Glucose is a simple sugar that serves as a primary energy source for horses. It is metabolized through various biochemical pathways to support cellular functions and overall energy requirements. In equine physiology, glucose levels are influenced by factors such as diet, exercise, and metabolic health. Monitoring glucose concentrations is important for understanding metabolic conditions, such as insulin resistance and equine metabolic syndrome, which can affect a horse's health and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the regulation, metabolism, and clinical implications of glucose in equine health.
Carter RA, Geor RJ, Burton Staniar W, Cubitt TA, Harris PA.This study described a scoring system for the assessment of apparent neck adiposity and evaluated morphometric measurements for assessment of neck and overall adiposity. Twenty-one barren Thoroughbred mares, 13 Arabian geldings and 75 Welsh, Dartmoor, or crossbred pony mares, were clinically examined and blood samples analysed for insulin, glucose, leptin, and triglycerides. Bodyweight (BW), height, length, girth and abdominal circumferences, neck length, neck crest height and neck circumference were measured, and body condition scores (BCS) and cresty neck scores (CNS) were rated. Girth:heigh...
Treiber KH, Geor RJ, Boston RC, Hess TM, Harris PA, Kronfeld DS.Advances in modeling and tracer techniques provide new perspective into glucose utilization and potential consequences to health or exercise performance. This study used stable isotope and compartmental modeling to evaluate how adaptation to a feed high in sugar and starch (SS) compared with a feed high in fat and fiber (FF) affects glucose kinetics at rest and during exercise in horses. Six trained Arabians adapted to each feed underwent similar tests at rest and while running approximately 4 m/s on a treadmill. For both tests, horses received 100 micromol/kg body weight [6,6-(2)H]glucose thr...
Escribano BM, Castejón FM, Santisteban R, Agüera EI, Tovar P, Vivo R, Rubio MD.Gender differences have not been shown in relation to the immune system in athletic horses. The aim of the present paper was to elucidate gender differences in the non-specific immune response of the polymorphonuclear neutrophil (PMN), plasma glucose and in hormones before and after an exercise in the lactate threshold (LT). A group of 12 Anglo-Arabian horses (6 females and 6 males, 4-7 years old) was observed. A submaximal exercise test was carried out at the LT. The results showed that males had a higher PMN percentage, plasma glucose values, Adherence index (AI) and random migration than fe...
Tóth F, Frank N, Elliott SB, Geor RJ, Boston RC.To evaluate the effects of endotoxin administered IV on glucose and insulin dynamics in horses. Methods: 16 healthy adult mares. Methods: Each week of a 2-week randomized crossover study, each horse received an IV injection (duration, 30 minutes) of Escherichia coli O55:B5 lipopolysaccharide (LPS) in 60 mL of sterile saline (0.9% NaCl) solution (20 ng/kg) or sterile saline solution alone (control treatment). Frequently sampled IV glucose tolerance test procedures were performed at 24 hours before (baseline) and 24 and 48 hours after injection; glucose and insulin dynamics were assessed via min...
Tiley HA, Geor RJ, McCutcheon LJ.To determine the effects of dexamethasone treatment on selected components of insulin signaling and glucose metabolism in skeletal muscle obtained from horses before and after administration of a euglycemic-hyperinsulinemic clamp (EHC). Methods: 6 adult Standardbreds. Methods: In a balanced crossover study, horses received either dexamethasone (0.08 mg/kg, IV, q 48 h) or an equivalent volume of saline (0.9% NaCl) solution, IV, for 21 days. A 2-hour EHC was administered for measurement of insulin sensitivity 1 day after treatment. Muscle biopsy specimens obtained before and after the EHC were a...
Frank N, Elliott SB, Boston RC.To determine the effects of long-term oral administration of levothyroxine sodium (L-T(4)) on glucose dynamics in adult euthyroid horses. Methods: 6 healthy adult mares. Methods: Horses received L-T(4) (48 mg/d) orally for 48 weeks. Frequently sampled IV glucose tolerance test procedures were performed on 3 occasions (24-hour intervals) before and at 16, 32, and 48 weeks during the treatment period. Data were assessed via minimal model analysis. The repeatability of measurements was evaluated. Results: During treatment, body weight decreased significantly from the pretreatment value; mean +/- ...
Hollis AR, Boston RC, Corley KT.Hyperglycemia in critically ill humans is associated with increased glucose production and insulin resistance and is associated with death. This might also be true in horses presenting with acute abdominal disease. Objective: Throughout hospitalization, hyperglycemia will be common in adult horses presenting with acute abdominal disease. Hyperglycemia will be associated with a worse prognosis for survival to hospital discharge. Methods: Two hundred sixty-nine adult horses with acute abdominal disease. Methods: Observational retrospective study. Records were reviewed for 269 horses that had glu...
