Energy metabolism in horses refers to the biochemical processes that convert nutrients into energy within the body, supporting various physiological functions. This process involves the breakdown of carbohydrates, fats, and proteins to produce adenosine triphosphate (ATP), the primary energy carrier in cells. Key metabolic pathways include glycolysis, the citric acid cycle, and oxidative phosphorylation. Energy metabolism is essential for maintaining muscle function, thermoregulation, and overall health in horses. Factors such as diet, exercise, and health status can influence these metabolic processes. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and implications of energy metabolism in equine physiology.
Urschel KL, McKenzie EC.Skeletal muscle comprises 40% to 55% of mature body weight in horses, and its mass is determined largely by rates of muscle protein synthesis. In order to support exercise, appropriate energy sources are essential: glucose can support both anaerobic and aerobic exercise, whereas fat can only be metabolized aerobically. Following exercise, ingestion of nonfiber carbohydrates and protein can aid muscle growth and recovery. Muscle glycogen replenishment is slow in horses, regardless of dietary interventions. Several heritable muscle disorders, including type 1 and 2 polysaccharide storage myopath...
Jarvis N, McKenzie HC.Weight loss occurs when the supply of energy is insufficient to meet the energy needs of an individual. The energy supply may be reduced by inadequate provision of feed, inadequate consumption, reduced digestion and absorption, or disruption in metabolic processing. Increased energy expenditure occurs with exercise and during cold temperatures, pregnancy, and lactation. Underlying clinical disease, particularly chronic inflammation, neoplasia, and protein-losing conditions, can cause weight loss or exacerbate existing weight loss. A methodical approach to weight-loss investigation and treatmen...
Glycogen in skeletal muscle is a major source of energy during exercise and an important determinant of endurance capacity, so that its measurement may provide a meaningful marker of athletes' preparation and a possible predictor of performance, both in humans and in equines. Gold standard of glycogen concentration measurement is the histochemical and biochemical analysis of biopsy-derived muscle tissue, an invasive and potentially injuring procedure. Recently, high-frequency ultrasound (US) technology is being exploited in human sports medicine to estimate muscle glycogen content. Therefore, ...
Catandi GD, Obeidat YM, Broeckling CD, Chen TW, Chicco AJ, Carnevale EM.Advanced maternal age is associated with a decline in fertility and oocyte quality. We used novel metabolic microsensors to assess effects of mare age on single oocyte and embryo metabolic function, which has not yet been similarly investigated in mammalian species. We hypothesized that equine maternal aging affects the metabolic function of oocytes and in vitro-produced early embryos, oocyte mitochondrial DNA (mtDNA) copy number, and relative abundance of metabolites involved in energy metabolism in oocytes and cumulus cells. Samples were collected from preovulatory follicles from young (≤1...
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...
Herbert E, Ouerdane H, Lecoeur P, Bels V, Goupil C.Muscles are biological actuators extensively studied in the frame of Hill's classic empirical model as isolated biomechanical entities, which hardly applies to a living organism subjected to physiological and environmental constraints. Here we elucidate the overarching principle of a living muscle action for locomotion, considering it from the thermodynamic viewpoint as an assembly of actuators (muscle units) connected in parallel, operating via chemical-to-mechanical energy conversion under mixed (potential and flux) boundary conditions. Introducing the energy cost of effort as the generaliza...
Martin-Rosset W, Andueza D, Vermorel M.The metabolisable energy (ME) content of feeds is a better estimate of their 'true' energy value than their digestible energy (DE) content, because ME takes account of the gross energy of methane (GEgas) and the gross energy of urine (GEurine) losses. The accuracy and precision of the Gesellschaft für Ernährungsphysiologie (GfE) and Institut National de la Recherche Agronomique (INRA) systems for predicting the DE and ME contents of diets for horses were compared using the results of a study comprising 15 mixed diets. The INRA system was more accurate than the GfE system for predicting DE, G...
Mercier Q, Aftalion A.The objective of this work is to provide a mathematical analysis on how a Thoroughbred horse should regulate its speed over the course of a race to optimize performance. Because Thoroughbred horses are not capable of running the whole race at top speed, determining what pace to set and when to unleash the burst of speed is essential. Our model relies on mechanics, energetics (both aerobic and anaerobic) and motor control. It is a system of coupled ordinary differential equations on the velocity, the propulsive force and the anaerobic energy, that leads to an optimal control problem that we sol...
