top of page

Worming Youngstock at Turnout

With spring fast approaching thoughts are turning to cattle turnout throughout Wales. Apart from making sure the water troughs are working and doing some fencing repairs, what else should farmers consider?  If worming stock at this time then it requires careful planning because getting it wrong can be very costly!

Inappropriate use of long acting cattle wormers can interfere with the ability to gain immunity to lungworm – lungworm can kill adult cattle if they haven’t developed immunity! Feedback from cattle farmers during the 2016 grazing season suggests lungworm disease outbreaks are becoming more prevalent and unpredictable. An independent survey last year found that 40 per cent of 202 dairy farmers interviewed has heard cattle coughing at grass. A third of milk producers said that they had had lungworm confirmed in their stock at some point over the last three years.

Half the disease outbreaks were reported in dairy youngstock during their first grazing season, but 40 per cent occurred in second season grazers which points at issues with worming in the first season.


Because of this it means planning lungworm control strategies using Bovilis Huskvac vaccine for youngstock prior to their first grazing season makes sound financial sense. For dairy calves, vaccination should be completed at least two weeks before the calves are turned out to grass, and for suckled calves it should finish two weeks before the calves begin to eat significant amounts of grass.


Lungworm occurs as a result of infection with the worm Dictyocaulus viviparus after eating grass contaminated with infective larvae. Once in the gut, the larvae migrate through its wall to the lungs where they begin laying eggs after several weeks. A spell of mild, wet weather can create a sudden, dramatic increase in lungworm populations, which can be very harmful, even fatal, to any stock that have little or no immunity.


This is why vaccination is so critical, the vaccine produces a very good immune response against disease but it does not prevent all worms from natural infections completing their life cycle.

This allows for the continued development of natural immunity, which often fails to occur where there is an over-reliance on wormers.


Your vet or and experienced animal health advisor can identify parasite problems specific to your farm, and can therefore, formulate a targeted worming plan. Given the wet weather we have seen over the last year some consideration should also be given to fluke treatment. If stock were treated at housing with a product that only kills adult fluke, any immature fluke present at that time will now be adults. Treating stock now, with a flukicide that kills adult fluke will go a long way to minimising pasture contamination this spring!

bottom of page