bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasma aldosterone concentration and cardiovascular response to low sodium intake in horses in training
Authors: JANSSON A. , JOHANNISSON A. , KVART C. 
Published: November 2010

SummaryReason for performing the study:Horses in training lose large amounts of sodium but little is known about the cardiovascular response to low sodium intake.Objectives:To investigate the effect of low sodium intake on plasma aldosterone (pAldo) concentrations and the cardiovascular system of athletic horses, and to identify markers of low sodium intake.Methods:Seven Standardbred geldings in training (trained twice a week) were randomly offered a standardised diet supplemented (NaS, 58 mg Na/kg bwt) and not supplemented (NaN, 3 mg Na/kg bwt) with NaCl for 5 weeks in a changeover design. Blood samples were taken once a week and in Week 5, before and following an exercise test until 22.30 h and analysed for blood sodium (bNa), total plasma protein (TPP), pAldo, troponin I and packed cell volume (PCV). Blood pressure (BP) was measured and pulse wave recorded at rest with high definition oscillometric‐technique (HDO). ECG and echocardiography were recorded. Water intake was measured before and on the day of exercise and voluntary saline intake was measured for 2 days after each period. Faecal samples were taken weekly and analysed for sodium and potassium content.Results:The pAldo and the PCV was higher in NaN compared to NaS. There were no differences between diets in BP, ECG, plasma troponin I and echocardiogram but HDO pulse amplitude tended to be smaller on diet NaN. Water intake was lower on diet NaN and saline intake higher. The response to exercise in bNa, pAldo, PCV and TPP was different on the 2 diets. Faecal potassium/sodium ratio was higher on NaN than on NaS.Conclusion:This study shows that 5 weeks of low sodium intake increased plasma aldosterone concentration and PCV but no alterations in heart function was observed. Faecal potassium/sodium ratio could be used to assess sodium status in horses.
Factors contributing to plasma TCO2and acid‐base state in Ontario Standardbred racehorses
Authors: WALLER A. P. , PEARSON W. , LINDINGER M. I. 
Published: November 2010

SummaryReasons for performing study:Standardbred and Thoroughbred racehorses around the world are tested for performance enhancing substances. Among these are blood alkalising substances that raise plasma pH and total carbon dioxide (TCO2) concentration. However, many horses have an elevated TCO2due to dietary, environmental and health concerns without having been administered an alkalising substance.Objectives:The purposes of this study were to determine the acid‐base profile of a cross section of Standardbred horses in racing/race training in Ontario and the main independent variables that contributed to acid‐base state.Materials and methods:On nonracing days, blood from 211 horses at rest, from 9 training facilities, was analysed within 30 min for plasma pH (7.406 ± 0.039; mean ± s.e.), PCO2(50.0 ± 3.4 mmHg), from which [HCO3‐] (31.2 ± 2.8 mmol/l) and [TCO2] (33.1 ± 2.9 mmol/l; range 25.66–42.9) were calculated. From these, a subset of 161 horses had full data sets for plasma protein and strong ion concentrations. These data were further analysed by facility and level of TCO2. Data on nutrition, training, racing and medications were also collected.Results:There were significant differences amongst facilities with respect to plasma pH, TCO2, strong ion difference ([SID]), PCO2and total weak acid concentration ([Atot]). Horses having the highest TCO2(37.0–42.9 mmol/l, n = 16) had significantly higher [SID] (52.9 ± 0.8 mEq/l) and PCO2(52.5 ± 0.7 mmHg) and relatively low [Atot] (14.9 ± 0.7 mEq/l) compared to average TCO2(32.1.0–34.9 mmol/l) horses (n = 75). In horses with the lowest TCO2(n = 11) the greatest contributor was elevated [Atot] (21.0 ± 0.7 mEq/l) and unmeasured (acetate, citrate, proprionate, butyrate) weak acids (7.0 ± 0.2 mEq/l) while [SID] (49.6 ± 0.8 mEq/l) and PCO2(47.8 ± 1.0 mmHg) were similar to average TCO2horses. Thirty‐two horses had a TCO2ranging from 35.0–36.9 mmol/l).Conclusions:There is a wide range of acid‐base state and factors contributing to acid‐base state amongst Standardbred race horses in Ontario. Dietary, environmental and handling practices and health concerns, that elevate plasma [SID], lower [Atot] and lower the concentration of unmeasured weak acids are the primary contributors to alkalosis and elevated TCO2.
Goniometry: is it a reliable tool to monitor passive joint range of motion in horses?
Authors: LILJEBRINK Y. , BERGH A. 
Published: November 2010

