Halghton Hall Case Study


"Since we changed to a yellow wormer for the first dose based on FEC results and Techion’s advice, the lambs have just flown, and most have been sold as finished lambs by August."

Posted: Tuesday May 19, 2020

Name: David Lewis

Farm Name: Halghton Hall, Bangor-on-Dee, Wrexham

Farm Type: Lowland

Stock Numbers: 600 Ewes, 200 ewe lambs, 1200 lambs, 280 cattle

Land Area: 500 acres


Key Findings

  • 17 tests submitted from March to October.
  • Significant impact on performance after changing anthelmintic group.
  • Significant savings on wormers, labour and associated costs.


Parasite Control History

Lambs given Rycoben (1 BZ white) at 6/7 wks old for Nematodirus. Rycoben also used for 2nd and 3rd worming’s on most lambs. For later lambs they all have Cydectin drench at or around weaning – this carries them through to Autumn. Those left may be wormed again late Autumn / Winter. Singles graze other farm which clean graze grass in rotation with arable. These hardly get wormed at all.

Ewes had Fluke & Wormer at housing in December (Supaverm - white 1BZ). Also given Cydectin drench at turnout. All ewes also given Cydectin Drench Pre or at tupping in September. Quite excessive worming of adults as wormed 3 times, 2 of which are long acting oral wormers (Moxidectin)


FEC Monitoring Results

David wasn’t able to use the FECPAKG2 system on farm due to having poor internet connection at the premises. The system was therefore loaned to Daleside Vets who are the farms vet practice and David took samples to them to test. A total of 15 samples were completed which are summarised below.

There were still positive egg counts in ewes post lambing even after Cydectin was used – see notes on efficacy.

The September and October test in ewes meant David didn’t carry out the normal pre-tupping dose. This is a considerable saving over 600 ewes.

Acting on FEC results and because more lambs were sold sooner has meant far less worming. Historically, most lambs would have had 2 or 3 doses of white wormer before selling, and later lambs would also receive Cydectin at weaning and maybe again in Autumn. By end of August only 2 doses were given (an early white drench for Nematodirus and one yellow wormer end April – see below) – and only 15 lambs left on the farm!


Wormer Efficacy

Unfortunately, due to most lambs’ beings sold quickly (see performance below) the planned efficacy test couldn’t be completed. However, the testing of ewes in the spring provided a strong suggestion that there were issues with Moxidectin (3ML) as if worked, there should be no significant egg count for at least 6 weeks post treatment. As can be seen below there is now also strong suspicions that the white wormer was not effective as we saw a huge response when the wormer was changed.


Stock Performance

There has been a huge shift in lamb performance since the change of wormer in May following FEC testing. Before we take all the plaudits, David did stress that a few other things have changed with newer reseeds on the farm, better grass growth this year and the influence of performance recorded sires becoming more dominant. But he does believe that getting a better control of worms was the last key that unlocked the farm’s potential. So what changed:-

As highlighted in the table, we recorded high strongyle counts in David’s lambs in early May.





White wormer was normally used as 2nd (and sometime 3rd) dose as it was Nematodirus season.

Due to suspicions of the white wormer’s resistance in strongyle species of worms, David was advised to use a Levamisole wormer (yellow 2LV) instead.

The adjacent table shows the number of lambs left on farm at different time points and demonstrates the significant shift in lamb performance between years. 2018 would be comparable to previous years.

Likelihood is that the high strongyle challenge, which was present early in the season, wasn’t being controlled by the routine white wormer in previous years (even if used multiple times) and was holding back lamb performance.


There are multiple benefits to this shift in performance which can be summarised as :-

Change in lamb value - fixed price contract which changes over the year. Estimated that 100 lambs extra sold in July versus 100 lambs less sold in October. There is approximately a £10 difference in lamb price between those months which means those lambs realised an extra £1,000 income (approx.).

Cost of keeping those lambs on through Autumn. 150 less lambs on farm means much more available grass. This has allowed David to capitalise by increasing ewe numbers slightly as the farm has spare capacity. There is normally a separate block they use for Autumn grazing, which wasn’t required this year.

Reduction in creep feed. Lambs creep fed until weaning and any ram lambs left fed after. Estimated 6/7 tonnes less feed used at least due to lambs finishing earlier (better feed conversion). Approx. cost is £200 / t (home grown mix or locally sourced). Approximate cost saving = £1,400

Time and labour saving in handling all those lambs. Between 100 and 150 lambs on farm for extra 4 to 5 months would need to be dagged, footbathed, treated for lameness etc. Also, lambs sold before belly clipping required pre slaughter.

If we add in the labour savings of worming less often (2/3 less per lamb and 1 less per ewe) then estimated that in total that 20 hours labour may be saved. David uses paid labour for stock work which at @ £10 per hour saved him £200.


Future Advice

Continue to keep monitoring and using that as the basis of treatments. Monitor ewes at housing and at lambing / turnout to see if worming of ewes in Spring will change. If possible, try and carry out an efficacy test as we planned with the vets next year. Maybe do this on younger lambs pre-weaning, although more tricky to do at this point. We advise the strategic use of the two new 4th and 5th wormer groups (Zolvix and Startect) to help maintain the efficacy rates at the current level.

Our associates

New Zealand, Techion
Invermay Agriculture Centre
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