Obesity in horses is a condition characterized by excessive body fat accumulation that can negatively impact equine health and performance. It is often the result of an imbalance between energy intake and expenditure, influenced by factors such as diet, exercise, and metabolism. Obesity in horses can lead to various health issues, including insulin resistance, laminitis, and other metabolic disorders. Body condition scoring and other assessment tools are used to evaluate and monitor body fat levels in horses. This page compiles peer-reviewed research studies and scholarly articles that explore the causes, effects, and management of obesity in equine populations.
Duarte PC, Ribeiro RM, Machado ART, Faleiros RR, Pimenta LPS, Filho JDS.The incidence of equine metabolic syndrome, a condition that results in endocrinopathic laminitis, is increasing worldwide. Although it is well known that the development of this syndrome depends on imbalances in energy metabolism and genetic traits, its pathophysiology remains unclear. Hydrogen nuclear magnetic resonance (H NMR) is a powerful tool used to compare metabolic profiles and to discriminate metabolites in living beings. The aim was to apply this technology to detect blood biomarkers candidates in horses that were previously demonstrated to developed metabolic changes when subjected...
Ward AB, Stephen K, Argo CM, Harris PA, Watson CA, Neacsu M, Russell W, Grove-White DH, Morrison PK.The COVID-19 pandemic continues to impact human health and welfare on a global level. In March 2020, stringent national restrictions were enforced in the UK to protect public health and slow the spread of the SARS-CoV-2 virus. Restrictions were likely to have resulted in collateral consequences for the health and welfare of horses and ponies, especially those at risk of obesity and laminitis and this issue warranted more detailed exploration. The current study utilised qualitative methodology to investigate the implications of COVID-19 related policies upon equine management and welfare with a...
Dunkel B, Knowles EJ, Chang YM, Menzies-Gow NJ.Blood l-lactate concentrations are higher in people with developing or established diabetes mellitus and insulin resistance. Objective: To investigate whether blood l-lactate concentrations are positively correlated with measures of insulin dysregulation (ID) or increased autumnal ACTH concentrations in ponies. Methods: Systemically healthy client-owned ponies (n = 101). Methods: Prospective case-control study. Blood samples were obtained from 101 clinically healthy ponies. Breed, weight, height, and subjective and objective measures of body condition were recorded. Blood l-lactate, glucose, t...
Thomas SJ, de Solis CN, Coleman MC.Equine asthma is a common condition in horses, for which few host-related risk factors have been identified. The objective of this study was to identify host-related risk factors for the development of equine asthma. A retrospective, case-control study was performed, utilizing horses presented to the Texas A&M University, Veterinary Medical Teaching Hospital from January 2014 December 2018. Incident cases of mild to severe equine asthma (n = 37), diagnosed clinically with cytologic support of disease were examined. For each case, two control populations were identified, including one tem...
Shepherd M, Harris P, Martinson KL.Equine obesity is common, reducing quality of life and requiring dietary energy restriction. Equine obesity is identified using subjective body condition scoring. Considerations are given for life stage and health status when managing obese equines. Every effort should be made to maximize feeding duration, and minimize time spent without feed while meeting all essential nutrient requirements. Limiting total daily dry matter intake to 2% of current bodyweight per day of a low caloric, forage-based diet may result in adequate body weight loss. Weight loss and weight management plans should be mo...
Richards N, Nielsen BD, Finno CJ.Many forage types are available, typically divided into cool or warm season grasses and legumes, which can be fed as fresh pasture or after preservation. Testing for nutrient content confirms what should be supplemented to make up shortfalls. Although testing is recommended, it is not always practical. Typical values for the forage type are available; however, they cannot be relied on for actual content. Non-nutritional aspects must also be taken into account. The provision of complementary feeds to ensure adequate vitamin and mineral intake is recommended. Additional supplementary high-qualit...
Hesta M, Shepherd M.Inappropriate nutrition is a priority welfare challenge. Nutritional mistakes are common and can lead to adverse events, such as poor growth and performance, colic, laminitis, and obesity. A detailed nutritional assessment involving evaluating the equine patient, current diet/ration, and management is essential in creating an effective nutritional plan. Goal(s) should be established and used to inform the plan. Management or resource barriers should be considered. Effective communication and a team-based approach versus an authoritarian one are likely to enhance the success of the nutritional ...
