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.
Glunk EC, Hathaway MR, Grev AM, Lamprecht ED, Maher MC, Martinson KL.Modern horse management systems tend to limit a horse's opportunity to forage, rely on meal feeding, and may contribute to the increase in equine obesity. The use of slow-feed hay nets represents an opportunity to extend foraging time while feeding a restricted diet. The objectives of this study were to determine if limit feeding combined with a slow-feed hay net would affect morphometric measurements and postprandial metabolite and hormone patterns in overweight adult horses. Eight adult Quarter horses (BW 563 kg ± 4.6 kg; BCS 7.2 ± 0.3) were used in a randomized complete block design, with...
Coverdale JA, Hammer CJ, Walter KW.Many environmental factors can alter the phenotype of offspring when applied during critical periods of early development. In most domestic species, maternal nutrition influences fetal development and the fetus is sensitive to the nutrition of the dam during pregnancy. Many experimental models have been explored including both under- and overnutrition of the dam. Both nutritional strategies have yielded potential consequences including altered glucose tolerance, pancreatic endocrine function, insulin sensitivity, body composition, and colostrum quality. Although the impact of maternal nutritio...
Jellyman JK, Valenzuela OA, Fowden AL.Adrenal glucocorticoids, such as cortisol, are essential for normal fetal development and for maintaining homeostasis in adults. Developmental studies in humans and other animals have shown that exposure to excess glucocorticoids during critical windows of perinatal development can program permanent changes in hypothalamic-pituitary-adrenal (HPA) axis function and metabolic function, with adverse implications for the long-term health of the exposed offspring. The current review compares the programming of postnatal HPA axis function and glucose homeostasis among different species overexposed p...
Bamford NJ, Baskerville CL, Harris PA, Bailey SR.The enteroinsular axis is a complex system that includes the release of incretin hormones from the gut to promote the absorption and utilization of glucose after a meal. The insulinogenic effect of incretin hormones such as glucagon-like peptide-1 (GLP-1) remains poorly characterized in the horse. The aim of this study was to compare postprandial glucose, insulin, and GLP-1 responses of different equine breeds adapted to twice-daily meals containing micronized maize. Four Standardbred horses, 4 mixed-breed ponies, and 4 Andalusian cross horses in moderate BCS (5.5 ± 0.2 out of 9) were fed mea...
Brennan KM, Graugnard DE, Spry ML, Brewster-Barnes T, Smith AC, Schaeffer RE, Urschel KL.To determine effects of a microalgae nutritional product on insulin sensitivity in horses. Methods: 8 healthy mature horses. PROCEDURES :Horses (n = 4/group) received a basal diet without (control diet) or with docosahexaenoic acid-rich microalgae meal (150 g/d) for 49 days (day 0 = first day of diet). On day 28, an isoglycemic hyperinsulinemic clamp procedure was performed. Horses then received dexamethasone (0.04 mg/kg/d) for 21 days. On day 49, the clamp procedure was repeated. After a 60-day washout, horses received the alternate diet, and procedures were repeated. Plasma fatty acid, gluco...
Martin Giménez T, Aguirre Pascasio CN, de Blas Giral I.Andalusian horses have been proposed as a breed predisposed to equine metabolic syndrome (EMS) phenotype [1] because they are prone to exhibiting regional, generalised adiposity and tendency to laminitis [2]. Insulin dysregulation represents the main pathophysiological cause for all the features of EMS, however there are no epidemiological studies in this breed. Objective: To assess insulin dysregulation through insulin proxies in Andalusian horses with different levels of obesity. Methods: Cross-sectional study. Methods: One hundred and sixty-four Andalusians (78 stallions and 86 mares, 2-15 ...
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...
Karikoski NP, Patterson-Kane JC, Singer ER, McFarlane D, McGowan CM.Hoof lamellar pathology in horses with pituitary pars intermedia dysfunction (PPID) has not been described previously. Objective: To describe the histomorphometry and pathological lesions in hoof lamellar tissue of animals that had PPID with or without concurrent laminitis, with reference to age-matched controls. We hypothesised that lamellar lesions consistent with laminitis would be associated with PPID, even in animals without current or historical laminitis. Methods: Prospective case-control study. Methods: Mid-dorsal hoof histological sections were obtained post mortem from the forelimbs ...
