A Study to Examine the Interactions between Cattle and Badgers

<p>Bovine tuberculosis (TB) is a cattle disease which has serious impacts on farmers and the farming industry; hence its control is a priority for Defra. One impediment to TB control is the fact that some populations of badgers are infected with TB’s causative agent, Mycobacterium bovis.</p>
<p>Strong evidence shows that badgers transmit M. bovis to cattle, but the mechanism of interspecific transmission remains unknown. In principal such transmission might occur both through direct contact between host species, and through indirect contact caused by contamination of the environment. However, the relative importance of these two transmission mechanisms is unknown.</p>

<p>Both direct and indirect contact between badgers and cattle can occur in pastures where cattle graze and badgers forage, and inside farm buildings where cattle are housed, and cattle feed stored, and which badgers visit. However, once again, the relative importance for M. bovis transmission of outdoor and indoor contacts is unknown.</p>

<p>Scientists’ poor understanding of the most important route(s) of interspecific M. bovis transmission compromises the control of cattle TB. Were it known how and where badgers transmit infection to cattle, specific management could be implemented to reduce transmission. Lacking such information, guidelines on keeping badgers and cattle apart are necessarily based on judgement rather than evidence of cost-effectiveness, potentially discouraging farmers from implementing effective methods, and perhaps wasting resources on ineffective techniques.</p>

We therefore propose to:
<ol><li>Quantify direct and indirect contact between badgers and cattle;</li>
<li>Describe the spatial distribution of badger-cattle contact, especially distinguishing indoor and outdoor contact;</li>
<li>Investigate risk factors for badger-cattle contact;</li>
<li>Assess how badger-cattle contact is influenced by management to restrict animal movement; and</li>
<li>Compare the likely cost-effectiveness of general approaches to reducing badger-cattle contact.</li></ol>

<p>The project will be conducted at four sites in TB “hotspots” in Cornwall, representing a range of badger densities. A combination of GPS-collars (which monitor animal locations using the same mechanism as vehicle satellite navigation systems) and video surveillance will give an unbroken picture of badger and cattle movements both indoors and outdoors. Proximity sensors (which record events when tagged badgers come close to collared cattle) will provide additional information on contact. The resulting data will be analysed to provide indices of direct and indirect contact. These indices can be compared with environmental conditions, and with the characteristics of individual farms, cattle and badgers. Having observed patterns of badger-cattle contact over a full year, we shall explore the cost-effectiveness of management proposed to reduce such contact, by experimentally excluding badgers from farm buildings and/or excluding cattle from field margins.</p>

The project’s findings should help to inform policy development by:
<ul><li>focusing management on the most likely form(s) of interspecific transmission, in the most likely location(s);</li>
<li>helping to explain why certain previously-identified risk factors influence cattle TB risk; and hence</li>
<li>allowing improvement of methods to limit M. bovis transmission between badgers and cattle.</li></ul>