Work of breathing in exercising ponies.

This paper attempts to evaluate the changes in the mechanical work of breathing induced by the increase of ventilation in ponies exercising on a treadmill. Airflow, tidal volume (VT) and oesophageal pressure were simultaneously recorded in eight ponies (four to six years old and weighing 258 +/- 11 kg) before, during and after standardised exercise. Respiratory frequency, VT and minute volume (Ve) for each phase of the experimental protocol were calculated from the collected data.

Respiratory and pulmonary haemodynamic changes during experimental organophosphate poisoning in goats.

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.

Investigation of the effects of histamine inhalation on the tracheobronchial tree of calves by the forced oscillation technique.

Effects of histamine inhalation were investigated with two different techniques in nine conscious, healthy calves. The oesophageal balloon technique was used to measure the dynamic respiratory compliance (Cdyn) and the pulmonary resistance (RL). The reactance (Xrs) and the resistance (Rrs) of the respiratory system were measured at high frequencies by the forced oscillation technique.

Pulmonary function values and growth in Belgian white and blue double-muscled cattle.

Seventy-five double-muscled cattle of the Belgian white and blue breed, two days to 50 months old and weighing 45 to 680 kg, were investigated. Transpulmonary pressure changes, measured with an oesophageal balloon, variations of air flow and volume at the mouth were obtained during spontaneous breathing to calculate pulmonary function data. Oxygen and carbon dioxide tensions in arterial blood were also recorded.

Mechanics of breathing in goats.

Common pulmonary function tests used in man and domestic mammals were adapted to the goat. Requirements for intrathoracic pressure record and pulmonary function investigation were determined. The elastance of the mid-thoracic portion of the oesophagus was measured in 17 healthy goats.

Effect of environmental temperature and relative humidity on breathing pattern and heart rate in ponies during and after standardised exercise.

A preliminary study attempted to assess the influence of atmospheric conditions on the breathing pattern of ponies. The respiratory airflow, tidal volume, breathing frequency, minute volume, total pulmonary resistance and heart rate of five ponies (257 +/- 9 kg and three to five years old) were measured by a standardised procedure. Data were collected at rest, during a nine minute period of treadmill exercise and during a five minute recovery period.

Effect of enrofloxacin therapy on shipping fever pneumonia in feedlot cattle.

The effect of enrofloxacin therapy was investigated in 110 male double-muscled cattle weighing 275 +/- 3 kg, during a spontaneous outbreak of shipping fever occurring 11 +/- 2 days after they arrived in the feedlot. Forty-six diseased animals were divided randomly into three groups A, B and C, containing 17, 19 and 10 animals, respectively; the animals in group A were injected intramuscularly once daily for three consecutive days with 2.5 mg/kg of enrofloxacin, those in group B with 5 mg/kg of enrofloxacin and those in group C with 10 mg/kg of oxytetracycline.

Effect of exercise on the partitioning of equine respiratory resistance.

Pleural, tracheal, pharyngeal and mask pressures as well as airflow and tidal volume of five ponies on a treadmill (incline 8.3 degrees) were recorded simultaneously while resting, walking, trotting slowly, trotting fast, after standing for 30 secs and 5 mins after the end of the exercise. The curves obtained were used to calculate total pulmonary resistance (RL), lower airway resistance (RLA) and upper airway resistance (RUA).

Respiratory airflow patterns in ponies at rest and during exercise.

The exercise-induced changes in the equine breathing pattern were studied by analyzing tidal breathing flow-volume loops recorded in ten ponies both at rest and during a standardized exercise. Airflow, tidal volume, esophageal pressure and mask pressure were simultaneously recorded before, during and after a treadmill exercise. From the collected data, respiratory frequency and total pulmonary resistance were calculated, tidal breathing flow-volume loops were retraced using a computerized method and loop indices were measured for each period of the experimental protocol.

Measurement of total respiratory impedance in calves by the forced oscillation technique.

We have determined the resistance (Rrs) and the reactance (Xrs) of the total respiratory system in unsedated spontaneously breathing calves at various frequencies. A pseudorandom noise pressure wave was produced at the nostrils of the animals by means of a loudspeaker adapted to the nose by a tightly fitting mask. A Fourier analysis of the pressure in the nostrils and flow signals yielded mean Rrs and Xrs, over 16 s, at frequencies of 2-26 Hz.

Cardio-pulmonary function values in double-muscled cattle during muscular exercise.

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.

The topographical distribution of the inhalation-to-perfusion ratio in double-muscled and Friesian calves.

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.

Pulmonary mechanics during treadmill exercise in race ponies.

Exercise-induced variations in their ventilatory mechanics were studied in 8 healthy ponies 4.2 +/- 1.4 years old and weighing 282 +/- 11 kg.

Influence of inertance on measurements of the mechanical properties of the bovine respiratory system.

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.

A critical assessment of pulmonary function testing in exercising ponies.

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.

A comparison of pO2, pCO2, pH and bicarbonate in blood from the carotid and coccygeal arteries of calves.

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 effect of common bovine respiratory diseases on tidal breathing flow-volume loops.

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.

Oxygen transport properties of blood in two different bovine breeds.

1. The whole oxygen dissociation curve of oxyhemoglobin has been determined in double-muscled cattle of the Belgian White Blue breed and in Friesian cattle of different body weight. 2.

Functional changes induced by necrotic laryngitis in double muscled calves.

The effects of necrotic laryngitis on the mechanics of breathing and gas exchange were investigated in five Belgian blue double muscled calves two to three months old. All the animals showed the typical clinical picture of the respiratory syndrome associated with naturally occurring necrotic laryngitis. Highly significant increases in total pulmonary resistance, minute viscous work of breathing and alveolar-arterial oxygen gradient, and highly significant decreases in dynamic lung compliance and arterial oxygen tension were recorded in the infected animals, when compared to reference values for healthy cattle.

Partitioning of upper airway resistance in Friesian and double-muscled calves.

Respiratory resistance in calves was partitioned in two components: upper airway resistance and pulmonary resistance. The former one was divided into naso-pharyngeal and laryngeal resistance. A comparison between seven healthy unsedated double-muscled calves of the Belgian White and Blue breed (BWB) and five healthy unsedated Friesian (F) calves was performed.

Partitioning of pulmonary resistance in Friesian calves.

Eight right cranial lobes of healthy Friesian calves were suspended in an airtight box. They were inflated at a constant transpulmonary pressure (Ptp) and ventilated from the outside by modifying pressures in the box with a quasi-sinusoidal pump at a frequency of 30 counts per minute. Peak-to-peak changes were 0.

Mechanical properties of excised calf lungs: effects of airway obstruction with beads.

Isolated lungs of five calves were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure. Dynamic compliance (Cdyn) and total pulmonary resistance (RL) were measured.

Mechanical properties of excised calf lungs.

Five isolated calf lungs were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure (Ptp). The static pressure-volume curve characteristics of the lungs were measured.