(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:
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.
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.