Seasonal Risk for Barber’s Pole Roundworm in Sheep
With strong autumn and early winter rainfall, now is the peak risk period for Barber’s Pole in sheep.
Barber’s Pole Roundworm is a blood sucking parasite which is quite dangerous for sheep, causing an infection known as Haemonchosis which can result in anaemia, lethargy and death. Barber’s Pole is most commonly found in areas that are dominate of summer rainfalls but are now becoming quite prominent in the southern states.
Figure 1: The lifecycle of Barber’s Pole worm in sheep
The female worm bears the pink and white pattern that resembles a barber’s pole and gives the Haemonchus Contortus its’ common name. The male worm is pale pink in colour and much shorter in length (15mm) than the female (23-30mm).
The female worm can lay up to 10,000 eggs a day, compared to other worms only laying 100’s of eggs a day. It only takes 3 weeks for larvae to grow into an adult, therefore infection levels can build very rapidly providing a much higher worm egg count than compared to other common worms.
Overall, Roundworms cost the sheep and wool industry in excess of $430 million per year (Lane et al. 2015); well up from the $350 million estimated by Sackett et al (2006). The impact of Roundworms represents the highest animal health cost to the Australian sheep industry. The annual cost of Roundworms is estimated around $6.00/head being lower in the sheep/cereal zone and highest in summer high rainfall zones (HRZ) where the Barber’s Pole predominates. About 80% of the annual cost is attributed directly to lost production with the remaining 20% associated with the costs of control (Worm Boss).
Barber’s Pole Roundworms have a very strong ability to develop resistance to the various classes of worm drench so great care must be taken when working out a program. Combination drenches, with actives such as Moxidectin, Closantel and Abamectin, are most affective. Please do not hesitate to contact your Western AG Animal Health Specialist’s to help design your drench program today.
Article produced by - Katrina Ridgway, Western AG Ballarat