Pazzola M, Pira E, Sedda G, Vacca GM, Cocco R, Sechi S, Bonelli P, Nicolussi P.Several concerns have been raised over the health of animals used in equestrian games that have their origins in historical or religious events and are currently held in many countries. This study investigated physiological stress response and health status of horses participating in the Sartiglia, a historical horse tournament held in the city of Oristano, Italy, which is principally based on the attempts of masked horsemen at a gallop to run a sword through a hole in a suspended silver star. Blood samples were collected from 21 horses the day before the tournament (D0), during the tournament...
de Laat MA, Robinson MA, Gruntmeir KJ, Liu Y, Soma LR, Lacombe VA.Equine metabolic syndrome is characterized by obesity and insulin resistance (IR). Currently, there is no effective pharmacological treatment for this insidious disease. Glucose uptake is mediated by a family of glucose transporters (GLUT), and is regulated by insulin-dependent and -independent pathways, including 5-AMP-activated protein kinase (AMPK). Importantly, the activation of AMPK, by 5-aminoimidazole-4-carboxamide-1-D-ribofuranoside (AICAR) stimulates glucose uptake in both healthy and diabetic humans. However, whether AICAR promotes glucose uptake in horses has not been established. I...
Bamford NJ, Potter SJ, Harris PA, Bailey SR.The relative influences of obesity and adaptation to high glycaemic diets on the development of insulin dysregulation in equids are unclear. Objective: To determine whether increased adiposity per se is responsible for the decreased insulin sensitivity often observed in obese horses or whether a dietary glycaemic response is critically important. Methods: Randomised controlled trial. Methods: Eighteen horses and ponies were studied over a 20-week period. They received ad libitum hay plus either a high fat (low glycaemic) diet (FAT; n = 6) or a similar (isocaloric) diet containing 1.5 g/kg bwt ...
Smith S, Harris PA, Menzies-Gow NJ.The in-feed oral glucose test (OGT) and oral sugar test (OST) are advocated as field tests of insulin sensitivity in horses and ponies but have not been directly compared. Objective: To compare the insulin response to OGT and OST in 8 ponies and 5 horses of unknown insulin sensitivity. Methods: Experimental, randomised crossover study. Methods: Animals were fasted for 8 h overnight before and throughout testing. They were fed 1 g/kg bwt glucose powder with chaff (OGT) or 0.15 ml/kg bwt corn syrup (Karo™ Light Syrup; OST) was administered per os in a randomised crossover study with 48...
Choi YH, Ross P, Velez IC, Macías-García B, Riera FL, Hinrichs K.Equine embryos develop in vitro in the presence of high glucose concentrations, but little is known about their requirements for development. We evaluated the effect of glucose concentrations in medium on blastocyst development after ICSI. In experiment 1, there were no significant differences in rates of blastocyst formation among embryos cultured in our standard medium (DMEM/F-12), which contained >16 mM glucose, and those cultured in a minimal-glucose embryo culture medium (<1 mM; Global medium, GB), with either 0 added glucose for the first 5 days, then 20 mM (0-20) or 20 mM for th...
Medina-Torres CE, Underwood C, Pollitt CC, Castro-Olivera EM, Hodson MP, Richardson DW, van Eps AW.Failure of lamellar energy metabolism, with or without ischaemia, may be important in the pathophysiology of sepsis-associated laminitis. Objective: To examine lamellar perfusion and energy balance during laminitis development in the oligofructose model using tissue microdialysis. Methods: In vivo experiment. Methods: Six Standardbred horses underwent laminitis induction using the oligofructose model (OFT group) and 6 horses were untreated controls (CON group). Microdialysis probes were placed in the lamellar tissue of one forelimb (all horses) as well as the skin dermis of the tail in OFT hor...
Mendoza FJ, Estepa JC, Gonzalez-De Cara CA, Aguilera-Aguilera R, Toribio RE, Perez-Ecija A.Donkeys are commonly afflicted by endocrine and metabolic disturbances but few studies have investigated endocrine variables involved in energy regulation and their association with morphometric indices, age or gender in this species. Hemostatic and clinical differences have been demonstrated between horses and donkeys, so to consider both species as metabolically and endocrinologically similar could lead to misdiagnosis. In this study, plasma concentrations of glucose, triglycerides and endocrine factors involved in energy homeostasis (insulin, glucagon, leptin, adiponectin, ghrelin and insul...
