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2020 March

The quiz questions are taken from:

The online learning pages focus on the important topics within worms, flies and lice and offer two approaches to learning: structured reading and question and answer.

We also welcome suggested questions for the quiz, (either reply on the ParaBoss News email if you are subscribed or use Contact Us, at the bottom of the web page).

Answers and links to further information are provided below the image.

Questions

1. When you next drench, how can your check how effective the drench has been?

2. What are the signs that indicate that blowflies on your property are becoming resistant to the flystrike preventative chemicals you use?

3. If your sheep are now starting to rub, bite or scratch at their wool, what are the chances it is lice, what might the other causes be?

4. What is the fungus that can kill worm larvae in goat dung and how does it work?

Sheep with clear signs of rubbing
Sheep with clear signs of rubbing

Answers

1. When you next drench, how can you check how effective the drench has been?

A DrenchCheck provides a simple, fast and low cost indication of possible drench resistance. It is the use of two WormTests—one used before and one after a drench—to see how the drench reduces the worm egg count.

The first WormTest within the DrenchCheck is done up to 10 days before a mob is drenched with a short-acting drench and the second is done exactly 14 days after the mob is drenched (testing earlier or later than 14 days can be inaccurate). The second WormTest should be based on individual samples and not the bulk collection method.

Sheep or goats do not need to be yarded for either of the dung sample collections; dung is collected in the paddock as for a WormTest.

2. What are the signs that indicate that blowflies on your property are becoming resistant to the flystrike preventative chemicals you use?  

These signs indicate you might have resistance:

  • a shortening of the protection period (specified on product labels)
  • flystrike in multiple treated sheep rather than just a few.
  • Before you conclude your flies are resistant, check that:
  • the sheep affected were actually treated
  • the chemical was applied following the manufacturer’s instructions
  • the appropriate amount of chemical was applied
  • the wool length was adequate to retain the treatment
  • wool or dags did not make penetration of the product difficult
  • there was not unusually heavy rain following treatment, resulting in chemical wash out.

3. If your sheep are now starting to rub, bite or scratch at their wool, what are the chances it is lice, what might the other causes be?  

The LiceBoss Rubbing Tool can calculate the likelihood of some of the following causes of rubbing and help you decide the most likely cause:

4. What is the fungus that can kill worm larvae in goat dung and how does it work?

Australian strains of the nematode-destroying fungus, Duddingtonia flagrans, were first discovered in a CSIRO survey of grazing properties during the early 1990s. When fed to livestock, the fungal spores pass through the gut of the animal and are excreted with the worm eggs in the dung. The fungal spores then germinate and grow networks of traps that ensnare and kill the worm larvae soon after they emerge from the eggs. The adult worms living in the animals do not live forever, so this cycle of constant re-infection is required to maintain the worm infestation in the sheep.

Even though the fungus is fed to livestock, the product does not kill the worms inside the stock, it targets the larvae as they emerge from eggs in the dung. Feeding the product to livestock is the means to get the fungus into the faeces.

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