The goat population in Great Britain (GB), which is mostly oriented to milk production, is small compared to that in other European Union (EU) countries and contributes a very small fraction of the total livestock production. The recent confirmation and cull of scrapie-affected goat herds has raised the concern that the risk of re-introducing scrapie by mass restocking after the cull of a scrapie-affected herd, may not have been fully considered at the time of implementing statutory eradication measures. A conditional probability model has been developed to estimate the probability of introducing at least one animal infected with classical scrapie into a British goat herd under two scenarios: restocking over one year under normal operating conditions (Scenario 1); and restocking post a whole herd cull as part of the compulsory eradication measures (Scenario 2). Several of the parameters were based on expert opinion, as there is a paucity of data regarding goat industry norms for all sectors. Considering all herds, of which 99% have less than 100 animals, the probability of introduction is approximately 2 times higher for Scenario (2) than for Scenario (1). The risk of subsequently re-introducing the disease through the introduction of replacement stock is not insignificant, although it can be considered very low for the vast majority of herds (>99%). In the case of very large herds (>1000 heads), mass restocking would almost certainly reintroduce the disease since it would require purchases from a very large number of herds.
- great britain