Longland AC, Barfoot C, Harris PA.Obesity can negatively impact upon equine welfare and bodyweight (BW) of pastured equines is often difficult to manage. Objective: To compare the effects of three restricted grazing regimens on changes in pony BW and morphometric measurements. Methods: Randomised study. Methods: Twelve mature ponies were individually grazed in 10m wide, rectangular, electric fenced paddocks. The dry matter (DM) herbage yield of each paddock was determined, and paddock length adjusted on Day 1 to provide 1.5% of individual pony BW as herbage DM daily, for 28 days. There were four ponies per treatment. Treatmen...
Ribeiro RM, Ribeiro DS, Cota LO, Leme FO, M Carvalho A, Faleiros RR.This study aimed to characterize and correlate physiological and metabolic changes in horses fed a hypercaloric diet (HD). Nine mature horses with a mean initial body condition score of 2.9 ± 1 (scale, 1-9) were fed a high-calorie diet for 5 months. Fasting blood samples were collected before the study and biweekly for the duration of the project to determine the concentrations of cholesterol (CHOL), very low (VLDL), low (LDL) and high-density (HDL) lipoproteins, triglycerides, non-esterified fatty acids, and fructosamine. A low-dose oral glucose tolerance test (LGTT) was conducted before, 75...
Bourebaba L, Kornicka-Garbowska K, Al Naem M, Röcken M, Łyczko J, Marycz K.Protein tyrosine phosphatase 1B (PTP1B) is one of the major negative regulators of leptin and insulin signaling, and has been strongly implicated in insulin resistance development in the course of obesity and metabolic syndrome conditions; however, its exact role in controlling adipose tissue biogenesis is still poorly understood. This investigation aimed to elucidate whether selective inhibition of PTP1B using MSI-1436 compound may improve and restore the defective adipogenicity of ASCs isolated from EMS-affected horses. Equine ASC EMS cells were cultured under adipogenic conditions in the pr...
D'Fonseca NMM, Gibson CME, Hummel I, van Doorn DA, Roelfsema E, Stout TAE, van den Broek J, de Ruijter-Villani M.Obesity has been associated with altered reproductive activity in mares, and may negatively affect fertility. To examine the influence of long-term high-energy (HE) feeding on fertility, Shetland pony mares were fed a diet containing 200% of net energy (NE) requirements during a three-year study. The incidence of hemorrhagic anovulatory follicles (HAF) and annual duration of cyclicity were compared to those in control mares receiving a maintenance diet. Day-7 embryos were flushed and transferred between donor and recipient mares from both groups; the resulting conceptuses were collected 21 day...
Delarocque J, Frers F, Huber K, Jung K, Feige K, Warnken T.Insulin dysregulation (ID) is an equine endocrine disorder, which is often accompanied by obesity and various metabolic perturbations. The relationship between weight variations and fluctuations of the insulin response to oral glucose tests (OGT) as well as the metabolic impact of ID have been described previously. The present study seeks to characterize the concomitant metabolic impact of variations in the insulin response and bodyweight during repeated OGTs using a metabolomics approach. Methods: Nineteen Icelandic horses were subjected to five OGTs over one year and their bodyweight, insuli...
Gehlen H, Schwarz B, Bartmann C, Gernhardt J, Stöckle SD.Appropriate medical care for donkeys is challenging despite being important working animals in non-industrialized countries and pets in first world countries. Although the same principles of diagnosis and therapy as in horses are commonly applied, there are differences in reference values and physiologic reaction to dynamic tests. However, donkeys seem to suffer from typical equine diseases, such as metabolic syndrome and pituitary pars intermedia dysfunction (PPID). Asinine metabolic syndrome (AMS) comprises obesity, insulin dysregulation, and laminitis. The principles of diagnosis are simila...
Carslake HB, Pinchbeck GL, McGowan CM.The epidemiology of equine metabolic syndrome (EMS) is poorly described. Objective: To estimate the prevalence of EMS in native UK ponies and cobs in England and Wales and identify associated risk factors. Methods: Cross-sectional study. Methods: Breeders registered with UK native pony breed societies and registered riding schools and livery yards within a set radius were invited to participate. All native UK ponies and cobs aged 3-14 years and not diagnosed or being treated for conditions likely to affect insulin regulation at participating premises were eligible. Animals underwent a clinica...
