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Victoria wom update - March 2013

Tricia Veale, Benalla (triciav7@bigpond.com)

Here in the North East of Victoria we had a big fall of rain at the end of February. The Benalla area received 119 mm. So far for March there have been a couple of very small showers and continuing warm conditions. This week the area has experience the cool autumn change.

Worm egg counts in most stock are rising rapidly so it's best to check out what is happening on your property by getting a worm egg count done.

Barber’s pole worms, Haemonchus contortus, are active on quite a few properties in worm egg counts from clients in VIC and NSW. If you own a sheep property where barber’s pole worms are present, then we suggest that you keep an eye out for them increasing in numbers. Haemonchus worms are blood suckers and can cause severe anaemia and deaths in sheep and goats. Female worms are very prolific egg-layers. They seed the paddock quite rapidly with thousands of eggs. These usually hatch within 4–6 days. Then the animals ingest huge numbers of the infective larvae that speedily travel to the abomasum (stomach). Here they attach themselves to the mucosal lining and start to suck blood. Haemonchus are thought to inject an anti-coagulant into the wound they have made. The host animal then actually loses more blood than the worms ingest. The host must replace this blood, particularly the lost red cells, by drawing on its limited iron reserves; when these are exhausted an iron deficiency anaemia results. This may be one of the reasons why apparently healthy-looking sheep or goats suddenly become anaemic and collapse.

On an infected property, Haemonchus are likely to be prevalent in paddocks where a high worm egg count is found and possibly at a low, chronic level in the rest.

Mature cattle are not usually so severely affected by Haemonchus placei but very heavy burdens can cause death in young animals. The disease haemonchosis is characterized by anaemia, subcutaneous oedema (swellings) and weight loss.

If you are concerned that Haemonchus may be present on your property, then you can get a Larval Culture done. Dung samples are pooled and incubated for several days to hatch the worm larvae from the eggs. Only by a microscopic examination of the larvae can the species of worms present be confirmed. This is because worm eggs look very similar to each other under the microscope.

Finally, remember it's very important to quarantine drench all newly purchased animals onto your property. This ensures that any barber's pole and drench resistant worms are eliminated before the animals are allowed onto your paddocks.