OCCASIONAL CHECKING of samples; and recognising that faecal egg counts (FECs) are only one part of the decision-making process when assessing when to worm lambs, are the key to successful use of FECs, according to Welsh producer Jack Foulkes.

Attending a Mordun Institute roadshow three years ago led Mr Foulkes to decide that FECs were the best way to tackle a growing problem of anthelmintic resistant worms.

“White drenches had become ineffective in our flock because we bought in a resistance problem with the large number of store lambs we finished over several years,” says Mr Foulkes.

“The roadshow convinced me that with more than 3000 breeding ewes we had to make worm control more precise. Egg counting seemed the obvious first step.”

A Fecpak on-farm FEC kit was bought over the internet from New Zealand. It cost £600 plus VAT and Mr Foulkes thinks it was one of the best investments made at Marchynys Farm, Penmynydd, Anglesey.

“I have not calculated how much we have saved on chemicals by only treating lambs when necessary, but the reduction in labour in a single season more than covered the kit cost.”

In the past, most lambs were dosed three times between birth and sale at about 40kg liveweight, usually reached by mid-June. But this meant a lot of time spent gathering and dosing lambs, which increased farm workload and placed stress on ewes and lambs.

Now they are treated only when egg counts are rising steeply and most receive only one or two treatments. Mr Foulkes, who farms with his father John and mother Eirwen, had used a microscope and prepared slides while studying for his degree at Harper Adams, so he had little difficulty picking up the Fecpak routine.

Though he is now confident about his proficiency, he still checks it occasionally by comparing his count with one done by a skilled technician at CBS technologies in Aberystwyth.

“I am pleased to say results are pretty close, which they should be when the instructions are followed.”

The partnership’s sheep are run on five parcels of land and worm problems vary because some share grazing with cattle. “Where sheep graze with cattle, FECs are much lower than where sheep graze on their own.”

MOB average

Faeces are usually collected from pastures at feeding time and care is taken to collect from a number of lambs for a good mob average sample.

This is weighed before water is added and faeces crushed. After sieving, the solution is thoroughly mixed and 30ml diluted with saline solution to make the 230ml sample from which microscope slides are prepared.

“I find the lines on the slides supplied make it fairly simple to do an accurate count and with a bit of experience it becomes much easier to identify different types of worm eggs.”

As the kit’s instructions advise, the count is regarded as one element in the whole picture of the worm burden of lambs and the need to treat. “Occasionally FECs can be above the 300 eggs/g limit at which treatment is recommended, but lambs are not treated when looking well. The important thing is the trend in the number of eggs and how this could affect lamb thriftiness,” reckons Mr Foulkes.

Thrifty lambs

The partners’ 3500 Mule-type breeding ewes are put to Texel and Suffolk rams and regularly scan at more than 185%. The aim is to keep lambs alive and growing well, and effective worm control is seen as vital.

The policy of checking FECs also extends to replacement breeding ewes which are quarantined, injected with Ivermectin and then checked to see whether they are shedding worm eggs before joining the main flock.

“I have heard some producers have found it difficult doing their own egg counts, but I think it would be worth their while to persevere, or send samples for checking.”

However, Mr Foulkes has found there is one downside of dosing less. The products he used in the past contained traces of selenium and cobalt and now he has to blood-test to keep an eye on trace element status.