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.

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.

Increased plasma bromide concentration in the horse after halothane anesthesia.

A long-lasting increase of the plasma bromide concentration was found in 25 horses after clinical halothane anesthesia. The plasma bromide concentration was significantly (P less than 0.005) increased at the end of anesthesia. In 18 horses, peak values were reached between 48 and 72 hours after anesthesia. Eighteen days after horses had been anesthetized, the plasma bromide concentration remained significantly (P less than 0.005) increased. Significant correlation was not found between the total dose of halothane and the plasma bromide concentration. In 1 horse reanesthetized with halothane 4 days after initial halothane anesthesia, the plasma bromide concentration increased to high concentrations.

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.

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.

[Halothane-induced malignant hyperthermia (MH) in the Belgian Landrace breed of pigs: some findings concerning the role of subcellular fractions (author's transl)]. / Halothaan geïnduceerde maligne hyperthermie (MH) bij het Belgisch Landvarken: enkele gegevens in verband met de rol van subcellulaire fracties.

Both calcium ++-activated magnesium++ adenosine triphosphatase and the calcium++-accumulating activity of SR isolated from white skeletal muscle of pigs of the Yorkshire breed resistant to MH and pigs of the Belgian Landrace breed susceptible to MH continue to be stable throughout the process of growth. There was not any detectable difference between the two breeds and therefore it could not be concluded that there was a defective SR membrane. Abnormal contractions induced by halothane and caffeine in biopsy specimens of muscle of MH-susceptible pigs of the Belgian Landrace breed are mainly produced by external calcium++, CN--not having any inhibitory effect in these cases. The contractions induced by combined caffeine and halothane in susceptible animals are more marked than those occurring in resistant animals. These increased contractions are mainly due to external Ca++ and, to a less extent, to CN--sensitive mitochondrial Ca++ fluxes.

Malignant hyperthermia in Belgian Landrace pigs rested or exercised before exposure to halothane.

Thirteen of 31 Belgian Landrace pigs developed malignant hyperthermia (MH) after breathing halothane. A short period of exercise 1 h before the administration of the triggering agent increased the incidence of the syndrome to 100% in eight similar pigs. Clinical symptoms were more marked and developed more rapidly in the exercised pigs. All the reacting pigs became typically acidotic, developed rigor and died. Serum Na+, K+, Ca2+, c.p.k., l.d.h. and protein concentrations were increased to a variable extent during the reaction and there was an increase in p.c.v. also. No hyperglycaemia was detected in pigs which were rested before receiving halothane. Four of the eight exercised pigs became markedly hyperglycaemic and plasma noradrenaline increased to higher values. Phosphocreatine and ATP decreased to low values and lactate increased in the muscles of all pigs which reacted. At the time of death, muscle glycogen had decreased significantly in the rested, but not in the exercised, MH pigs.

Biochemical profiles in cows with abomasal displacement estimated by blood and liver parameters.

The metabolic status of normal lactating cows and of cows suffering from abomasal dilatation was evaluated by examination of blood parameters and by determination of the fat and glycogen content in liver biopsies. The method for examination of the liver biopsies is described. In clinically normal lactating cows the liver contains less than 20 mg triglycerides (TG) and more than 20 mg glycogen per gram of wet tissue. Cows suffering from abomasal displacement all showed hyperglycemia and in most of them a fatty to very fatty liver was found. The degree of hyperglycemia depends on the amount of liver glycogen and is independent of the liver TG content. The degree of ketonemia also depends on the liver glycogen content.