bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptations to daily exercise in hot and humid ambient conditions in trained Thoroughbred horses
Authors: GEOR R. J. , McCUTCHEON L. J. , LINDINGER M. I. 
Published: June 2010

SummaryThe objectives of this study were to: 1) determine the effects of heat and high relative humidity (RH) on the clinical and physiological responses of horses during and after daily exercise training and 2) determine whether repeated exposure to, and exercise in, the heat would result in improved thermal tolerance (heat acclimation). Six trained Thoroughbred horses completed 1 h of submaximal exercise in cool, dry conditions (CD) and during a daily 4 h period of exposure to high heat and humidity (HH, room temperature = 33–35°C, RH = 80–85%) for 22 days. Rectal temperature (Tre) and heart rate (HR) were measured before, during and after exercise and respiratory rate (RR) was measured before exercise and during a 2 h recovery. In HH, the rate of rise in Trewas significantly higher than in CD. However, by HH Day 5, Trebefore, during and after exercise was significantly lower than on HH Day 1. The day‐to‐day decrease in Treduring exercise was reflected in significant decreases in heat storage following exercise by HH Day 10 (910 ± 47 kcal) when compared to HH Day 1 (1211 ± 75 kcal). At rest, RR was initially higher in HH than CD, and a further increase in pre‐exercise RR from HH Day 1 to Day 10 may have contributed to the lower pre‐exercise Tre. Recovery RR was higher after HH Day 1 and was associated with a lower end‐of‐exercise Treand reduced heat storage by HH Day 5. Pre‐exercise HR did not change in the 1 h before exercise in CD and did not differ from HH Days 1–22. By HH Day 10, mean HR during the latter part of exercise was lower than HH Day 1 and was not different from pre‐exercise by 60 min of recovery. Pre‐exercise body mass did not change during the 3 wk period, and the decrease in body mass that occurred during the 4 h training period was significantly attenuated by HH Day 15 (9.8 ± 0.8 kg) when compared to HH Day 1 (12.5 ± 0.8 kg). Over the 3 week period of HH, mean 24 h water consumption increased from 26.0 ± 2.1 litres to 39.5 ± 3.2 litres, largely reflecting a 2‐fold increase in water intake during the 4 h period of heat exposure. It is concluded that 3 weeks of daily exposure to, and exercise in, hot and humid ambient conditions resulted in a progressive reduction in thermal and cardiovascular strain. Furthermore, the reported physiological adaptations are consistent with an improved thermal tolerance (heat acclimation).
Physiological responses in nonheat acclimated horses performing treadmill exercise in cool (20°C/40%RH), hot dry (30°C/40%RH) and hot humid (30°C/80%RH) conditions
Authors: MARLIN D. J. , SCOTT C. M. , SCHROTER R. C. , MILLS P. C. , HARRIS R. C. , HARRIS PATRICIA A. , ORME C. E. , ROBERTS C. A. , MARR CELIA M. , DYSON SUE J. , BARRELET F. 
Published: June 2010

