Whereas in the past many worm control programmes were “dose heavy” at the start of the season as a way of trying to completely suppress the challenges they present, now the best practice is aimed at trying to reduce the number of doses.

The emphasis must be on reducing challenge using informed grazing strategies, knowing the previous grazing history and keeping a close eye on local weather events.

Some “clean” grazing strategies include:

  • Keep the cleanest grazing, such as reseeded ground, hay/silage aftermath or forage crops, for the most naïve animals, eg first season grazing dairy-bred calves or autumn-born sucklers.
  • Graze naïve calves ahead of older animals in a leader-follower system - but beware of the naïve group coming back to these pastures on the next rotation.
  • On mixed farms, if possible, alternate or co-graze with sheep, as most worms that infect cattle don’t infect sheep and vice versa.
  • Monitoring programme

    In addition to regular observation and good stockmanship, it is wise to have a monitoring programme in place once the ground is damp and the temperatures rise above 10oC.

    This is when worm eggs hatch and infective larvae move onto the sward. The same conditions allow grass to flourish too!

    If it is cold and dry, grazing will be tight, but the challenge from worms will be reduced.

    Taking dung samples

    Most years, from the end of May onwards, it would be wise to take regular dung samples to be tested for faecal egg counting (FEC).

    Samples need to be fresh and tested within 24 hours of collection.

    They can be picked off the ground, provided you see the dung being passed, ie it is hot and steamy.

    Take a spoonful from the centre of a dung pat and put it into an individual pot. Collect five pots and ask the vet or lab to pool them.

    Once the pooled FEC is over 250 eggs per gram, discuss with your vet which dose to use.

    However, lungworm will not be detected via dung samples quickly enough.

    The early warning system for lungworm (or 'hoose') is your own two ears! Even if FEC is low, but you can hear a number of animals coughing, ask your vet for a suitable dose.


    They may well recommend using a persistent product, such as Cydectin or Dectomax.

    Both give minimum five weeks' protection against reinfection with stomach and lungworm, and are therefore labour-saving.

    The dosing interval with Cydectin or Dectomax can be increased to every eight weeks (versus five weeks for ivermectins).

    To find out which protocol is most suitable for your farm, download the dosing chart. The chart helps you and your vet design a bespoke plan for your farm and it will help you use the Right dose, on the Right animals at the Right time - the 3 Rs of worm control.


    Product and Company details

    All Cydectin® products contain moxidectin.

    All Dectomax® products contain doramectin.

    For further information please check the SPC or contact Zoetis on (01) 2569800.

    www.zoetis.ie. Legal category POM.

    Use medicines responsibly. www.apha.ie.