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NSW Non-Seasonal Rainfall

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Drench Decision Guide

NSW Non-Seasonal Rainfall

Please confirm that you have read the disclaimer details below and accept the conditions of use of the Drench Decision Guide before proceeding.
Disclaimer:
Future events cannot reliably be predicted accurately. ParaBoss, UNE and Sheep CRC makes no statement, representations or warranties about the accuracy or completeness of, and you should not rely on any information relating to the Drench Decision Guide ('Information'). ParaBoss, UNE and Sheep CRC disclaims all responsibility for the Information and all liability (including without limitation liability and negligence) for all expenses, costs, losses and damages you may incur as a result of the Information being inaccurate or incomplete in any way for any reason.
Are these sheep showing signs[1] suggesting a worm infection or have they been in high worm-risk conditions (or are you returning to this Drench Decision Guide from a previous recommendation)?

1Signs of worms

Closely examine for signs of worms, yard or hold sheep against a fence. Catch and examine 5—10 animals.

Scour worms (black scour worm [Trichostrongylus species]; brown stomach worm [Teladorsagia circumcincta]; and others [incl. Nematodirus]): dark scours; weight loss; death.

Barber's pole worm: anaemia (pale inside eyelids and gums); 'bottle jaw' (swelling under the jaw); lagging or collapse when mustered; death.

NOTE: Other diseases can cause similar signs. Consider seeking veterinary advice.

Are these sheep in the eastern Riverina (including Griffith, Jerilderie and Finley and east of the Newell Hwy)?
Are these ewes about to lamb within 4 weeks?
Are these lambs about to be weaned?
Which sheep class and time of year applies?
I have a WormTest result.
In the table below, find the worm egg count threshold for the class of sheep and the type of WormTest result you have.
Worm egg count (epg) thresholds
Class of sheep or time of yearNo culture OR less than 60% barber's poleGreater than 60% barber's pole
Ewes (dry to mid-pregnancy) or wethers250400
Ewes pre-lambing150250
Sheep under 18 months or rams150300
Time of 1st or 2nd summer drench100100

Liver fluke: This requires a different test than for roundworms. Any positive liver fluke test is significant and requires action: treatment and grazing management.

Nematodirus (thin-necked intestinal worm): This can cause scouring and deaths with very low or zero worm egg counts (particularly in weaners), and after summer storms. Seek professional advice.


What is your worm egg count in relation to the threshold value?

WormBoss Drench Decision Guide Report

Region: NSW Non-Seasonal Rainfall

Date: %01 %May %2024

Your Selections

History of selection will appear here

Your Recommended Action

WormTest now, then return to this Drench Decision Guide to see if the worm egg count indicates the need for drenching. Include a larval culture if

  • Barber's pole worm has been a problem over the last year.
  • Late spring/summer is wetter than normal.

Treat now with a short-acting drench[1] effective against both barber's pole worm and scour worms[2]; WormTest in 4—6 weeks[3] after a short-acting drench. Consider a long-acting treatment for weaners, in particular, if worm challenge is high and low worm-risk paddocks are not available. Follow the guidelines[1] below for long-acting treatments. Remember that other parasites/diseases, including liver fluke, can cause similar signs. If signs have not improved in 4—7 days, seek veterinary advice. After drenching, do a DrenchCheck-Day10 if this drench group has not been tested in the last year.

There are 3 times to conduct worm control practices:

  • Weaning (when average age is 12 weeks): Treat lambs with an effective drench[1] and move them onto a paddock that has had no sheep under 2 years of age on it since the end of February.
  • Around cereal harvesting and before sheep are moved onto stubble: (choose one option)
    • Before starting cereal harvest, treat with an effective short-acting drench[1]; however, in dry years, particularly in adult sheep, WormTest first and only drench if egg count exceeds 150 epg to minimize development of drench-resistance.
    OR
    • As soon as cereal harvest is finished WormTest and treat with an effective drench[1] if egg count exceeds 150 epg.
  • Late February: WormTest and treat with an effective drench[1] if egg count exceeds 150 epg.

After drenching, do a DrenchCheck-Day10 on each drench group that has not been tested in the last year.

