On farms where cattle have been at grass since early April, herd owners should keep an eye on spring-born calves and autumn weanlings for early signs of worm burdens.

As temperatures pick up, worm levels will start building on grazing swards. The lack of grass growth during spring means cattle have been grazing low covers, increasing the exposure risk.

Young calves and weanlings will have no immunity to worms and are therefore at most risk. Yearling stores, maiden and first calved heifers should also be included within a dosing programme.

In contrast, mature cows will have developed immunity and will not require a treatment for worms.

Types

Gut and stomach worms are more common during May and June than lungworm. But all three can cause issues under the right conditions.

Therefore, make sure you choose an appropriate dosing product that targets the correct type of parasite when treating cattle.

Signs

Calves with a high worm burden will be starting to scour more than normal. Scouring will be a more common sight throughout a group of animals, rather than individual cases.

But be aware that when cattle are grazing leafy swards, or recently fertilised grass, this will naturally cause loose, watery like dung similar to scour.

As such, farmers should be alert for other signs of a worm burden, such as lack of thrive, anemic looking calves and dry hair.

When herding cattle, animals with a worm burden will cough more when moved from paddock to paddock.

Treatment

Choose an effective product to control worm burdens and follow the correct dosing rate. If using a pour-on treatment, make sure cattle are restricted in a handling race before applying the product.

As far as possible, group similar sized cattle in the race as this reduces the variation in liveweight and makes it easier to set the dosing gun at the correct dosage.

With oral drenches, or an injected product, catching animals in a headlock will improve dosing technique and accuracy.

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