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See detailTechnical and methodological requirements for reliable haemodynamic measurements in the unsedated calf.
Amory, Hélène ULg; Linden, Annick ULg; Desmecht, Daniel ULg et al

in Veterinary Research Communications (1992), 16(5), 391-401

The purpose of this study was (1) to evaluate the technical and methodological problems associated with invasive haemodynamic measurements in unsedated cattle; (2) to assess the reproducibility of such ... [more ▼]

The purpose of this study was (1) to evaluate the technical and methodological problems associated with invasive haemodynamic measurements in unsedated cattle; (2) to assess the reproducibility of such measurements both within and between days; and (3) to compare the values with those previously reported. Twenty-one healthy calves, aged from 5.5 to 12 months, were studied. The central venous, the right ventricular, the pulmonary arterial, the pulmonary capillary wedge and the systemic arterial pressures were obtained by means of fluid-filled catheters, and the cardiac output was measured by the thermodilution technique. The heart rate, the stroke volume, the pulmonary and systemic vascular resistances and the pulmonary and systemic ventricular workloads were calculated. An adverse reaction, consisting of severe pulmonary hypertension, tachycardia, tachypnoea and transient weakness, occurred in 7 calves during the catheterization procedures. Such a reaction might be due to a local reflex induced by stimulation of mechano-receptors by the catheter tip. It should be avoided by reducing the manipulation of the catheter as much as possible and by inflating the tip of the balloon when moving it forwards. A comparison of the vascular pressures with those previously reported was difficult because of methodological or technical limitations, such as, for instance, a lack of standardization of the baseline. The reproducibility of the haemodynamic measurements obtained was satisfactory, in contrast to previous studies performed in conscious animals. This was attributed to our animals being better trained to the experimental conditions and emphasizes the importance of reducing mental stress in obtaining reliable haemodynamic measurements in unsedated and potentially uncooperative animals. [less ▲]

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See detailThe Effect of Shape, Age and Extension on the Compliance of Equine Tracheal Segments
Art, Tatiana ULg; Lekeux, Pierre ULg

in Veterinary Research Communications (1991), 15(2), 135-146

The influence of the age and weight of the animal as well as that of the extension and the shape of the trachea on the mechanical properties of the cervical trachea was studied in 33 isolated tracheal ... [more ▼]

The influence of the age and weight of the animal as well as that of the extension and the shape of the trachea on the mechanical properties of the cervical trachea was studied in 33 isolated tracheal segments obtained from freshly slaughtered horses. The relationship between intraluminal pressure and volume was determined in the cervical tracheal segments positioned firstly under normal longitudinal tension and secondly in hyperextension. At the same time, changes in the area of the cross-section of the lumen (X-SA) at the midpoint of the segment were measured using photographs obtained by slit-lamp transillumination and endoscopy. The sagittal (DS) and transverse (DT) diameters were determined for each segment and the DT/DS ratio was calculated to give an estimate of the shape of the X-SA. The results showed that (i) neither the age nor the weight of the horses had any influence on the mechanical properties of the trachea; (ii) extension decreases the compressibility of the tracheal segment in vitro; (iii) there is a wide variation in the extrathoracic tracheal X-SA shape in horses; and (iv) the shape of the X-SA has a major influence on the mechanical properties of the trachea. It was concluded that (i) hyperextension of the neck will partly facilitate respiration at high levels of ventilation by elongating the trachea and by decreasing its collapsibility; and (ii) the tracheal collapse which may occur during high levels of ventilation will be more or less important depending on the individual X-SA shape. [less ▲]

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See detailThe relationship between carcass characteristics, plasma hormones and metabolites in young fattening bulls.
Istasse, Louis ULg; Van Eenaeme, Christian ULg; Gabriel, Annick ULg et al

in Veterinary Research Communications (1990), 14(1), 19-26

Six Belgian Blue bulls (double-muscled type) and six Friesian bulls were offered a fattening diet for 34 weeks. Plasma samples were obtained once a week and also every 20 min over a 24 h period, 7 weeks ... [more ▼]

