Grazing cattle will be picking up internal parasites with every mouthful of grass and if left untreated, performance will suffer and the risk of mortality increases.

When it comes to worm control, under or overdosing and a poor dosing technique is a waste of money and also increases anthelmintic resistance on-farm.

When worming cattle, outlined are five tips to get the most effective cover against internal parasites.

Which cattle to treat?

Not all cattle will need worming. Animals at most risk are autumn and spring-born calves, yearling or store cattle in their second grazing season, in-calf and first calved heifers.

Mature cows should have developed resistance to gut and stomach worms. So, if cows are in in good flesh and holding condition, they will not need wormed.

Choosing the right wormer

When purchasing a cattle wormer, don’t automatically lift the cheapest product off the shelf. Think about why you are dosing cattle.

Cattle normally experience greater issues with gut worms in the early stages of summer. Lungworm or hoose is more common in mid to late summer.

Keep this in mind when choosing a wormer, as some products cover all bases, while others do not. Also, choose a product that gives an effective cover period.

Cheaper products may only offer worm control for four or five weeks, so multiple treatments are required.

This means some cheaper wormers can work out more expensive in the long run. Pay attention to withdrawal dates if cattle will be killed off grass.

Wormers differ in terms of active ingredient i.e the chemical component that targets certain parasites, and they all work differently when controlling worms.

Wormers are generally classed as white drenches (benzimidazoles), yellow drenches (levamisoles) and clear drenches (avermectins).

In terms of choosing between a pour-on wormer, oral drench or injected product, they all have merits. How effective they are depends on whether they are properly administered.

Dosing technique

When dosing cattle, they should be secured in a crush or race and product guidelines should be followed. Do not try to apply pour on products to animals standing freely in a loose pen.

With oral drenches, a head scoop will improve the accuracy of the dose administered. Using a long reach hook is also recommended.

With injected wormers, check if the dose should be given into the muscle or under the skin and change the needle regularly.

Grouping cattle when dosing

Ideally, cattle would be weighed individually when dosed to ensure the product is given at the correct rate.

But this is not an option for the majority of farms. So, as an alternative, when cattle are collected in the handling pen, try to run animals up the race that are similar in size and age.

This should cut down the variation in liveweight. Once the race is full, set the dosing rate to the heaviest animal in each pass.

Changing wormers

Do not use the same wormer every time cattle are being dosed. Change the type of wormer every so often, as this slows anthelmintic resistance building in the herd.

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