THE GUTWORM THREAT
Infections with gutworms are an underestimated cause of
reduced performance in pastured dairy herds. Previously, it was
always assumed that adult dairy cows could easily deal with
parasitic infection and that such infections would not have any
detrimental eff ect on productivity. But numerous studies show
the negative impact that gutworms can have on the productive
performance of adult dairy cows.
The eff ects of gutworms in dairy cows can be divided into
clinical and subclinical eff ects. Outward clinical signs of
gutworms, including scouring and rough coat, are relatively
uncommon in adult dairy cows. These symptoms are more
common in young stock during their fi rst or second grazing
Reduced productivity without outward clinical signs,
otherwise known as subclinical eff ects, are the more common
presentation in adult dairy cows.
Subclinical infections are more diffi cult to detect but are costly
in terms of reduced productivity in dairy herds.
Adult dairy cows can harbour a large number of gastrointestinal
parasites. Studies found that between 83 and 100 per cent of
culled dairy cows were infected with gutworms. If, as this study
suggests, most herds are suff ering from a high gutworm burden,
it means Irish dairy farmers are losing money as a result.
CONTROL IN THE
Increasing productivity is critical to the sustainability
of the Irish dairy herd. Maximising the number
of litres produced and minimising the cost of
production are paramount. Cows need to be
in optimal condition, allowing them to deliver
in terms of milk yield and solids, writes
Langan, veterinary advisor Ireland, Norbrook