Barbers pole worm is normally a parasite we start paying close attention to during late summer and autumn. However, this season is shaping up differently.
At Vetora, we've already diagnosed cases in the Te Awamutu area and have heard reports of cases emerging elsewhere across the Waikato. Seeing Barbers pole this early in the season is unusual and serves as an important reminder that parasite risks don't always follow the calendar.
Every season is different. Changes in rainfall, temperature, pasture conditions and feed availability can all influence when problems appear and how severe they become. Even if your current parasite control programme has worked well in the past, this season may require a different approach.
Barbers pole worm (Haemonchus contortus) is one of the most damaging internal parasites affecting sheep.
The parasite gets its name from its distinctive red and white striped appearance. The red colour comes from the blood it removes from the sheep. Unlike many other gut worms, Barbers pole attaches to the lining of the stomach and feeds directly on blood.
A heavy burden can significantly reduce production, slow growth rates, cause severe anaemia and, in extreme cases, result in sudden deaths of lambs and adult sheep.
Why Is It Such a Serious Parasite?
Barbers pole has several characteristics that make it particularly challenging to manage.
It survives longer on pasture than many other worm species, develops more rapidly under the right conditions and reproduces at an incredible rate. Female worms can produce thousands of eggs every day, compared with only a few hundred eggs from most common sheep parasites.
Given warm temperatures and moisture, Barbers pole can develop from an egg to an infective larval stage in as little as a week. This means pasture contamination can increase very quickly.
The other challenge is that larvae can survive through hot, dry periods and then emerge in large numbers following rain, heavy dews or increased humidity. This can create a sudden and severe parasite challenge across a flock.
One of the biggest misconceptions about Barbers pole is that affected sheep will scour.
In reality, scouring is not a typical sign of Barbers pole infestation.
Because the worms are removing blood rather than damaging the intestine, the signs are related to anaemia and blood loss instead.
Watch for sheep that:
A useful check when handling sheep is to look at the inside of the lower eyelid. Healthy sheep should have a salmon-pink colour. Animals suffering from significant anaemia due to Barbers pole often have very pale or almost white eye membranes.
As temperatures increase, larvae that have survived on pasture can rapidly develop into the infective stage once moisture arrives.
When conditions are favourable, large numbers of larvae may become available to grazing animals at the same time. Sheep can then pick up heavy burdens very quickly.
This also means that animals can become reinfected only days after receiving a short-acting drench if pasture contamination levels are high.
Monitoring and prevention are key.
Some practical steps include:
In some situations, a drench with residual protection against Barbers pole may be worth considering. Products containing Closantel or Moxidectin can provide extended protection compared with short-acting drenches, although factors such as meat withholding periods need to be considered.
The most appropriate option will depend on your farming system, stock class and production goals, so we recommend discussing this with your Vetora veterinarian.
The early cases we're already seeing are a reminder that Barbers pole can appear when conditions suit it, not when we expect it.
Assessing weather conditions, pasture history, faecal egg counts and stock performance can help identify risk before significant production losses occur.
If you've had Barbers pole issues previously, or if you are seeing sheep that seem lethargic, pale or unthrifty, now is the time to act.
Talk to your local Vetora team. We can help assess your risk, interpret faecal egg count results and develop a parasite management plan tailored to your farm.
Early action can make all the difference when it comes to protecting flock health and maintaining production.