SummaryReasons for performing study: Simple objective assessment tools are essential to monitor the clinical efficacy of therapeutic interventions used in equine orthopaedics and rehabilitation. In human medicine, goniometry is a validated tool to quantify restrictions in joint range of motion (ROM); however, the technique is not validated in horses.Objectives: To validate 2 different goniometry techniques for the measurement of passive flexion of the fetlock, carpus and hock by examining; 1) the intra‐ and inter‐tester reliability; 2) the differences between 2 goniometry techniques and 3) differences between standing and anaesthetised horses.Methods: The study is composed of three parts: 1) the intra‐ and inter‐tester reliability was examined on 10 horses, where each horse was assessed by 5 pairs of testers measuring ROM with a universal goniometer; 2) the differences between 2 goniometry techniques were examined on 14 horses, each assessed by 2 investigators (either working in pairs with one investigator holding the limb and the other measuring the joint angle, or working individually at the same time holding and measuring); 3) on 6 horses, the differences between standing and anaesthetised horses were assessed by 2 investigators with the same techniques as described above. Nonparametric tests (Mann‐Whitney, Wilcoxon sign‐rank) and Intraclass Correlation Coefficient (ICC) were used for statistical analysis (P<0.05).Results: 1) The intra‐tester reliability was high to excellent (ICC 0.8–1) and the inter‐tester reliability low to average (ICC 0.1–0.5); 2) significant differences in joint ROM were registered in carpus and hock when measuring in pairs compared to singly and 3) significant differences in joint ROM were registered measuring anaesthetised compared to standing horses.Conclusions: As shown in human studies, goniometry is a promising tool in documenting passive flexion of fetlock, carpus and hock, if used by the same investigator. However, additional studies are needed for further validation.
Age related decreases in thermoregulation and cardiovascular function in horses
Authors: McKEEVER K. H. , EATON T. L. , GEISER S. , KEARNS C. F. , LEHNHARD R. A. 
Published: November 2010

SummaryReason for performing study:Older horses have an increased risk of hyperthermia due to impaired cardiovascular function. While many studies have investigated thermoregulation in horses during exercise, none have investigated the effects of ageing.Objective:To test the hypothesis that there is a difference in thermoregulation during exercise and plasma volume (PV) in young and old horses.Methods:Study 1: 6 young (Y, 7.7 ± 0.5 years) and 5 old (O, 26.0 ± 0.8 years) unfit Standardbred mares (507 ± 11 kg, mean ± s.e.) ran on a treadmill (6% grade, velocity calculated to generate a work rate of 1625 watts) until core temperature reached 40°C. Core (CT), skin (ST), rectal temperature (RT) and heart rate (HR) were measured every min until 10 min post exertion. Packed cell volume (HCT), lactate (LA) and plasma protein (TP) were measured in blood samples collected before, at 40°C and every 5 min until 10 min post exercise. Sweat loss was estimated using bodyweight.Study 2: Plasma volume was measured in 26 young (8.2 ± 0.7 years) and 8 old (26.6 ± 0.7 years) Standardbred mares (515 ± 12 kg) using Evans Blue dye. Pre‐exercise blood (rBV) and red cell (rRCV) volumes were calculated using PV and HCT. Data analysis utilised repeated measures ANOVA andttests and data are expressed as mean ± s.e.Results:Old horses reached 40°C faster (998 ± 113 vs. 1925 ± 259 s; P<0.05) with a greater HR at 40°C (184 ± 6 vs. 140 ± 5 beats/min; P<0.05) and greater sweat losses (P<0.05). Heart rate did not differ (P>0.05) post exercise. Age did not alter (P>0.05) CT, ST, RT, LA, HCT or TP. Plasma volume was greater in Y vs. O horses (P<0.05, 28.5 ± 1.4 vs. 24.1 ± 1.6 l) as was rBV (41.3 ± 2.0 vs. 35.3 ± 2.3 l) and rRCV (13.3 ± 0.6 vs. 11.1 ± 0.8 l).Conclusion:Ageing compromises the ability to handle the combined demand of exercise and thermoregulation in part due to decreased absolute pre‐exercise PV.
Electromyography activity of the equine splenius muscle and neck kinematics during walk and trot on the treadmill
Authors: ZSOLDOS R. R. , KOTSCHWAR A. B. , KOTSCHWAR A. , GROESEL M. , LICKA T. , PEHAM C. 
Published: November 2010

