Posted: Tuesday May 19, 2020
Name: Rhodri Lloyd-Williams
Farm Name: Moelgolomen, Talybont, Aberystwyth
Farm Type: Hill, Organic
Stock Numbers: 850 Ewes, 240 Ewe Lambs, 1000 Lambs, 25 Suckler Cows and Calves (Sold As Stores)
Rhodri had been monitoring on farm FEC tests using FECPAKG2 since 2015 through his involvement in the Sainsbury’s FECPAKG2 and TAG projects. Ewes are either wormed pre lambing or given a fluke and wormer in mid-winter. This year Levafas Diamond was given to all ewes in February. For lambs, the previous year they had their 1st wormer for Nematodirus in May, then another wormer mid-summer following high FEC counts, but he admits last year he didn’t test FEC as regularly as he wanted / should have. Moelgolomen is a long-established organic farm, hence parasite control is more challenging as they are limited with how often they can treat, and more so with the choice of wormers they are permitted to use.
Rhodri has started using the system more often this year than last with regular counts throughout the season. The results of the 19 samples submitted by Rhodri are summarised here.
Lamb tests show quite high burdens, and these can be seen early in June and September and coincides with when most lambs were grazing in bye fields which are more intensive.
No lambs were wormed between June and September due to low FEC levels. At weaning (end of July) the FEC levels were low and weights / growth rates were satisfactory, so he decided not to worm them then.
When yearling ewes returned from their summer grazing in Cumbria in early October, they were looking extremely poor. The FEC tests indicated a surprisingly high worm burden so this helped identify the cause of performance issue. Next year Rhodri will instigate more testing of these ewes while away on summer ground.
Part of the project was to determine the efficacy of the four main classes of wormers. A simple efficacy test was carried out in a controlled manner by Techion’s technicians, based on pre and post pooled samples. Although not as accurate as the gold standard full Faecal Egg Count Reduction Test (FECRT) it provides a good indication of efficacy. The results are summarised here, a full detailed report on the wormer efficacy was provided separately (see WormerCHECK report).
The results show a definite lack of efficacy for the white and yellow group of wormers. Although the Ivermectin result shows only a 93% reduction (which is an ‘use with caution’ category) we had less confidence in this result due to a lower FEC test for that group at day of treatment.
The good news is that both ML wormers are probably OK to use. However, being an organic farm the use of normal Ivermectin (3ML) wormers is not normally permitted unless you have a special derogation / mitigating circumstance (resistance to other wormers would justify it). Some certification bodies do allow the use of Moxidectin and this should be checked.
The performance of lambs was generally good in the first half of the season with lambs hitting satisfactory 8 week and weaning weights. This was partly helped by FEC picking up a high worm burden before it affected condition (see 30/05/19 high FEC where condition was reported as ‘Good’). After weaning and going on to aftermaths, performance has dropped and several reasons for this include an outbreak of orf and lameness. This has been confounded by the high burdens recorded in September.
The strategy needs to be to try and lower the apparent high parasite challenge on the in-bye ground. There are a few suggestions to help with this:-
When worming ewes pre-lambing, consider using a Moxidectin oral wormer (e.g. Cydectin, Zermex). Ewes lamb outside on the in-bye fields where there appears to be a problem. If done just before lambing the Moxidectin will work for 6 weeks and help those ewes clean up the pastures. We advise this strategy for maybe 2 years at most only before switching back to a shorter acting wormer. Check first that Moxidectin is allowed under your organic scheme.
We advise the strategic use of the two new 4th and 5th wormer groups (Zolvix and Startect) in mid to late summer when high FEC’s recorded on those in-bye fields. This will help reduce burdens as well as help maintain the efficacy rates at the current level.
Zolvix has been used when ewe lambs are sent away in the autumn for grazing (regardless of FEC). It’s worth discussing if this policy is needed as grazing is the same land every year and is the investment in Zolvix better placed in mid-summer to help issues in the in-bye fields?
Continue the good work and keep monitoring and using that as the basis of treatments.
Other on farm management strategies can help such as grazing management, using alternative forages in the pasture and sheep bred for natural resistance against worms.