Relationship of Plasma Lactate Production to Cortisol Release Following Completion of Different Types of Sporting Events in Horses

in Veterinary Research Communications (1996), 20(4), 371-9

Fifty-eight healthy horses were studied during five sporting events of various intensities and durations, namely show-jumping (n = 6), cross-country in a three-day event (n = 30), trotting races (n = 7 ... [more ▼]

Fifty-eight healthy horses were studied during five sporting events of various intensities and durations, namely show-jumping (n = 6), cross-country in a three-day event (n = 30), trotting races (n = 7), galloping races (n = 7) and endurance rides (n = 8). Venous blood samples were collected at rest and immediately after exercise and analysed for plasma cortisol (CORT) and lactate (LA) levels. The experimental procedure was the same throughout the investigation so as to permit a reliable comparison between the five types of exercise. The type of event significantly affected both the resting (p < or = 0.05) and the post-exercise (p < or = 0.01) plasma CORT. The degree of exercise-induced hypercortisolaemia was related to both the intensity and the duration of exercise for all five sporting events, but the endurance ride induced the most and show-jumping the least serious post-exercise CORT changes. LA production was much more closely related to the intensity of the exercise than was CORT. It is concluded that simultaneous measurements of plasma CORT and LA levels may be useful to discriminate between different types of exercise, adjust training programmes, and improve our comprehension of the physiology of sport horses at exercise. [less ▲]

La thermographie infrarouge dans l'étude de la thermorégulation : revue de la littérature

in Annales de Médecine Vétérinaire (1995), 139

Infrared thermography is a method to assess the skin temperature by means of a camera equipped with an infrared detector. It makes thermograms that represents the surface temperature of skin patterns ... [more ▼]

Infrared thermography is a method to assess the skin temperature by means of a camera equipped with an infrared detector. It makes thermograms that represents the surface temperature of skin patterns. This article summerizes the different information about thermography and thermoregulation of horses. In fact, lots of information exist about thermoregulation of most of the domestic animais but very little exists as far as horses are concerned. Two different types of devices are used for thermography : contacting and noncontacting which measure the infrared radiation either with a thermometer or with a themographic camera. The blood circulation dictates the thermic model which is at the origin of thermographic interpretation. This latter is a good method helping to study thermoregulation. [less ▲]

Effect of an alpha-adrenergic stimulation on the face temperature of horses with Horner's syndrome

in Pflügers Archiv : European Journal of Physiology (1995), 430

Physiological measurements in horses after strenuous exercise in hot, humid conditions

in Equine Veterinary Journal. Supplement (1995), 20

The purpose of this study was 1) to measure and compare some physiological parameters in horses during a standardised treadmill exercise performed either in temperate atmospheric conditions (TC) (ambient ... [more ▼]