Seddighi MR, Mohri M.To evaluate some of the clinical and laboratory parameters following diazepam-acepromazine, thiopental, and halothane anesthesia in Caspian ponies. Methods: Prospective experimental trial. Methods: Six healthy Caspian ponies of both sexes, aged 11 +/- 3 years and weighing 318 +/- 71 kg. Methods: The ponies were pre-medicated with diazepam (0.2 mg kg(-1)) and acepromazine (0.05 mg kg(-1)) IV. Sodium thiopental 5% was administered IV, 10 minutes later and anesthesia was maintained with halothane in oxygen for 1 hour. Heart and respiratory rates, mean arterial blood pressure, cardiac rhythm, and ...
Beaudry F, Vachon P.Glucosamine is an amino sugar involved in the biosynthesis of glycosylated proteins and lipids. Recently, with increased public interest in natural products medicine, glucosamine has been widely used to treat osteoarthritis, even though demonstrations of its actual efficacy remain relatively unknown. Information related to the pharmcokinetics of glucosamine is sparse. A recent analytical method published used 13C-glucosamine as an internal standard to analyse study samples. The method lacked accuracy owing to an important natural isotopic contribution of glucosamine to 13C-glucosamine ion abun...
Tiley HA, Geor RJ, McCutcheon LJ.To determine effects of dexamethasone on glucose dynamics and insulin sensitivity in healthy horses. Methods: 6 adult Standardbreds. Methods: In a balanced crossover study, horses received dexamethasone (0.08 mg/ kg, IV, q 48 h) or an equivalent volume of saline (0.9% NaCl) solution (control treatment) during a 21-day period. Horses underwent a 3-hour frequently sampled IV glucose tolerance test (FSIGT) 2 days after treatment. Minimal model analysis of glucose and insulin data from FSIGTs were used to estimate insulin sensitivity (Si), glucose effectiveness (Sg), acute insulin response to gluc...
Storer WA, Thompson DL, Waller CA, Cartmill JA.We previously reported that a rise in plasma leptin concentrations followed the rise in insulin and glucose in meal-fed horses, whereas horses maintained on pasture had little fluctuations in hormonal patterns. We have also described a hyperleptinemic-hyperinsulinemic condition that occurs in about 30% of our light horse mares of high body condition maintained on pasture. The present experiment was designed to 1) study the effect of 3 common feeding-housing regimens on leptin and other metabolic hormones in mares and 2) determine whether the hyperleptinemic condition interacted with these regi...
Pratt SE, Geor RJ, Spriet LL, McCutcheon LJ.The time course of insulin sensitivity, skeletal muscle glycogen and GLUT4 content, and glycogen synthase (GS) activity after a single bout of intense exercise was examined in eight horses. On separate days, a euglycemic-hyperinsulinemic clamp (EHC) was undertaken at 0.5, 4, or 24 h after exercise or after 48 h of rest [control (Con)]. There was no increase in mean glucose infusion rate (GIR) with exercise (0.5-, 4-, and 24-h trials), and GIR was significantly decreased at 0.5 h postexercise (GIR: 8.6 +/- 2.7, 6.7 +/- 2.0, 9.0 +/- 2.0, and 10.6 +/- 2.2 mg.kg(-1).min(-1) for Con and at 0.5, 4, ...
Varloud M, Fonty G, Roussel A, Guyonvarch A, Julliand V.Our knowledge of the microflora of the stomach of the horse is still limited, although some data indicate its important role in nutrition. The objective of this experiment was to investigate the microbial and biochemical profiles in the stomach of the horse and to quantify the disappearance of dietary starch. Total anaerobic bacteria, lactate-utilizing bacteria, lactobacilli, and streptococci were determined, and biochemical characteristics (pH, and DM, D- and L-lactate, D-glucose, NH3, and VFA concentrations) were measured in chyme collected from 4 horses by naso-gastric intubation aided by e...
Vervuert I, Bothe C, Coenen M.This study was conducted to evaluate the effects of different barley processing techniques on the glycaemic and insulinaemic responses in horses. It was hypothesized that the changes in pre-caecal starch digestibility caused by barley processing would affect metabolic responses. Six horses were fed in random order: whole (WB), finely ground (FGB), steamed (SB), steam-flaked (SFB) and popped barley (PB). The total barley intake was adjusted to 630 g starch/horse/day (1.2-1.5 g starch/kg BW/day). During a 10-day stabilization period, the horses also received 6 kg grass hay/horse/day. On the bloo...
