Cattle lungworm cases on increase. But why?
SUGGESTIONS that last years increase in lungworm in adult dairy cows is due to reduced vaccination and over-effective anthelmintic practices have been refuted by animal health company Merial.
Andy Forbes, head of technical services, told a London Press briefing that there was no evidence to show that either practice had contributed to the last years rise in husk.
Several other factors were more likely to be associated with the changed disease pattern, including weather and farm management.
The weather in recent years resulted in low levels of lungworm on pasture during the hot, drier months. Immunity had, as a result, not been boosted. When heavy rain follows, large numbers of lungworm larvae may be released to pasture from the dung pats, causing husk. "This is exactly what appeared to happen last year," said Mr Forbes.
Management practices, such as moves towards maize silage, may also have contributed to the changing pattern of disease as the land available for grazing animals has become more concentrated. "Some modern grass management techniques may be increasing risk of lungworm in adult stock."
He also felt the move to two-year calving – putting animals under greater pressure – could have influenced disease patterns.
Mr Forbes advice to protect cattle against husk is, for those with an insurance mentality, to vaccinate and worm animals in the first grazing season.
For the less risk-adverse, worm in the first grazing season without vaccinating, he said, then vaccinate and worm in the second year.
Whats causing the increase in lungworm in adult dairy cattle? Vets suggest reduced vaccination is one reason but animal health firm Merial disagrees.