SCOPS - Be alert to haemonchus risk

Utilise free testing where appropriate

SCOPS is warning producers to be alert to ewes and lambs being hit by the Haemonchus contortus worm – a tropical/sub-tropical worm that is increasingly prevalent in the UK as the climate warms.

APHA has confirmed sudden deaths due to haemonchosis in adult ewes from two flocks in Devon.

A spokesperson from APHA says: “At this point in the summer, be alert to the possibility of haemonchosis in grazing sheep and goats, particularly after heavy rains, as Haemonchus contortus is better able to survive in warmer temperatures in contrast to our more usual gastro-intestinal parasites.

The worm attaches itself to the wall of the fourth stomach (the abomasum) where it sucks the animal’s blood. One adult worm can suck 0.05ml of blood a day so this can result in huge volumes of blood lost when a high burden of worms builds up (this could be thousands of worms in some cases).

The main signs of a Haemonchus infection are:

  • Pale mucous membranes (this is the pink skin on the inside of the eyelids)
  • Bottlejaw (fluid collecting under the lower jaw)
  • Sudden death

All ages of sheep are susceptible, as they do not gain immunity as they grow older. As such, ewes and lambs should both be monitored. All classes of wormer should be effective against this parasite, but prevention is best. To avoid bringing Haemonchus onto your farm, quarantine and worm incoming sheep before introducing them to your flock and perform regular worm egg counts.

If you know that there has been historic Haemonchus infection on your farm, it is even more important to monitor the sheep for signs of infection.

Free Testing

SCOPS encourages producers, their vets and advisers to take advantage of free testing for haemonchosis being offered by APHA through to October. The offer is for sheep that present with anaemia, no diarrhoea and bottle jaw, or where haemonchosis is suspected. Submissions are via the APHA Small Ruminant Submission Form, which must be completed by a vet and accompanied by a treatment history.

All classes of anthelmintics have activity against H. contortus. In addition, closantel (which producers will be more familiar with as a treatment for liver fluke) will kill the parasite.

Learn more about haemonchosis in the relevant part of the SCOPS Technical Manual.

1st September 2022

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