MANAGING wormer resistance through the responsible use of cattle products was the key take home message at a recent AHDB beef and lamb and COWS (Control of Worms Sustainably) farmer meeting.
Guest speakers spoke of the importance of understanding the lifecycle of cattle parasites and then managing parasitic challenges through grazing management strategies and the targeted use of wormers, taking into account different farm systems.
“Selecting for anthelmintic resistance of cattle parasites is inevitable,” explained Dr John Graham-Brown, from the University of Liverpool. “This doesn’t mean ‘we’re doomed’, but it’s why initiatives such as COWS are so important to ensure the sustainable use of anthelmintics.
“The lifecycle of gutworms, lungworms and liver fluke mean infected cattle will excrete infective eggs and larvae contaminating pastures. Consequently, there is a risk of animals being re-infected or youngstock in their first grazing season being exposed to high worm burdens, if this is not managed effectively.
“Controlling worm burdens via anthelmintics is often necessary. However, when we continue to use the same product repeatedly and for the same reason year-on-year, levels of worms with a gene that makes them resistant to said wormer will increase, hence wormers become less effective over time.   
“Unfortunately, it’s not something that can be avoided, but it’s something the cattle industry can reduce and control to ensure resistance doesn’t become unmanageable.
“If we work collectively as an industry, we can stay one step ahead of resistance,” said Dr Graham-Brown.
Also speaking at the event, vet Rachel Hayton, of Synergy Farm Health, spoke of responsible wormer use, but also looked at grazing management strategies to help reduce the challenge.  
“In beef cattle, gut worms are very common and something I frequently diagnose. It’s a common cause of poor performing animals and one which can be very costly if left untreated,” she said.    
“When it comes to controlling parasites, it’s important to consider a holistic approach. For example, recent research has proven that grassland management can provide a degree of parasite control without compromising production.”

The Scottish Farmer:

EVENT SPEAKERS Rachel Hayton, Dr John Graham-Brown and Nicola Beesley

A recent paper published by Andy Forbes, honorary professor at the University of Glasgow’s School of Veterinary Medicine and COWS’ technical representative, re-emphasized that mixed aged grazing, rotational grazing and using low risk pastures, such as silage and hay aftermaths, have a role to play.
These tactics can reduce the exposure of naïve animals to high worm burdens which can subsequently increase daily liveweight gain in youngstock.
“With anthelmintic resistance recognised as a potential risk to the cattle industry, we can’t overlook the role that grassland management can play as part of a farms parasite control plan,” added Mrs Hayton.
“Wormers are the mainstay to help keep on top of parasitic burdens, but when choosing the right wormer, it must be suited to the situation.
“It’s important to consider the efficacy of the product, whether you have any resistance issues on-farm, and its spectrum of activity. Not all wormers are effective against all stages of parasite lifecycles.
“It comes back to the COWS’ ‘5 Rs’ to effective use. If anything, I would always make the point that farmers should be weighing every animal or using a weighband to calculate the correct dose each time – and always read the product label.
“This may sound simple, but they are key factors that are often forgotten and can result in cattle being under or over dosed,” said Mrs Hayton.
Bespoke parasite control plans required a degree of co-operation between your vet, SQP or veterinary pharmacist, and taking note of the ‘best practice’ guidelines.

Mixed age grazing: It’s highly likely that older cattle have a more robust immunity to common gastrointestinal worms. As a result, they can tolerate infections better and excrete lower concentrations of worm eggs in their dung when grazing, potentially reducing the level of pasture contamination.
Therefore, grazing naïve first season animals with older cattle may offset the risk of parasite burdens due to the reduced level of exposure.
Leader-follower systems: This involves youngstock, in their first grazing season being grazed ahead of older cattle and moved to fresh pasture when the grass is grazed to a level that continues to provide adequate grazing for the cattle that are following on.
As cattle rotate through the paddocks, so long as they remain on each paddock for less than three weeks, they should not be exposed to a high parasite challenge.
Grazing low risk pastures: silage and hay aftermaths that have not been grazed for 12 months provide a low risk option to move youngstock onto during early or mid-July.
In this instance, susceptible cattle are moved to ‘clean’ pastures in advance of the peak larval season, and therefore the mid-season build-up of infective larvae is largely prevented.

The 5 Rs to effective wormer use:

The Right product for the type of worm
The Right animal
The Right time
The Right dose rate
Administered in the Right way