Kowalik S, Wiśniewska A, Kędzierski W, Janczarek I.Skeletal muscle is considered to be the largest endocrine organ determining the maintenance of energy homeostasis. Adaptive changes in skeletal muscles in response to physical exercise influence the production as well as secretion of myokines, which are bioactive factors that play a crucial role in energy expenditure processes. The aim of the study was to investigate the impact of two different types of exercise on the circulating level of two of these, myostatin and irisin, in trained horses. Twenty purebred Arabian horses were involved in the study: 10 three-year-old horses trained on the ra...
Myćka G, Musiał AD, Stefaniuk-Szmukier M, Piórkowska K, Ropka-Molik K.The gene encodes peroxisomal acyl-coenzyme A oxidase 1, the first enzyme in the fatty acid β-oxidation pathway, which could be significant for organisms exposed to long periods of starvation and harsh living conditions. We hypothesized that variations within , revealed by RNA Sequencing (RNA-Seq), might be based on adaptation to living conditions and had resulted from selection pressure. There were five different horse breeds used in this study, representing various utility types: Arabian, Thoroughbred, Polish Konik, draft horses, and Hucul. The single-nucleotide polymorphism (SNP) located i...
Ebert M, Moore-Colyer MJS.The aim of this study was to estimate the energy requirements of Thoroughbred racehorses in active training for flat racing. Twenty-two Thoroughbred racehorses in England were measured over periods from 6 to 15 wk, which included periods of active race training and temporarily reduced training. Energy intake was determined by measuring daily feed consumption. Energy output was measured using heart rate monitors during 730 training sessions, relating heart rate (HR) to oxygen consumption (VO2) and converting VO2 to energy. Field maintenance requirements were calculated by deducting the marginal...
van Eps AW, Belknap JK, Schneider X, Stefanovski D, Engiles JB, Richardson DW, Zedler ST, Medina-Torres CE, Watts MR.Supporting limb laminitis (SLL) is suspected to be caused by lamellar ischaemia as a consequence of increased mechanical load. Objective: Examine the effects of prolonged preferential weight bearing (PWB) on lamellar perfusion and metabolism. Methods: In vivo experiment. Methods: Microdialysis probes were inserted in the lamellar and sublamellar dermis of one forelimb in 13 Standardbred horses. In six horses, a platform shoe (contralateral forelimb) was used to induce increased load on the microdialysis-instrumented forelimb (PWB). The remaining seven horses were controls (CON). All horses wer...
DeBoer M, Konop A, Fisher B, Martinson K.Thermoregulation is an energy-expensive process, which can be mitigated by blanketing horses in cold climates, potentially preventing weight loss or leading to decreased feed intake. The objective of this study was to evaluate feed intake, body weight (BW), and body condition scores (BCSs) in blanketed and nonblanketed horses. In October 2019, 16 mature adult horses were blocked by breed and BCS and randomly assigned to a blanketed (n = 8) or nonblanketed (n = 8) treatment; blankets were placed. Data were collected in December 2019 and January 2020 in River Falls, Wisconsin. During the study...
Ekici S, Ozmen O.The active roles of microribonucleic acids (miRNAs) in gene regulation have made miRNAs a key point for the scientific world in the study of physiological processes. Although saliva includes the largest number of miRNAs, there is no miRNA study in saliva on horses has been found. Our study is the first study on miRNAs isolation from saliva in horses. In the present study, saliva was studied in Arabian racehorses to better understand the molecular mechanisms of expression levels that are effective in lipid metabolism of miRNAs and their target genes during the race. Identification of lipid meta...
Valberg SJ.There are 5 single-gene mutations that are known to cause muscle disease in horses. These mutations alter the amino acid sequence of proteins involved in cell membrane electrical conduction, muscle energy metabolism, muscle contraction, and immunogenicity. The clinical signs depend on the pathway affected. The likelihood that an animal with a mutation will exhibit clinical signs depends on the mode of inheritance, environmental influences, and interactions with other genes. Selection of a genetic test for use in diagnostic or breeding decisions requires a knowledge of clinical signs, mode of i...