Ghajar SM, McKenzie H, Fike J, McIntosh B, Tracy BF.Introduced cool-season grasses are dominant in Virginia's grasslands, but their high digestible energy and nonstructural carbohydrate (NSC) levels pose a risk for horses prone to obesity and laminitis. Native warm-season grasses (NWSGs) have lower digestible energy and NSC levels that may be more suitable for horses susceptible to laminitis. Although NWSGs have desirable characteristics, they are novel forages for horses. Little is known about NWSG intake or potential toxicity to horses or how grazing by horses may affect NWSG swards. The overall objectives of this research were to 1) assess v...
Wallis N, Raffan E.Obesity is one of the most prevalent health conditions in humans and companion animals globally. It is associated with premature mortality, metabolic dysfunction, and multiple health conditions across species. Obesity is, therefore, of importance in the fields of medicine and veterinary medicine. The regulation of adiposity is a homeostatic process vulnerable to disruption by a multitude of genetic and environmental factors. It is well established that the heritability of obesity is high in humans and laboratory animals, with ample evidence that the same is true in companion animals. In this r...
Furtado T, Perkins E, Pinchbeck G, McGowan C, Watkins F, Christley R.Equine obesity is considered one of the most serious welfare concerns in UK leisure horses, yet little is known about how horse owners conceptualise their horse's weight as part of its health, or how they plan and carry out weight management. Objective: This study aimed to further our understanding of leisure horse owners' perceptions of equine health and awareness of excess fat in order to clarify our understanding of successful strategies for managing equine weight. Methods: This study used a qualitative research methodology. Methods: Data comprised 16 threads from online UK equine discussio...
Patterson Rosa L, Mallicote MF, Long MT, Brooks SA.An analogous condition to human metabolic syndrome, Equine Metabolic Syndrome (EMS) is defined by several clinical signs including obesity, hyperinsulinemia, and peripheral insulin dysregulation (ID). Affected horses may also exhibit hypertension, hyperlipemia and systemic inflammation. Measures of ID typically comprise the gold-standard for diagnosis in veterinary care. Yet, the dynamic nature of insulin homeostasis and complex procedures of typical assays make accurate quantification of ID and EMS challenging. This work aimed to investigate new strategies for identification of biochemical ma...
Fernandez EB, De Blas Giral I, Thiemann AK, Vázquez Bringas FJ.In the UK, there are thousands of donkeys being cared for by charities; however, little is known about the reasons for relinquishment or their previous health status, with even less information available in published literature. Such information could help to identify factors contributing to poor equine welfare and guide the development of appropriate educational resources. Objective: To describe the characteristics of the relinquished donkeys and to better understand the current preventative healthcare status of donkeys relinquished into The Donkey Sanctuary. Methods: Cross-sectional observat...
Nostell K, Lindåse S, Winqvist E, Bröjer J.Obesity is associated with insulin resistance, vascular dysfunction and altered cortisol metabolism both in humans and in horses. Objective: Evaluate the effect of weight gain induced by a haylage diet low in nonstructural carbohydrates (NSC) on insulin sensitivity, blood pressure and serum cortisol concentrations. Methods: In vivo experiment. Methods: Nine adult Standardbred mares fed a fat supplemented haylage diet at 250% of the horses' daily metabolisable energy requirements for 22 weeks. Horses were then turned out on pasture for 4 weeks. Insulin sensitivity (SI ) was measured before an...
Box JR, McGowan CM, Raekallio MR, Mykkänen AK, Carslake H, Karikoski NP.Obesity and insulin dysregulation (ID) predispose horses to laminitis. Determination of management practices or phenotypic markers associated with ID may benefit animal welfare. Objective: Determine ID status of a population of Finnhorses using an oral sugar test (OST) and compare phenotypes and management factors between ID and non-ID Finnhorses. Methods: One hundred twenty-eight purebred Finnhorses ≥3 years of age. Methods: Owners were recruited using an online questionnaire regarding signalment, history, feeding, and exercise of their horses. Selected contributing stables within a prede...
Salinas C, Espinosa G, Morales N, Henríquez C, Morán G, Gajardo G, Uberti B.Obesity is a highly prevalent condition in horses. Dysfunctional neutrophil activity has been reported in metabolically healthy obese humans, but minimal data exist regarding horses. The present study evaluated the effect of obesity on apoptosis, phagocytosis and oxidative burst activity of peripheral blood neutrophils from lean and obese non-insulin dysregulated horses. Seven lean (BCS, body condition score 4-6/9) and five obese (BCS 8-9) horses were enrolled in the study. All animals underwent two metabolic tests (OGT, oral glucose test; IRT, insulin response test) before their selection to ...