Radcliffe RM, Buchanan BR, Cook VL, Divers TJ.To summarize the current medical literature and provide a clinical perspective of whole blood point-of-care (POC) biomarkers in large animal emergency and critical care practice. Methods: Original studies, reviews, and textbook chapters in the human and veterinary medical fields. Conclusions: POC biomarkers are tests used to monitor normal or disease processes at or near the patient. In both human and veterinary medicine these tools are playing an increasingly important role in the management of critical diseases. The most important whole blood POC biomarkers available for veterinary practitio...
Pratt-Phillips SE, Geor RJ, McCutcheon LJ.To compare, in horses, estimates of insulin sensitivity obtained from minimal model analysis (MMA) of a frequently sampled IV glucose tolerance test (FSIGTT) with estimates from the euglycemic-hyperinsulinemic clamp (EHC) and to evaluate the validity of surrogate estimates of insulin sensitivity derived from an oral glucose tolerance test (OGTT). Methods: 18 mature Standardbreds (mean ± SD body weight, 428.9 ± 35.9 kg; mean ± SD body condition score, 4.4 ± 1.0 [on a scale of 1 to 9]). Methods: All horses underwent at least 2 of the 3 procedures (EHC [n = 15], insulin-modified FSIGTT [18], ...
Medina-Torres CE, Underwood C, Pollitt CC, Castro-Olivera EM, Hodson MP, Richardson DW, van Eps AW.Lamellar perfusion is thought to be affected by weightbearing and limb load cycling; this may be critical in the development of supporting limb laminitis. Objective: To document the effects of unilateral weightbearing and altered limb load cycling on lamellar energy metabolism and perfusion. Methods: Randomised, controlled (within subject), experimental trial. Methods: Nine Standardbred horses were instrumented with microdialysis probes in the foot lamellar tissue and skin (over the tail base). Urea (20 mmol/l) was added to the perfusate. Samples were collected every 15 min for a 1 h con...
Collicutt NB, Garner B, Berghaus RD, Camus MS, Hart K.Although delays between blood sample collection and analysis are common in veterinary medicine, the effect of prolonged serum-clot contact time on serum glucose concentration is not well established and species differences have not been elucidated. Objective: The objective was to investigate the effect of storage time and temperature on serum glucose concentration in stored whole blood samples from horse, dog, alpaca, and sturgeon. Methods: Whole blood specimens were divided into 7 no-additive tubes and serum was separated from one sample within one hour, serving as the reference sample. The r...
Brunner J, Liesegang A, Weiss S, Wichert B.The aim of this study was to compare the nutritional management of show jumping horses in practice with recommendations from the literature. Additionally, the effects of these feeding practices on several blood metabolic parameters before and after exercise were studied. Blood samples were collected in the field from 27 different horses at 71 trials on the level M1 to S2 show jumping competitions in Switzerland and questionnaires on feeding practice of the studied horses were evaluated. The questionnaires revealed that during training and on tournament days horses received on average 3.1 kg o...
de Laat MA, Clement CK, Sillence MN, McGowan CM, Pollitt CC, Lacombe VA.An increased incidence of metabolic disease in horses has led to heightened recognition of the pathological consequences of insulin resistance. Laminitis, failure of the weightbearing digital lamellae, is an important consequence. Altered trafficking of specialised glucose transporters (GLUTs), responsible for glucose uptake, is central to the dysregulation of glucose metabolism and may play a role in the pathophysiology of laminitis. Objective: We hypothesised that prolonged hyperinsulinaemia alters the regulation of glucose transport in insulin-sensitive tissue and digital lamellae. Our obje...
Mastro LM, Adams AA, Urschel KL.Equine pituitary pars intermedia dysfunction (PPID) has been associated with reduced insulin sensitivity in comparison with younger adult horses; however, the difference in insulin sensitivity between horses with PPID and aged-matched controls has not been well characterized. The objective of the study was to determine if aged horses with PPID had reduced insulin sensitivity and alterations in the insulin-mediated signaling pathways in the skeletal muscle when compared with healthy aged horses. Isoglycemic hyperinsulinemic clamp procedures were conducted in 12 horses that were classified as ei...
Salazar-Ortiz J, Monget P, Guillaume D.Feed intake affects the GH-IGF system and may be a key factor in determining the ovarian follicular growth rate. In fat mares, the plasma IGF-1 concentration is high with low GH and a quick follicular growth rate, in contrast to values observed in thin mares. Nothing is known regarding the long-term effects of differential feed intake on the IGF system. The objective of this experiment was to quantify IGFs, IGFBPs, GH, glucose, insulin, gonadotropin and progesterone (P4) in blood and in preovulatory follicular fluid (FF) in relation to feeding levels in mares. Methods: Three years prior to the...