The purpose of this study was 1) to measure and compare some physiological parameters in horses during a standardised treadmill exercise performed either in temperate atmospheric conditions (TC) (ambient temperature: 15 degrees C; relative humidity: 55%), or in hot and humid conditions (HHC) (ambient temperature: 30 degrees C; relative humidity: 75%) and 2) to follow the recovery of the same horses during 1 h after both tests. Five healthy fit Standardbred horses were investigated twice at 8 days interval, in TC and in HHC. Some measurements were made during a standardised treadmill exercise test (SET), others during a 1 h recovery period. The SET consisted of 8 min warm-up and 8 min exercise. During the SET, respiratory airflow and O2 and CO2 fraction in the respiratory gases were continuously recorded, using 2 ultrasonic pneumotachographs connected to a face mask and a mass spectrometer. Oxygen uptake (VO2), carbon dioxide output, respiratory quotient and expired minute volume (VE) were obtained on a breath-by-breath basis. The maximal values obtained during the highest intensity of the SET and the values obtained 2 min after the end of the test were used for the comparison between both tests. Heart rate (HR) and skin temperature were continuously recorded, using a heart rate recording system and a real time infrared thermographic unit, respectively. After both SETs in TC and HHC, the horses recovered in TC. Heart rate, respiratory frequency (f) and rectal temperature were regularly measured during 1 h after the test. Venous blood was sampled after the completion of the test for biochemical analysis, namely plasma electrolytes and enzymatic activities. Exercising in HHC induced a reduction of the aerobic metabolism to the total energy requirement, i.e. a 20% decrease of VO2 and 55% increase in lactate, as well as a decrease in VE. The increase in rectal and skin temperature, the dehydration and the weight loss were higher in HHC than in TC. During the recovery period the HR and f remained higher up to 30 min after the end of the SET in HHC while the rectal temperature remained higher up to 60 min after the end of this test. Therefore, despite the fact that our horses recovered in TC after exercising in HHC, there were significant differences between their physiological parameters measured during the recovery. This means that the recovery in air-conditioned unit would probably be an insufficient measure to ensure an adequate cooling of the horses and justify consequently the adaptations proposed by the Federation Equestre Internationale (FEI), i.e. the decrease of the distance of the run and the increase of the time devoted to the halt between phases [less ▲]

Prévention de l'hémorragie pulmonaire induite par l'effort

in Pratique Vétérinaire Equine (1995), 27(2), 121

Pulmonary function tests in exercising COPD horses

in Pflügers Archiv : European Journal of Physiology (1995), 430(16-16), 185

Scintigraphical V/Q ratios analysis in healthy and disearsed horses: a theoretical approach

in Pflügers Archiv : European Journal of Physiology (1995), 429

Ventilatory and arterial blood gas tension adjustments to strenuous exercise in standardbreds

in American Journal of Veterinary Research (1995), 56(10), 1332-1337

Five healthy, fit Standardbreds (mean +/- SEM, 490.4 +/- 15.0 kg, 4.0 +/- 0.5 years) were studied during a standardized test carried out on a treadmill. The test consisted of an 8-minute warm-up and a 9 ... [more ▼]

Five healthy, fit Standardbreds (mean +/- SEM, 490.4 +/- 15.0 kg, 4.0 +/- 0.5 years) were studied during a standardized test carried out on a treadmill. The test consisted of an 8-minute warm-up and a 9-minute exercise period (1 minute at 1.7, 4, 7, 8, 9, and 10 m/s; 2 minutes at 4 m/s; and a 1-minute walk at a 6% slope). Respiratory airflow, tidal volume (V(T)), and respiratory frequency (f) were continuously recorded, using 2 ultrasonic pneumotachographs connected to a face mask and mass spectrometer. Oxygen uptake, carbon dioxide output, and expired minute volume (V(E)) were obtained on a breath by breath basis. Arterial blood was tested at the end of each step for O2 and CO2 partial pressures. Heart rate was continuously recorded, using a heart rate recording system. Stride frequency was measured at each step, and the stride frequency-to-f ratio was calculated. Venous blood was tested for plasma lactate concentration be fore and 2 minutes after completion of the test. Some horses had a locomotion-respiration coupling (LRC), but this coupling was occasional and intermittent. The f was lower and V(T) was higher than values reported for thoroughbreds working under similar experimental conditions. Nevertheless, maximal V(E) did not overshoot maximal V(E) reported in Thoroughbreds. All horses were hypoxemic and hypercapnic, but there was wide variability between subjects. The horses with the highest oxygen uptake and the lowest plasma lactate concentration were more hypoxemic and hypercapnic. The Standardbreds, studied under our laboratory conditions, did not have constant LRC and had lower f with higher V(T) than did Thoroughbreds under similar experimental conditions. Despite these differences in breathing strategy, the Standardbreds did not have higher V(E) than did Thoroughbreds, and they were hypoxemic and hypercapnic. The fact that these Standardbreds, which obviously freely selected their breathing strategy, were unable or unwilling to adopt compensatory hyperventilation reinforces the hypothesis that, in strenuous exercising horses, there could be a physiologic limit to ventilation, most probably related to mechanical factors, but independent of any LRC. [less ▲]