Schedlbauer C, Blaue D, Raila J, Vervuert I.Vitamin A, vitamin E and retinol-binding protein 4 (RBP4) are a focus of current obesity research in humans. The impact of body weight (BW) gain on fat-soluble vitamins and its associated parameters in equines has not been previously reported. Ten Shetland ponies and 9 Warmblood horses, all adult geldings, non-obese and healthy, were fed an excessive energy diet for 20 months to induce BW gain. Serum α-tocopherol (vitamin E), retinol (vitamin A), retinol-binding protein 4 (RBP4) and retinol/RBP4 ratio were analysed before BW gain induction and at six timepoints during the BW gaining period. ...
d' Fonseca NMM, Gibson CME, van Doorn DA, de Ruijter-Villani M, Stout TAE, Roelfsema E.Overfeeding is associated with obesity and insulin dysregulation (ID), which are both risk factors for equine metabolic syndrome. How chronic overfeeding affects development of these factors is poorly understood. Objective: To examine the influence of long-term high-energy diet provision on body condition and ID. Methods: Eleven Shetland pony mares. Methods: In a 3-phase study, the high-energy group (n = 7) was fed 200% of net energy (NE) requirements (hay; concentrate: 36% sugar and starch, 13% fat) for 24 weeks, followed by 17 weeks hay-only feeding before resuming the high-energy diet (...
Dosi MCM, Kirton R, Hallsworth S, Keen JA, Morgan RA.Obesity is a growing problem in UK equine population. Achieving weight loss in obese horses and ponies at risk of laminitis is an important but often challenging objective. Methods: We hypothesised that supplementing poor winter pasture with a mix of barley straw and hay (50:50) rather than hay alone (group B) would lead to weight loss in grazing equids over winter. For this purpose, a group of 40 horses were fed either the straw mix (group A) or hay alone (group B) over winter. Results: Over the study period, all animals in group A (n=25) lost weight with a mean weight change of -27±17 kg,...
Blaue D, Schedlbauer C, Starzonek J, Gittel C, Brehm W, Blüher M, Pfeffer M, Vervuert I.Human obesity is linked with systemic inflammation. However, it is still controversial if equines produce more inflammatory cytokines with increasing body weight and if the production of those show breed type specific patterns. The main objective of this study was to determine if diet induced obesity is associated with increased inflammatory signatures in adipose tissue of equines and if a breed predisposition exists between ponies and horses. Additionally, we aimed to identify adipose tissue depot differences in inflammatory cytokine expression. Nineteen healthy, non-overweight and metabolica...
Camacho-Rozo CA, Santos GO, Wenzen DP, Cousseau SB, Wronski JG, Argenta FF, Winter GHZ, Pavarini SP, Mattos RC.This report describes a case of sudden death of a pregnant miniature mare due to an acute ovarian hemorrhage leading to fatal hemoperitoneum. The miniature horse was a 12-year-old female, 60 days pregnant, with a body condition score of 7 (1-9), with a history of obesity and laminitis. Necropsy revealed hemoperitoneum due to an ovarian capsule rupture and hemorrhage after a physiological supplementary ovulation and luteinization. Ovarian rupture after ovulation is uncommon in mares.
Rioja-Lang FC, Connor M, Bacon H, Dwyer CM.Equine welfare issues are receiving increasing attention in the UK, but welfare problems can arise from a wide range of causes. In order to identify the most important welfare concerns for horses, we used a Delphi method with 19 equine welfare experts. An initial list of 84 equine welfare issues was generated using an online discussion board and NVivo thematic analysis. Subsequently, experts ranked these welfare issues for perceived prevalence, severity and duration of suffering associated with each issue on a 6-point Likert scale. All issues with a mean score of 3 or above ( = 37) were includ...
Langner K, Blaue D, Schedlbauer C, Starzonek J, Julliand V, Vervuert I.Obesity is a major health concern in many domesticated equids animals since it is related to metabolic abnormalities such as insulin dysregulation, hyperlipidaemia or laminitis. Ponies especially are known as "easy keepers" and are often affected by obesity and its related metabolic disorders. Research in the last decade indicated that the intestinal microbiota may play an important role in the development of obesity, at least in humans. Therefore, the objective of our study was to characterize changes in the faecal microbiota during a two-year weight gain programme which compared ponies and w...