SummaryReasons for performing study:Skeletal muscle activity can be concentric or eccentric, anisometric or isometric and correlation of the equine splenius muscle activity with the movement of its effector joints at walk and trot has not yet been fully characterised.Objective:Investigating activity of the splenius muscle together with kinematics of head and cranial neck at walk and trot.Materials and methods:Kinematics and surface electromyography were measured in 6 horses (8–20‐years‐old, 450–700 kg) without signs of neck pain. Markers were placed on left and rightcrista facialis, and on left and right cervical vertebrae 1 and 3. Head and neck angle was calculated in sagittal and horizontal planes. Electrodes were placed over both splenius muscles at the level of C2. Left and right muscle activity was compared using Studentttest for paired samples and correlations calculated using Pearson correlation coefficient. Significance was set at P<0.05.Results:In all horses, maximum surface electromyography (sEMG) values at the trot were higher than at the walk. The intraindividual differences between maximum and minimum values of the EMG ranged from 45–127 mV in walk and from 154–524 mV in trot. Flexion‐extension C1 angle changed by 43° in walk and 27° in trot. For each motion cycle, 2 EMG maxima were found in both gaits, occurring just prior to maximum extension of the C1 angle. Lateral bending at C1 angle changed by 16° in walk and 17° in trot and EMG reached maximum values bilaterally during maximum lateral bending at walk.Conclusions:The splenius muscle reaches maximum activity at the beginning of the forelimb stance phases in trot, indicating functional stabilisation against flexion of the head and neck. Unilateral activity of the splenius muscle representing stabilisation against lateral movement was not found.
Effects of competitive and noncompetitive showjumping on total and free iodothyronines, β‐endorphin, ACTH and cortisol levels of horses
Authors: CRAVANA C. , MEDICA P. , PRESTOPINO M. , FAZIO E. , FERLAZZO A. 
Published: November 2010

SummaryReasons for performing study:Limited knowledge exists about the differentiated effects of competitive and noncompetitive showjumping on thyroid function and relationships with hypothalamic‐hypophysis‐corticoadrenal hormones.Objectives:To obtain preliminary data about differentiated effects of competitive and noncompetitive showjumping on total and free iodothyronines, β‐endorphin, ACTH and cortisol of horses.Material and methods:Five trained healthy jumper horses were studied during competitive and noncompetitive showjumping, performed in the same circuit design over 10 fences of 1.10 m. Hormone levels before, 5 and 30 min post exercise were recorded. Serum iodothyronines and cortisol concentrations were measured in duplicate utilising EIA kits. Serum ACTH and plasma β‐endorphin concentrations were analysed in duplicate utilising RIA kits. Two‐way RM ANOVA was applied to test for effects of interaction between different type of session and time. Significant differences between post exercise and basal values were established using Bonferroni's multiple comparison test. A linear correlation analysis (Pearson's method) was performed to analyse the relationships between total and free iodothyronines and between iodothyronines and β‐endorphin, ACTH and cortisol.Results:In sampling times adopted no statistical different effects of type of session were recorded on hormone variables. Sampling time affected ACTH (F = 4.25; P<0.02) and T4(F = 4.43; P<0.02) post exercise changes. During the noncompetitive session, significant correlations existed between T4and β‐endorphin (r =−0.56), ACTH (r =−0.65), between β‐endorphin and ACTH (r = 0.52) and between T3and fT3(r = 0.72); during competition between β‐endorphin and T3(r =−0.67), fT3(r =−0.59).Conclusions:These preliminary results could demonstrate correlations between thyroid hormones and β‐endorphin response to showjumping, although no definitive conclusion can be produced concerning the relationships between HPA and thyroid function during exercise.
Oral supplementation with superoxide dismutase in Standardbred trotters in training: a double‐blind placebo‐controlled study
Authors: NOTIN C. , VALLON L. , DESBORDES F. , LELEU C. 
Published: November 2010