Six Belgian Blue bulls (double-muscled type) and six Friesian bulls were offered a fattening diet for 34 weeks. Plasma samples were obtained once a week and also every 20 min over a 24 h period, 7 weeks before slaughter. No differences were observed between the breeds in plasma glucose, urea and free amino nitrogen concentrations, while creatinine was significantly higher in the Belgian Blue bulls. Tri-iodothyronin, tetra-iodothyronin, insulin-like growth factor 1, insulin and testosterone concentrations were higher in the Holstein group. In contrast, the Belgian Blue bulls appeared to produce more growth hormone. The slaughter weight, carcass weight, dressing percentage and proportion of lean meat were significantly higher in the Belgian Blue group. The characteristics of muscle mass (carcass weight, dressing percentage and proportion of lean meat) were positively correlated with creatinine and with the total peak area or peak amplitude of growth hormone. The insulin concentration was positively correlated with the proportion of adipose tissue in the carcass and negatively correlated with the proportion of muscle. There were no correlations between the carcass characteristics and insulin-like growth factor 1 or testosterone. No further information was provided when the ratios of the hormones were correlated with carcass characteristics. [less ▲]

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See detailGrowth-Related Changes in the Pulmonary Function of Goats
Bakima, M.; Lomba, Fernand; Lekeux, Pierre ULg

in Veterinary Research Communications (1990), 14(2), 141-146

Growth-related changes in pulmonary function values were investigated in 20 healthy French Alpine goats, aged between 20 and 550 days, weighing 7-55 kg. Pulmonary ventilation, mechanics of breathing and ... [more ▼]

Growth-related changes in pulmonary function values were investigated in 20 healthy French Alpine goats, aged between 20 and 550 days, weighing 7-55 kg. Pulmonary ventilation, mechanics of breathing and arterial oxygen tension were measured using standardized techniques and methods adapted for goats of different body sizes. The Ppl values and the tI/tTOT ratio showed no significant changes with age and body size. The ventilation values (Vt, Ve, mVI and mVE) increased linearly with growth. There was a significant correlation of age and body weight with dynamic lung compliance (Cdyn), total pulmonary resistance (RL), viscous work of breathing (Wvis tot) and minute viscous work (Wvis min) throughout the age range studied. Cdyn, Wvis tot and Wvis min increased and RL decreased with age and body weight. Arterial blood gases (PaO2 and PaCO2) did not show significant changes over the age range studied. Regression equations for each pulmonary function parameter are given with body weight as the independent variable. Data for the mechanics of breathing were compared with those elsewhere for cattle, horses, man and dogs. [less ▲]

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See detailRespiratory-Induced Variability of Pulmonary Arterial Pressure Measurements in Cattle
Amory, Hélène ULg; Art, Tatiana ULg; Desmecht, Daniel ULg et al

in Veterinary Research Communications (1990), 14(3), 227-33

The purpose of this study was to investigate the variability of the peak systolic (PAPs) and the end diastolic (PAPd) pulmonary arterial pressures induced by intrapleural pressure changes in cattle. The ... [more ▼]

The purpose of this study was to investigate the variability of the peak systolic (PAPs) and the end diastolic (PAPd) pulmonary arterial pressures induced by intrapleural pressure changes in cattle. The pleural pressure (Ppl), the electrocardiogram and the pulmonary arterial pressure (PAP) were simultaneously recorded in five healthy calves under three different conditions, i.e. normoxia (N), normoxia with an added airflow resistance (R) and hypoxia (H). PAPs, PAPd and their corresponding transmural pressures were measured and averaged over 10 successive regular cardiac cycles. The maximum Ppl changes (max delta Ppl) were measured on the same tracings. The variance and coefficients of variation were calculated for each set of vascular measurements. Max delta Ppl was significantly increased with regard to N values during R and H conditions. This increase in max delta Ppl induced a simultaneous rise in the variability of PAP measurements, while in each condition, this variability was greatly lowered by use of the corresponding transmural pressure. It was concluded that, in calves with high max delta Ppl, the influence of respiration on PAP becomes considerable. In such cases, the use of transmural pressures rather than luminal pressures can greatly reduce the variability of these pulmonary pressure measurements and therefore increase their sensitivity. [less ▲]

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See detailRespiratory and Pulmonary Haemodynamic Changes During Experimental Organophosphate Poisoning in Goats
Bakima, M.; Baudet, H. M.; Lekeux, Pierre ULg et al

in Veterinary Research Communications (1989), 13(2), 127-133

Five French Alpine goats received 2 mg kg-1 of dichlorvos (DDVP) by intravenous injection and 0.15 mg kg-1 of atropine sulphate 5-10 min later. Ventilatory mechanics, gas exchanges, pulmonary ... [more ▼]