Sato T, Itou T, Sato G, Kobayashi Y, Endo H, Sakai T.In order to investigate the utilization of glucose in equine skeletal muscle, we determined the coding and proximal promoter sequences of the hexokinase type II (HKII) gene in thoroughbred horse, Grevy's zebra and Hartmann's mountain zebra. The deduced amino acid sequence of thoroughbred horse HKII showed 100, 100, 94.4, 92.7 and 92.6% identities with Grevy's zebra, Hartmann's mountain zebra, human, mouse and rat HKIIs, respectively. In equine HKIIs, specific amino acid substitutions, Ile 159 and Arg 610, were found in the potential binding site for glucose. In addition, the nucleotide sequenc...
Boscan P, Watson Z, Steffey EP.To investigate the changes in colloid osmotic pressure (COP) and total protein concentrations during routine general anesthesia in horses. Methods: Prospective, clinical study. Methods: Twelve adult healthy horses aged 9.1 +/- 4.7 years and weighing 474 +/- 79 kg presented for elective surgery and 14 adult horses aged 8.7 +/- 7.3 years and weighing 510 +/- 85 kg. Methods: All horses were premedicated with xylazine and anesthesia induced with ketamine, diazepam and guaifenesin, and maintained with isoflurane for 2.5 hours. Lactate Ringer's solution was administered at 11 mL kg(-1) hour(-1). Osm...
Cameron EZ, Linklater WL.Adaptive theory predicts that mothers would be advantaged by adjusting the sex ratio of their offspring in relation to their offspring's future reproductive success. Studies investigating sex ratio variation in mammals have produced notoriously inconsistent results, although recent studies suggest more consistency if sex ratio variation is related to maternal condition at conception, potentially mediated by changes in circulating glucose level. Consequently, we hypothesized that change in condition might better predict sex ratio variation than condition per se. Here, we investigate sex ratio v...
Reinprecht B, Hackl S, Reisinger R, Zickl M, Spona J, Stanek C, Zentek J.The objective of this study was to investigate some metabolic and clinical effects of feed deprivation in horses that were submitted for orthopaedic surgery. The effects of preoperative feed restriction were investigated in 20 horses submitted for elective orthopaedic surgery. The patients were fasted from 12 hours before until 4 hours after surgery. Serum free amino acids, glucose,free fatty acids (FFA), white blood cell counts, creatine kinase (CK) and aspartate aminotransferase (AST) were determined 24 hours before surgery, 2 hours after the end of anaesthesia and 24 and 72 hours after surg...
Bröjer J, Holm S, Jonasson R, Hedenström U, Essén-Gustavsson B.The degradation of glycogen and its two forms, proglycogen (PG) and macroglycogen (MG) has been studied in horses performing different types of exercise, but no information is available about the resynthesis of PG and MG after exercise. Objective: To determine the resynthesis of PG and MG in skeletal muscle after intermittent uphill exercise. Methods: At a training camp 9 well-trained Standardbred trotters performed a training session comprising a warm-up period, 7 repeated 500 m bouts of exercise on an uphill slope and a recovery period. Muscle biopsies (m. gluteus medius) for analysis of PG,...
Geor RJ, Larsen L, Waterfall HL, Stewart-Hunt L, McCutcheon LJ.No studies in horses have examined the effect of route of carbohydrate (glucose) administration on the rate of muscle glycogen storage following glycogen-depleting exercise. Objective: Glucose delivery from the gastrointestinal tract limits the rate of muscle glycogen storage following glycogen-depleting exercise. Methods: In a crossover design, 7 fit horses completed treadmill exercise (EX) on 3 occasions to deplete muscle glycogen by approximately 50%. After EX horses received: 1) i.v. glucose infusion (IV; 0.5 g/kg bwt/h for 6 h), 2) oral glucose boluses (OR; 1 g/kg bwt at 0, 2 and 4 h post...
Gordon ME, McKeever KH, Bokman S, Betros CL, Manso-Filho H, Liburt N, Streltsova J.Horses in training tend to become inappetant; however, the mechanism responsible for this training-induced inappetance is not known. Objective: Training and/or ulcers alter the feed intake (FI) and hormonal and/or biochemical (active ghrelin, leptin, glucose, insulin and cortisol) responses to acute high intensity exercise. Methods: Eight Standardbred mares underwent 3 interval exercise tests (IET) and 3 parallel control tests (CON) before (IET1) and after 8 weeks of training (IET2) and after treatment for gastric ulcers (IET3). Plasma samples were taken before (0 min), during (last 10 sec of ...