Grimsrud KN, Ait-Oudhia S, Durbin-Johnson BP, Rocke DM, Mama KR, Rezende ML, Stanley SD, Jusko WJ.The present study characterizes the pharmacokinetic (PK) and pharmacodynamic (PD) relationships of the α2-adrenergic receptor agonists detomidine (DET), medetomidine (MED) and dexmedetomidine (DEX) in parallel groups of horses from in vivo data after single bolus doses. Head height (HH), heart rate (HR), and blood glucose concentrations were measured over 6 h. Compartmental PK and minimal physiologically based PK (mPBPK) models were applied and incorporated into basic and extended indirect response models (IRM). Population PK/PD analysis was conducted using the Monolix software implementing t...
Peugnet P, Wimel L, Duchamp G, Sandersen C, Camous S, Guillaume D, Dahirel M, Dubois C, Jouneau L, Reigner F, Berthelot V, Chaffaux S, Tarrade A....In equids, placentation is diffuse and nutrient supply to the fetus is determined by uterine size. This correlates with maternal size and affects intra-uterine development and subsequent post-natal growth, as well as insulin sensitivity in the newborn. Long-term effects remain to be described. In this study, fetal growth was enhanced or restricted through ET using pony (P), saddlebred (S) and draft (D) horses. Control P-P (n = 21) and S-S (n = 28) pregnancies were obtained by AI. Enhanced and restricted pregnancies were obtained by transferring P or S embryos into D mares (P-D, n =...
Gim JA, Ayarpadikannan S, Eo J, Kwon YJ, Choi Y, Lee HK, Park KD, Yang YM, Cho BW, Kim HS.Physical exercise induces gene expression changes that trigger glucose metabolism pathways in organisms. In the present study, we monitored the expression levels of LDHA (lactate dehydrogenase) and GYS1 (glycogen synthase 1) in the blood, to confirm the roles of these genes in exercise physiology. LDHA and GYS1 are related to glucose metabolism and fatigue recovery, and these processes could elicit economically important traits in racehorses. We collected blood samples from three retired thoroughbred racehorses, pre-exercise and immediately after 30 min of exercise. We extracted total RNA and ...
Sørensen MA, Petersen LJ, Bundgaard L, Toft N, Jacobsen S.As in other fibroproliferative disorders, hypoxia has been suggested to play a key role in the pathogenesis of exuberant granulation tissue (EGT). The purpose of this study was to investigate metabolism and blood flow locally in full-thickness wounds healing with (limb wounds) and without (body wounds) formation of EGT. Microdialysis was used to recover endogenous metabolites from the wounds, and laser Doppler flowmetry was used to measure blood flow. Measurements were performed before wounding and 1-28 days after wounding. Blood flow was consistently lower in limb wounds than in body wounds t...
Kranenburg LC, Westermann CM, de Sain-van der Velden MG, de Graaf-Roelfsema E, Buyse J, Janssens GP, van den Broek J, van der Kolk JH.Insulin resistance in horses is an emerging field of interest as it is thought to be a contributing factor in the pathogenesis of many equine conditions. Objective: The objectives of the present study were to determine the effects of long-term oral administration of L-carnitine on insulin sensitivity, glucose disposal, plasma leptin concentrations and acylcarnitine spectrum both in plasma and urine. Methods: Six 3-year-old healthy warmblood geldings were used. In a double blind 2 × 2 Latin square design at a dosage of 100 mg/kg body weight (BW)/day for 28 days the effects of oral supplementat...
Medina-Torres CE, Pollitt CC, Underwood C, Castro-Olivera EM, Collins SN, Allavena RE, Richardson DW, van Eps AW.Failure of lamellar energy metabolism may contribute to the pathophysiology of equine laminitis. Tissue microdialysis has the potential to dynamically monitor lamellar energy balance over time. The objectives of this study were to develop a minimally invasive lamellar microdialysis technique and use it to measure normal lamellar energy metabolite concentrations over 24 h. Microdialysis probes were placed (through the white line) into either the lamellar dermis (LAM) (n = 6) or the sublamellar dermis (SUBLAM) (n = 6) and perfused continuously over a 24 h study period. Probes were pl...