Salari F, Licitra R, Altomonte I, Martini M.We evaluated the daily intake in donkeys during maintenance, late pregnancy, and early lactation. The growth curves of the foals in the first eight weeks of life and the milk production in lactating jennies were also investigated. Donkeys were separated into two groups: seven pregnant jennies (group 1: pregnant/lactating) and seven nonpregnant, nonlactating jennies (group 2). The groups were fed two different diets each. The feeding period for group 1 covered eight weeks before parturition and eight weeks postpartum. Group 2 was managed during the same time period (16 weeks). Diet 1 consisted...
Lewis N, Hinrichs K, Leese HJ, McGregor Argo C, Brison DR, Sturmey RG.The use of in vitro embryo production in the horse is increasing in clinical and research settings; however, protocols are yet to be optimised. Notably, the two most commonly used base media for in vitro maturation (IVM) supply glucose at markedly different concentrations: physiological (5.6 mM, M199) or supraphysiological (17 mM, DMEM/F-12). Exposure to high glucose has detrimental effects on oocytes and early embryos in many mammalian species, but the impact has not yet been examined in the horse. To address this, we compared the energy metabolism of equine COCs matured in M199-based maturat...
Kuchler M, Zeyner A, Susenbeth A, Kienzle E.Renal energy losses of horses are high in comparison with other species. In the present study, more data were obtained on this parameter to improve predictive equations for renal energy losses. Four adult ponies (247-344 kg body weight [BW]) were fed with eight different diets based on first cut hay, second cut hay, early first cut fresh grass, late cut herbs-grass mix, early cut clover-grass mix, sugar beet pulp, rice bran and straw. Feed intake was measured, and urine and faeces were quantitatively collected for 3 × 12 hr at daytime and afterwards 3 × 12 hr at nighttime. Feed was an...
Ferlazzo A, Cravana C, Fazio E, Medica P.The review discusses the hormonal changes during exercise stress. The exercise generally produces a rise of adrenaline (A), noradrenaline (NA), adrenocorticotropic hormone (ACTH), cortisol, glucagon, growth hormone, arginine vasopressine, etc., and a drop of insulin. The hormonal events during reestablishment of homeostasis due to exercise stress can be divided into a catabolic phase, with decreased tolerance of effort, and reversible biochemical, hormonal and immunological changes, and an anabolic phase, with a higher adaptive capacity, and enhanced performance. The two main hormonal axes act...
Ebert M, Moore-Colyer MJS.The aim of this study was to estimate the energy requirements of performance horses in active, variable training in the field. Sixty horses in England and Switzerland were measured over 2-wk periods and, for 15 of these, the measurement period was extended, ranging from 21 to 42 wk. Energy intake was estimated by measuring daily feed consumption. Energy output was measured using heart rate (HR) monitors during 608 training sessions, relating HR to volume of oxygen (VO₂) and converting VO₂ to energy. Field maintenance requirements were calculated by deducting the marginal energy cost of tra...
Lewis N, Hinrichs K, Leese HJ, McG Argo C, Brison DR, Sturmey R.Horses are one of the few species, beside humans, in which assisted reproductive technology has important clinical applications. Furthermore, the horse can serve as a valuable model for the study of comparative reproductive biology. Here we present the first comprehensive characterisation of energy metabolism and mitochondrial efficiency in equine cumulus-oocyte complexes (COCs) during in vitro maturation (IVM), as determined using a combination of non-invasive consumption and release assays and mitochondrial function analysis. These data reveal notable species-specific differences in the rate...
Stokes SM, Bertin FR, Stefanovski D, Poulsen L, Belknap JK, Medina-Torres CE, Pollitt CC, van Eps AW.Continuous digital hypothermia (CDH) prevents lamellar failure in the euglycaemic hyperinsulinaemic clamp (EHC) and oligofructose (OF) laminitis models, but the mechanisms remain unclear. Objective: To evaluate the effects of CDH on lamellar energy metabolism and perfusion in healthy horses and during EHC and OF laminitis models. Methods: In vivo experiment. Methods: Archived samples were used from Standardbred geldings that received no treatment (CON) (n = 8) or underwent EHC (n = 8) or OF (n = 6) laminitis models. Both forelimbs were instrumented with a lamellar microdialysis system, a...
