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Spring Worming Decisions – What should we be thinking about?

Andy Adler BVM&S MBA MRCVS, Veterinary Director of Lifetime

With winter now behind us and the sun occasionally showing over the hedge we can now begin to look ahead to the upcoming spring turnout. Before the turnout arrives there will be a few decisions that you need to make with regards to parasite control, and below I set out some key questions and considerations to help prepare you for a successful season.

There are several things to control and that need careful consideration when preparing for the turnout. The principle parasites which are growth weight limiting are Cooperia and Ostertagia, as well as others which are less significant. These parasites will all cause your animals to not put on weight as efficiently. Lungworm immunity is an important factor to be considered as it can cause rapid decline in weight which can be fatal.

There are drugs and treatment programmes that can be designed to cover all of these key parasites, and we would recommend engaging with your vet, SQP or animal health advisor to devise a plan that is most effective for you, your farm and your animals.

The key factors and questions to bear in mind when devising your health plan are set out below:


When considering which treatment plan you would like to use it is important to consider if your facilities are suitable and allow your treatment plan to be a viable option. Typically when advising farmers I would ask them to consider the following;

  • Handling facilities – are they safe and easy to negotiate with the treatment plan in mind?
  • What access do you have to the animals throughout the year? Will it be easy to apply topical treatments throughout the season?
  • Are you able to weigh your animals to ensure accurate dose rates?


Do your staffing levels allow for animals to be treated before they go to grass with one long acting treatment, or is it easier at a busy time of year to put them out and then treat them later in the season? What plan is the most cost and time effective for your resources?


It is important to assess the pasture available for the season, and what its previous uses have been. This directly impacts the different parasites and risk profiles that your animals are likely to come up against in the season and should therefore be a key consideration for treatment plans. For example, pastures that have had young animals in the previous 6 months compared to a silage aftermath which has not been grazed or new lay arable field will have very different risk profiles for parasites.

Reflecting on last season

Did you have any concerns about the growth rates of your animals or the wormer efficacy that you used last year? Were your growth rates as expected? All sheep should have a wormer resistance profile however with cattle so far, we have seen less resistance. There are farms with known parasite problems and so if you are struggling it is always worth discussing with your vet or SQP.

What animals are you worming?

You may have different targets for different animals. Replacement heifers will need to build up a good lungworm immunity whereas this is not so important with beef animals which will never become adult. Second year grazing animals may have a strong immunity already or could be close to finishing and thus meat withdrawals need to be kept in mind.

The 5 R’s

Whenever you give an animal a wormer we would recommend you think about the 5 R’s as described by the COWS guide to effective use of cattle wormers:

  1. The RIGHT product for the type of worm – make sure you are not using a fluke treatment at turnout.
  2. The RIGHT animal – focus prevention on young animals who have been weaned.
  3. The RIGHT time – as above.
  4. Dose cattle at the RIGHT dose rate – weigh animals before giving a dose depended wormer
  5. Administer wormer in the RIGHT way – making sure you give a pour-on wormer on the skin and oral wormer orally.

The first sign of a parasite problem is a lack of growth rate, and so it is important to weigh animals throughout the season, where possible, to ensure the most accurate recording of growth weight as this helps to identify issues where other clinical signs may not be presenting. This also allows you to reflect on the wormer strategy or on the amount and quality of nutrition the animals are receiving.

We would always recommend having a treatment strategy in place as best practice, which is effective, practical and deliverable.

Considerations should also be made with regards to using a long- acting worming bolus, pour-on or injection. Using shorter acting pour-on or injection products throughout the summer is effective alternative to long-acting products when the treatment strategy is followed. However, with all products, lungworm can still be a risk in the Autumn and it is important to remember that no product lasts more than 4 or 5 months.

If you would like to discuss your worming strategies, or need assistance in creating a plan for the new season then contact one of the SQPs at Mole Valley or speak to our vets at Molecare who will be happy to help.

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