Jaqueth AL, Iwaniuk ME, Burk AO.It has been estimated in the United States and abroad that 20%-51% of the equine population suffers from over-conditioning or obesity. The objective of this study was to evaluate the prevalence of over-conditioning in the equine population in Maryland, to characterize weight control measures used, and to ascertain how control measures impact the operation. Over-conditioning was defined as a body condition score of 4 or 5 on a 5-point scale. All licensed horse operators in Maryland were invited to participate in an online survey. A total of 93 farm operators completed the survey with 238 ponies...
Carslake HB, Pinchbeck GL, McGowan CM.The epidemiology of equine metabolic syndrome (EMS) is poorly described. Objective: To estimate the prevalence of EMS in native UK ponies and cobs in England and Wales and identify associated risk factors. Methods: Cross-sectional study. Methods: Breeders registered with UK native pony breed societies and registered riding schools and livery yards within a set radius were invited to participate. All native UK ponies and cobs aged 3-14 years and not diagnosed or being treated for conditions likely to affect insulin regulation at participating premises were eligible. Animals underwent a clinica...
Johnson PJ, Wiedmeyer CE, Messer NT, Ganjam VK.There is growing recognition that obesity is common and represents a significant detriment to the health of companion animals in a manner similar to that by which it is affecting the human population. As is the case for other species, obesity appears to promote insulin resistance in horses and it is through this pathophysiological process that many of the adverse medical consequences of obesity are being characterized. Equine medical conditions that have been described in the context of obesity and insulin resistance differ from those in humans. Chronic human conditions that have been attribut...
Burns TA, Watts MR, Weber PS, McCutcheon LJ, Geor RJ, Belknap JK.Hyperinsulinaemia has been implicated in the pathogenesis of laminitis; however, laminar cell types responding to insulin remain poorly characterised. Objective: To identify laminar cell types expressing insulin receptor (IRc) and/or insulin-like growth factor-1 receptor (IGF-1R); and to evaluate the effect of dietary nonstructural carbohydrate (NSC) on their expression. Methods: Mixed-breed ponies (n = 22) received a conditioning hay chop diet (NSC ∼6%); following acclimation, ponies were stratified into lean (n = 11, body condition score [BCS]≤4) or obese (n = 11, BCS ≥7) groups and ea...
Lewis SL, Holl HM, Streeter C, Posbergh C, Schanbacher BJ, Place NJ, Mallicote MF, Long MT, Brooks SA.Equine obesity can cause life-threatening secondary chronic conditions, similar to those in humans and other animal species. Equine metabolic syndrome (EMS), primarily characterized by hyperinsulinemia, is often present in obese horses and ponies. Due to clinical similarities to conditions such as pituitary pars intermedia dysfunction (formerly equine Cushing's disease), conclusive diagnosis of EMS often proves challenging. Aside from changes in diet and exercise, few targeted treatments are available for EMS, emphasizing the need for early identification of at-risk individuals to enable imple...
Wooldridge AA, Edwards HG, Plaisance EP, Applegate R, Taylor DR, Taintor J, Zhong Q, Judd RL.To characterize adiponectin protein complexes in lean and obese horses. Methods: 26 lean horses and 18 obese horses. Procedures-Body condition score (BCS) and serum insulin activity were measured for each horse. Denaturing and native western blot analyses were used to evaluate adiponectin complexes in serum. A human ELISA kit was validated and used to quantify high-molecular weight (HMW) complexes. Correlations between variables were made, and HMW values were compared between groups. Results: Adiponectin was present as a multimer consisting of HMW (> 720-kDa), low-molecular weight (180-kDa)...
Holbrook TC, Tipton T, McFarlane D.Equine metabolic syndrome is characterized by obesity and regional adiposity coupled with evidence of recurrent laminitis. Although inflammation has been well characterized in several experimental models of acute laminitis, the inflammatory events associated with endocrinopathic laminitis are not well documented. The aim of this study was to characterize selected markers of inflammation in horses with clinical evidence of equine metabolic syndrome (EMS). Neutrophil phagocytosis and oxidative burst, as well as endogenous and stimulated cytokine expression were evaluated. A marked increase in ne...
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 ...
Lane HE, Burns TA, Hegedus OC, Watts MR, Weber PS, Woltman KA, Geor RJ, McCutcheon LJ, Eades SC, Mathes LE, Belknap JK.Insulin dysregulation, obesity, and exposure to high-nonstructural carbohydrate (NSC) forage are risk factors for equine metabolic syndrome-associated laminitis (EMSAL); high systemic insulin concentrations in EMSAL are proposed to induce cellular dysregulation in the digital lamellae through activation of the insulin-like growth factor-1 receptor. Objective: To use a dietary challenge model (DCM) and a euglycaemic-hyperinsulinaemic clamp (EHC) model to assess lamellar growth factor-related signalling. Methods: Lamellar phospho (P)-protein concentrations of signalling proteins important in gro...