Stokes SM, Bertin FR, Stefanovski D, Belknap JK, Medina-Torres CE, Pollitt CC, van Eps AW.Hyperinsulinaemia is associated with the development of endocrinopathic laminitis; however, the mechanisms remain unclear. Objective: Evaluate the effects of hyperinsulinaemia on lamellar energy metabolism and perfusion during laminitis development. Methods: In vivo experiment. Methods: Eight Standardbred horses were instrumented with a microdialysis probe in the lamellae of a forelimb. A 24 hours baseline period (BASELINE) was followed by 48 hours of a continuous euglycaemic hyperinsulinaemic clamp (EHC) from 24 to 72 hours (CLAMP). Microdialysate was collected every 6 hours and analysed ...
Moreno-Irusta A, Dominguez EM, Marín-Briggiler CI, Matamoros-Volante A, Lucchesi O, Tomes CN, Treviño CL, Buffone MG, Lascano R, Losinno L....Sperm chemotaxis may facilitate the finding of the oocyte. Only capacitated spermatozoa can orient their movement by chemotaxis, which as well as capacitation, is regulated in part by the cAMP-PKA pathway. Reactive oxygen species (ROS) are produced during sperm capacitation which is closely related to chemotaxis. Then, the ROS participation in the chemotactic signaling can be expected. Here we studied the role of ROS in the chemotaxis signaling of equine spermatozoa which produce high quantities of ROS because of their energy metabolism. The level of capacitated and chemotactic spermatozoa was...
Martin-Rosset W, Andueza D, Vermorel M.The accuracy and precision of the National Research Council (NRC), Gesellschaft für Ernährungsphysiologie (GfE) and Institut National de la Recherche Agronomique (INRA) systems for predicting the digestible energy (DE) value of hays were determined from the results of 15 digestibility trials with natural grassland hays and 9 digestibility trials with lucerne hays that all met strict experimental and a tight corpus of methods. The hays were harvested in the temperate zone. They covered broad ranges of chemical composition and DE value. The INRA system was more accurate than the other two syst...
van der Kolk JH, Thomas S, Mach N, Ramseyer A, Burger D, Gerber V, Nuoffer JM.Mitochondrial β-oxidation is essential in fat metabolism and can be monitored with blood acylcarnitine profiling, as partly degraded fatty acids accumulate as their carnitine esters. To guarantee continuous energy supply during long-distance exercise, endurance horses oxidise considerable amounts of fat in the mitochondrion. In endurance races over 80 km, glycogen depletion is evident in equine slow-twitch high oxidative muscle fibres and as a consequence, horses participating in endurance races over 80 km rely almost entirely on β-oxidation of fatty acids. This study investigated mitoch...
Işık R, Özdil F.Leptin receptor is a fundamental regulator in physiological functions of the regulation of food intake, energy homeostasis, immune function, and reproduction as well as on ovarian follicular cells on the placenta and lactating mammary glands. The aim of this study was to investigate the LEPR gene polymorphism in 60 donkeys reared in Thrace region of Turkey. A 585 bp long partial intron 6, exon 7, intron 7, and exon 8 regions of LEPR gene were amplified, and polymerase chain reaction products analyzed via DNA sequencing. A novel single-nucleotide polymorphism (SNP) was identified as g.713668A>...
Connysson M, Rhodin M, Jansson A.This study examined the effects of two housing systems (free-range and box stalls) on recovery of energy balance after competition-like exercise in Standardbred horses. Eight adult geldings (mean age 11 years) were used. The study had a change-over design, with the box stall (BOX) and free-range group housing (FreeR) treatments each run for 21 days. The horses were fed forage ad libitum and performed two similar race-like exercise tests (ET), on day 7 and day 14 in each treatment. Forage intake was recorded during the last 6-7 days in each period. Blood samples were collected before, during, a...
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...
Hobbs SJ, Clayton HM.One of the goals of the neuromotor control system is to minimize the cost of locomotion by reducing mechanical energy losses. Collisional mechanics, which studies the redirection of the downwards motion of the center of mass (COM) by ground reaction forces (GRF) generated by the limbs, represents an important source of energy loss. The primary objective of this study was to compare collisional mechanics and the associated mechanical energy losses in horses performing diagonally-synchronized gaits over a range of speeds. It is to be expected that collisional energy losses will be high when the ...
