PubMed Health⌕ Search

Biomedical subjects

R K Greenall

Publications and source records attributed to R K Greenall.

2 recordsLinked to original sources

Compliance of Victorian dairy farmers with current calf rearing recommendations for control of Johne's disease.

Questionnaires were posted to 800 randomly selected registered Victorian dairy farmers in 1996. Five hundred and thirty-four responses were received and analysed. Johne's disease (JD) had been diagnosed on the farm of 13.2% of respondents in the last 5 years. JD was rated second only to neonatal diarrhoea in importance as a disease of calves, even though other diseases occurred more frequently. However, there was a low level of compliance with JD control recommendations by the respondents. There was no significant difference in the number of JD control recommendations adopted by farmers between the three major Victorian regions. There was a significant difference in compliance between farms having had a diagnosed case of JD and those that had not. Although there is awareness among dairy farmers of the importance of JD, there appears to be a poor implementation of measures by farmers to prevent the spread of the disease. Current JD control recommendations and the method of information transfer to Victorian dairy farms should be reassessed to ensure that dairy heifers are reared with minimal risk of transmission of JD.

Animals↗

The intraaortic balloon pump: a nonlinear digital computer model.

A computer based model for in-series cardiac assistance by intraaortic balloon pumping was developed in this study. The model, obtained from the Navier-Stokes and Continuity equations, was capable of computing pressures, volumetric flow rates and radii through the arterial system. The model was used to study the effects of a wide range of assist device timing adjustments on the benefits of ventricular assistance under conditions corresponding to those measured during animal experiments. The model was also used to study the relationship between device timing adjustments and the benefits of ventricular assistance under constant cardiovascular state conditions. Such studies are important in isolating the response of the system to assist device phasing from the response associated with system state. The results obtained in this study demonstrate that the hemodynamic response of the cardiovascular system to intraaortic balloon pumping is a sensitive function of both the state of the cardiovascular system and phasing of the assist device.

Animals↗