Haemonchus is a concern for sheep farms from as early as December through to as late as April. Mature Haemonchus living in the sheep's gut feed off the animal’s blood, causing death by anaemia in a relatively short period of time. All classes of stock are at risk but lambs are more susceptible and usually first to be affected. A heavy Haemonchus burden can kill a lamb within days.
A mature female Barbers Pole Worm can lay up to 10,000 eggs per day.
Being prepared and early prevention is the best defence against this deadly worm, not only for protecting stock but in reducing the re-burdening of the soil by the next generation of larvae. Stock new to farm should receive a good quality three-way quarantine drench prior to going into grazing areas.
Many drenches will kill Haemonchus but only a select few will give a persistent activity, providing you with worry free protection. Contact your nearest vet centre to discuss selecting the most effective drench with the most appropriate withhold time.
A farmer once told me that if it is a one-dog day they’re fine, if it’s a two-dog day, drench them. I thought this was a good way of describing what to look for. When sheep start showing signs of anaemia they begin to slow down, become lethargic, eventually go down, and finally die. The inside of the eyelid and gums will be pale in colour due to the lack of blood.
This can all happen in a remarkably short space of time. Sheep showing signs of slowing is a good indicator for immediate drenching for Haemonchus. The entire flock should be drenched as it is usually wide spread. Early prevention is the best cure.