Treiber KH, Hess TM, Kronfeld DS, Boston RC, Geor RJ, Friere M, Silva AM, Harris PA.Glucose regulation is critical for health and exercise performance. Objective: To quantify the effects of exercise and diet on insulin sensitivity (SI), glucose effectiveness (Sg), acute insulin response to glucose (AIRg) and disposition index (DI) in horses. Methods: This study applied the minimal model of glucose and insulin dynamics to exercise-trained Arabian geldings during rest or constant moderate-intensity exercise after 8 weeks adaptation to feeds high in sugar and starch (SS, n = 6) or fat and fibre (FF, n = 6). Horses underwent 2 frequently sampled i.v. glucose tolerance tests (FSIG...
Matsui A, Ohmura H, Asai Y, Takahashi T, Hiraga A, Okamura K, Tokimura H, Sugino T, Obitsu T, Taniguchi K.In man, muscle protein synthesis is accelerated by administering amino acids (AA) and glucose (Glu), because increased availability of amino acids and increased insulin secretion, is known to have a protein anabolic effect. However, in the horse, the effect on muscle hypertrophy of such nutrition management following exercise is unknown. Objective: To determine the effect of AA and Glu administration following exercise on muscle protein turnover in horses. We hypothesise that administration of AA and Glu after exercise effects muscle hypertrophy in horses, as already shown in man and other ani...
Zeyner A, Hoffmeister C, Einspanier A, Gottschalk J, Lengwenat O, Illies M.Quarter Horses are particularly susceptible to polysaccharide storage myopathy (PSSM). Nutritional therapy and possibly prophylaxis includes fat-supplemented diets whilst starch supply should be kept to a minimum. Objective: To investigate the glycaemic and insulinaemic response of clinically normal Quarter Horses to concentrates high in fat and low in starch. Methods: Twelve Quarter Horses were studied. The precondition for inclusion in the study population was that the horses had not shown clinical signs of myopathy. The Quarter Horses were fed according to a 4 x 4 Latin square design haylag...
Lindberg JE, Essén-Gustavsson B, Dahlborn K, Gottlieb-Vedi M, Jansson A.High starch intakes increase the risk for metabolic disorders and therefore alternative feedstuffs are of interest. High-fat oat varieties have a lower starch and higher energy content than regular oats and may therefore be useful in this context. Objective: Feeding high fat oats causes no adverse effects on the response to exercise and that the total amount of oats offered could be reduced compared to feeding with regular oats. Methods: Twelve Standardbred trotters were fed regular oats (diet C), high-fat oats (F), and a mixture (50:50) of C and F (M), together with haylage (30:70), in a Lati...
Stewart-Hunt L, Geor RJ, McCutcheon LJ.Increased insulin sensitivity occurs after a period of exercise training, but the mechanisms underlying this training-associated increase in insulin action have not been investigated. Objective: To examine the effects of short-term endurance training (7 consecutive days) and a subsequent period of inactivity (5 days) on whole body insulin sensitivity and GLUT-4 protein and the activities of glycogen synthase (GS) and hexokinase (HK) in skeletal muscle. It was hypothesised that training would increase insulin sensitivity in association with increased GLUT-4 protein and activities of GS and HK, ...
Pratt SE, Geor RJ, McCutcheon LJ.There is evidence that adaptation to diets rich in nonstructural carbohydrates (NSC) contributes to the development of insulin resistance in horses. To date, however, no study in horses has examined the effects of physical conditioning on diet-associated alterations in insulin sensitivity and glucose tolerance. Objective: To examine the effects of adaptation to concentrate feeds rich in NSC or fat on insulin sensitivity and glucose tolerance in horses, both in the sedentary state and after a subsequent period of physical conditioning. Methods: Fourteen mature Standardbred horses underwent both...
de Graaf-Roelfsema E, van Ginneken ME, van Breda E, Wijnberg ID, Keizer HA, van der Kolk JH.To study the possible long-term effect of improved glucose tolerance in horses after long-term training, as the impact of exercise training on glucose metabolism is still unclear in the equine species. It is not known whether there is a direct long-term effect of training or if the measurable effect on glucose metabolism is the residual effect of the last exercise session. Objective: To determine the chronic effect on glucose metabolism and peripheral insulin sensitivity of long-term training in horses by use of the euglycaemic hyperinsulinaemic clamp technique. Methods: Eleven Standardbred ho...
McCutcheon LJ, Geor RJ, Pratt SE, Martineau E, Ho K.Exercise is an important stimulus for the regulation of numerous metabolic functions in muscle, but there has been little investigation of the mechanism of exercise-enhanced glucose utilisation. Objective: To examine the effects of exercise on the signalling components Akt and glycogen synthase kinase-3 (GSK3) involved in insulin regulation of glycogen synthase (GS) activity. It was hypothesised that hyperinsulinaemia and prior exercise would alter the extent of Akt phosphorylation and GSK3beta deactivation and increase insulin stimulation of GS activity in skeletal muscle. Methods: Eight Stan...