Jellyman JK, Valenzuela OA, Allen VL, Holdstock NB, Fowden AL.Pancreatic β cells are responsive to a range of stimuli during early post natal life in healthy pony foals. However, little is known about whether these responses are sex-linked. Objective: To determine pancreatic β cell responses to the insulin secretagogues, glucose, arginine and tolbutamide, in fillies and colts during the first 3 months after birth. Methods: In vivo experiment examining sex differences in pancreatic β cell function in foals. Methods: Female (n = 8) and male (n = 5) pony foals were infused i.v. with glucose (0.5 g/kg bwt 40% dextrose), arginine (100 mg/kg bwt) or tol...
Kang OD, Ryu YC, Yun YM, Kang MS.The changes in physiologic parameters by swim exercise duration were examined in five female well-trained Jeju crossbred riding horses that had riding experience of more than three years without swim training experience. The horses were performed with swim exercise for 10 min (60.0 m/min) once a day for 14 days. Physiologic characteristics and haematic parameters were measured before swimming, immediately after swimming, and after a 10 min rest at first day (D0), 7 days (D7), and 14 days (D14) of training. After 14 days of swim training, heart rate (p<0.05), blood glucose (p<0.05), lacta...
Pojprasath T, Lohachit C, Techakumphu M, Stout T, Tharasanit T.Cryopreservation of stallion semen is often associated with poor post-thaw sperm quality. Sugars are among the important components of a freezing extender and act as non-permeating cryoprotectants. This study aimed to compare the quality of stallion sperm frozen with glucose, fructose or sorbitol-containing freezing extenders. Semen was collected from six stallions of proven fertility and cryopreserved using a freezing extender containing different types of monosaccharide sugars (glucose, fructose or sorbitol). After thawing, the semen was examined for sperm motility, viability, acrosome integ...
Olsman AF, Huurdeman CM, Jansen WL, Haaksma J, Sloet van Oldruitenborgh-Oosterbaan MM, Beynen AC.In a cross-over study with six mature horses, the effect of iso-energetic replacement of dietary glucose by beet pulp on macronutrient digestibility, nitrogen metabolism and mineral absorption was studied. The test ration contained 25% beet pulp in the total dietary dry matter. Beet pulp feeding significantly lowered crude fat and non-structural carbohydrate digestibility, but had no significant effect on digestibility of other macronutrients, faecal and urinary nitrogen excretion and the faecal to urinary nitrogen excretion quotient. However, on the beet pulp diet, plasma ammonia and creatini...
French KR, Pollitt CC.Acute laminitis is characterised by hoof lamellar dermal-epidermal separation at the basement membrane (BM) zone. Hoof lamellar explants cultured in vitro can also be made to separate at the basement membrane zone and investigating how this occurs may give insight into the poorly understood pathophysiology of laminitis. Objective: To investigate why glucose deprivation and metalloproteinase (MMP) activation in cultured lamellar explants leads to dermo-epidermal separation. Methods: Explants, cultured without glucose or with the MMP activator p-amino-phenol-mercuric acetate (APMA), were subject...
Sumbria D, Singla LD, Sharma A, Bal MS, Randhawa CS.Equine piroplasmosis caused by Theileria equi, an apicomplexan intracellular haemoprotozoan parasite effects equids throughout the world. Current investigation is the first detailed epidemiological survey report based on conventional (blood smear) and primary polymerase chain reaction (PCR) for the detection of T. equi on 464 equids (426 horses and 38 donkeys/mules) in Punjab province of India. PCR targeting 18S rRNA gene of T. equi produced high fidelity 709bp amplification products with 100% concordance with blood films. The prevalence of infection was proportional (P≤0.01) to temperature ...
Frank N, Sojka JE, Latour MA.To measure and compare the concentration and composition of very low-density lipoprotein (VLDL) in plasma and selected lipids in serum of horses fed mixed grass hay ad libitum or denied feed for 36 hours. Methods: 4 healthy adult mares. Methods: Mares were either fed mixed grass hay ad libitum or denied feed for 36 hours beginning at 8:00 AM. Blood samples were collected every 2 hours during the study period and analyzed for nonesterified fatty acid (NEFA), triglyceride (TG), VLDL, and glucose concentrations and composition of VLDL. Results: Withholding feed significantly increased mean serum ...
Pazzola M, Pira E, Sedda G, Vacca GM, Cocco R, Sechi S, Bonelli P, Nicolussi P.Several concerns have been raised over the health of animals used in equestrian games that have their origins in historical or religious events and are currently held in many countries. This study investigated physiological stress response and health status of horses participating in the Sartiglia, a historical horse tournament held in the city of Oristano, Italy, which is principally based on the attempts of masked horsemen at a gallop to run a sword through a hole in a suspended silver star. Blood samples were collected from 21 horses the day before the tournament (D0), during the tournament...
