Effect of Climate on Bovine TB in Cattle
As well as wildlife, many factors such as mineral deficiency, cubicle
housing, soil type and spreading slurry that has not previously been
stored, may be linked with the spread of cattle TB. The impact of climate
has been little considered yet cool damp conditions predispose many cattle
diseases, particularly those that are airborne.
The paper presented results from Elaine King's PhD research which
examined the effect of climate on the incidence of btb in cattle and
investigated the survival of btb under simulated environmental
The effect of climatic conditions on the number of herd breakdowns
over a ten-year period was examined using the 'WINDOW' computer
software program, which is used in the US to predict the severity of
The program found that high rainfall, low temperatures and low
levels of sunlight were very closely matched to outbreaks of btb in
cattle. The accuracy of these matches was highly significant: 87% for
rainfall; 80% for temperature and 71% for sunlight.
WINDOW also identified periods of greatest risk to cattle from late
March to early June. A shorter window of high risk was also identified
in the autumn.
Laboratory experiments supported the findings. They showed that low
levels of sunlight, low temperatures and high relative humidity,
favour btb survival.