Five French Alpine goats received 2 mg kg-1 of dichlorvos (DDVP) by intravenous injection and 0.15 mg kg-1 of atropine sulphate 5-10 min later. Ventilatory mechanics, gas exchanges, pulmonary haemodynamics and pulmonary vascular resistance (PVR) were measured before treatment, 5 min after DDVP injection and 5 min after atropine injection. Within 2 min of DDVP administration, all the goats showed acute respiratory distress, excitation and slight muscle fasciculations. A post-inspiratory pause was recorded in 3 goats. Hypersecretion of saliva or nasal discharge was not observed. Dynamic compliance and heart rate decreased significantly and total pulmonary resistance, pulmonary artery and wedge pressures increased significantly. On the other hand, minute ventilation, arterial oxygen and carbon dioxide tensions were not significantly altered by DDVP. Atropine treatment reversed all the clinical and functional parameters, with the exception of the central nervous and muscular signs, which disappeared within 12 h. It was concluded that experimental DDVP toxicosis induced changes in the mechanics of breathing and pulmonary haemodynamics associated with diffuse bronchoconstriction and cardiac insufficiency respectively. [less ▲]

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See detailA Comparison of Po2, Pco2, Ph and Bicarbonate in Blood from the Carotid and Coccygeal Arteries of Calves
Gustin, Pascal ULg; de Groote, A.; Dhem, A. R. et al

in Veterinary Research Communications (1988), 12(4-5), 343-346

A technique is described for the subcutaneous deviation of the carotid artery into the jugular groove of calves weighing between 90 and 200 kg. This makes sampling arterial blood or chronic cannulation ... [more ▼]

A technique is described for the subcutaneous deviation of the carotid artery into the jugular groove of calves weighing between 90 and 200 kg. This makes sampling arterial blood or chronic cannulation for further experimentation very easy. Values of oxygen tension, carbon dioxide tension, pH and bicarbonate concentration in blood sampled from the ventral coccygeal artery were compared with the values obtained in blood from carotid artery puncture. The high correlations observed indicate that blood samples from the ventral coccygeal artery can be used for measurement of blood gases and pH in calves. [less ▲]

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See detailThe effect of common bovine respiratory diseases on tidal breathing flow-volume loops
Lekeux, Pierre ULg; Art, Tatiana ULg; Amory, Hélène ULg

in Veterinary Research Communications (1988), 12(6), 463-473

In order to better understand the bovine breathing pattern, tidal breathing flow-volume loops (TBFVL) were analyzed in 24 healthy cattle of different body weights (range: 37-660 kg) (Group A) and in 28 ... [more ▼]

In order to better understand the bovine breathing pattern, tidal breathing flow-volume loops (TBFVL) were analyzed in 24 healthy cattle of different body weights (range: 37-660 kg) (Group A) and in 28 cattle suffering from the common respiratory diseases: verminous bronchitis (Group B); shipping fever (Group C); acute respiratory distress syndrome (Group D); respiratory syncytial virus pneumonia (Group E); organophosphate poisoning (Group F); and necrotic laryngitis (Group G). Respiratory airflow and tidal volume were measured with a breathing mask-Fleisch pneumotachograph assembly. TBFVL were traced from these values using a computerized method. All the loop indices proposed by Amis and Kurpershoek (1986a) were calculated from 5 representative breathing cycles for each of the 52 animals. The TBFVL shapes and indices were relatively constant in most healthy cattle and were not correlated with the body size. When compared to normal values, animals with moderate respiratory syndromes (Groups B and C) had a more flattened shape to their TBFVL. On the other hand, in most cattle with severe respiratory pathologies (Groups D, F and G expiration tended to be biphasic with the peak expiratory flow (PEF) occurring significantly later than in healthy animals. Both PEF and peak inspiratory flow were increased in all the pathological conditions. The TBFVL indices were more frequently and more severely changed during expiration than during inspiration. [less ▲]

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See detailA Critical Assessment of Pulmonary Function Testing in Exercising Ponies
Art, Tatiana ULg; Lekeux, Pierre ULg

in Veterinary Research Communications (1988), 12(1), 25-39

Pulmonary function measurements during exercise were tested for accuracy and reproducibility in 5 saddle ponies weighing 267 +/- 9 Kg. Airflow (V) and tidal volume (VT) were measured with a Fleisch ... [more ▼]

