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WormBoss

Drench Decision Guide

Qld/NSW Summer Rainfall / Tablelands and Slopes

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DownloadPrint a copy of the Qld/NSW Summer Rainfall / Tablelands and Slopes Drench Decision Guide (222 KB)
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 ewes that will lamb within 4 weeks (or are you returning to this Drench Decision Guide from a previous recommendation)?

1Low worm-risk paddocks

Preparing low worm-risk paddocks involves preventing worm contamination in March and April for a spring lambing paddock, and in the 3 months prior to use for a summer weaning paddock.

Are these lambs that will be weaned within 2 weeks?

1Low worm-risk paddocks

Preparing low worm-risk paddocks involves preventing worm contamination in March and April for a spring lambing paddock, and in the 3 months prior to use for a summer weaning paddock.

On close inspection (with sheep yarded or held tightly against a fence), are these sheep showing signs[1] suggesting a worm infection?

1Signs of worms

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

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

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

NOTE: Other diseases can cause similar signs. Consider getting animal health advice.

What 'length of protection' treatment type was last used?
What type of WormTest results do you have?

NOTE: If treatment was less than 3 weeks ago and you now have a positive result, your drench may be ineffective. Seek professional advice because a DrenchTest might be required.

Is the percentage of barber's pole worm (Haemonchus contortus), shown in the larval culture, higher than 60%?
There are greater than 60% barber's pole worms.

In the table below, find the worm egg count threshold for the average sheep condition of your mob and the condition of the pasture they will graze.

(If pasture[1] or sheep condition[2] is unknown, use a worm egg count value of 1000).

Worm egg count (epg) thresholds for barber's pole worm
Sheep condition[2]
(or growth rate for weaners)
Pasture condition[1]
PoorModerateGood
Poor6008001000
Moderate80010001100
Good100011001200

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

1Pasture condition

Pasture condition can also be defined by the amount of green herbage mass in kg DM/ha

  • Poor: less than 600 kg DM of green herbage mass/ha
  • Moderate: 600—1200 kg DM of green herbage mass/ha
  • Good: more than 1200 kg DM of green herbage mass/ha

2Sheep condition

Sheep condition can also be defined by body condition scores

  • Poor: score 2 or less
  • Moderate: score 2.5
  • Good: score 3 or better
There are greater than 40% scour worms.

In the table below, find the worm egg count threshold for the average sheep condition of your mob and the condition of the pasture they will graze.

(If pasture[1] or sheep condition[2] is unknown, use a worm egg count value of 500).

Worm egg count (epg) thresholds for scour worm
Sheep condition[2]
(or growth rate for weaners)
Pasture condition[1]
PoorModerateGood
Poor300400500
Moderate400500600
Good500600700

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

1Pasture condition

Pasture condition can also be defined by the amount of green herbage mass in kg DM/ha

  • Poor: less than 600 kg DM of green herbage mass/ha
  • Moderate: 600—1200 kg DM of green herbage mass/ha
  • Good: more than 1200 kg DM of green herbage mass/ha

2Sheep condition

Sheep condition can also be defined by body condition scores

  • Poor: score 2 or less
  • Moderate: score 2.5
  • Good: score 3 or better

WormBoss Drench Decision Guide Report

Region: Qld/NSW Summer Rainfall / Tablelands and Slopes

Date: %21 %Oct %2017

Your Selections

History of selection will appear here

Your Recommended Action

Treat lambing ewes with an effective short-acting drench[1] and then WormTest 1 week before lamb marking. In a well-prepared low worm-risk paddock, ewes often do not need treatment at lamb marking.

NOTE: While mid-length (some combined with vaccine) and long-acting 'mectin'/ML (macrocyclic lactone) products provide convenience, their use in this situation can increase drench resistance on your farm. It is best to reserve these treatments for the higher and longer worm-risk times later in summer and autumn. They are not required when low worm-risk paddocks are used.