O'Reilly J, Cheng HL, Poon ET.Weight-making practices have been shown to impair musculoskeletal and physiological function of jockeys. This study investigated the "in-race" heart rate (HR) responses and hydration status during competitive racing, as well as selected physiological and lifestyle parameters of professional jockeys based in Hong Kong. "In-race" HR responses and early morning hydration status of 20 male jockeys were examined in hot and moderate climactic occasions. Additionally, bone mineral density (BMD), dietary intake and lifestyle choices were assessed. Osteopenia was observed in the calcanei of jockeys (le...
Barsnick RJ, Hurcombe SD, Smith PA, Slovis NM, Sprayberry KA, Saville WJ, Toribio RE.Endocrine dysregulation of hormones of energy metabolism is well documented in critically ill humans, but limited information exists in septic foals. The purpose of this study was to provide information on the hormonal response to energy metabolism in critically ill foals, focusing on insulin, glucagon, and leptin. Objective: Concentrations of insulin, glucagon, leptin, and triglycerides will be higher, whereas glucose concentration will be lower in septic foals than in healthy and sick nonseptic foals. The magnitude of these differences will be associated with severity of disease and nonsurvi...
Cameron EZ, Stafford KJ, Linklater WL, Veltman CJ.Studies of parental investment in mammals have frequently used suckling behaviour to estimate energy transfer from mother to offspring, and consequently to measure maternal input. Such studies assume that the more an offspring sucks, the more milk it will receive. This assumption has been questioned, and a review of the literature found little support for it. To test if suckling behaviour provided an accurate index of milk or energy intake we used a radioactive isotope technique to label the milk of thoroughbred mares and to measure milk transfer to foals. We found no significant linear relati...
Schober D, Aurich C, Nohl H, Gille L.Cryopreservation of spermatozoa is of essential importance for artificial insemination and breeding programs in horses. Besides other factors, spermatozoal motility depends on mitochondrial energy metabolism. Based on changes of single mitochondrial functions it has been suggested that mitochondrial damage during cryopreservation could be a major reason for diminished post thaw semen quality. However, it is still unclear to which extent this influences the whole bioenergetic performance of mitochondria and whether this plays a role during routine cryopreservation procedures. Therefore, it was ...
Szcześniak KA, Ciecierska A, Ostaszewski P, Sadkowski T.β-Hydroxy-β-methylbutyrate (HMB) is a popular ergogenic aid used by human athletes and as a supplement to sport horses, because of its ability to aid muscle recovery, improve performance and body composition. Recent findings suggest that HMB may stimulate satellite cells and affect expressions of genes regulating skeletal muscle cell growth. Despite the scientific data showing benefits of HMB supplementation in horses, no previous study has explained the mechanism of action of HMB in this species. The aim of this study was to reveal the molecular background of HMB action on equine skeletal m...
Mach N, Moroldo M, Rau A, Lecardonnel J, Le Moyec L, Robert C, Barrey E.Endurance exercise has a dramatic impact on the functionality of mitochondria and on the composition of the intestinal microbiome, but the mechanisms regulating the crosstalk between these two components are still largely unknown. Here, we sampled 20 elite horses before and after an endurance race and used blood transcriptome, blood metabolome and fecal microbiome to describe the gut-mitochondria crosstalk. A subset of mitochondria-related differentially expressed genes involved in pathways such as energy metabolism, oxidative stress and inflammation was discovered and then shown to be associa...
Li G, Lee P, Mori N, Yamamoto I, Arai T.Continuous high intensity training may induce alterations to enzyme activities related to glucose and lipid metabolism in horses. In our study, five Thoroughbred race horses (3 male and 2 female, avg age=5 yrs old) were compared against five riding horses (1 male, 1 female, 3 gelding, avg age=13 yrs old) in terms of energy metabolism, by examining plasma malate (MDH) and lactate (LDH) dehydrogenase activities and M/L ratio. MDH is involved in NADH and ATP generation, whereas LDH can convert NADH back into NAD(+) for ATP generation. An increase in plasma M/L ratio can reflect heightened energy ...
McGowan CM, Dugdale AH, Pinchbeck GL, Argo CM.Few studies have examined the effect of dietary restriction in horses with equine metabolic syndrome (EMS). This study aimed to determine improvements in insulin sensitivity following dietary restriction for 6 weeks, and to determine if the improvement would be greater in horses receiving short-chain fructo-oligosaccharides (sc-FOS). Dietary management involved feeding grass hay, restricted to 1.25% of body mass (BM) as daily dry matter intake and soaked in cold water prior to feeding, with the addition of a vitamin and mineral nutraceutical supplement with or without the addition of sc-FOS (1...