SummaryReasons for performing study: Intense physical exercise produces an excess of reactive oxygen species which can disturb the antioxidant/oxidant balance of the horse in training. Several classes of antioxidant dietary compounds have been suggested to provide health benefits and there is evidence that consumption of these products leads to a reduction in the expression of various pro‐inflammatory and/or oxidative stress biomarkers. The recent development of a new galenic system allows the oral delivery of the antioxidant enzyme: superoxide dismutase (SOD). This has been developed from a specific melon variety with a particularly high SOD activity.Objectives: To study the influence of an oral supplementation with an encapsulated melon rich in SOD on muscular and antioxidant balance variables in a population of Standardbreds in training.Methods: Twenty‐four Standardbreds in training were paired by age, sex and training level. They were randomly split into 2 groups: SOD group (520 iu/day) and placebo group. At the beginning of the study (T0) and after 30 days (T30) and 60 days (T60) of supplementation, physiological response during a standardised exercise test, plasma muscular enzymes at rest and post exercise (creatine kinase), oxidative stress markers (erythrocyte SOD) and blood resistance to haemolysis (KRL test) were assessed. Analysis of variance of time, treatment and interaction time x treatment was calculated.Results: Between T0 and T60, in contrast with placebo group, a significant increase in the plasma resistance to haemolysis in the SOD group was observed and it was significantly higher (P<0.05) in the SOD group than in the placebo group on T60. Between T0 and T60, resting CK remained constant in SOD group whereas a significant increase in plasma CK in the placebo group was observed. On T60, the CK level was significantly lower (P<0.05) in SOD group than in the placebo group.Conclusions: These results suggest that oral SOD supplementation might increase blood resistance to haemolysis and reduce the increase in muscular membrane permeability induced by training.
Muscular microRNA expressions in healthy and myopathic horses suffering from polysaccharide storage myopathy or recurrent exertional rhabdomyolysis
Authors: BARREY E. , BONNAMY B. , BARREY E. J. , MATA X. , CHAFFAUX S. , GUERIN G. 
Published: November 2010

SummaryReasons for performing study:MicroRNAs (miRNA) are small endogenous noncoding interfering RNA molecules (18–25 nucleotides) regarded as major regulators in eukaryotic gene expression. They play a role in developmental timing, cellular differentiation, signalling and apoptosis pathways. Because of the central function of miRNAs in the proliferation and differentiation of the myoblasts demonstrated in mouse and man, it is assumed that they could be present in equine muscles and their expression profile may be related to the muscle status.Objective:To identify miRNA candidates in the muscles of control and affected horses suffering from polysaccharide storage myopathy (PSSM) and recurrent exertional rhabdomyolysis (RER).Methods:Muscle biopsies were collected in thegluteus mediusof horses allocated into 4 groups: French Trotters (3 control‐TF vs. 3 RER‐TF) and Norman Cob (5 control‐Cob vs. 9 PSSM‐Cob). Blood samples were collected for miRNA analysis. Total RNA were extracted and real time quantitative RT‐QPCR analysis were conducted using 10 miRNA assays (mir‐1‐23‐30‐133‐181‐188‐195‐206‐339‐375).Results:All the miRNA candidates were significantly detected in the muscles and some in blood samples. Variance analysis revealed highly significant (P<0.0001) effects of the miRNA type, breed and pathology on the miRNA expression. A specific miRNA profile was related to each myopathy: a higher expression of mir‐1, 133, 23a, 30b, 195 and 339 in RER‐TF vs. control‐TF (P<0.05); a higher expression of mir‐195 in PSSM‐Cob vs. control‐Cob (P<0.05). The miRNA profile was different between breeds for mir‐181, 188 and 206 (P<0.05). The mir‐1, 133, 181, 195 and 206 were detected in blood of control‐Cob and PSSM‐Cob horses.Conclusions:This first study about muscular miRNA profile in equine myopathies indicated that it is possible to discriminate pathological from control horses according to their miRNA profile. The RER miRNA profile was more specific and contrasted than the PSSM profile.
Effect of a 120 km endurance race on plasma and muscular neutrophil elastase and myeloperoxidase concentrations in horses
Authors: SERTEYN D. , SANDERSEN C. , LEJEUNE J.‐P. , De La REBIÈRE de POUYADE G. , CEUSTERS J. , MOUITHYS‐MICKALAD A. , NIESTEN A. , FRAIPONT A. , Van ERCK E. , GOACHET A. G. , ROBERT C. , LECLERC J. L. , VOTION D.‐M. , FRANCK T. 
Published: November 2010