SummaryThe aim of the present study was to determine the effect of different environmental conditions on physiological response to exercise. Four winter acclimatised, nonheat acclimated horses of different breeds were exercised at 20°C/40%RH (CD), 30°C/40%RH (HD) and 30°C/80%RH (HH). The exercise test was designed to represent the structure and intensity of a One star Speed and Endurance test (competition exercise test [CET]). All 4 horses were able to complete the full CET (60 min + 30 min active recovery) in CD and HD, but only one horse completed the CET in HH. Two horses were stopped because of pronounced general fatigue and one because of a right atrial temperature (TRA) of 43°C. Oxygen uptake on each phase was not different between CD and HD, but was higher duringPhases B, CandDin HH. Mean peak TRAat the end ofPhase Dwas 40.3 ± 0.2, 41.6 ± 0.4 and 42 ± 0.3°C for CD, HD and HH, respectively. Corresponding, mean peak rectal temperatures (TREC) followingPhase Dwere 39.5 ± 0.1, 40.6 ± 0.1 and 41.5 ± 0.1°C for CD, HD and HH, respectively. Mean time to peak TRECwas 9.3 ± 1.1 (CD), 7.3 ± 1.8 (HD) and 10.8 ± 2.3 (HH) min and was not significantly different between conditions (P>0.05). Heat dissipation amounted to 83 ± 1, 73 ± 2 and 70 ± 1% of heat production in CD, HD and HH, respectively. Weight loss was significantly correlated with both body surface area (CD r = 0.85; HD r = 0.87; HH r = 0.81) and bodyweight (CD r = 0.97; HD r = 0.93; HH r = 0.94). The greatest weight loss recorded was 4.6% bodyweight in one horse in HD. The mean increase in exercise intensity over the whole CET (in terms of V̇O2) of HD and HH compared with CD was 5 ± 3 and 14 ± 3% higher, respectively. The exercise induced hyperthermia and the reduced capacity for heat dissipation produced partial compensatory responses in minute ventilation (V̇E), particularly duringPhase C, when the horses were trotting. In HD, the increase in V̇Ewas achieved mainly through an increase in frequency, whilst in HH it was achieved through an increase in tidal volume (VT). The horses demonstrated a high degree of tolerance to environmental heat load, suggesting a high thermoregulatory capacity. However, for unacclimatised animals exercising in severely hot and humid conditions, performance may be limited.
Biochemical changes in Three‐day‐event horses at the beginning, middle and end ofPhase Cand afterPhase D
Authors: WILLIAMSON LISA H. , ANDREWS F. M. , MAYKUTH PATRICIA L. , WHITE SUSAN L. , GREEN ELEANOR M. 
Published: June 2010

SummaryBlood samples were collected 12–16 h before the Speed and Endurance test, immediately after steeplechase, midway throughPhase C(4 km marker), at the end ofPhase Cand immediately after cross‐country from 36 horses that completed a 3‐day‐event at the CCI* (n = 19) or CCI**(n = 17) level. Packed cell volume (PCV), plasma concentrations of sodium, potassium, chloride, ionized calcium, pH and lactate; and serum concentrations of total protein (TP), albumin, total calcium, alkaline phosphatase (AP), gamma glutamyl transferase (GGT), creatine kinase (CK), aspartate aminotransferase (AST), glucose and creatinine were measured. No differences were noted in any biochemical measurements between the CCI* and CCI** horses at any sampling time, despite differences in speed and length of various phases of the Speed and Endurance test. For all horses (n = 36), biochemical parameters changed significantly over time (P<0.01). The PCV, calcium, potassium, lactate, total protein and albumin concentrations were significantly increased over pre‐exercise concentrations immediately afterPhase B.DuringPhase C, these parameters decreased towards pre‐exercise concentrations, thereby supporting the concept thatPhase Cis a recovery phase. In contrast, chloride concentration decreased, and the creatinine concentration and CK increased compared to pre‐exercise concentrations from the end ofPhase Bto the end ofPhase C.These changes probably resulted from fluid and electrolyte losses in sweat, reduced renal blood flow and continued muscular activity. Many parameters did not change significantly between the 4 km marker (midway point onPhase C) and the end ofPhase C.However, there were a few notable exceptions: potassium, chloride, lactate and glucose concentrations decreased, whereas pH and creatinine concentrations increased significantly from the 4 km marker to the end ofPhase C.The most significant benefit of the extra distance from the 4 km marker to the end ofPhase Cwas that it facilitated further dissipation of lactate concentrations prior to the start ofPhase D.
Strategies for voluntary rehydration in horses during endurance exercise
Authors: NYMAN S. , JANSSON A. , DAHLBORN K. , LINDHOLM A. 
Published: June 2010