Hyyppä S, Räsänen LA, Pösö AR.To determine glycogen resynthesis rate and changes in plasma metabolite concentrations in horses before and after repeated exercise. Methods: 6 clinically normal Standardbred trotters. Methods: Horses trotted distances of 3,000, 3,000, and 2,000 m (trial A) and 3 days later, trotted 2,100, 2,100, and 1,600 m (trial B). Horses had 1 hour rest periods between bouts of exercise. Trotting speed was increased with each exercise bout, up to a near maximal. Muscle biopsy specimens and venous blood samples were obtained before each trial and 0, 4, 24, 48, and 72 hours after the third bout. Blood sampl...
Nolazco Sassot L, Villarino NF, Dasgupta N, Morrison JJ, Bayly WM, Gang D, Sanz MG.A comprehensive study of the effect of supramaximal exercise in lipid homeostasis of Thoroughbreds provides the basis for future research on the role of lipids on energy metabolism in racehorses. Objective: To compare the plasma lipidome of Thoroughbreds before and after supramaximal exercise using an untargeted lipidomics approach. Methods: Pilot experimental study. Methods: Four Thoroughbred horses were used. The maximal oxygen consumption (VO ) was calculated for each horse. Horses then underwent treadmill exercise at the speed for which the oxygen requirements had been calculated to be 11...
Bobbert MF, Santamaría S.The purpose of the present study was to gain more insight into the contribution of the forelimbs and hindlimbs of the horse to energy changes during the push-off for a jump. For this purpose, we collected kinematic data at 240 Hz from 23 5-year-old Warmbloods (average mass: 595 kg) performing free jumps over a 1.15 m high fence. From these data, we calculated the changes in mechanical energy and the changes in limb length and joint angles. The force carried by the forelimbs and the amount of energy stored was estimated from the distance between elbow and hoof, assuming that this part of the le...
Edouard N, Fleurance G, Martin-Rosset W, Duncan P, Dulphy JP, Grange S, Baumont R, Dubroeucq H, Pérez-Barbería FJ, Gordon IJ.Food intake is a key biological process in animals, as it determines the energy and nutrients available for the physiological and behavioural processes. In herbivores, the abundance, structure and quality of plant resources are known to influence intake strongly. In ruminants, as the forage quality declines, digestibility and total intake decline. Equids are believed to be adapted to consume high-fibre low-quality forages. As hindgut fermenters, it has been suggested that their response to a reduction in food quality is to increase intake to maintain rates of energy and nutrient absorption. Al...
Arai T, Inoue A, Uematsu Y, Sako T, Kimura N.The activities of the enzymes involved in the malate-aspartate shuttle and lactate dehydrogenase (LDH) and the pattern of the isoenzymes of LDH were determined in plasma and peripheral leukocytes of lactating Holstein cows and thoroughbred riding horses as representative herbivorous animals. In the horse plasma, LDH activities were significantly lower and AST activities were significantly higher than those in the cow plasma. The specific activities of cytosolic malate dehydrogenase (MDH), LDH and AST in the horse leukocytes were higher than those in the cows. The cytosolic ratio of MDH/LDH act...
Jones JH, Carlson GP.The metabolic power required for sustained exercise in the horse is proportional to running speed. Moderately fast speeds require substantial energy expenditure and result in the generation of a massive metabolic heat load. Quantitative estimates of energy expenditure and heat production of horses at various running speeds were developed using empirically derived data from treadmill studies. Total metabolic power represents the sum of aerobic power indicated by the rate of oxygen consumption and net anaerobic power indicated by the rate of plasma lactate accumulation. These data were applied t...
Sticker LS, Thompson DL, Fernandez JM, Bunting LD, DePew CL.Sixteen light horse mares were fed diets of bermudagrass hay and a corn/cottonseed hull-based supplement formulated to contain either 100% (control) or 50% (restricted) of the protein and(or) energy requirements for maintenance in a 2 x 2 factorial arrangement of treatments. Plasma IGF-I, prolactin, cortisol, triiodothyronine, and thyroxine were monitored for 33 d. On the 27th d, frequent blood samples were drawn throughout the day for the measurement of growth hormone (GH), and on the 29th d, an epinephrine challenge and an i.v. glucose tolerance test (IVGTT) were performed in the morning and...