Treat lambing ewes with an effective short-acting drench[1]. A WormTest 1 week before lamb marking is essential.

Consider preparing a low worm-risk lambing paddock from autumn next year.

NOTE: While mid-length (some combined with vaccine) and long-acting 'mectin'/ML (macrocyclic lactone) products provide convenience, their use in this situation can increase drench resistance on your farm. It is best to reserve these treatments for the higher and longer worm-risk times later in summer and autumn. They are not required when low worm-risk paddocks are used.

Treat weaners with an effective short-acting drench[1] and then WormTest 4 weeks later[2].

NOTE: While mid-length (some combined with vaccine) and long-acting 'mectin'/ML (macrocyclic lactone) products provide convenience, their use in this situation can increase drench resistance on your farm. It is best to reserve these treatments for the higher and longer worm-risk times later in summer and autumn. They are not required when low worm-risk paddocks are used.

Treat weaners with an effective short-acting drench[1] and then WormTest 4 weeks later[2].

However, a long-acting treatment may be warranted at weaning because low worm-risk weaning paddocks were not prepared and if the next few months are predicted to be high worm-risk weather conditions. Follow the guidelines below for long-acting drenches[1].

Treat the entire mob now with a drench[1] shown to be effective against the worms present and then WormTest 4 weeks later[2].

NOTE: Do not use an organophosphate drench on severely worm-affected or stressed sheep. Consider that other parasites/diseases cause similar signs.

  • If the paddock to be used after treatment is not considered to be highly contaminated with worm larvae, give an effective short-acting drench[1] and WormTest in 4 weeks[2].
  • If the paddock to be used after treatment is considered to be highly contaminated with worm larvae, give an effective long-acting treatment. Follow the guidelines below for long-acting drenches[1]. Usually, long-acting 'mectin'/ML (macrocyclic lactone) treatments are best restricted to February–April to minimize development of ML resistance, but high worm-risk may require its use at other times.

Treat affected individuals now with an effective short-acting drench[1] and WormTest the mob now. Also, investigate other causes of their signs.

NOTE: Do not use an organophosphate drench on severely worm-affected or stressed sheep.

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

  • If the test shows that scour worms do not require treatment, then the scouring may be from coccidiosis or feed and you should seek professional advice on treatment or management.
  • If treatment is required, use an effective short-acting drench[1].
  • If WormTest results are greater than 100 epg, treat with an effective short-acting drench[1] and then WormTest 4—6 weeks later[2].
  • If you have no WormTest results (or worm egg counts are below 100 epg), follow the instructions below to check effectiveness of your treatment at day 60. Also follow the guidelines below for long-acting drenches[1].

Anytime that you are concerned that the treatment is not providing protection, WormTest immediately.

WormTest in 4 weeks (summer) or 6 weeks (winter) after the last treatment was given and observe sheep closely for signs of worms[1].

WormTest in another 4 weeks (summer) or 6 weeks (winter) and observe sheep closely for signs of worms[1].

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.

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

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

NOTE: Other diseases can cause similar signs. Consider getting animal health advice.


2High risk barber's pole worm conditions

Sheep can sometimes be rapidly re-infected with worms, causing illness and death within 2 weeks of a drench. In these situations (i) check at least weekly for visual signs of barber's pole worm; (ii) use the Haemonchus Dipstick Test; and (iii) conduct a DrenchCheck-Day10. To reduce this risk, prepare low worm-risk pastures.


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 (you can delay drenching if this occurs in the cold period, see next column).

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 100 days (15 weeks) (long-acting) after the treatment was given (in the tablelands' cold period, you can delay the exit drench, as described below).
  • WormTest 4—6 weeks after the exit drench.

Delay the exit drench if the protection from the persistent treatment runs out during the cold period (average daily maximum temperatures are consistently below 18°C) and an egg count indicates drenching is not required. The exit drench can simply then be given as the next drench that is required, but not later than 3 weeks before the end of the cold period, to ensure removal of any drench-resistant worms.

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