Schneider N, Mouithys-Mickalad A, Lejeune JP, Duyckaerts C, Sluse F, Deby-Dupont G, Serteyn D.We investigated the oxygen (O(2)) uptake of equine articular chondrocytes to assess their reactions to anoxia/re-oxygenation. They were cultured under 5% or 21% gas phase O(2) and at glucose concentrations of 0, 1.0 or 4.5g/L in the culture medium (n=3). Afterwards, the O(2) consumption rate of the chondrocytes was monitored (oxymetry) before and after an anoxia period of 25min. The glucose consumption and lactate release were measured at the end of the re-oxygenation period. The chondrocytes showed a minimal O(2) consumption rate, which was hardly changed by anoxia. Independently from the O(2...
Liburt NR, McKeever KH, Malinowski K, Smarsh DN, Geor RJ.This study tested the hypotheses that age-induced alteration in cortisol, ACTH, and glucose concentrations are due to differences in the response of the hypothalamic-pituitary-adrenal axis and that exercise training would attenuate these differences. Six old (22.0±0.7 yr; mean±SE) and 6 young (7.3±0.6 yr) unfit Standardbred mares ran 3 graded exercise tests (GXT): before (GXT1), after 8 wk of training (GXT2), and at study end at 15 wk (GXT3). Mares trained 3 d/wk at 60% maximum heart rate. Each mare underwent 5 endocrine stimulation tests pre- and posttraining: 1) control (CON), 2) adrenoco...
Hurd H.A total of 28 components were detected in the free amino acid (FAA) pool of hydatid fluid from primary and secondary equine cysts, secondary ovine cysts and host plasma. Examination of data from equine cysts revealed that the majority of FAAs were present in significantly greater concentrations in secondary cysts, glycine being over 30 times more concentrated. Values for total carbohydrates and glucose did not, however, differ significantly and total protein content was greater in primary cysts. Comparison of the (FAA) pool of secondary equine and ovine cysts revealed strain variation. It was ...
Alonso JM, Esper CS, Pantoja JCF, Rosa GDS, Giampietro RR, Dos Santos B, Guerra ST, Ribeiro MG, Takahira RK, Watanabe MJ, Alves ALG, Rodrigues CA....Difference in blood and peritoneal glucose (DBPG) is used in clinical practice to support a diagnosis of septic peritonitis in horses. It is inexpensive, easy and rapid to perform. The aim of this study was to evaluate the accuracy of the DBPG to differentiate between septic and non-septic peritonitis in horses. Blood and peritoneal fluids were harvested from suspected animals. Plasma and peritoneal glucose levels, total nucleated cell count, direct microscopic and microbiological examinations of the peritoneal fluid were evaluated. Using DBPG levels, the animals were classified into two group...
Sticker LS, Thompson DL, Bunting LD, Fernandez JM, DePew CL, Nadal MR.Twelve light horse mares were fed a control diet that provided 100% of their maintenance protein and energy requirements for 7 d and were then either continued on the control diet or totally deprived of feed (with access to water) for 3 d . Plasma samples were drawn twice daily throughout the experiment, at 15-min intervals for 9 h beginning 45 h after feed removal, and at 10-min intervals around an exercise bout beginning 73 h after feed removal. Feed deprivation increased (P < or = .06) whole blood beta-hydroxybutyrate and plasma NEFA, urea N, L-lactate, and glucagon concentrations, decrease...
Martínez R, Godoy A, Naretto E, White A.1. Packed cell volume (PCV) and plasma catecholamines, cortisol and glucose were determined in blood samples obtained from race horses, after competition. 2. All these parameters were higher than basals but catecholamines increased 6-7 times while cortisol was enhanced only by 25%. 3. The increase of glucose and PCV was related to the rise of catecholamines. 4. In samples withdrawn after overnight stress caused by change of horseshoes, it was not possible to find values from basal values significantly different. 5. Influence of nervous temperament was observed only in the higher hematocrit fou...
Fowden AL, Ralph MM, Silver M.Prostaglandins (PGs) are produced by a variety of uteroplacental tissues during pregnancy and are released into the fetal fluid sacs and both the uterine and umbilical circulations. Uterine PG output increases towards term and is enhanced by maternal undernutrition in pregnant ewes and mares. In both species, withdrawal of food but not water for 30-48 h increases uterine venous PG levels and the uterine venous arterial concentration differences in PGE and 13, 14, dihydro-15-keto-prostaglandin F2 alpha (PGFM), the stable metabolite of PGF2 alpha. The increments in uterine V-A concentration diff...
de Laat MA, Fitzgerald DM.Equine insulin dysregulation (ID) comprises amplified insulin responses to oral carbohydrates or insulin resistance, or both, which leads to sustained or periodic hyperinsulinaemia. Hyperinsulinaemia is important in horses because of its clear association with laminitis risk, and the gravity of this common sequela justifies the need for a better understanding of insulin and glucose homoeostasis in this species. Post-prandial hyperinsulinaemia is the more commonly identified component of ID and is diagnosed using tests that include an assessment of the gastrointestinal tract (GIT). There are se...
