VIC WormBoss Worm Control Programs
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Livestock Logic Key Recommendations
Drought conditions are continuing in the south-west with most animals reliant on supplementary feeding for at least 90% of their energy intake. Even areas south of Hamilton are now looking incredibly dry with limited green or dry feed in paddocks.
The below chart shows that our lab’s egg counts have risen slightly, perhaps as a result of the cooler conditions and the rainfall that was experienced throughout January. In February and so far throughout March, it has been very dry and we would expect egg counts to dip further in April.
Graph 1: Percentage of Sheep Requiring Drenching from Livestock Logic Laboratory
We have, as is typical over summer, seen some barber’s pole activity from the usual suspects, such as Portland, Strathdownie, Wangaratta and North East Vic.
We would urge producers that haven’t drenched in the last 6 weeks to check the worm status of their animals. Any eggs passed in faeces in April will lead to worms on pasture and much higher worm pressure in the winter. Minimising worm contamination in April and May is a key to healthier and better performing stock and weaner survival throughout the winter.
Here in the North East of Victoria we had only 45 mm of rain by the end of February and conditions since have been very dry. Most property owners are now feeding their stock and the water levels in the dams are diminishing rapidly. So far for March, there has been no rain and continuing warm dry conditions.
Flies appeared rapidly when it did rain. Now they are searching for moisture.
Worm egg counts are low to moderate, so it's best to check out what is happening on your property by getting a worm egg count done, before drenching.
It's also 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.
Barber’s pole worms, Haemonchus contortus, are now active on quite a few properties in worm egg counts from clients in damper parts of 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.
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.
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. Providing there is sufficient rain and a warm temperature, these 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 may actually lose 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 may result.
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.