Pagan JD, Hintz HF.Energy balance studies using indirect calorimetry were conducted with four mature equids ranging in weight from 125 to 856 kg. Each animal was fed three different levels of intake of the same diet. The amounts of digestible and metabolizable energy required for zero energy balance were determined by calculating regression equations for energy balance against energy intake. It was concluded that the maintenance requirements of equids vary linearly with body weight. No advantage was found for the use of weight for the comparison of equids within the range studied. The digestible energy (DE) requ...
Bond SL, Greco-Otto P, Sides R, Kwong GPS, Léguillette R, Bayly WM.A prospective, randomized, controlled study was designed to determine relative aerobic and anaerobic (lactic and alactic) contributions at supramaximal exercise intensities using two different methods. Thoroughbred racehorses ( = 5) performed a maximal rate of oxygen consumption (V̇o) test and three supramaximal treadmill runs (105, 115, and 125% V̇o). Blood lactate concentration (BL) was measured at rest, every 15 s during runs, and 2, 5, 10, 20, 30, 40, 50, and 60 min postexercise. In , oxygen demand was calculated for each supramaximal intensity based on the V̇o test, and relative aerobi...
Bruynsteen L, Janssens GP, Harris PA, Duchateau L, Valle E, Odetti P, Vandevelde K, Buyse J, Hesta M.The present study evaluated the effect of different levels of energy restriction on metabolic parameters in obese ponies. Relative weight changes, markers of lipid metabolism and oxidant/antioxidant balance were monitored. A total of eighteen obese (body condition score ≥ 7/9) Shetland ponies were studied over a 23·5-week trial, which was divided into three periods. The first period involved a 4-week adaptation period in which each animal was fed 100% of their maintenance energy requirements needed to maintain a stable obese body weight (MERob). This was followed by a 16·5-week weight-loss...
Lemieux H, Boemer F, van Galen G, Serteyn D, Amory H, Baise E, Cassart D, van Loon G, Marcillaud-Pitel C, Votion DM.Equine atypical myopathy in Europe is a fatal rhabdomyolysis syndrome that results from the ingestion of hypoglycin A contained in seeds and seedlings of Acer pseudoplatanus (sycamore maple). Acylcarnitine concentrations in serum and muscle OXPHOS capacity were determined in 15 atypical myopathy cases. All but one acylcarnitine were out of reference range and mitochondrial respiratory capacity was severely decreased up to 49% as compared to 10 healthy controls. The hallmark of atypical myopathy thus consists of a severe alteration in the energy metabolism including a severe impairment in muscl...
Pagan JD, Hintz HF.Energy expenditure was measured in four geldings (433 to 520 kg) during submaximal exercise on a racetrack using a mobile open-circuit indirect respiration calorimeter. A total of 304 5-min measurements of O2 consumed and CO2 produced were taken. Measurements were made with and without riders. The amount of energy expended by the horses was exponentially related to speed and was proportional to the body weight of the riderless horse or the combined weight of the horse plus rider and tack. Total energy expended by the four horses walking, trotting, cantering was best described by the equation: ...
Wilson G, Chester N, Eubank M, Crighton B, Drust B, Morton JP, Close GL.Professional jockeys are unique among weight-making athletes, as they are often required to make weight daily and, in many cases, all year-round. Common methods employed by jockeys include dehydration, severe calorie restriction, and sporadic eating, all of which have adverse health effects. In contrast, this article outlines a structured diet and exercise plan, employed by a 22-yr-old professional National Hunt jockey in an attempt to reduce weight from 70.3 to 62.6 kg, that does not rely on any of the aforementioned techniques. Before the intervention, the client's typical daily energy intak...
Velie BD, Fegraeus KJ, Solé M, Rosengren MK, Røed KH, Ihler CF, Strand E, Lindgren G.Although harness racing is of high economic importance to the global equine industry, significant genomic resources have yet to be applied to mapping harness racing success. To identify genomic regions associated with harness racing success, the current study performs genome-wide association analyses with three racing performance traits in the Norwegian-Swedish Coldblooded Trotter using the 670 K Axiom Equine Genotyping Array. Following quality control, 613 horses and 359,635 SNPs were retained for further analysis. After strict Bonferroni correction, nine genome-wide significant SNPs were id...