Jose-Cunilleras E, Hinchcliff KW, Sams RA, Devor ST, Linderman JK.In a randomized, balanced, crossover study each of six fit, adult horses ran on a treadmill at 50% of maximal rate of oxygen consumption for 60 min after being denied access to food for 18 h and then 1) fed corn (51.4 kJ/kg digestible energy), or 2) fed an isocaloric amount of alfalfa 2-3 h before exercise, or 3) not fed before exercise. Feeding corn, compared with fasting, resulted in higher plasma glucose and serum insulin and lower serum nonesterified fatty acid concentrations before exercise (P < 0.05) and in lower plasma glucose, serum glycerol, and serum nonesterified fatty acid conce...
Arai T, Hosoya M, Nakamura M, Magoori E, Uematsu Y, Sako T.The activities of the enzymes involved in the malate-aspartate shuttle and m RNA expression of malate dehydrogenase (MDH), a crucial enzyme for the NADH shuttle that produces ATP in glucose metabolism in the peripheral leukocytes of horses, were measured to investigate the change in metabolic states with training. There were no significant differences in plasma glucose and immunoreactive insulin concentrations between race horses and riding horses, used as a comparable reference. The cytosolic and mitochondrial MDH activities in leukocytes of race horses were significantly higher than those of...
Rendle DI, Armstrong SK, Heller J, Hughes KJ.Point-of-care glucometry is used commonly in clinical and research settings; however, accuracy and precision of this method are concerns. The objectives of this study were to determine the accuracy of glucometry in adult horses and the precision of duplicate measurements. Blood samples were collected from 62 horses into one plain syringe, one EDTA tube and three fluoride oxalate (FO) tubes. Immediately after collection, glucose concentrations in whole blood were determined, in duplicate, by glucometry from the syringe (plain whole blood [WB] group), EDTA tube (EDTA group) and one FO tube (FO g...
Anwer MS, Chapman TE, Gronwall R.Variables of glucose metabolism determined by the use of [U-14C]glucose were compared in fed and fasted ponies. Relative recycling of glucose carbon with respect to tritium in fed animals was negligible for 6-T and 3-T and 16% for 2-T studies; in fasted animals relative recycling was 12 and 14% for 6-T and 3-T studies, respectively. Minimal mass of total-body glucose decreased significantly in the fasted ponies. Based on relative recycling of carbon to tritium, a negligible fraction of plasma glucose was produced via the Cori cycle or from glycerol in fed ponies; recycled tricarbon units contr...
Tóth F, Frank N, Geor RJ, Boston RC.To investigate the effects of dexamethasone or levothyroxine sodium on endotoxin-induced alterations in glucose and insulin dynamics. Methods: 24 horses. Methods: Horses were randomly allocated to 3 treatment groups and received 48 mg of levothyroxine mixed with 200 g of oats, 20 mg of dexamethasone plus oats, or oats alone (control) for 15 days, followed by IV infusion of lipopolysaccharide (20 ng/kg) while individually housed in stalls. Frequently sampled IV glucose tolerance tests were performed prior to pretreatment, after pretreatment, and 20 hours after lipopolysaccharide administration....
Roşu O, Melega I, Evans AL, Arnemo JM, Küker S.Feral horses are immobilized for a variety of reasons including population control via contraceptives. Although opioid combinations have been successfully used for immobilization of feral horses, there is a need for combinations using drugs that are more readily available and present less of a human health hazard. We evaluated the chemical immobilization with physiological measurements and blood gas analyses of 91 free-ranging feral horses () remotely immobilized with a combination of 30 mg medetomidine and 775 mg ketamine in a single disposable 6 ml dart. During immobilization, heart rate, re...
Jansen WL, Geelen SN, van der Kuilen J, Beynen AC.The aim of the present study was to establish whether the inhibitory effect of fat feeding on fibre digestion has been underestimated due to the substitution of fat for corn starch. A high fat intake has been shown to lower total intestinal tract apparent digestibility of crude fibre in horses but, since fat was substituted for nonstructural carbohydrates, including starch, the specific effect of fat could not be ascertained. The possibility could not be excluded that starch also inhibits fibre digestibility, so that the fat effect observed earlier would have been underestimated. In this study...