SummaryTo avoid dehydration and a decrease in performance capacity in horses, fluid and electrolyte losses need to be compensated for during long distance rides as well as on other occasions when sweat losses are high during exercise. Thirteen endurance‐trained horses, age 5–14 years, were used to compare 3 strategies of voluntary rehydration during prolonged exercise, offering 1)water, 2) water after administeringsalt paste(3 times 30 g of NaCl)per osand 3) 0.9% saline. The ride covered 62 km and consisted of 3 rounds, of 20, 22 and 20 km, respectively. During the first 20 km, no fluid was offered to any of the horses. Thereafter, fluid was repeatedly offered from buckets at the ‘vet gates' and at fluid stations situated in the middle of the rounds. Fluid intake and bodyweight were measured during the ride and up until 3 h after the ride. The low heart rates and unchanged plasma glucose concentration indicated that the work load was moderate. Total fluid intake was significantly higher in thesalinegroup than in thewatergroup or thesalt pastegroup. The total plasma protein concentration (TPP) fell below resting values in thesalinegroup post exercise, indicating an increase in plasma volume. No changes in TPP were seen in the other groups. Plasma sodium concentration during the ride increased in thesalt pastegroup but not in thesalinedrinking horses despite their higher NaCl intake. Thewatergroup had an increased plasma aldosterone concentration post exercise, indicating that sodium‐conserving mechanisms had been activated. Plasma potassium concentration decreased in all treatments from pre‐ to post ride. It was concluded, that drinking saline solution during and after exercise is a good strategy for rehydration since this group showed the fastest recovery of their bodyweight losses. The persistently elevated plasma sodium concentration in thesalt pastegroup during the ride, is indicative of a disturbance in the fluid distribution between the body fluid compartments, which can be exacerbated by the low water intake. To give salt paste immediately before or during exercise is, therefore, not recommended.
Impact during equine locomotion: techniques for measurement and analysis
Authors: BURN J. F. , WILSON A. , NASON G. P. 
Published: June 2010

SummaryImpact is implicated in the development of several types of musculoskeletal injury in the horse. Characterisation of impact experienced during strenuous exercise is an important first step towards understanding the mechanism for injury. Measurement and analysis of large, short duration impacts is difficult. The measurement system must be able to record transient peaks and high frequencies accurately. The analysis technique must be able to characterise the impact signal in time and frequency. This paper presents a measurement system and analysis technique for the characterisation of large impacts.A piezo‐electric accelerometer was securely mounted on the dorsal surface of the horses hoof. Saddle mounted charge amplifiers and a 20 m coaxial cable transferred these data to a PC based logging system. Data were down‐loaded onto a UNIX workstation and analysed using a proprietary statistics package.The values of parameters calculated from the time series data were comparable to those of other authors. A wavelet decomposition showed that the frequency profile of the signal changed with time. While most spectral energy was seen at impact, a significant amount of energy was contained in the signal immediately following impact. Over 99% of this energy was contained in frequencies less than 1250 Hz.The sampling rate and the frequency response of a measurement system for recording impact should be chosen carefully to prevent loss or corruption of data. Time scale analysis using a wavelet decomposition is a powerful technique which can be used to characterise impact data. The use of contour plots provides a highly visual representation of the time and frequency localisation of power during impact.
Noninvasive photoelastic method to show distribution of strain in the hoof wall of a living horse
Authors: DAVIES H. M. S. 
Published: June 2010

SummaryA photoelastic method used for materials testing in industry was adapted to show the distribution of strain through the hoof wall in the living horse. Strain was a change in length per unit length in the material of the loaded hoof wall compared with the unloaded condition. Coloured fringes appeared in the photoelastic plastic where there were differences in strain between adjacent sites (strain gradients) in the hoof. Strain distribution was observed in the shod and unshod hoof wall of the front hooves of 6 sound horses with hooves that appeared ‘good’ to visual inspection, and one unsound horse with hoof cracks. No significant differences in strains were apparent across the hoof walls of the sound horses when the horses were standing normally. Steep strain gradients were apparent in hooves, associated with defects such as cracks, unstable nail holes, and long toes.
Image analysis to measure activity index of animals
Authors: BLOEMEN HEIDI , AERTS JEAN‐MARIE , BERCKMANS D. , GOEDSEELS V. 
Published: June 2010

