The presence of a worm infection prevents animals from utilising the nutrients in their food properly, leading to poor growth and performance rates. If left untreated, infection with these parasites can cause serious disease and even death.
There are three main parasite groups to consider when deciding on which anthelmintic we should be giving our cattle and these are Gut Worms, Lung Worms and Fluke. The risk of infection will differ for each type of parasite and at different times of the year with the level of infection often dependent on the weather. One aspect we should remember is that cattle will acquire natural immunity to Gut and Lung Worms following repeated exposure.
Some animals are more susceptible to high levels of infection, youngstock and poorer quality adults are the most likely at-risk groups here. To treat these animals there are a wide range of cattle wormers available and when considering which one to use, we should be looking at the individual farm. Not all farms are the same and working out a worm control strategy is best discussed with your vet or one of our Registered Animal Medicines Advisors (RAMAs).
What is Anthelmintic Resistance?
This is the inherited ability of a parasite to tolerate a normally effective dose of a wormer. Resistance builds up in successive parasite generations on a farm. Although cases are still relatively rare, we are beginning to see reported cases of resistance to some products which may be due to treatment failures or as a result of poor practice. Most experts agree that resistance is inevitable but can be delayed by responsible wormer use.
Factors that increase the chances of resistance are:
- Under- dosing
- Continuous use
- Continued use of wormers with the same mode of action
- Using combination wormers/flukicides when only one parasite group is targeted
- Speed of re-infection from contaminated pastures with non-resistant parasites
COWS – Control of Worms Sustainably – is a new approach to cattle worming to ensure the responsible use of wormers and in brief their guidelines are:
- Work out a worming strategy with your vet or RAMA
- Quarantine imported animals to avoid introducing resistant strains
- Test how well a wormer works on your farm
- Use wormers correctly
- Use wormers only when necessary
- Use the right wormer in the right way
- Preserve susceptible worms on the farm
To summarise here are a few questions you should be asking yourself.
- Do I need to treat?
- Have internal parasites been a problem in the past?
- Have Faecal Worm Egg counts been taken and the results indicated a problem?
- What are the target parasites?
- What is the preferred application method?
- Do I need a persistent or short acting product?
- What are the withdrawal periods?
- What products have been used recently?
- What pack size is required? – If a pack size is slightly less than required, it’s far better to leave one or two fit animals not dosed than under dose the whole group. And don’t’ forget, as a veterinary practice we are able to dispense open bottles to smaller herds who don’t require large quantities.
The Practice has a team of qualified RAMAs (Registered Animal Medicine Advisors) who would be more than happy to offer you all the help and advice you need on the control of internal parasites in your animals. And who knows, as a result it may mean you won’t need to do or buy anything.
Jean Gibson – Synergy Farm Health, K_SQP