Engle CC, Foley CW.Uterine tubal fluids were collected twice a day from mares for 5 consecutive estrous cycles between March 15 and September 1. Follicular fluids were aspirated from the follicles of exteriorized ovaries of 3 mares between days 2 and 5 of estrus. Uterine tubal fluid and follicular fluid were analyzed for osmolarity, dry matter, total lipids, total free fatty acids, glucose, fructose, and lactic acid. Blood samples were collected (jugular venipuncture) throughout the estrous cycle, and the same physical and biochemical analyses were made on blood plasma. A difference (P less than 0.01) was found ...
Sloet van Oldruitenborgh-Oosterbaan MM, Wensing T, Barneveld A, Breukink HJ.To determine whether a clinical examination was adequate to assess the fitness of horses in an endurance ride, and to characterise the relationship between a clinical assessment of the horse's fitness and its blood biochemistry, 23 horses were monitored before, during and after an 87 to 100 km endurance ride. Blood samples were taken before the ride, at three checkpoints on the ride, immediately after the ride and one day later for the determination of packed cell volume, total protein, lactate, glucose, non-esterified fatty acids, creatine phosphokinase, aspartate aminotransferase and plasma ...
Rose RJ, Hodgson DR.Eleven horses were studied throughout a 12 week training schedule. Serial blood samples were taken for haematological analysis and an extensive biochemical profile, including the following parameters: sodium, potassium, chloride, bicarbonate, glucose, creatinine, urea, bilirubin, iron, total protein, albumin, alkaline phosphatase, aspartate aminotransferase, creatine kinase, gamma glutamyl transferase, calcium phosphate and cholesterol. There were few significant changes detected and it was concluded that routine haematological and biochemical screening has no useful role in assessing the fitn...
Lucke JN, Hall GM.Blood samples were taken before and after a cross country race over the marathon distance of 42 km. There was a rise in blood glucose and plasma free fatty acids and glycerol associated with a rise in plasma cortisol and glucagon but the fall in insulin was not significant (P > 0.05). Plasma potassium and albumin concentrations increased, calcium decreased and there was no change in sodium or bicarbonate concentrations. There was an increase in plasma urea, creatinine, uric acid, bilirubin and isocitrate dehydrogenase but no change in alkaline phosphatase. There was a rise in plasma creatine k...
Kinsella HM, Hostnik LD, Rings LM, Swink JM, Burns TA, Toribio RE.The endocrine pancreas and hypothalamic-pituitary-adrenal axis (HPAA) are central to energy homeostasis, but information on their dynamics in response to energy challenges in healthy newborn foals is lacking. Objective: To evaluate glucagon, insulin, ACTH, and cortisol response to fasting and carbohydrate administration in healthy foals. Methods: Twenty-two healthy Standardbred foals ≤4 days of age. Methods: Foals were assigned to fasted (n = 6), IV glucose (IVGT; n = 5), PO glucose (OGT; n = 5), and PO lactose (OLT; n = 6) test groups. Blood samples were collected frequently for 210 min...
Graham-Thiers PM, Bowen LK.Feeding management in horses suggests feeding horses in advance of exercise, particularly the grain portion of the diet. Plasma amino acids () peak at 3 to 6 h postfeeding depending on the AA. The timeframe between feeding and exercise may affect the availability of AA during and after exercise. The purpose of this study was to observe the differences in plasma AA in horses fed prior to exercise or after exercise. Eight light type horses were fed a diet with adequate protein and AA for horses in light to moderate exercise. After an adjustment period, horses completed a standardized exercise te...
Nelis H, Wojciechowicz B, Franczak A, Leemans B, D'Herde K, Goossens K, Cornillie P, Peelman L, Van Soom A, Smits K.The oviduct undergoes dramatic functional and morphological changes throughout the oestrous cycle of the mare. To unravel the effects of steroids on the morphology, functionality and gene expression of the equine oviduct, an in vitro oviduct explant culture system was stimulated with physiological concentrations of progesterone and 17β-oestradiol. Four conditions were compared: unsupplemented preovulatory explants, preovulatory explants that were stimulated with postovulatory hormone concentrations, unsupplemented postovulatory explants and postovulatory explants that were stimulated with pre...
Williams CA, Kronfeld DS, Staniar WB, Harris PA.Plasma concentrations of glucose and insulin following a meal were compared in twelve Thoroughbred mares fed a pelleted concentrate (PC), a traditional sweet feed high in sugar and starch (SS), or a feed high in fat and fiber (FF). The feeds had similar DE and CP but differed in fat (19, 32, and 166 g/kg DM, respectively), NDF (199, 185, and 369 g/kg DM, respectively) and nonstructural carbohydrates (574, 645, and 247 g/kg, respectively). Mares were randomly assigned to two groups balanced for foaling date and weight. All mares received PC in late gestation; then, after foaling, one group was ...