Treat at weaning with a short-acting drench[1] effective against scour worms[2] (and barber's pole worm if this is a problem on your property), (this may coincide with the first summer drench); then WormTest in 4—6 weeks[3] after a short-acting drench. Consider a long-acting treatment for weaners in particular if worm challenge is high and low worm-risk paddocks are not available. Follow the guidelines[1] below for long-acting drenches. After drenching, do a DrenchCheck-Day10 if this drench group has not been tested in the last year.

Treat all sheep with an effective short-acting 'first summer drench'[1] when the pastures are haying off in late spring/early summer. After drenching, do a DrenchCheck-Day10 if this drench group has not been tested in the last year.

Treat now with a short-acting drench[1] effective against scour worms[2] (and barber's pole worm if there were greater than 60% barber's pole worm in the WormTest culture results). In 4—6 weeks proceed from Question 1 of the Drench Decision Guide with this mob. Consider a long-acting treatment for weaners in particular if worm challenge is high and low worm-risk paddocks are not available. Follow the guidelines[1] below for long-acting drenches. After drenching, do a DrenchCheck-Day10 if this drench group has not been tested in the last year.

No treatment is required. If the mob showed signs[1] suggesting worms, investigate other causes. In 4—6 weeks proceed from Question 1 of the Drench Decision Guide with this mob.

This recommendation should be read with the information provided below.

1Signs of worms

Closely examine for signs of worms, yard or hold sheep against a fence. Catch and examine 5—10 animals.

Scour worms (black scour worm [Trichostrongylus species]; brown stomach worm [Teladorsagia circumcincta]; and others [incl. Nematodirus]): dark scours; weight loss; death.

Barber's pole worm: anaemia (pale inside eyelids and gums); 'bottle jaw' (swelling under the jaw); lagging or collapse when mustered; death.

NOTE: Other diseases can cause similar signs. Consider seeking veterinary advice.

2High risk barber's pole worm conditions

Sheep can sometimes be rapidly re-infected with worms, causing illness and death within 3 weeks of a drench when WECs will still be low or zero. If the onset of scouring, weight loss or deaths is sudden, urgently seek veterinary advice.

3Guidelines for worm control treatments to slow drench resistance

When giving all treatments

Follow the product labels. Dose to the heaviest sheep in the mob or groups. Calibrate equipment to ensure the right dose is delivered with the right procedures. Do not mix drenches unless the label states they are compatible. Check withholding periods and export slaughter intervals.

Choosing treatment options on your property

Use these 4 principles together, where possible:

  1. Use drenches most effective on your property; ideally those shown to reduce worm egg count by at least 98%. If drench effectiveness is unknown, conduct a DrenchCheck-Day10 after drenching.
  2. Use a combination of 2 or more drench groups.
  3. Rotate drench groups each time a mob is drenched and for each paddock.
  4. Use short-acting treatments.

For more details read the drench resistance section in the WormBoss Worm Control Program.

Check effectiveness of long-acting treatments

WormTest with a culture at 60 and 90 days after treatment.

If WormTest results are 100 epg or above, drench resistance is likely. Drench immediately with an effective short-acting drench with a different active to the long-acting treatment.

Seek professional advice on the further use of this product.

If WormTest results are less than 100 epg, then treat with an exit drench at 100 days (15 weeks) after the long-acting treatment was given.

Seek professional advice if WormTests are positive at or before 60 days.

Primer and exit drenches

These help to slow drench resistance to persistent treatments.

Protection period of persistent treatments

Mid-length: 7—28 days. Long-acting: 91—100 days.

NOTE: The protection period against susceptible black scour worm with a long-acting moxidectin injection is 49 days.

Use a primer before long-acting treatments

Primer drenches (effective short-acting treatments that do not include the active in the long-acting treatment) should be given concurrently with all long-acting treatments.

Use an exit drench after all mid-length and long-acting treatments

  • Treat with an 'exit drench'—an effective short-acting treatment that does not include the active in the mid-length or long-acting treatment. Also called a 'tail-cutter' drench.
  • Give this at 6 weeks (mid-length) or 15 weeks (long-acting) after the treatment was given.
  • WormTest 4—6 weeks after the exit drench.

Anytime that you are concerned that the persistent treatment is not providing protection, WormTest immediately and seek professional advice regarding drench resistance.