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Top strategies to form the backbone of your sheep worm program.

To maximise sheep productivity and profitability, an effective parasite management program is crucial
To maximise sheep productivity and profitability, an effective parasite management program is crucial
by Virbac Animal Health
April 2018

For farmers wishing to maximise their sheep productivity and profitability this season, an effective parasite management program is crucial. And because different sheep drench products can vary dramatically in their efficacy, here are a few golden rules to remember:

Be proactive, not reactive

Forewarned is forearmed – so faecal egg counts can be one of the best weapons in your arsenal to help monitor the incidence, type and levels of infection. Worm egg counts enable farmers to determine whether drenching is necessary in the first place, the effectiveness of a drench program, and also to monitor worm resistance levels. Used strategically at key times, faecal egg counts enable farmers to get ahead of the problem and take a proactive approach, rather than waiting until worms proliferate in their livestock.

Incorporate combination drenches into your program

With resistance to treatment becoming an increasing problem, the type of drench a farmer uses can make a huge difference in a worm control program’s success – as Virbac Australia Sheep Product Manager Terrance Loughlin explains:

“One of the most challenging issues for farmers is the decline in effectiveness of single active drenches. A traditional method of maintaining single active drench efficacy was to rotate between drenches. However, this strategy has now been surpassed, with the advent of three-way combination drenches. The benefit of three-way combination drenches is that the chance of a worm having gene-resistance to a drench containing three active ingredients is much lower than being resistant to just one. This leaves fewer resistant worms to reproduce, minimising any further resistance development.”

Virbac believes there is a place for highly effective single active drenches, provided they’re used alongside combination drenches in a tailored program. These combination drenches should, where possible, include actives that are still effective on a property. In the absence of knowing drench effectiveness, farmers are advised to use a drench with highly potent actives.

Higher potency, higher kill rate

Quite simply, high potency products work better. That’s because they create a higher kill rate, which means fewer worms and eggs, as well as less pasture contamination. This reduces the overall requirement for increased drenching, driving improved long-term sustainability.

Within the macrocyclic class of drenches, moxidectin has proven to be the most potent active. Moxidectin potency is derived from pharmacodynamics that are different to other ML actives. 

Make Tridectin the backbone of your drench program

Virbac recently launched Tridectin, a new class of combination drench backed by the power of moxidectin, and developed with micellar technology, for improved efficacy.

Tridectin is designed to provide maximum protection against highly resistant worms. It is the only combination drench in Australia to include moxidectin, the most potent and persistent mectin. Tridectin is the only drench in the world with registered claims against triple resistant and monepantel resistant worms. Terrance Loughlin explains exactly how it works:

“This new drench is unique in being a pre-mixed broad-spectrum combination of moxidectin, albendazole and levamisole. The micellar technology helps to improve the pharmacokinetics of the drench, making it more effective, because it reaches higher concentrations faster and is retained in the sheep for longer.

“Using advanced chemistry, we’ve been able to combine Moxidectin with Levamisole and Albendazole, for improved efficacy.”

Its unique combination provides a more sustainable solution because the product also delivers a higher kill rate, which means fewer worms and eggs, resulting in less pasture contamination and thereby minimising the development of resistance.

Tridectin also has a shorter-than-usual ESI of just 17 days (much shorter than other combination drenches), and it continues working for up to 14 days, providing protection from reinfection for at least 14 days for moxidectin-sensitive strains of barber’s pole worm and small brown stomach worm.

Terrance also explains that farmers who drench using Tridectin will also reduce the requirement for regular drenching. “This helps delay the development of resistance, with the end result being healthier, more productive sheep, and increased productivity and profit.”

Tridectin is suitable Australia-wide, for use at any time of the year, and is available in rural merchandise stores across the country.

To learn more about Tridectin, and to arrange for a Virbac animal health professional to develop a sheep drench program specific to your property, visit