Knowles EJ, Withers JM, Mair TS.The use of plasma fructosamine concentration ([fructosamine]) as a marker of abnormal glucose homeostasis in laminitic horses has not been investigated. Objective: Plasma fructosamine concentration may be higher amongst laminitic horses than normal horses; this might relate to underlying insulin resistance. Objective: 1) To compare [fructosamine] between laminitic and normal horses. 2) To investigate associations between [fructosamine] at presentation in laminitic horses with a) single sample markers of insulin resistance and b) outcome. Methods: Plasma fructosamine concentration, fasting seru...
Burrows GE.Phenylbutazone (PBZ), a classic anti-inflammatory and prostaglandin-synthesis inhibitor drug, was used to determine the role of prostaglandins and other mediators on the development and perpetuation of the response to intraperitoneal Escherichia coli endotoxin administration. The PBZ (15 mg/kg of body weight) was administered IV 30 minutes after endotoxin administration and was repeated later at 6 and 12 hours at a dose of 10 mg/kg. A variety of evaluation measurements (hematologic, blood glucose, pyruvate, lactate and fibrinogen, serum beta-glucuronidase, prothrombin time, blood gases, hepati...
de Laat MA, van Haeften JJ, Sillence MN.Managing equine hyperinsulinemia is crucial for preventing laminitis, but our understanding of the mechanisms involved in insulin dysregulation in this species is incomplete. C-peptide is co-secreted with insulin but is resistant to hepatic metabolism and can be used to study insulin dysregulation. This study examined C-peptide secretion in serial blood samples collected after oral and i.v. dextrose (0.75 g/kg) administration to 9 ponies (BCS, 7.1 ± 0.5). The ponies were designated as hyperinsulinemic (HI) or normoinsulinemic (NI) responders before the study, using oral glucose tests and fast...
Breuhaus BA.Certain breeds of horses may be genetically predisposed to developing insulin dysregulation, which is a risk factor for development of endocrinopathic laminitis in horses. This study was performed to test the hypotheses that Paso Fino horses exhibit evidence of insulin dysregulation compared with Thoroughbred horses and that obesity exaggerates the insulin dysregulation. Intravenous glucose tolerance tests were performed in 14 moderate-weight Thoroughbreds, 12 moderate-weight Paso Finos, and 12 overweight Paso Finos. Moderate Paso Finos had greater baseline serum insulin concentrations, area u...
Myers CJ, Magdesian KG, Kass PH, Madigan JE, Rhodes DM, Marks SL.This retrospective study describes the use of and complications associated with parenteral nutrition (PN) administration to 53 equine neonates at the University of California Veterinary Medical Teaching Hospital. Medical records were examined and information obtained on signalment, physical examination, clinical diagnosis, outcome, total hospitalization time, insulin administration, microbiology culture results, other complications (i.e. thrombophlebitis) and necropsy findings. Complete blood count and serum biochemistry analytes, venous blood gas, serum electrolyte and glucose concentrations,...
Eades SC, Stokes AM, Johnson PJ, LeBlanc CJ, Ganjam VK, Buff PR, Moore RM.To quantify changes in endothelium-derived factors and relate those changes to various aspects of digital hemodynamics during the prodromal stages of carbohydrate overload (CHO)-induced laminitis in horses. Methods: 20 adult horses without abnormalities of the digit. Methods: Digital and jugular venous blood samples were collected at 1-hour intervals (for assessment of endothelin-1 [ET-1] immunoreactivity and measurement of glucose, insulin, and nitric oxide [NO] concentrations) or 4-hour intervals (CBC and platelet-neutrophil aggregate assessment) for 8 hours or 16 hours after induction of CH...
Dunkel B, Knowles EJ, Chang YM, Menzies-Gow NJ.Blood l-lactate and glucose concentrations were higher in ponies with gastrointestinal disease than in horses, possibly because of differences in body condition (BC). Objective: To investigate whether l-lactate and glucose concentrations correlate with BC and differ between healthy horses and ponies. Methods: Systemically healthy client-owned ponies (n = 101) and horses (n = 51). Methods: Prospective observational study. Breed, weight, height, and subjective and objective measures of BC were recorded and l-lactate and glucose concentrations were measured. Correlations between l-lactate and glu...
Thompson JC, Ellison R, Gillett R, Badcoe L.Thyrotropin releasing hormone (TRH) stimulation tests were carried out on a number of horses, including one clinically affected horse whose age and clinical signs suggested that a pituitary adenoma was most unlikely. The results of these tests indicated that, according to criteria published overseas, the majority of these horses had pituitary adenomas. The fact that clinically normal or affected horses may have marked increases in cortisol concentrations indicates that the TRH stimulation test is not suitable for the diagnosis of pituitary adenoma. Other tests, including alterations in glucose...