SummaryThe objective of the study was to present a method to quantify the behavioural response of animals to their micro‐environment by using a camera system and a digitiser board. An algorithm was developed for analysing images and calculating activity, occupied zone and boundary of the animals. The developed method was tested on 3 different applications and animals. In the first application, the behavioural responses of broiler chickens to their thermal environment was measured. In the second application behavioural responses of pigs to their thermal environment were measured. In the third application, the response of water fleas to a chromium pollution was measured using the developed technique.Based on the experimental results, it can be concluded that the developed image analysis technique can be employed to quantify the behavioural responses of the tested animals to their micro environment, in an easy and accurate way.
Mechanical properties of pathological equine superficial digital flexor tendons
Authors: CREVIER‐DENOIX NATHALIE , COLLOBERT CLAIRE , POURCELOT P. , DENOIX J.M. , SANAA M. , GEIGER D. , BERNARD NADINE , RIBOT X. , BORTOLUSSI C. , BOUSSEAU B. 
Published: June 2010

SummaryThe objective of this study was to mechanically characterise superficial digital flexor tendon (SDFT) lesions. Eight pathological SDFTs, isolated from 6 adult horses, were tested in traction until rupture (at 1 mm/s). The stresses and strains simultaneously undergone by each of the 7 segments of a tendon were determined throughout the test, and the modulus of elasticity of each segment was evaluated from the segmental stress‐strain curve thus obtained. These mechanical data were compared to those obtained on 10 normal SDFTs. After the test, the tendinous segments were submitted to a histological examination in order to characterise the tissues. Three lesionalcategories(ItoIII, of increasing maturity), as well as the normal tendinous tissue, were defined and assessed quantitatively according to their extent in the histological sections.The most recent and severe lesions (categories IandII) were correlated with a large degree of hypertrophy (often above 200%) of the corresponding segments, with a resulting decrease in the stress at tendon rupture, and a slight decrease in the strain at tendon rupture in spite of a low modulus of elasticity (low stiffness). In contrast, the adjacent areas, less or not injured, underwent compensatory strains. This relative overstraining was especially critical withcategory IIItissue, often present in the transitional areas between sound and severely injured segments. Here the modulus of elasticity was low whereas the hypertrophy was only slight. Therefore, the corresponding segments seemed to be the most fragile sites, and those most predisposed to recurring injury, in an injured SDFT.
Components of the total kinetic moment in jumping horses
Authors: GALLOUX P. , BARREY E. 
Published: June 2010

SummaryThirty horses were filmed with a panning camera operating at 50 frames/s as they jumped over a 1.20 times 1.20 m fence. The markers of 9 joints on the horse and 7 joints on the rider were tracked in 2D with the TrackEye system. The centre of gravity and moment of inertia of each segment were calculated using a geometric algorithm and a cylindric model, respectively. The kinetic moment of each part of the horse was calculated after filtering, and resampling of data. This method showed the relative contribution of each body segment to the body overall rotation during the take‐off, jump and landing phases. It was found that the trunk, hindlimbs and head‐neck had the greatest influence. The coordination between the motion of the body segments allowed the horse to control its angular speed of rotation over the fence. This remained nearly constant during the airborne phase (120 ± 5°/s). During the airborne phase, the kinetic moment was constant because its value was equal to the moment of the external forces (722 ± 125 kg.m2/s).
Analysis of the equine jumping technique by accelerometry
Authors: BARREY E. , GALLOUX P. 
Published: June 2010

SummaryThe purpose of this study was to demonstrate the relationships between jumping technique and dorsoventral acceleration measured at the sternum. Eight saddle horses of various jumping abilities competed on a selective experimental show jumping course including 14 obstacles. An accelerometric belt fastened onto the thorax continuously measured the dorsoventral acceleration during the course. At each jump, 11 locomotor parameters (acceleration peaks, durations and stride frequency) were obtained from the dorsoventral acceleration‐time curves. The type of obstacle significantly influenced the hindlimb acceleration peak at take‐off and the landing acceleration peak (P<0.01). The poor jumpers exhibited a higher mean forelimb acceleration peak at takeoff, a higher forelimb/hindlimb ratio between peaks of acceleration (F/H), and a lower approach stride frequency than good jumpers. Knocking over an obstacle was significantly associated with a low hindlimb acceleration peak at take‐off and a high F/H ratio (P<0.01). In order to observe the continuous changes in the frequency domain of the dorsoventral acceleration during the approach and take‐off phase, a Morlet's wavelet analysis was computed for each horse jumping over a series of 3 vertical obstacles. Different patterns of time‐frequency images obtained by wavelet analysis were found when the horse either knocked over a vertical obstacle or cleared it. In the latter case, the image pattern showed an instantaneous increase in stride frequency at the end of the approach phase, and a marked energy content in the middle frequency range at take‐off.
Classification of collected trot, passage and piaffe based on temporal variables
Authors: CLAYTON HILARY M. 
Published: June 2010

