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2020 April

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. Do Strategic drenches rely on worm egg counts?

2. Can you graze sheep when preparing low worm risk paddocks?

3. What are the five withholding periods/intervals for worm, lice and fly treatments for sheep?

4. At what time of year is the most important time to give a strategic treatment for liver fluke to either goats or sheep?

The preparation of low worm-risk paddocks involves allowing time for most of the existing worm eggs and larvae to die and preventing more worms for contaminating the pasture
The preparation of low worm-risk paddocks involves allowing time for most of the existing worm eggs and larvae to die and preventing more worms for contaminating the pasture

Answers

1. Do Strategic drenches rely on worm egg counts?

Strategic drenches are generally given regardless of the average worm egg count of the mob, with some exceptions.

In summer rainfall areas it is best to give these drenches (weaning and pre-lambing) without a count being done.

In winter-rainfall, scour-worm regions where second-summer drenches are used these should be based on a worm egg count. Likewise adults can be checked in drier areas/times before other strategic drenches. In either case if the count is greater than 100 epg, drench.

There are seven common strategic drenches; not all are used in every region. The WormBoss programs outline which strategic drenches to use in each region.

2. Can you graze sheep when preparing low worm risk paddocks?

Yes, but only in two situations:

a) When sheep/goats do not have worm eggs in their dung.

This is in the 2–4 weeks immediately after the stock received a short-acting drench product proven effective on that farm:

  • 2 weeks for goats,
  • 3 weeks for sheep in barber’s pole worm areas
  • 4 weeks for sheep in scour worm areas

Longer with a mid-length or long-acting drench—don’t assume the label claim is what you will achieve, monitor worm egg counts regularly to identify the length of protection you actually achieve.

b) During lengthy periods of either/both cold or dry—when it is too cold or too dry for worm eggs to hatch. The temperature varies for the worm species.

3.  What are the five withholding periods/intervals for worm, lice and fly treatments for sheep? 

The five withholding periods/intervals for worm, lice and fly treatments for sheep are:

  • The Meat Withholding Period (Meat WHP) is the time from chemical application to when an animal is slaughtered for domestic use.
  • The Milk Withholding Period (Milk WHP) is the time from chemical application to when milk can be taken from the animal for human consumption.
  • The Wool Harvest Interval (WHI) is defined as the time from application of a chemical to when the wool can be harvested to satisfy Australian environmental requirements (also includes crutching).
  • The Export Slaughter Interval (ESI) is the time from chemical application to when an animal is slaughtered for export.
  • The Sheep Rehandling Interval (SRI) is the time between treatment and when wool/sheep can be safely handled without the need for protective clothing.

These limits are set in Australia to ensure that:

  • Lamb and sheep-meat is safe to eat.
  • Wool is safe to handle.
  • Wool scour effluent is safe for the environment.

4.  At what time of year is the most important time to give a strategic treatment for liver fluke to either goats or sheep?

The most important treatment is the April–May treatment, and a highly effective flukicide (one based on triclabendazole) should be used.

One to three treatments may be needed per year, depending on the severity of the problem, these are generally:

  • February
  • April–May
  • August–September
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