The influence of the administration of sow's milk on the post-weaning excretion of hemolytic E. coli in the pig.

The postweaning excretion rate of hemolytic E. coli was determined in piglets from herds affected with edema disease and on control farms. No distinct difference in rate of excretion was observed. A split litter trial was set up to evaluate the importance of sow's milk in the postweaning rise of fecal hemolytic E. coli. 525 ml of sow's milk a day, mixed with the feed, completely inhibited that postweaning rise, even after oral challenge with a pathogenic strain.

The effect of clenbuterol on lung function parameters in calves suffering from bronchopneumonia.

Pulmonary function testing was performed in calves affected with bronchopneumonia. In these calves respiratory rate, viscous work per litre air and per minute, intrapleural pressure difference, mean inspiratory and expiratory flow rate and ventilation per minute were significantly increased. Total resistance of the lung was just not significantly increased. Dynamic compliance and tidal volume were significantly reduced. The main effect of clenbuterol was a significant increase in dynamic compliance. The reduction in the total resistance of the lung was just not significant. These results indicate that clenbuterol can antagonise, at least partly, the alterations caused by bronchopneumonia.

The influence of clenbuterol on prostaglandin F2 alpha-induced dyspnoea in calves.

Pulmonary function tests were performed in six healthy calves. Prostaglandin F2 alpha causes severe narrowing of both upper and lower airways (total lung resistance increased, dynamic compliance decreased). Clenbuterol administered intravenously fifteen minutes prior to prostaglandin F2 alpha aerosol, and in increasing doses (0, 0.4, 0.8, 1.2 micrograms/kg), on days 1, 2, 4 and 6 of the experiment, effectively but not entirely suppressed these responses. These data indicate that beta-adrenergic receptors are present in the bovine airways and that the use of clenbuterol (0.8 micrograms/kg) may be effective in treating clinical respiratory disease such as bronchopneumonia in calves.

Determination of red blood cell potassium content in horses with diarrhoea: a practical approach for therapy.

The concentration of potassium in the red blood cells in 15 horses with severe diarrhoea was determined. The red blood cell potassium content (RBCK+) was low compared with levels obtained in normal horses. The decrease in the RBCK+ was used to evaluate the total body potassium deficit. This calculated amount was administered orally, following each RBCK+ determination. In those horses which recovered, RBCK+ content returned to normal levels. During treatment, refilling of the red blood cells with potassium occurred only gradually as long as the diarrhoea persisted. In each case, oral loading with the calculated dose resulted in an improvement of the general condition and no side effects were observed. The importance of using RBCK+ levels as a diagnostic and therapeutic parameter is discussed.

Potassium concentration in equine red blood cells: normal values and correlation with potassium levels in plasma.

The concentration of potassium in plasma and in red blood cells was determined in 948 horses. The coefficient of correlation between the two parameters was low. In 436 of these horses, which were clinically healthy, the red blood cell potassium (RBCK+) levels did not fit within a normal distribution curve, but a bimodal distribution was observed with a section point at 90 mmol/litre. In 90 per cent of these normal horses, mean RBCK+ content was 97.5 mmol/litre. In the remaining 10 per cent, mean RBCK+ concentration was 93.8 mmol/litre. A subdivision into a 'low potassium group' and a 'high potassium group' was made. In 10 out of 15 horses in the 'low potassium group', bimonthly sampling over a period of one year showed that RBCK+ content remained low. In the remaining five horses an increase was observed.

Influence of prostaglandins on bovine abomasum: biosynthesis and in vitro motility experiments.

Pieces of the fundus, antrum pyloricum and pyloric sphincter of abomasa from freshly killed cows were studied for their capacity to biotransform arachidonic acid (AA) and for the effects of PG's on their in vitro motility. Biotransformation experiments revealed an AA-conversion (3.8 to 11.5%) into cyclooxygenase and lipoxygenase metabolites. The mucosa mainly synthetized hydroxy-eicosatetraenoic acids (HETE's) and PGE2 + TXB2. For the muscularis PGI2 was the major AA-metabolite. Incubation in the presence of indomethacin resulted in a reduction of the AA-conversion into cyclooxygenase metabolites. In the fundic strips the three PG's induced an increase in tension. In the antral strips PGF2 alpha and PGE2 resulted in an activation of spontaneous motility whereas PGI2 provoked a dose-dependent inhibition. The three PG's induced an inhibitory response in the tissue strips from the pyloric sphincter. The results suggest a possible function for PG's in the control of tone and motility of the bovine abomasum.