Wallis N, Raffan E.Obesity is one of the most prevalent health conditions in humans and companion animals globally. It is associated with premature mortality, metabolic dysfunction, and multiple health conditions across species. Obesity is, therefore, of importance in the fields of medicine and veterinary medicine. The regulation of adiposity is a homeostatic process vulnerable to disruption by a multitude of genetic and environmental factors. It is well established that the heritability of obesity is high in humans and laboratory animals, with ample evidence that the same is true in companion animals. In this r...
Stogdale L.The nomenclature of human diabetes mellitus (DM) has been revised, and this classification has been accepted throughout the medical world and literature. The major categories of diabetes are: insulin-dependent DM, type I or IDDM; noninsulin-dependent DM, type II or NIDDM; secondary DM or type S; impaired glucose tolerance, IGT; gestational diabetes; and previous abnormality of glucose tolerance, PrevAGT. A review of the literature has shown that over half of the documented diabetic dogs, with a single medical diagnosis, appear to be type I, IDDM, with a substantial proportion being type S, and...
Dugdale AH, Curtis GC, Milne E, Harris PA, Argo CM.Excessive accumulations or depletions of body fat have been associated with increased morbidity and mortality in horses and ponies. An objective, minimally-invasive method to accurately quantify body fat in living animals is required to aid nutritional management and define welfare/performance limits. Objective: To compare deuterium oxide (D(2) O) dilution-derived estimates of total body water (TBW) and body fat with values obtained by 'gold standard' proximate analysis and cadaver dissection. Objective: D(2) O dilution offers a valid method for the determination of TBW and body fat in equids....
Ungru J, Blüher M, Coenen M, Raila J, Boston R, Vervuert I.Fifteen obese ponies were used in a body weight (BW) reduction programme (BWRP, daily energy intake: 7.0-8.4 MJ/100 kg BW). A frequently sampled intravenous glucose tolerance test was used to assess insulin sensitivity. Subcutaneous adipose tissue biopsies of the tail head were obtained for mRNA gene expression profiles of adiponectin, retinol-binding protein 4 (RBP4), interleukin 6 (IL-6) and macrophage activation marker (CD68) before and after BWRP. Blood samples were analysed for serum leptin, serum RBP4 and plasma adiponectin. Significant BW losses occurred with 7 MJ DE/100 kg BW. Serum le...
Firshman AM, Valberg SJ.Insulin resistance is thought to be involved in the pathogenesis of many equine conditions such as pars intermedia dysfunction, equine metabolic syndrome, diabetes mellitus, hyperlipaemia, laminitis, endotoxaemia and osteochondrosis dissecans (OCD); whereas polysaccharide storage myopathy in Quarter Horses and equine motor neuron disease (EMD) have been associated with increased insulin sensitivity. However, it is clear that there is not one ideal test, in terms of both practicality and accuracy, for evaluating insulin sensitivity in horses and improved diagnostic techniques are required. This...
Johnson PJ, Wiedmeyer CE, LaCarrubba A, Ganjam VK, Messer NT.Analogous to the situation in human medicine, contemporary practices in horse management, which incorporate lengthy periods of physical inactivity coupled with provision of nutritional rations characterized by inappropriately high sugar and starch, have led to obesity being more commonly recognized by practitioners of equine veterinary practice. In many of these cases, obesity is associated with insulin resistance (IR) and glucose intolerance. An equine metabolic syndrome (MS) has been described that is similar to the human MS in that both IR and aspects of obesity represent cornerstones of it...
Giles SL, Nicol CJ, Harris PA, Rands SA.The aim of our study was to explore the association between dominance rank and body condition in outdoor group-living domestic horses, . Social interactions were recorded using a video camera during a feeding test, applied to 203 horses in 42 herds. Dominance rank was assigned to 194 individuals. The outcome variable body condition score (BCS) was recorded using a 9-point scale. The variables age and height were recorded and considered as potential confounders or effect modifiers. Results were analysed using multivariable linear and logistic regression techniques, controlling for herd group as...
