Mr. Eoin Ryan:

His paper summarises some of this. We will be happy to go into as much detail and provide further detail if the Deputy would like. In any case, there is no doubt that cattle to cattle spread of TB happens.

With regard to samples when animals go to a factory, when animals that are not thought to have TB go to a factory and a suspect lesion is discovered, that lesion is sent to our central veterinary research laboratory in Backweston, which is the national reference laboratory for TB. It is tested to see whether it is something else or TB. Where it is TB, the herd is restricted, and where it is not TB, it is derestricted.

Approximately one third of reactors have lesions. This is a continuing issue on which we need to communicate better. It is something we try to communicate better on. Collectively, the veterinary profession has done a poor job in the past 100 years of conveying to farmers that just because they cannot see the bacteria does not mean they are not there. We all know there are bacteria on our hands but we cannot see them. Cattle can be infected with TB without it being visible. With one third of them the disease has progressed to the stage where we can see the rotten tubercular flesh, such as we can see in pictures of people back in the day when TB was tragically too common. One of the problems we have is that when we say an animal had lesions, people infer that animals that do not have lesions do not have TB, but actually they do. It is just that in most cases, because we do annual testing, we catch the animal before the flesh has started putrefying and rotting. Back in the old days, in the 1940s or 1950s when 27% of cows were TB positive, it was very common to have visible lesions. We regularly get comments on this.

On the zero grazing issue, there are a number of reasons a farm that does zero grazing can get infected. The Deputy touched on several of them and I agree with him. For instance, even if the herd and the yard is badger proofed, if the silage is collected and there is contamination by badger latrines in the field from which the grass is taken, and if those badgers have TB - not all badgers have TB but if it is an area where the badgers do - it can bring it in. Sometimes also a dead badger might be caught in a feeder wagon. There can also be residual infection. If an animal in the herd was infected with TB six or seven years ago in a previous herd and since then was sold into this herd, or if the herd last had a breakdown five or six years ago, unfortunately, one of the failings of the skin test, because it relies on a functioning immune system, is that an animal can be infected and some of them will not test positive. In fact, the skin test misses on average approximately 20% of infected cattle. This is one of the reasons we have this residual population.

It is the same as some people getting infected with TB as children and then years later they developed the disease. Some cattle can become infected at a younger stage in their lives and then, two, three, four, five or six years later, the disease recrudesces and they spread it to their comrades. It is only then that it is discovered. It could be residual infection. It could also be bought in. In Ireland there are 2.8 million cattle movements a year and there is no doubt a small proportion of these are likely to include infected cattle, particularly those coming from herds with a history of TB for the reason I have just outlined.

Having two clear tests means the herd is free to trade but it is not a guarantee that none of those animals has TB because, unfortunately, the test is not perfect.