SummaryThe objective was to determine whether collected trot, passage and piaffe could be distinguished as separate gaits on the basis of temporal variables. Sagittal plane, 60 Hz videotapes of 10 finalists in the dressage competitions at the 1992 Olympic Games were analysed to measure the temporal variables in absolute terms and as percentages of stride duration. Classification was based on analysis of variance, a graphical method and discriminant analysis. Stride duration was sufficient to distinguish collected trot from passage and piaffe in all horses. The analysis of variance showed that the mean values of most variables differed significantly between passage and piaffe. When hindlimb stance percentage was plotted against diagonal advanced placement percentage, some overlap was found between all 3 movements indicating that individual horses could not be classified reliably in this manner. Using hindlimb stance percentage and diagonal advanced placement percentage as input in a discriminant analysis, 80% of the cases were classified correctly, but at least one horse was misclassified in each movement When the absolute, rather than percentage, values of the 2 variables were used as input in the discriminant analysis, 90% of the cases were correctly classified and the only misclassifications were between passage and piaffe. However, the 2 horses in which piaffe was misclassified as passage were the gold and silver medallists. In general, higher placed horses tended toward longer diagonal advanced placements, especially in collected trot and passage, and shorter hindlimb stance percentages in passage and piaffe.
Comparison of the temporal kinematics of the canter pirouette and collected canter
Authors: BURNS THERESA E. , CLAYTON HILARY M. 
Published: June 2010

SummaryThe objectives were to compare the temporal characteristics of canter pirouette strides with collected canter strides in elite dressage horses, and to determine whether the stride kinematics of the canter pirouettes fulfilled the requirements specified in the Fédération Equestre Internationale Rules for Dressage Events. Eleven horses were videotaped (60 fields/s) during the individual medal competition at the 1992 Olympic Games. Temporal variables were extracted from the videotapes using standard methods. Two strides were analysed on each of the left and right leads and these were pooled to give mean values for the collected canter and the pirouettes. The pirouettes were completed in 4–9 strides, (mean of 6.4). In the collected canter strides, mean duration of the suspension was 0.013s. There was no suspension in any of the pirouette strides, instead the stance phases of the leading forelimb and trailing hindlimb overlapped by a mean of 0.163s. In 9 horses the trailing forelimb contacted the ground before the diagonal leading hindlimb in the collected canter, whereas in the pirouettes the leading hindlimb always made contact before the trailing forelimb (mean dissociation 0.164s), giving the strides a distinct 4 beat rhythm. Due to increases in advanced placement between the diagonal limb pair and between the 2 forelimbs, the stride duration was longer in the pirouette (0.879s) than the collected canter (0.629s). It is concluded that the canter pirouette strides did not maintain the rhythm and timing of the the collected canter strides in any of the 11 horses.
Aspects of postural development in the rat
Authors: GRAMSBERGEN A. , VAN DER AA M. , GEISLER H. C. 
Published: June 2010

SummaryThe activation patterns in the longissimus and gastrocnemius muscles during the development of the mature type of locomotion were studied in rats from the 11th day until maturity. The EMG's of these muscles were recorded and movements were simultaneously recorded on videotape. Results indicate that during locomotion at early ages, the longissimus muscles are activated irregularly. From the 16th day, the bursts in the longissimus muscle become more pronounced. During locomotion, they are activated differentially and often a simultaneous activation of the longissimus and the contralateral gastrocnemius muscle was observed. From the 20th day, bursts in the gastrocnemius muscle during walking coincide with bursts in the ipsilateral longissimus muscle. Our results demonstrate that the mature type of postural control (from the 20th day) develops a few days after the development of the mature type of fluent walking (around the 15th‐16th day).