Barber’s Pole in Sheep

(Haemonchus contortus) Barbers Pole is a parasite of major importance in sheep.

Symptoms of Barber’s Pole.

The Barber’s Pole worm has some features that make it different from other sheep worms and explain why the worm can be a major problem at certain times during the year. These features mean the Barber’s Pole worm should be regarded as a sheep disease condition in its own right.

Special features of the Barber’s Pole worm include:

• A relatively large parasite which can be easily seen in the abomasum with the naked eye-. In females infestation is particularly noticeable because the uterus full of eggs (white) contrasts with a red gut full of blood giving the candy stick or “Barber’s Pole” appearance.  
   
• Barber’s Pole is one of the most pathogenic worms – 500 have much the same effect on sheep as other worm species such as 5,000 Ostertagia or 10,000 Cooperia.
   
• Very soon after ingestion the immature larvae start to suck blood. They have a special mouth part that attaches to the gut lining.
   
• Feeding by the 4th stage and adults may remove 0.05ml of blood per worm. A burden of 1000 worms may remove 50ml of blood per day from the sheep.
   
• Barber’s Pole can put out up to 10,000 eggs per day – other worms about 200.
   
• Barber’s Pole can become inhibited in the host over the cooler autumn/winter periods and re-emerge in spring.
   
• Barber’s Pole eggs and infective larvae survive better than other worms during hot dry periods.
   
• Eggs and infective L3 survive inside faecal material during hot dry conditions and emerge en masse with moisture and warmth. This can be as short as 4 days under optimal conditions – other worms the minimum time is about 21 days.

The effects on the sheep are due to anaemia. The costs are associated with deaths, reduced appetite, developing anaemia, and reduced weight gain or weight loss.

Sheep with heavy infections of Barber’s Pole worms lack stamina, have pale gums and conjunctiva, and may also have bottle-jaw or constipation.

The Impact

Barber’s Pole worms will nearly always be part of the “normal” make-up of worms in sheep throughout the year but their impact does not become significant until the weather conditions allow them to rapidly multiply and infect the grazing sheep.

The cost associated with deaths is straightforward and very noticeable. However, the cost associated with decreased growth rate due to sub-clinical Barber’s Pole can be significant.

Over 30 days at a growth rate of 150g/day lambs put on 4.5kg and increase value by $6.75 (at $1.50/kg live weight).

At 100g/day the lamb value is $4.50

At 50g/day the lamb value is only $2.25

We can’t find any research information about the effect of Barber’s Pole on ewe mating performance. However, in a study done on seven Southern Hawkes Bay farms, it was estimated that Barber’s Pole infection may have cost one farm $16,000 in lost lamb production due to a 13% drop in scanning %.

Management and Control

Risk management to prevent outbreaks of Barber’s Pole should be based on understanding the worm, the conditions that increase the risk, the potential cost of an outbreak and the treatment options available.

There is a vast range of oral anthelmintic drenches which can be used to manage Barber’s Pole in sheep with some having persistent activity to offer protection for sheep for significant periods long after treatment.

The correct timing of drenching is critical and weather observation is a key component of determining the correct time to drench for Barber’s Pole.