The hot summer and autumn temperatures, in combination with sporadic rain showers provide ideal conditions for this blood sucking worm to develop. High larval burdens infect lambs, causing outbreaks of significant production loss and often sudden death.
Haemonchus contortus (Barber's Pole) is an internal parasite that sucks blood from the lining of the abomasum (the fourth stomach). Outbreaks in lambs and adult sheep are likely to occur following heavy overnight dews or rain, during or after a hot dry spell. Occasionally, rather than an outbreak, Barber's Pole can cause chronic ill-thrift and a large tail-end.
The volume of blood the worms eat causes anaemia. The signs seen include:
- Ill-thrift
- Pale gums
- Rapid, shallow breathing
- Animals lagging at the end of the mob
- Collapsed or dead animals
There will not be a typical parasite scour unless there is a mixed parasite infection.
This is one of the critical diseases to be looking for from January to May. Many drenches have a claim to kill Haemonchus but will only eliminate the current infection. These parasites are continually picked up from the environment, so it is recommended to treat with a product that has extended protection against Haemonchus.
Diagnosis can be made by faecal egg counts and larval culture or at post-mortem where the large worms can be seen in the abomasum.
Treatment and prevention is based on strategic drenching at this time of year. The drug of choice is Moxidectin (Vetdectin or Cydectin - 10 day meat withholding period) or a Closantel containing product such as Genesis Ultra (56 day meat withholding period). This should be followed up in 4 to 5 weeks by a second drench in the case of an outbreak.
If you suspect you have a Barber's Pole problem developing or have experienced the problem in previous years, please ring us to discuss the current level of risk and the best options for prevention and treatment
