News & Advice

Sheep and Barbers Pole

Feb 5, 2019 | Dry stock, Sheep

Sarah Clarke, Veterinarian, Anexa Vets Morrinsville

Barbers Pole (Haemonchus contortus) is a dangerous stomach worm that feeds on blood.
This means that a relatively low number of worms can cause lambs and adult sheep to get very sick, and even die. As the worms feed on blood, the sheep become anaemic and the normally pink gums and conjunctiva of eyes become white. While the sheep are sick, they don’t necessarily scour, so you may not realise worms are the cause of the problem.

A single female worm can produce up to 20,000 eggs per day, so infection levels can increase rapidly when weather conditions are favourable. Barbers pole larvae typically live on pasture over summer, and develop to infective stage after the first rain, about February. As all the larvae become infective at the same time, this causes a high pasture challenge.

Barbers pole can be managed through a regular drench programme. A preventative programme is best, as you may lose some lambs if you wait until an outbreak occurs. Regular (short acting) drenches will kill the Barbers pole, but the worms can reinfect sheep after a few days. This might look like drench resistance, when it is actually a high challenge reinfection. Long acting drenches are useful to prevent this, and options include products containing closantel (e.g. Genesis Ultra), or moxidectin (e.g. Cydectin). Some long-acting products are only suitable for use in ewes and replacement hoggets as they have long meat withholds (e.g. Genesis Ultra is 56 days), so it pays to check the withhold times.

Sheep parasites can cross-infect alpacas, so if you have any resident camelids, this information is valid for them too.

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