Many colic horses are compromised due to the disease state and from hours of starvation and sometimes long trailer rides. This could influence their muscle energy reserves and affect the horses' ability to recover. The principal aim was to follow metabolic parameter before, during, and up to 7 days after anaesthesia in healthy horses and in horses undergoing abdominal surgery due to colic. Methods: 20 healthy horses given anaesthesia alone and 20 colic horses subjected to emergency abdominal surgery were anaesthetised for a mean of 228 minutes and 183 minutes respectively. Blood for analysis o...
Sosa León LA, Davie AJ, Hodgson DR, Rose RJ.Effects of different tonicities, glucose concentrations and temperatures of an oral rehydration solution (ORS) on its uptake and elimination in resting horses were studied. Fluid and electrolyte deficits similar to those occurring during prolonged exercise were induced by the administration of 1 mg/kg bwt of frusemide i.m., 3 h prior to the ORS. Fluid was administered via nasogastric tube at a volume equivalent to 4% bodyweight, which approximated diuretic induced losses. The uptake of fluid was evaluated by changes in haematocrit (PCV) and plasma total protein concentration (TP). Changes in e...
Wong DM, Sponseller BA, Alcott CJ, Agbedanu PN, Wang C, Hsu WH.To evaluate the effect of IV administration of polymyxin B on clinical and serum biochemical variables in foals with experimental endotoxemia. Methods: Prospective experimental study. Methods: 14 healthy neonatal foals. Methods: Foals were randomly assigned to a treatment or control group and were administered a single dose of lipopolysaccharide (0.5 μg/kg [0.23 μg/lb]) IV over 30 minutes. The treatment group received polymyxin B (6,000 U/kg [2,727 U/lb], IV) immediately after completion of lipopolysaccharide infusion; the control group was administered an equal volume of saline (0.9% NaCl) ...
McCoy DJ.Both ovaries in a 10-year-old American Saddle Horse mare were determined to be larger than normal. The mare had problems with infertility during the preceding 3 years. Clinical evaluation revealed that the mare was polyuric, polydypsic, hyperinsulinemic, and hyperglycemic, and had reduced tolerance to exogenous glucose. Bilateral granulosa cell tumors were identified on histologic examination of the ovaries. The precise mechanism for the secondary diabetes mellitus was not determined; however, the cause was suspected to be a result of the synthesis and release of a hormonal substance by the tu...
Dunkel B, Mason CJ, Chang YM.A recent study described increased l-lactate concentrations in ponies with gastrointestinal disease compared to horses, but blood glucose (BG) concentrations were not considered. The study tested the hypothesis that BG and l-lactate concentrations are correlated in horses and ponies with gastrointestinal disease and that BG concentrations, not equid type (pony vs horse), are an independent predictor of L-lactate concentrations. It was further hypothesized that equid type was an independent predictor of BG concentrations. Methods: Retrospective study 2008-2016. Methods: University teaching hosp...
Snow DH, Mackenzie G.The effects of prolonged cantering before and after a 10 week training programme were studied in 6 horses. Determinations were carried on on venous blood for packed cell volume, glucose, glycerol, free fatty acids, beta-hydroxybutyrate, 11-hydroxycorticosteroids, pH and pCO2. Exercise caused a slight increase in glucose, lactate and pH, a moderate rise in PCV, glycerol and free fatty acids, and a marked rise in 11-hydroxycorticosteroids. A decrease in venous pCO2 occurred and a slight but not significant decrease in beta-hydroxybutyrate. Training was found to cause no significant difference in...
Underwood C, Southwood LL, Walton RM, Johnson AL.To determine: (1) changes in blood ammonia, bile acid (BA), bilirubin, triglyceride, and glucose concentrations and liver enzyme activities in perioperative colic patients and (2) the association between these laboratory findings and short-term survival. Methods: Prospective observational clinical study. Methods: Thirty-two adult horses undergoing exploratory celiotomy for colic. Methods: None. Results: Blood samples were collected preoperatively and at 24-36 and 72-84 hours postoperatively and analyzed for blood ammonia, BA, bilirubin, triglyceride, and glucose concentrations and sorbitol deh...
