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

Assessment of nebulisation of sodium ceftiofur in the treatment of calves naturally infected with bovine respiratory disease

Twelve screened cases of bovine respiratory disease (BRD) in calves were enrolled. Six of the calves were treated intramuscularly with sodium ceftiofur (1 mg/kg), and six were treated with nebulised sodium ceftiofur (1 mg/kg). Comparative evaluation of the two therapeutic modalities was based on repetitive analysis of hematological profile of calves on days 0, 5, and 10 post-therapy. The mortality rate in the group of calves treated with the nebulised sodium ceftiofur was significantly (p < 0.001) lower, and their clinical and hematological parameters returned to normal significantly (p < 0.001) faster than in calves treated intramuscularly. Nebulisation of sodium ceftiofur is the most effective treatment in calves with BRD under field conditions. Nasal lavage fluid analysis indicating a high rise of neutrophil count and macrophages may be used as an alternative method to detect pulmonary inflammation in BRD-affected calves.

Investigations on the ability of clenbuterol hydrochloride to reduce clinical signs and inflammation associated with equine influenza A infection

Twenty-four Quarter Horse and Quarter Horse-cross yearlings were experimentally infected with influenza A virus (Influenza A/equine/Saskatoon/90 [H3N8]) by nebulisation. In a double blind controlled trial the horses were randomly assigned to 3 groups of 8 animals. Group 1 received a placebo, (carrier syrup), Group 2 the labelled dose and Group 3 twice the labelled dose of clenbuterol hydrochloride. All treatments were given per os b.i.d. for 10 days and started on the day of infection. The horses were monitored for clinical signs of influenza infection for 14 days. Bronchoalveolar lavages were performed 4 days prior to, and 5 and 13 days after infection. Cell counts and concentrations of prostaglandin E2 and prostaglandin F2alpha in the lavage fluid were determined. Blood samples for haematology and serology were taken 4 days before, on the day of infection, 5, 9 and 13 days after infection. All horses experienced a typical influenza infection with fever, coughing and secondary bacterial infections with mainly Actinobacillus spp. and Streptococcus spp. There was no statistically or clinically significant effect of treatment with clenbuterol hydrochloride on measured clinical or laboratory parameters within 14 days of infection.

Evaluation of the nebulisation of sodium ceftiofur in the treatment of experimental Pasteurella haemolytica bronchopneumonia in calves

Severe acute bronchopneumonia was induced in 24 conventional Friesian Holstein calves by inoculating them intratracheally with Pasteurella haemolytica type A1. Twelve of the calves were treated intramuscularly with sodium ceftiofur and 12 were treated with an aerosol of sodium ceftiofur. The mortality rate in the group of calves treated with the aerosol was significantly lower, and their clinical and haematological parameters returned to normal significantly faster than in the calves treated intramuscularly.

Oscillatory measurements, blood gas analysis and clinical observations after intravenous clenbuterol administration in healthy and acutely pneumonic calves

The effects of clenbuterol (Ventipulmin, Boehringer Ingelheim) on respiratory functions were investigated in 6 calves aged 4-6 weeks prior to and after experimental infection with Pasteurella haemolytica A1. On days 1-3 (prior to infection) and on days 7-9 (after infection), blood gas analysis, monofrequency forced oscillation techniques and clinical examinations (heart rate, respiratory rate) were conducted for 135 min after the intravenous administration of clenbuterol (0.8 microgram/kg body weight). In healthy calves prior to Pasteurella infection, intravenous administration of clenbuterol induced a mild tachycardia and a reduction in the mean oscillatory respiratory resistance. Using the same dose of clenbuterol in diseased calves after infection, the statistically significant reduction in oscillatory respiratory resistance was more impressive and it was accompanied by a significant increase in the oxygen pressure of the arterialized blood. Heart rate and respiratory rate did not change significantly after the administration of clenbuterol in infected calves.

Pulmonary function changes and clinical findings associated with chronic respiratory disease in calves

Thirteen field cases of chronic respiratory disease in crossbred calves aged between 1 and 8 months were subjected to a standardized examination in which clinical criteria were scored and weighted to allow quantification. Predicted values for pulmonary function variables were generated using regression equations previously established in normal calves which related measured pulmonary function variables to thoracic perimeter. Subsequent pulmonary function testing of each calf was undertaken and values obtained compared with predicted values and correlated with clinical scores. Diagnosis was confirmed at post-mortem examination. Calves with chronic respiratory disease had significantly reduced inspiratory and expiratory times, tidal volume, dynamic compliance and PaO2, significantly increased respiratory frequency, airway resistance and PaCO2 and more negative transpulmonary pressure values when compared to predicted pulmonary function values for the same calves. PaO2 and PaCO2 were the only variables correlated with clinical scores, suggesting their value in the assessment of severe cases of calf respiratory disease.

Treatment of low arterial oxygen tension in anesthetized horses with clenbuterol

Clenbuterol (0.8 microgram/kg intravenously) was administered to 10 anesthetized horses with an abnormally low PaO2 (less than 90 mm Hg) despite controlled ventilation with an oxygen-rich gas mixture. Results were compared with those from 10 controls to which no clenbuterol was given and in which conventional methods to increase PaO2 were ongoing. Horses treated with clenbuterol had higher PaO2 values for at least 90 minutes. Clenbuterol was associated with increased heart rate and profuse sweating. Clenbuterol can be administered intravenously to increase the PaO2 of mechanically ventilated horses that have low arterial oxygen tension while under inhalation anesthesia. Further studies are warranted to define more precisely the circumstances under which clenbuterol may be used safely.

The effects of a beta 2-agonist (clenbuterol), and anti-bacterial drugs (trimethoprim with sulphadiazine; oxytetracycline) on calf mucociliary clearance

A non-invasive radio-aerosol technique was employed to study mucociliary clearance patterns in three groups of four calves of different ages. The initial clearance pattern, the percentage cleared in 1 h, and the percentage cleared between 1 and 19 h were used as indices of clearance efficiency. (Percentage retention at 19 h was used as an index of alveolar deposition.) These measurements were recorded in a series of experiments designed to investigate the effects of: clenbuterol (given as a single intravenous injection, 0.75 microgram/kg); a combination of trimethoprim and sulphadiazine-TMPS (administered by intramuscular injection twice daily for 3 days: 2.5 mg/kg trimethoprim; 12.5 mg/kg sulphadiazine) alone, or with a supplementary injection of clenbuterol; and oxytetracycline (administered by intramuscular injection twice daily for 3 days; 3 mg/kg). Clenbuterol alone tended to increase clearance rate, although this effect did not achieve statistical significance. The combination of TMPS with clenbuterol produced results similar to those of clenbuterol alone. Neither TMPS nor oxytetracycline had any significant effect on indices of mucociliary clearance. Differences were observed between calves of different age groups, particularly in clearance phases between 1 and 19 h.