Please be aware that this website relies on the use of cookies to function correctly and involves some cookies being downloaded onto your device. This helps us to improve the content of the website so that it is more useful and relevant to you.
Allow cookiesPrivacy and Cookies Policy
banner image

Case study

A planned worming strategy to optimise flock health and performance

Speak to Wiltshire farmer, Rob Hawke about his flock and worming specifically, and he says:
“With all our land in either stewardship or environmental schemes, it is vital to us to maintain the efficacy of the wormers we use. We are not set up to follow the sheep with cattle, and our acreage means that every last field is in constant use. All our pasture has to work hard and is grazed throughout the year meaning we have to stay on top of worming and any resistance issues at all times.”

Rob and Anna Hawke manage their own 1000-head Romney ewe flock in addition to managing their landlord’s 600 organic ewes. The farm at Bishopstone near Salisbury is around 500 acres, all of which is under some form of environmental stewardship scheme. The land is grazed without a break meaning that the worm burden could become a serious problem. “With input from our consultant vet, Emily Gascoigne of Synergy Farm Health, we develop flock health plans that ensure anthelmintic resistance (AR) is known and understood, as well as managed,” says Mr Hawke.

How does this work?
Several years of faecal egg count (FEC) testing means Mr Hawke knows there is slight yellow wormer (Group 2-LV) resistance in the flock and no clear drench resistance (Group 3-ML) or white drench resistance (1-BZ).

“This still allows us a certain degree of flexibility with wormer choice and rotation and is a situation we aim to maintain,” says Mr Hawke.

“An important part of this was opting to start using Zolvix® from Elanco as soon as it was launched. As a group 4-AD wormer, it is an important tool to allow us to keep on top of the worm burden.

“We tend to use Zolvix when egg counts are likely to be high in late summer/early autumn and rotate it with wormers from the other groups,” he adds.

Flock management
The year commences with a busy January for Rob and Anna as 200 older draught ewes lamb inside in January. The aim, by using a higher input system, is to get the lambs off from April to the middle of June.

Then, come April, the main flock, as well as the landlord’s flock, starts lambing outside. These go onto a lower input system and the lamb crop is finished on turnips from August through to the last ones going in March. Ewes are overwintered on fodder beet.

All lambs, from whichever group, are sold deadweight and Mr Hawke aims for around a 19kg carcass grading out at R3L. All sheep have EID tags meaning that data can be collected throughout the year in order to help monitor performance.

Starting this year, the flock will be part of the AHDB Challenge Sheep Project allowing Mr Hawke to access FEC Pak, which means that FEC testing can be done on the farm itself, with samples taken every two to three weeks. Results are generally available within a few hours of the test being taken and are emailed straight back to the farm.

“As graziers, every sheep and lamb on the farm has to pay its way; we do not receive any subsidies,” says Mr Hawke. ‘Keeping the flock in top condition is important to us – and results show that Zolvix clearly reduces worm burden. We believe its use is essential for the flock’s health, welfare and performance.”

Act now, find out more about how you can incorporate Zolvix for your mid-late season break dose

Rob Hawke is a sheep farmer and a part-time contractor with Elanco



1.The production costs of anthelmintic resistance in sheep managed within a monthly preventive drench program I.A. Sutherland, J. Shaw, R.J. Shaw Veterinary Parasitology 171 (2010) 300 -304.

Zolvix™ 25mg/ml oral solution is a broad spectrum anthelmintic for the treatment and control of gastro-intestinal nematode infections and associated diseases in sheep including lambs, hoggets, breeding rams and ewes. POM-VPS in UK. Information regarding the side effects, precautions, warnings and contra-indications can be found in product packaging and leaflets; further information can also be found in the Summary of Product Characteristics. Advice should be sought from the medicine prescriber prior to use. Zolvix, Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates. Use medicines responsibly (