Le Moyec L, Robert C, Triba MN, Bouchemal N, Mach N, Rivière J, Zalachas-Rebours E, Barrey E.Endurance racing places high demands on energy metabolism pathways. Metabolomics can be used to investigate biochemical responses to endurance exercise in humans, laboratory animals, and horses. Although endurance horses have previously been assessed in the field (i.e., during races) using broad-window Nuclear Magnetic Resonance metabolomics, these studies included several different race locations, race distances, age classes, and race statuses (finisher or elimination). The present NMR metabolomics study focused on 40 endurance horses racing in three race categories over 90, 120, or 160 km. T...
Seminati E, Nardello F, Zamparo P, Ardigò LP, Faccioli N, Minetti AE.We hypothesized that, as occurring in cars, body structural asymmetries could generate asymmetry in the kinematics/dynamics of locomotion, ending up in a higher metabolic cost of transport, i.e. more 'fuel' needed to travel a given distance. Previous studies found the asymmetries in horses' body negatively correlated with galloping performance. In this investigation, we analyzed anatomical differences between the left and right lower limbs as a whole by performing 3D cross-correlation of Magnetic Resonance Images of 19 male runners, clustered as Untrained Runners, Occasional Runners and Skille...
Dugdale AH, Curtis GC, Cripps PJ, Harris PA, Argo CM.Changes in appetite, body mass (BM), body condition score (BCS), direct (ultrasonographic) and indirect (deuterium oxide dilution technique) measures of body fat were monitored in Welsh Mountain pony mares (n=11, 5-19 years of age) offered ad libitum access to a complete diet (gross energy 16.9±0.07 MJ/kg dry matter) for 12 weeks during summer (n=6; 246±20 kg) and winter (n=5; 219±21 kg). At the outset, each group comprised two thin (BCS 1-3/9), moderate (BCS 4-6/9) and obese (BCS 7-9/9) animals. For ponies that were non-obese at the outset, BM was gained more rapidly (P=0.001) in summer (0...
George LA, Staniar WB, Cubitt TA, Treiber KH, Harris PA, Geor RJ.To characterize the effects of pregnancy on insulin sensitivity (SI) and glucose dynamics in pasture-maintained mares fed supplemental feeds of differing energy composition. Methods: Pregnant (n = 22) and nonpregnant (10) healthy Thoroughbred mares. Methods: Pregnant and nonpregnant mares underwent frequently sampled intravenous glucose tolerance tests at 2 times (period 1, 25 to 31 weeks of gestation; period 2, 47 weeks of gestation). Following period 1 measurements, mares were provided a high-starch (HS; 39% starch) or high-fat and -fiber (14% fat and 70% fiber) supplemental feed. From a sub...
Cahill JI, Goulden BE.Recent research on the muscular and nervous changes which occur in idiopathic equine laryngeal hemiplegia has indicated that many of the traditional concepts of the aetiology of this disease are erroneous. In light of the new knowledge gained, the various predispositions and possible causes of laryngeal hemiplegia are discussed, and it is suggested that the underlying mechanism of axonal damage in this neuropathy of horses may be related to abnormal energy metabolism in the axon.
Ramírez-Agámez L, Hernández-Avilés C, Ortíz I, Love CC, Varner DD, Hinrichs K.Equine spermatozoa appear to differ from spermatozoa of other species in using oxidative phosphorylation preferentially over glycolysis. However, there is little information regarding effects of different energy sources on measured parameters in equine spermatozoa. Objective: To determine the effect of three individual energy substrates, glucose, pyruvate, and lactate, on motion characteristics, membrane integrity, and acrosomal status of stallion spermatozoa. Methods: Freshly ejaculated stallion spermatozoa were incubated with combinations of glucose (5 mm), pyruvate (10 mm), and lactate (1...
Kline KH, Bechtel PJ.1. Cross sections from the middle of the gluteus medius were removed from 10 adult horses and used to evaluate changes in histochemically determined muscle fiber type and biochemically determined metabolic enzyme activities as a function of sample depth. 2. Muscle fiber types determined using histochemical methods for myosin ATPase (pH 9.4) and succinic dehydrogenase (SDH) activity indicated percent fast-twitch glycolytic (FG) muscle fibers decreased and slow-twitch oxidative (SO) fibers increased as a function of increasing sampling depth. 3. Percent histochemically determined fast-twitch oxi...