Fowden AL, Barnes RJ, Comline RS, Silver M.Insulin secretion and the factors influencing beta-cell function were investigated in the chronically catheterized fetal foal and mare during the second half of gestation. The response of the fetal beta cells to exogenous glucose was also examined. The mean concentration of insulin in the fetal foal was 7.5 +/- 0.5 (S.E.M.) microunit./ml (n = 20) which was significantly less than the corresponding maternal value of 49.0 +/- 5.0 microunit./ml (n = 20, P < 0.01). The insulin concentration in non-pregnant horses was 24.5 +/- 1.5 microunit./ml (n = 5) which was significantly less than the value...
Mills PC, Ng JC, Kramer H, Auer DE.Five clinically healthy Thoroughbred geldings were injected with Freund's adjuvant 3 times to induce a chronic inflammatory response. Blood was collected at various times before and after adjuvant administration. Clinical responses (rectal temperature and general demeanor) were also monitored. Adjuvant injection induced increases in rectal temperature and plasma fibrinogen concentration (maximum levels measured were mean +/- s.d. 39.7 +/- 0.5 degrees C and 8.2 +/- 0.3 g/l, respectively), indicative of an inflammatory response. A mild clinical depression was also observed in the horses for 24 h...
Piccione G, Giannetto C, Assenza A, Casella S, Caola G.We examined the response to exercise of selected physiological variables in horses performing the identical routine for eight days, in the morning (a.m.) or in the afternoon (p.m.). Heart rate (HR), systolic and diastolic blood pressure (BP), and body temperature (BT) were all consistently greater in the p.m. For BP and BT, the absolute increase above the a.m. values was the same at rest and during exercise. For HR, the absolute increase was greater during exercise, but the percent increase was the same as during rest. During exercise, blood glucose decreased, while blood lactate and skin temp...
Fessler JF, Bottoms GD, Roesel OF, Moore AB, Frauenfelder HC, Boon GD.A study was made of flunixin meglumine (FM), an analgesic agent with antiprostaglandin activity, in the management of endotoxin-induced changes in ponies. Three groups of 5 ponies each were used: A--controls, B--nontreated ponies with endotoxin-induced shock, and C--ponies with endotoxin-induced shock treated with FM. Shock was induced in anesthetized ponies with IV injections of Escherichia coli endotoxin. Disruption of glucose homeostasis, insulin levels, hemograms, aerobic metabolism, and cell damage as indicated by plasma enzymes were observed. Treatment with FM (5 minutes) after shock was...
Sánchez-Calabuig MJ, Fernández-González R, Hamdi M, Smits K, López-Cardona AP, Serres C, Macías-García B, Gutiérrez-Adán A.Equine embryos exhibit an unusual pattern of glucose tolerance in vitro and are currently cultured in hyperglycaemic conditions. Objective: Our main objective was to analyse the effect of different glucose concentrations on in vitro-produced equine embryo development and quality. Methods: Experiments comparing in vitro and in vivo produced embryos. Methods: Oocytes (n = 641) were collected from post-mortem ovaries, matured in vitro and fertilised by intracytoplasmic sperm injection (ICSI). Embryo culture was divided from Day 0 to Day 4 and from Day 4 to Day 9 in three groups: 5-10 (5 and 10...
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...
Pösö AR, Essén-Gustavsson B, Persson SG.Plasma concentrations of lactate, amino acids, ammonia and products of purine catabolism were studied before, during and after a standardised incremental exercise test in 29 Standardbred trotters admitted to the clinic for exercise tolerance testing. According to their red cell volume the horses were divided into red cell normovolaemic and red cell hypervolaemic (polycythaemic) groups. The exercise-response curve for taurine differed significantly in the two groups, whereas all the other amino acids behaved similarly. The [branched-chain amino acid]/[alanine] ratio, a proposed indicator for th...
Sheldon S, Aleman M, Costa L, Santoyo AC, Howey Q, Madigan J.Trigeminal-nerve-mediated headshaking represents a major welfare challenge for owners and veterinarians and is caused by a low threshold firing of the trigeminal nerve resulting in pain manifested as violent head jerking that often terminates the horse’s career and life due to poor quality of life and suffering. As metabolic changes such as acid⁻base status and electrolytes play a role in nerve firing, this study sought to assess the effects following administration of hypertonic solutions on headshaking behavior in affected horses. This prospective randomized controlled crossover desi...