Van Weyenberg S, Hesta M, Buyse J, Janssens GP.In nine initially obese ponies, a weekly weight loss according to 1% of their ideal body weight was evaluated for its impact on insulin sensitivity and metabolic profile. Weight loss was obtained solely through energy restriction, initially at 70% of maintenance energy requirements, but to maintain constant weight loss, feed amount had to be decreased to 50% and 35% of maintenance energy requirement during the course of the trial. An oral glucose tolerance test (OGTT) was performed at weeks 0, 10 and 17. Fasted blood samples were taken on weeks 0, 3, 10, 17 for analysis of triglycerides (TG), ...
Tinworth KD, Boston RC, Harris PA, Sillence MN, Raidal SL, Noble GK.Metformin may be an effective therapeutic option for insulin-resistant (I-R) horses/ponies because, in humans, it reportedly enhances insulin sensitivity (SI) of peripheral tissues without stimulating insulin secretion. To determine the effect of metformin on insulin and glucose dynamics in I-R ponies, six ponies were studied in a cross-over design by Minimal Model analysis of a frequently-sampled intravenous glucose tolerance test (FSIGT). Metformin was administered at 15 mg/kg bodyweight (BW), orally, twice-daily, for 21 days to the metformin-treated group. The control group received a place...
Mendoza FJ, Toribio RE, Perez-Ecija A.The donkey evolved under harsh and arid environmental conditions, developing unique energy-efficiency traits, with an efficiency to rapidly mobilize fat in situations of increased energy demands or when food is scarce. This evolution has led to an inherent predisposition of donkeys to obesity, dyslipidemias, insulin dysregulation/metabolic syndrome, pituitary pars intermedia dysfunction, and endocrinopathic laminitis. Marked differences have been described in hormone dynamics and testing protocols for the diagnosis of these endocrine and metabolic diseases in donkeys compared with horses, unde...
Gehlen H, Schwarz B, Bartmann C, Gernhardt J, Stöckle SD.Appropriate medical care for donkeys is challenging despite being important working animals in non-industrialized countries and pets in first world countries. Although the same principles of diagnosis and therapy as in horses are commonly applied, there are differences in reference values and physiologic reaction to dynamic tests. However, donkeys seem to suffer from typical equine diseases, such as metabolic syndrome and pituitary pars intermedia dysfunction (PPID). Asinine metabolic syndrome (AMS) comprises obesity, insulin dysregulation, and laminitis. The principles of diagnosis are simila...
Robles M, Nouveau E, Gautier C, Mendoza L, Dubois C, Dahirel M, Lagofun B, Aubrière MC, Lejeune JP, Caudron I, Guenon I, Viguié C, Wimel L....Obesity is a growing concern in horses. The effects of maternal obesity on maternal metabolism and low-grade inflammation during pregnancy, as well as offspring growth, metabolism, low-grade inflammation, testicular maturation and osteochondrotic lesions until 18 months of age were investigated. Twenty-four mares were used and separated into two groups at insemination according to body condition score (BCS): Normal (N, n = 10, BCS ≤4) and Obese (O, n = 14, BCS ≥4.25). BCS and plasma glucose, insulin, triglyceride, urea, non-esterified fatty acid, serum amyloid A (SAA), leptin and adiponect...
Morrison PK, Newbold CJ, Jones E, Worgan HJ, Grove-White DH, Dugdale AH, Barfoot C, Harris PA, Argo CM.Obesity is an important equine welfare issue. Whilst dietary restriction is the most effective weight-loss tool, individual animals range in their weight-loss propensity. Gastrointestinal-derived bacteria play a fundamental role in host-health and have been associated with obesity and weight-loss in other species. This study evaluated the faecal microbiome (next-generation sequencing of 16S rRNA genes) of 15 obese Welsh Mountain pony mares, in the same 11-week period across 2 years (n = 8 Year 1; n = 7 Year 2). Following a 4-week acclimation period (pre-diet phase) during which t...
Lange Consiglio A, Dell'Aquila ME, Fiandanese N, Ambruosi B, Cho YS, Bosi G, Arrighi S, Lacalandra GM, Cremonesi F.The identification of the adipocyte-derived obesity gene product, leptin (Ob), and subsequently its association with reproduction in rodents and humans led to speculations that leptin may be involved in the regulation of oocyte and preimplantation embryo development. In mice and pigs, in vitro leptin addition significantly increased meiotic resumption and promoted preimplantation embryo development in a dose-dependent manner. This study was conducted to determine whether leptin supplementation during in vitro maturation (IVM) to horse oocytes could have effects on their developmental capacity ...
