Weaner Cattle – Is Your Drench Doing Its Job?

A recent scientific article in the Australian Cattle Veterinarians (ACV) journal highlights the need to check that your weaner drench is effective.  Drench resistance is widespread in Australia. ^6-13,16  It is recommended that combination drenches (more than one active against the same parasite) be the standard treatment of cattle.

The ACV journal article outlines valuable data from 2018-2021 on:

• The extent of drench resistance in Australian cattle worms
• How different drenches are working against different worm types
• Productivity responses when more effective drenches are used on-farm

Effective drench programs are essential to drive good productivity in young Australian cattle.^1,2,3,4  The important worms in Australian cattle are Barber’s Pole Worm, Cooperia and Ostertagia.⁵  Drench resistance in these worms can lead to a decrease in productivity.^1,2,3,14,16   The ACV article collates 25 trial results to show that overall mean efficacy of single active drenches in Australian cattle can be estimated at only 72%.  Drenches need to be working at 95% or better. A summary of the mean results for pour-on drenches and worm type is found in Table One. Other key findings include:

• The dual-active combination of moxidectin and levamisole (Cydectin Platinum) was 99-100% effective against all key worms of cattle.
• Barber’s Pole Worm and Cooperia resistance to ‘Mectin’ drenches is common.  Levamisole is generally effective against these worms. 
• Moxidectin (as in Cydectin) has an advantage against ‘Mectin’ resistant worms, especially Barber’s Pole Worm, when compared to ivermectin and doramectin.^15,16  Mean efficacy of doramectin pour-on against Barber’s Pole Worm across 8 studies was 28.9% while mean efficacy of moxidectin pour-on was 75%.  In one study, doramectin 1% injectable had an efficacy of 8% ,while Cydectin injectables were 99%- 100% effective.
• Mectins are performing adequately against Ostertagia on many farms but resistance has been detected. Moxidectin was still 97-100% effective in controlling Ostertagia in five scientific studies. Levamisole used on its own was not always reliable against Ostertagia and should be used in combination with another active for reliable worm control.
• A nitroxynil and ivermectin combination (Nitromec) had very high efficacy (100%) against mectin-resistant Barber’s Pole Worm suggesting that nitroxynil might be an undervalued active for treatment of this parasite.

The impact of drench resistance in cattle is often not severe illness or death, like in sheep; but instead, significant loss of productivity. Over a period of eight weeks, the failure to effectively remove worm burdens in growing cattle can mean a potential loss of 8-12 kg.^1,2  While many cattle producers can visually identify a difference of 30-50 kg, it is difficult to identify a productivity loss of 8-12 kg. This is one reason that drench resistance may remain unidentified on some cattle properties.  This is a  problem, because investment in genetics and feed may be undermined by failings in the animal health program.  In 2020-21 James Cook University (Townsville, Northern Australia) and NSW DPI (North Coast, NSW) investigated cattle weight gain following treatment of weaners with different drench products. The combination drench, Cydectin Platinum, led to increased weight gain (for example 8 kg more than doramectin pour-on over 2 months).

Virbac senior livestock technical services manager Dr Matt Ball encourages farmers to ensure they choose the most effective cattle drench to fight parasites.  “We now recognise that single active drenches are no longer effective to control all key worms or protect productivity,”

Cydectin Platinum is the next generation dual-active pour-on drench for cattle containing moxidectin and levamisole. 

• Unrivalled worm control (99-100%)
• Highly effective against single and dual-resistant worms
• Short 7 day withholding period
• Only combination drench with persistency – prevents pasture contamination for up to 35 days
• No known impact on dung beetles

It also is the first veterinary use of  DMI-Sorb^TM technology to keep the product concentrated to the areas where it was applied and reduce absorption variability.All in the convenience of an easy to use low volume pour-on. Cattle producers are encouraged to work with advisors to seek improvements in their parasite management programs.  The use of combination drenches should be the default position when chemicals are needed to protect the health and productivity of cattle.