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 ▲]

Determination of cardiac performance in healthy dogs during maximal inotropic stimulation with dobutamine.

in Proceedings of the 4th Annual Congress of the ESVIM (1994)

Measurement of Right Ventricular Ejection Fraction and Volume by the Thermodilution Technique in the Unsedated Calf

in Research in Veterinary Science (1994), 56(1), 75-81

This study was designed to test the applicability and the reproducibility of the thermodilution method in the measurement of right ventricular ejection fraction (EF), end-diastolic volume (EDV) and end ... [more ▼]

This study was designed to test the applicability and the reproducibility of the thermodilution method in the measurement of right ventricular ejection fraction (EF), end-diastolic volume (EDV) and end-systolic volume (ESV) in unsedated cattle. In the 16 healthy calves studied, it was possible, using a fast response thermodilution catheter, to obtain characteristic exponential steplike washout curves, allowing the calculation of right ventricular EF, EDV and ESV. Five to 10 successive thermodilution curves were recorded within a few minutes and two to five similar sets of measurements were performed throughout the same day to test the reproducibility of the technique. The same protocol was repeated the following day. Right ventricular EF, EDV and ESV were reproducible successively, throughout a given day and on following days. The mean intraset, intraday and interdays coefficients of variation ranged from a mean of 4.0 (SD 4.1) per cent to a mean of 18.2 (SD 7.9) per cent. Values of right ventricular volumes and EF agreed with those previously reported in various animal species. Thermodilution was, therefore, shown to be a useful method for measuring with a satisfactory reproducibility, right ventricular EF, EDV and ESV in the unsedated healthy calf [less ▲]

Comparison of the cardiac pumping capability and cardiac pumping reserve in double muscled and conventional calves

in Canadian Journal of Physiology & Pharmacology (1993), 71(12), 946-951

Hereditary muscular hypertrophy is a character that has been selected in several animal species for industrial meat production. The selection of this character in cattle produces animals of exceptional ... [more ▼]

Hereditary muscular hypertrophy is a character that has been selected in several animal species for industrial meat production. The selection of this character in cattle produces animals of exceptional commercial value but ones with a lower aerobic capacity than that of conventional cattle. The purpose of this work was to study the role of cardiac function as a potential limiting factor of aerobic capacity in double-muscled calves. Two groups of healthy calves were studied, one consisting of nine calves of conventional conformation and the other of nine double-muscled calves. Pulmonary arterial and capillary wedge, central venous, and systemic arterial pressures were measured by fluid-filled catheters and recorded together with the electrocardiogram. Cardiac output was measured by the thermodilution technique. From these measurements, the heart rate, the cardiac and the stroke indices, the pulmonary and the systemic vascular resistances, and the cardiac power output were calculated. The parameters were recorded under basal resting conditions and during incremental dobutamine challenge, which allowed determination of the resting cardiac power output, the cardiac pumping capability, and the cardiac reserve. Dobutamine challenge induced a significant rise in cardiac and stroke indices, heart rate, and cardiac power output, a significant decrease in pulmonary and systemic vascular resistances, and no change in systemic and pulmonary arterial pressures. The cardiac reserve obtained in the present study was low in comparison with those previously reported in humans, dogs, and horses. This may be related to the poor running capability of bovine species relative to that of the former species.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]

Effect of the double-muscled conformation selection on the cardiovascular function in cattle

in Archives Internationales de Physiologie et de Biochimie (1992)