The Journal of nutritionJune 15, 2006
Volume 136, Issue 7 Suppl 2094S-2098S doi: 10.1093/jn/136.7.2094S
Treiber KH, Kronfeld DS, Geor RJ.Insulin is a major regulatory hormone in glucose and fat metabolism, vascular function, inflammation, tissue remodeling, and the somatotropic axis of growth. Insulin resistance alters insulin signaling by decreasing insulin action in certain resistant pathways while increasing insulin signaling in other unaffected pathways via compensatory hyperinsulinemia. In humans, altered insulin signaling is implicated in reduced glucose availability to insulin-sensitive cells, vasoconstriction and endothelial damage, and inflammatory response. Although no direct evidence exists for insulin's role in thes...
Tadros EM, Frank N, Donnell RL.To test the hypothesis that inflammatory responses to endotoxemia differ between healthy horses and horses with equine metabolic syndrome (EMS). Animals-6 healthy horses and 6 horses with EMS. Methods: Each horse randomly received an IV infusion of lipopolysaccharide (20 ng/kg [in 60 mL of sterile saline {0.9% NaCl} solution]) or saline solution, followed by the other treatment after a 7-day washout period. Baseline data were obtained 30 minutes before each infusion. After infusion, a physical examination was performed hourly for 9 hours and at 15 and 21 hours; a whole blood sample was collect...
Selim S, Elo K, Jaakkola S, Karikoski N, Boston R, Reilas T, Särkijärvi S, Saastamoinen M, Kokkonen T.Obesity and insulin resistance have been shown to be risk factors for laminitis in horses. The objective of the study was to determine the effect of changes in body condition during the grazing season on insulin resistance and the expression of genes associated with obesity and insulin resistance in subcutaneous adipose tissue (SAT). Sixteen Finnhorse mares were grazing either on cultivated high-yielding pasture (CG) or semi-natural grassland (NG) from the end of May to the beginning of September. Body measurements, intravenous glucose tolerance test (IVGTT), and neck and tailhead SAT gene exp...
Argo CM, Dugdale AH, McGowan CM.The addition of hay soaking to current nutritional advice for weight loss management for equine obesity lacks clinical evidence. Twelve overweight/obese horses and ponies were used to test the hypothesis that feeding soaked hay at 1.25% of body mass (BM) daily as dry matter (DM) before soaking would elicit weight losses within the target 0.5-1.0% of BM weekly. Six animals were used to evaluate the impact of nutrient-leaching on the digestibility and daily intakes of dietary energy and nutrients. Soaked hay DM was corrected in accordance with the 'insoluble' ADF content of fresh and soaked hays...
Walshe N, Cabrera-Rubio R, Collins R, Puggioni A, Gath V, Crispie F, Cotter PD, Brennan L, Mulcahy G, Duggan V.Obesity is endemic in human populations in the western society, and with mounting evidence that the intestinal ecological environment plays a major role in its pathogenesis, identification of therapies based on intestinal microbiota modulation are gaining attention. Obesity in companion animals is also a common clinical problem. We set out using a multidimensional approach, to determine the effectiveness and safety of a weight loss program for horses incorporating diet restriction and exercise. In addition, we aimed to investigate the effect of this program on the overall intestinal health of ...
Geor RJ.Epidemiologic studies indicate that most laminitis cases occur in horses and ponies kept at pasture, hence the term 'pasture-associated laminitis'. Clinical cases of laminitis most often occur under conditions that favor accumulation of rapidly fermentable nonstructural carbohydrates (fructans, simple sugars, or starches) in pasture, and animals with an equine metabolic syndrome (EMS) phenotype (insulin resistance, abnormal insulin dynamics, +/- obesity) seem to be at highest risk for developing the condition. Although the mechanisms linking consumption of pasture forage with development of la...
Martinson KL, Coleman RC, Rendahl AK, Fang Z, McCue ME.Excessive BW has become a major health issue in the equine (Equus caballus) industry. The objectives were to determine if the addition of neck circumference and height improved existing BW estimation equations, to develop an equation for estimation of ideal BW, and to develop a method for assessing the likelihood of being overweight in adult equids. Six hundred and twenty-nine adult horses and ponies who met the following criteria were measured and weighed at 2 horse shows in September 2011 in Minnesota: age ≥ 3 yr, height ≥ 112 cm, and nonpregnant. Personnel assessed BCS on a scale of 1 t...
