases and plasma lactic acid were determined periodically throughout the 180 minutes of the study. Arterial hypoxemia occurred within 5 minutes despite intense hyperventilation. Colic and diarrhea occurred in all ponies within 30 minutes after endotoxin administration. Metabolic acidosis developed within 30 minutes and persisted throughout the study, indicating widespread reduced tissue perfusion.
Intravenous anaesthesia in horses after xylazine premedication. The effects of combining large doses of xylazine (1.1 mg per kg intravenously) with ketamine, methohexitone and thiopentone were studied in four experimental ponies. Onset of anaesthesia was more delayed after ketamine than after the barbiturates. Assessment of smoothness of induction and recovery indicated that all three combinations were effective and acceptable. Injection of xylazine was followed by atrioventricular (A-V) block which could be prevented by the prior administration of atropine. Blood pressure was well maintained with all three combinations of drugs. Arterial oxygen tension de...
Pathogaenicity of Toxoplasma gondii oocysts to ponies. Nine ponies were fed 100,000 infective Toxoplasma gondii oocysts and were given corticosteroid injections before and after feeding the T gondii oocysts. Titers to the Sabin-Feldman dye tests (1:2 to 1:16,384) developed within postinoculation days (PID) 7 to 21 and antibodies persisted to PID 133. Toxoplasma organisms were isolated from the tissues of 4 ponies (heart of 4, brain of 2, spinal cord of 3, diaphragm of 1, skeletal muscle of 1, liver of 1, kidneys of 1) killed between PID 36 and 63, but not from 5 ponies killed between PID 117 and 150. Seemingly, ponies are one of the more resistant...