Livestock Matters - Spring 2018

WORM CONTROL WORKING TOGETHER FOR A HEALTHIER FUTURE... 2 1 LIVESTOCK MATTERS Mark explains: “Nematodirosis can strike very quickly. Farmers can’t afford to have a ‘wait and see’ policy because the damage is done by large numbers of immature larvae that are not producing eggs. So a FWEC is not a reliable indicator of the risk. Rapid action is often required and this has to be based on a risk assessment and forecast for the area. Six weeks later, another FWEC is carried out, and if egg numbers warrant it, then the white drench is used again. Mark explains: “There is a lot of worm resistance to white drench on sheep farms, but very little for nematodirus. So it is the perfect time to use this type of drench.” Elaine starts sending lambs away in June and continues through to the next April, selling most at 36 - 46kg to an abattoir, with some going to a local butcher. Lambs still on the farm in mid-summer will get a third drench - this time, a clear drench. Then in August, a fourth drench - a yellow one. And the fifth drench used in October will be a knock-out drench - either an orange or purple one. Nowadays Elaine weighs the lambs before drenching them instead of estimating weights, so as not to under-dose them. She also calibrates the drench gun - at the start and again halfway through. Mark says: “Last year we carried out some drench tests as lambs had mucky back ends despite being wormed two weeks previously. For the first time on Elaine’s farm, some drench resistance was seen: FWECs revealed high levels of Trichostrongyles - 1,800 epg in the fat lambs which had received white drench, and in a batch of seven month old ewe lambs that had received clear drench - 2,200 epg. So I prescribed an orange drench to use on them all next.” A knock-out drench is also used on all bought-in lambs, shearlings and tups, as part of the quarantine protocol. “Previously I would drench lambs 5-7 times. So I’m using less drench now than I used to,” says Elaine. “And if I’m concerned that a group of lambs aren’t finishing fast enough, I take faecal samples and get worm and fluke counts. I don’t just reach for the drench gun.” When submitting a pooled faecal sample, Elaine labels the pot with the date, field name, and specific group of sheep. She takes samples collected freshly in the morning to the Willows practice where they are analysed that day or early the next. Results come back within 24 hrs. Mark adds: “Worms aren’t the only cause of poor performance. Depending on the situation, and recent events, we may decide to blood-test for mineral deficiency.” Successful worm control Mark explains: “Flock health plans are reviewed annually, and so prove invaluable in ensuring that worming programmes are updated to a particular farm’s situation each year, based on its recent history of drench efficacy, and worm resistance challenges. “Ewe/lamb nutrition and pasture management are also factors affecting sheep’s ability to withstand worm burdens, and form part of flock health plans.“ But with or without flock plans, every sheep farmer should be carrying out a series of FWECs through the year to evaluate the levels of worm burden in different groups of sheep, and drench efficacies. Only then can informed decisions be made on which wormers to use, dosing frequency and timings. “FWEC tests are very cheap, and the results are likely to save costs in drench and time. And having a science-based strategic worming programme also ensures the responsible use of the limited chemistry we have available to protect animal health and performance.” ‘Best practice’ worm control advice Farmers who join the Willows Sheep Club pay a monthly fee and receive three vet visits during the year: pre-lambing, post-lambing and pre-tupping. An SQP will accompany the vet to provide input on parasite control strategies. A flock health plan specific to the farm is drawn up. Members then benefit from vet support with e.g. body condition scoring, ram MOTs, blood tests to evaluate ewe nutrition levels or identify mineral deficiencies or disease. Mineral analyses of forages can also be made. Farmers can submit an unlimited number of samples for FWECs to the practice’s in-house lab and monitor worm burdens, drench efficacies and coccidiosis levels. The Willows Sheep Club Grazing sheep on cattle ground Sam explains: “Alan and Elaine both send their ewes and lambs out to keep on dairy farms over the winter. “There is no evidence of transfer of resistance to wormers between sheep and cattle. “Besides, they are each affected by different species of worms, so there is no cross-over of infection. The only exception is Nematodirus, but this is only a threat in May/June. “Grazing sheep on cattle ground actually reduces the population of cattle worms because sheep eat them, and they then die in the sheep. As a result, there will be a lower worm burden for cattle when they come out to graze in the spring - which is beneficial for both parties!” “Every sheep farmer should be doing worm egg counts.” • Drench strategically not tactically - ask your vet or SQP to draw up a programme for the year, tailored to your farm, that year. Don’t just drench out of habit! • Monitor worm burdens using FWECs through the year - It’s a really cheap test! • Ask for worm species to be identified to help guide choice of wormer. • Don’t drench if FWEC results are less than 500epg! (And save money and time). • Ensure the drench gun is in good working order (is it time for a new one ? ). • Calibrate the drench gun at the start, and re-calibrate at least every 50 sheep. • Weigh animals to avoid under-estimating liveweights and under-dosing. • Use a knock-out drench as part of quarantine protocols. • Drench tests (and faecal egg reduction tests) should be performed regularly to determine resistance levels to anthelmintics on the farm. • Leftover drench ? Don’t just put it in sheep! Store for next year: out of sunlight, in a cool (not freezing) place. “Every sheep farmer should be doing worm egg counts.”