SummaryReasons for performing study:Intense physical exercise can induce the degranulation of neutrophils leading to an increase in plasma concentration of the neutrophil marker enzymes myeloperoxidase (MPO) and elastase (ELT). These enzymes have pro‐oxidative and pro‐inflammatory properties and may play a role in the exercised‐induced muscular damage.Objectives:To measure MPO and ELT concentrations in plasma and muscles of endurance horses and to correlate them to the extent of exercise‐induced muscular damage.Methods:Seven endurance horses qualified on 120 km races were tested in this study. Neutrophil count, serum creatine kinase (CK), plasmatic and muscular MPO and ELT concentrations were measured before and 2 h after a 120 km endurance race.Results:The race produced a significant increase of neutrophils, CK, and plasma MPO and ELT levels. A significant correlation was observed between the MPO and ELT values in plasma (r2= 0.92, P<0.01) and in muscles (r2= 0.89, P<0.01) while plasmatic concentrations of MPO and ELT were not significantly correlated to muscular ones. An increase of mean concentrations (± s.e.) of MPO (T0: 9.85 ± 3.9, T1: 228.9 ± 95.9 ng/mg proteins) and ELT (T0: 8.4 ± 2.4, T1: 74.5 ± 39.7 ng/mg proteins) in the muscles were observed after the race. Interestingly, the individual data showed large differences between the horses. Muscular MPO and ELT concentrations were significantly correlated to plasma CK levels. The coefficient of correlation (r2) was 0.69 (P<0.01) for MPO and 0.66 (P<0.01) for ELT, respectively.Conclusions:Results underline the possible role of MPO and ELT in exercise‐induced muscular damage.Potential relevance:Further studies should investigate the effect of exercise type and intensity, as well as the role of the training state on MPO and ELT involvement in muscular damage. The assessment of the intensity of exercise‐induced neutrophilic degranulation may have a potential role in the monitoring of the athletic career.
Effects of crude protein intake from forage‐only diets on muscle amino acids and glycogen levels in horses in training
Authors: ESSÉN‐GUSTAVSSON B. , CONNYSSON M. , JANSSON A. 
Published: November 2010

SummaryReasons for performing study:There is little information about the influence of crude protein (CP) intake on glycogen and free pool amino acid concentrations in the muscle of horses in training. High energy forage‐only diets may be an alternative to concentrate rich diets and may provide high levels of CP.Objective:To study the effect of feeding 2 forage‐only diets, containing either high or moderate CP concentrations on glycogen and free pool amino acid concentrations in the muscle.Materials and methods:Two high energy forage‐only diets based on high‐energy grass forage were fed for 23 days in a crossover design to 6 Standardbred horses in racing condition. One forage diet provided a high (HP) CP (16.6%) intake and the other diet provided recommended intake (RP) of CP (12.5%). At Day 19 a standardised treadmill test was performed to mimic a race. Blood samples were taken before, during and after (up to 90 min) the treadmill test and muscle biopsies (m. gluteus) were taken before and after exercise and after 90 min. Amino acids were analysed with a HPLC‐technique and glycogen with a fluorimetric method.Results:A main effect of the HP diet was that muscle glycogen and leucine concentrations were higher compared to the RP diet. Branched chain amino acid concentrations in plasma remained higher during early recovery from exercise on the HP diet compared to the RP diet. Intense exercise caused a similar decrease in glycogen, aspartate and glutamate concentrations in muscle and increase in alanine concentration on both diets.Conclusion:Feeding a forage‐only diet with a high CP intake increases glycogen and leucine concentrations in muscle of horses in training. This may be beneficial for muscle recovery following intensive exercise.