Dr. Orla Keane:

As I said, some of the costs are medicinal costs, so those are down to the medicines. On others, these parasites can have an impact on production and growth. However some exposure to parasites is needed to allow the animals to develop their own immunity. It is not possible to eliminate a lot of these parasites and if there is not some exposure, they will not develop immunity and will continue to present a problem, even in older animals that should have immunity. There will always be some trade-off between controlling the parasites sufficiently and allowing some exposure for immunity to develop.