DEAR SIR: Last week you made reference to the BVD eradication programme in a constructive way, noting its success to date in reducing the prevalence of calves born persistently infected (PI) with BVD virus each year. You also identified the retention of PI animals by a “small minority” of farmers as a key issue to be addressed in bringing the programme to a successful conclusion.

While the number of herds retaining PI calves has reduced in each year of the programme (currently the database shows that only 230 of 83,500 breeding herds contain a PI animal more than seven weeks after its first positive test), it is critical that these animals are removed as quickly as possible and that all PI animals identified from here on are removed promptly. This is what we must concentrate on to achieve the target set at the beginning of this unique, industry-led programme of eradicating this costly disease by 2020.