Delarocque J, Reiche DB, Meier AD, Warnken T, Feige K, Sillence MN.Insulin dysregulation (ID) is a key risk factor for equine endocrinopathic laminitis, but in many cases ID can only be assessed accurately using dynamic tests. The identification of other biomarkers could provide an alternative or adjunct diagnostic method, to allow early intervention before laminitis develops. The present study characterised the metabolome of ponies with varying degrees of ID using basal and postprandial plasma samples obtained during a previous study, which examined the predictive power of blood insulin levels for the development of laminitis, in ponies fed a high-sugar diet...
Wooding FB, Morgan G, Fowden AL, Allen WR.The placenta is the only channel for transport of nutrients to the conceptus and the fetal nutrient demands increase exponentially to term. The 9 kDa calcium binding protein (calbindin, 9CBP) and the iron binding protein uteroferrin (UF) are proving to be reliable markers for epithelia that mediate active transcellular calcium and iron transport and the glucose transporter proteins (GT1 and GT3) for glucose transport by facilitated diffusion. Light and electron microscope immunocytochemistry have been used on perfusion fixed resin embedded material to establish the distribution of 9CBP, UF, GT...
Gaesser AM, Usimaki AIJ, Barot DA, Linardi RL, Molugu S, Musante L, Ortved KF.Mesenchymal stem cell (MSC) extracellular vesicles (EVs) have emerged as a biotherapeutic for osteoarthritis; however, manufacturing large quantities is not practical using traditional monolayer (2-D) culture. We aimed to examine the effects of 3-D and 2-D culture 2 types of media: Dulbecco modified Eagle medium and a commercially available medium (CM) on EV yield. Methods: Banked bone marrow-derived MSCs (BM-MSCs) from 6 healthy, young horses were used. Methods: 4 microcarriers (collagen-coated polystyrene, uncoated polystyrene, collagen-coated dextran, and uncoated dextran) were tested in st...
Colmer SF, Adams AA, Adam E, Miller R, Stefanovski D, Kulp JC, van Eps A.A single dose of metformin administered 1 h prior to oral glucose challenge was previously shown to reduce insulinaemic responses in horses with experimentally-induced insulin dysregulation (ID). Targeted administration could be useful for controlling post-prandial hyperinsulinaemia in horses with naturally-occurring ID.
Dybdal NO, Gribble D, Madigan JE, Stabenfelt GH.The effects of prolonged exercise on plasma concentrations of corticosteroids, insulin, glucose, lactate and beta-hydroxybutrate were studied in a group of horses competing in a 160 km endurance ride. Of the 53 horses included in the study at the outset, 23 completed the course. Plasma corticosteroids increased while glucose and insulin decreased during exercise. Little change occurred in plasma lactate or beta-hydroxybutyrate. The parameters studied did not result in the finding of any consistent significant differences beteeen individuals that completed and those that did not complete the co...
Mueller PJ, Jones MT, Rawson RE, van Soest PJ, Hintz HF.Oxygen consumption (VO2) and concentration of venous blood metabolites were measured in donkeys trained to run and to pull loads on a treadmill. VO2 in two donkeys running at maximal speed on a 9.8% slope was 110 +/- 2 ml.min-1.kg-1, approximately 22 times preexercise VO2. Average heart rate at maximal VO2 (VO2max) was 223 +/- 2 beats/min, five times the preexercise heart rate. Blood lactate increased 14-fold, and blood glucose did not change (P > 0.05). Animals running up a 4% incline and incremental draft loading of five donkeys walking on the level were also studied. The total energy cost o...
Thurmon JC, Neff-Davis C, Davis LE, Stoker RA, Benson GJ, Lock TF.The effects of intravenous xylazine (1.1 mg/kg) were studied in six thoroughbred horses (five mares and a stallion). Plasma glucose concentration increased to 168% of control at 45 min and decreased to 112% of control at 180 min. Insulin had decreased to 31% of control at 15 min. Thereafter, insulin concentration increased, reaching its highest concentration at 150 min. The mechanism for these changes is not fully understood and further investigation is indicated.
Zavy MT, Clark WR, Sharp DC, Roberts RM, Bazer FW.In Experiment 1, 40 gilts and 30 pony mares were used to characterize changes in glucose, fructose, ascorbic acid and glucosephosphate isomerase (GPI) enzymatic activity in uterine flushings collected either during the estrous cycle or early pregnancy. Total recoverable glucose was greater (P less than 0.01) in uterine flushings from pregnant gilts, but pregnancy status had no effect on total recoverable glucose in pony mare uterine flushings. Fructose was undetectable in uterine flushings from nonpregnant gilts and pony mares and pregnant gilts and pony mares prior to Day 14, but occurred in ...