Cardio-respiratory, haematological and biochemical parameter adjustments to exercise: effect of a probiotic in horses during training

in Veterinary Research (1994), 25(4), 361-370

Two randomly distributed groups of thoroughbred horses were compared during a 12-week period for their cardio-respiratory and metabolic adjustment to strenuous exercise, training and detraining. The ... [more ▼]

Two randomly distributed groups of thoroughbred horses were compared during a 12-week period for their cardio-respiratory and metabolic adjustment to strenuous exercise, training and detraining. The horses were trained following the same standardized schedule and were regularly investigated using standardized treadmill exercise tests (SET) of increasing speed. After the first SET and during the whole experimental period, a group of 6 horses received a probiotic (Bioracing) once a day while a group of 5 horses received a placebo. All other conditions were similar for both groups. During each SET, the oxygen uptake, carbon dioxide output, tidal volume (inspired volume), respiratory rate and expired minute volume were obtained using 2 ultrasonic pneumotachographs and a mass spectrometer. All the parameters were the mean of the values calculated during the last 20 s of the SET. Heart rate was continuously measured with a polar horse tester. Venous blood was sampled before and after the test and analyzed for various biochemical parameters. In both groups, training induced significant modification in most of the cardio-respiratory parameters, ie peak oxygen uptake, peak carbon dioxide output, respiratory exchange ratio, ventilation/min to oxygen-uptake ratio and oxygen-uptake to heart-rate ratio. After the 3-week detraining period, most of the values were again similar to the pre-training values in both groups. However, the training-induced modifications of most of the cardio-respiratory parameters occurred earlier and were proportionally greater in the probiotic-treated group than in the control. The respiratory coefficient decreased in the control but not in the treated group. All other parameters changed similarly in both groups. This suggests that Bioracing could modify the physiological effects of training by improving some aerobic metabolic capacities for carbohydrate utilization, but that this effect occurs only during training and not during periods of physical inactivity [less ▲]

Tests standardisés de routine pour l'évaluation de la condition physique chez les chevaux d'endurance

in Pratique Vétérinaire Equine (1994), 26

The purpose of this study was to try to assess the fitness of endurance horses by using a simple routine standardized treadmill exercise test performed before and after a training period. Seven endurance ... [more ▼]

The purpose of this study was to try to assess the fitness of endurance horses by using a simple routine standardized treadmill exercise test performed before and after a training period. Seven endurance horses aged 7 to 13 years, unfamiliar with the treadmill conditions and competing in international championship were tested twice in an air-conditioned laboratory, i.e. before and after a 4-month training period. The test was preceded by a 20 min warm-7 period and consisted of 2 min walk and 2 min trot (4.2 m/sec) with a slope of 0, 2, 4, 6, 8 and 10 The whole test lasted 45 min. Venous blood was sampled before and 4 min after each test. Heart rate was continuously recorded before, during and after the test with a cardiometer. Rectal temperature, respiratory rate and body weight were measured before and after the test. The completion of the test induced a significant decrease of the body weight, a significant increase in packed cell volume, cortisol, white blood cells, proportion of granulocytes, lactate, free fat acids and iso-enzyme LDH 5, and no change in the ions and in the activity of the other enzymes. Training did not induce significant changes in blood parameters, except in hacked cell volume and cortisol. Training induced a significant decrease in heart rate at all exercise intensities and during recovery. It was concluded that the test proposed in this study is simple, safe, suitable for horses unfamiliar with the treadmill and applicable in a 1-day clinic routine examination. In these conditions, the most reliable parameter for the assessment of fitness in endurance horses seems to be the heart rate recorded during 2 standardized tests performed before and after a training period [less ▲]