Dr. John Griffin:

If that point is finished I want to come back on another point if that is all right. It concerns cattle movement. I do not want to give the impression cattle movement is the only factor that causes transmission of TB. Ultimately, there are two factors. As Dr. Barrett said, a herd does not get infected from nowhere. It either comes from other cattle or from wildlife, either directly or indirectly, and we have to deal with both sources. That is absolutely clear. The point I was trying to make is there is very strong scientific evidence that cattle movement is a really important factor in the transmission of TB. There are a number of reasons for that. First of all, there is very significant movement of cattle. It is something of the order of 1.3 million moves per year. We also have evidence there is a high level of movement from high-risk herds to low-risk herds, so that really is a mechanism for transmitting TB.

Also, as Dr. Barrett said, the test is not perfect. When a herd becomes free of tuberculosis and is derestricted there is still a strong possibility there could be some infected animals in that herd. Again, there is evidence to show there is a higher risk in animals that move from previously infected herds than from clear herds. That is evidence cattle movement can play an important role. The other point to mention is that it is not just the direct spread, so when an infected animal moves to a clear herd, it is not just the clear herd that becomes infected as the disease can by transmitted to badgers and deer, which can in turn retransmit it to cattle herds, so we kind of enter a vicious circle. Overall, it is essential we deal with this question. If we are to eradicate TB, we need to address issues about the movement of cattle. I wanted to make that point, but it is by no means the only factor and I completely agree with the Senator on that.