Pulmonary function measurements during exercise were tested for accuracy and reproducibility in 5 saddle ponies weighing 267 +/- 9 Kg. Airflow (V) and tidal volume (VT) were measured with a Fleisch pneumotachograph mounted on a face mask. The linearity of the response and the symmetry of this device were carefully checked. Pleural pressure changes were measured by pleural puncture (Ppl) and with an esophageal balloon catheter (Pes). The elastance of the esophageal wall and the effect of the position of the esophageal catheter tip on Pes were also investigated. Airflow, VT, Ppl, Pes, mask pressure, an electrocardiogram and limb movements were simultaneously recorded before, during and after exercise. These recordings were used to assess the validity of some pulmonary function measurements and to evaluate the influence of the breathing apparatus on the respiratory pattern. Maximal intrathoracic pressure changes and total pulmonary resistance values did not differ significantly when calculated on the basis of the Ppl and the Pes curves respectively. Although the absolute Ppl values were significantly different from the absolute Pes values, both pressures recorded at different workloads were closely correlated (R = 0.99). The mean specific elastance of the esophagus was 1.56 +/- 0.24 kPa.cm.ml.-1. Changes in the position of the esophageal catheter tip induced significant differences in the recorded Pes values. The pressure/flow relationship of the pneumotachograph pressure transducer system was linear within the range of the V measured during exercise. The mask had a significant influence on respiratory frequency and maximum difference in Pes, but did not modify the exercise-induced changes in these parameters. It was concluded that the technique and methods used in this study can allow accurate pulmonary function measurements in exercising ponies. [less ▲]

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See detailCardio-pulmonary function values in double-muscled cattle during muscular exercise.
Gustin, Pascal ULg; Dhem, A. R.; Lomba, F. et al

in Veterinary Research Communications (1988), 12(4-5), 407-416

Eleven double-muscled calves of the Belgian White and Blue breed and eleven Friesian calves have been investigated at rest, during exercise on a treadmill (11% incline; speed 1.3 m.sec-1) and 10 and 30 ... [more ▼]

Eleven double-muscled calves of the Belgian White and Blue breed and eleven Friesian calves have been investigated at rest, during exercise on a treadmill (11% incline; speed 1.3 m.sec-1) and 10 and 30 minutes after the end of this exercise. Blood gases and acid-base status were determined in mixed venous and arterial blood sampled from the pulmonary and the carotid artery respectively. Expired gases were collected in a balloon. The time of collection, volume of expired gases and fractional O2 and CO2 concentrations in expired gases were measured. In double-muscled calves, inadequate oxygen intake and carbon dioxide elimination were demonstrated by the increase in the carbon dioxide tension (PaCO2) and in the hydrogen ion concentration [H+]a and the decrease in the oxygen tension (PaO2) in arterial blood during exercise. In Friesian calves, an adequate increase in oxygen intake occurred and no acidosis was recorded. A metabolic acidosis explained by only a 1.5-fold increase in the cardiac output and by the small increase in haemoglobin concentration was recorded in double-muscled calves. It was concluded that some aspects of the cardio-pulmonary and metabolic responses to exercise in double-muscled calves can be related to their inability to greatly increase their O2 consumption. [less ▲]

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See detailPulmonary Mechanics During Treadmill Exercise in Race Ponies
Art, Tatiana ULg; Lekeux, Pierre ULg

in Veterinary Research Communications (1988), 12(2-3), 245-258

Exercise-induced variations in their ventilatory mechanics were studied in 8 healthy ponies 4.2 +/- 1.4 years old and weighing 282 +/- 11 kg. Airflow (V), tidal volume (VT), esophageal pressure, mask ... [more ▼]

Exercise-induced variations in their ventilatory mechanics were studied in 8 healthy ponies 4.2 +/- 1.4 years old and weighing 282 +/- 11 kg. Airflow (V), tidal volume (VT), esophageal pressure, mask pressure and electrocardiogram were simultaneously recorded before, during and after a treadmill (incline 8.3 degrees) exercise which consisted of 2 min walking (1.5 m.sec-1), 3 min slow trotting (3.0 m.sec-1) and 3 min fast trotting (3.5 m.sec-1). The results of three consecutive daily measurements were averaged for each pony. Heart rate, minute volume (Ve), respiratory frequency (f) and peak inspiratory and expiratory V, mean inspiratory and expiratory V, and peak to peak changes in transpulmonary pressure (maxdPtp) increased linearly and significantly with increasing velocity (v) (R2 = 0.99). Tidal volume and the inspiratory time to total breathing time ratio showed a curvilinar relation with v (R2 = 0.99). Minute volume, maxdPtp, total pulmonary resistance (RL) and VT increased from rest to fast trot 6.7, 5.7, 1.5 and 1.6 times respectively. When the ponies stopped all these values decreased significantly. After 5 min recovery, the Ve was approximately doubled, VT and max dPtp unchanged and RL 30% smaller than their respective resting values. The exercise-induced increase in Ve was achieved by an increase in f at both low and high intensity of work. [less ▲]

