Mr. Conor Geraghty:

I will take the questions on TB and I will respond to Deputy Cahill's question on Johne's disease. I will respond in the order in which the questions were asked. In response to Deputy Martin Kenny, the average length on farm is four weeks.

My understanding is that this is because of valuation. If there is more than one reactor, the farmer has the right to have it live-valued by an independent valuer and has the right of appeal. That accounts for some of the time. Deputy Cahill might be able to account for some of the other delays. The Department can appeal the valuation as well. When the test has been read within the 72-hour period, we have between 48 and 72 hours in which to upload it onto the system. If we stray outside that timeframe, which is in our contract, it goes down as a black mark against us and we have increased inspection levels as a result.

Deputy Kenny asked whether the vaccination of badgers would work. The studies we have seen are based on research done in Ireland by Professor More and others, led by the Department and UCD. Those studies suggest that vaccination is as good as culling. That is why it is intended to use it instead of culling. Obviously, we have not conducted any research of our own. We have to look at the peer-reviewed science and use it as a guide when determining what is scientifically correct.

A question was also asked about the issue of feed lots. As some farms have restricted status, they do not need to have multiple tests if they have reactors. Such farms generally finish a lot of cattle indoors. They might have grazing. It is my understanding that they are not allowed to have breeding herds. They must have biosecure fencing, which means electric fencing that is 3 m from the boundary.

The observation that wildlife does not respect boundaries is a valid one. We have not seen any research with regard to neighbours. We are not aware of any such research. I think Professor More mentioned that such research is just starting.

Deputy Kenny also asked about the accuracy of the testing. As Professor More has said, no test is 100% accurate. Tests are basically judged on sensitivity, which is the ability to pick up infected animals, and on specificity, which is the ability not to take out false positives. The skin test, which is used worldwide, is highly specific. Approximately two animals per 1,000 are false positives. In other words, they show up as reactors but do not have TB. That is quite important. Depending on the studies one reads, sensitivity can vary from below 50% to up to 90%. I think those variations account for animals at different stages of the disease. As Professor More mentioned earlier, it is not as good very early in the infected stage as it is when an animal is heavily infected. As the disease progresses in an animal, it gets clinical TB and might end up getting thin. When its immune system is affected by the disease, it does not have the same ability to respond. The reactor lump that one sees on an animal's neck is an immune response. When the animal's immune system is reduced, the ability of the test is affected. Of course there are other factors that depend on individual cows and on the level of infection. There are other disease states that might affect immunity.

While the test is quite good, it is limited when it comes to individual animals because its effectiveness drops to approximately 70%. There is a difference between finding an infected herd and finding an infected animal. If there is TB in an average herd of 70 cattle, it can be identified that the herd is infected but it might not be possible to identify all the animals within the herd that are infected. Animal testing varies between individual animal testing and herd testing. The animal screen that we do is a herd test. It looks primarily at identifying which herds are infected. The Department then comes in with the interferon gamma testing to try to identify more individuals within the herd that are infected. The interferon gamma test, which is a blood test, has a higher level of sensitivity. This means it will find more infected animals within the herd, but it has lower specificity, which means there can be a false positive rate of up to 10%. As a screening test, it will take out many more false positives than the skin test.

People think the factory test is the definitive one, but in fact it is approximately 33% sensitive only. It takes time for an animal that has been infected to develop a lesion that is visible to the naked eye at a glance. We are not talking about testing the glands; we are talking about a vet cutting the glands and seeing whether there is an actual lesion there. That is actually the least sensitive test. Some of the false positives mentioned during Professor More's presentation can be attributed to the fact that it is too early in the lifetime of the disease for a lesion to have formed, or the lesion is too small to be seen with the naked eye.

Deputy McConalogue asked about the efficacy of the current programme. As Mr. Murphy has outlined, there was a significant human health element in the TB programme when it started because of the levels of TB in the human population. Those levels reduced rapidly in the early years of the TB programme, which was long before my time. The programme then became as much about trade as anything else. When we joined the EU, we signed up to guidelines providing that we must have a certain level of TB control to trade with our European partners. Third countries have their own TB testing requirements.

As Professor More has rightly said, the notion of eradication does not become possible until the reproductive ratio goes below one. Vets have known for many years that is very difficult to get the reproductive ratio below one because of various external factors like cattle movements, fragmentation of farms, herd mixing and the presence of deer and other wildlife.