By Debbie James

A big reduction in the frequency of wormer treatments is being reported on Welsh sheep farms that have switched to faecal egg counting (FEC) to monitor parasite burdens.

Eight focus sites participating in the Farming Connect parasite management project changed their approach from the routine dosing of lambs and ewes to treating according to the number of parasite eggs per gram (epg) in sheep faeces.

As a result, the frequency of wormer treatments have generally reduced and farmers are targeting dosing to when it is most needed.

According to the study there is no decline in performance on any of the farms, despite less dosing and changes to parasite controls; some have reported improvements in performance, although other on-farm changes may have contributed to this position.

The project ran between March and September 2019 and was delivered on behalf of Farming Connect by Ceredigion-based Techion UK.

A total of 118 sheep samples were submitted with the majority, 84, taken from lambs.

Analysis of these samples showed that 43 per cent were in the ‘unlikely to treat’ category, 38 per cent ‘possibly treat’ and only 19 per cent had egg counts that put them in the ‘likely to treat’ category.

Without this information, many of the lambs may have been dosed as a matter of course, says Eurion Thomas of Techion UK, who led the project.

Lower egg counts were recorded in June, July and August with counts rising in the autumn.

The project also provided an interesting analysis of strongyle and nematodirus counts, says Mr Thomas.

Historically, nematodirus has been the dominant species of worms in spring, in April and May in particular, while the strongyle group of worms was more prominent from early summer; it was rare to see nematodirus later in the season.

The Farming Connect project showed evidence of nematodirus throughout the season, with some quite high levels recorded at times in the autumn, says Mr Thomas.

In contrast, strongyle worms were found much earlier in the spring than anticipated, as early as March.

This information is hugely important when considering the choice of wormer for the first dose of lambs, says Mr Thomas.

“Many of the focus farmers knew white drench wasn’t fully effective against those strongyle worms and could change to use another group which would work better for both.’’

If there had been no significant strongyle counts, white wormer would be the most appropriate treatment, he advises.

Mr Thomas did urge caution when interpreting nematodirus egg counts as, even though results may be in the low to medium category, the advice is to still worm if there is a known history and the conditions are favourable to the parasite.

The Nematodirus Forecast available on the SCOPS website is a useful tool to help with this, he says.

None of the farms recorded a decline in performance after changing their worm control policy which in most cases involved reducing the frequency of wormer treatments.

“This is an important message to convey as some farmers may not engage with activities like FEC monitoring because they are worried that regular worming is required for optimal performance. This project has in fact proven that this is not the case as long as it carried out properly and backed up by evidence,’’ says Mr Thomas.

One of the farms which took part in the study, Aberbranddu, near Pumpsaint, Carmarthenshire, didn’t dose ewes pre- or post-lambing after recording low FECs.

The farmer, Irwel Jones, had been FEC testing using the original on-farm microscope-based Fecpak system for several years but using the new image-based online Fecpakg2 system meant he could test more regularly.

“Monitoring on a regular basis and having quick results back via email without me needing to leave the farm means I can keep on top of the situation,’’ says Mr Jones, who runs an upland flock of 860 ewes and 200 ewe lambs.

Keeping a close eye on parasite burdens and using daily live weight gain data, he treated at the correct time and was rewarded with improvements in growth rates in some groups.

The Welsh male lambs achieved average growth rates of 170g/day since August 1 while the corresponding group in 2018 achieved 100g/day at that same time of year.