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See detailInfluence of Inertance on Measurements of the Mechanical Properties of the Bovine Respiratory System
Lekeux, Pierre ULg; Art, Tatiana ULg; Clercx, Cécile ULg et al

in Veterinary Research Communications (1988), 12(1), 61-66

The observation that dynamic compliance (Cdyn) tended to rise with respiratory frequency (f) in adult cattle led us to reassess the importance of inertial pressures in measuring Cdyn in large animals ... [more ▼]

The observation that dynamic compliance (Cdyn) tended to rise with respiratory frequency (f) in adult cattle led us to reassess the importance of inertial pressures in measuring Cdyn in large animals. Five healthy Friesian cows were selected for their ability to show an increase of f without significant change in tidal volume (VT). Dynamic compliance was measured three times, both at the resting f (21 +/- 1 cpm), and at higher f (49 +/- 3 cpm), obtained by an artificial increase in the dead space of the breathing mask. Frequency-response characteristics of the measuring instruments were matched up to 12 Hz. The inertia of the lungs and gas stream (In) was calculated as the ratio of the accelerative pressure change to the simultaneous change in volume acceleration. Inertance was also estimated from the dimensions of the bovine airways and from the relative linear flow velocities reported by Rohrer (1915). Dynamic compliance measured during rapid breathing was significantly higher (p less than or equal to 0.01) than base-line values. Dynamic compliance was strongly correlated with f (r = +0.96). Measured and estimated In were 0.002 and 0.003 kPa.sec2.L-1 respectively. Dynamic compliance did not differ significantly from base-line values when it was corrected for the estimated inertance effect. [less ▲]

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See detailThe topographical distribution of the inhalation-to-perfusion ratio in double-muscled and Friesian calves.
Gustin, Pascal ULg; Clercx, Cécile ULg; Lomba, F. et al

in Veterinary Research Communications (1988), 12(4-5), 401-5

Five healthy Friesian calves and five double-muscled Belgian White and Blue calves were studied, using a 99m Technetium (99mTc) aerosol inhalation combined with a 99mTc macroaggregate injection and ... [more ▼]

Five healthy Friesian calves and five double-muscled Belgian White and Blue calves were studied, using a 99m Technetium (99mTc) aerosol inhalation combined with a 99mTc macroaggregate injection and collimated scintillation counters. The inhalation-to-perfusion ratio (I/P) was calculated for both left and right sides of the thorax at four sites situated at three different levels in the auscultatory area on the same vertical axis and at a more anterior site just behind the scapulohumeral joint. I/P was higher in the left than in the right hemithorax. In both breeds, a vertical and a horizontal gradient were observed. I/P was higher in the lower and in the more cranial zones of the lungs. However the vertical gradient was more pronounced in Friesian calves while the horizontal one was greater in Belgian White and Blue animals. It was concluded that the factors affecting the topographical distribution of pulmonary ventilation and perfusion seem to be different in calves as compared to other species. [less ▲]

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See detailEquine postanaesthetic myositis: thromboxanes, prostacyclin and prostaglandin E2 production
Serteyn, Didier ULg; Deby, Ginette ULg; Pincemail, Joël ULg et al

in Veterinary Research Communications (1988), 12

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See detailElectrical activity of the bovine uterus prior to and post parturition.
Hanzen, Christian ULg

in Veterinary Research Communications (1981), 5(2), 143-50

Recordings of electrical activity of six different areas of the uterus were obtained from two pregnant cows before and after delivery of their calves. Periods of activity occurred as spike bursts of ... [more ▼]

Recordings of electrical activity of six different areas of the uterus were obtained from two pregnant cows before and after delivery of their calves. Periods of activity occurred as spike bursts of potentials which occupied 52% of the recording time before delivery and 92% at the expulsive phase. The mean duration of the bursts was nearly doubled in the last ten hours prior to parturition without changes in their frequency. After delivery, the activity of the uterus occupied 29% of the recording time and consisted of long-lasting periods of spike bursts whose frequency was nearly halved. The alternation of periods of activity and quiescence represents the basic motility pattern of the pregnant uterus. Periods of quiescence are shortened at the time of expulsion and become predominant in the empty uterus, a phenomenon paralleled by changes in the temporal organisation of the number of spike bursts with the periods of activity. [less ▲]

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