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Prepare for sheep parasite control in the season ahead


Plan ahead for season-long control of parasites in sheep to maintain productivity, says Merial Animal Health.

"All grazing animals are at risk of parasitic disease. The risk may vary between different groups of animals depending on previous immunity from exposure to parasites," says Merial's Veterinary Adviser, Sioned Timothy.

"Every farm has its own specific challenge, therefore it's important to understand regional variations of climate and environment that might increase the risk in a particular area."

Identifying what parasites are on farm and understanding what the risk period is for each species will help identify at-risk animals, and enable effective parasite control plans to be put in place to protect against losses in production.

"In the period around lambing, ewes may shed increasing numbers of worm eggs, due to a dip in immunity," says Ms Timothy. "It's important that this is managed, so that the resulting larvae don't come to pose a risk to growing lambs later in the season."

Nematodirus in lambs is normally the main concern post-turnout. Nematodirus may pose a significant risk, especially when lambs are turned out onto pasture grazed by lambs the previous year. Farmers should keep a close watch on the SCOPS or NADIS websites which will indicate when there is a high risk of infection in their region.

Tom Hume MRCVS, Director at Westover Veterinary Centre, Norwich says: "Small lambs will often scour from nematodirus infection, with no eggs present in the faeces. This is because it's the larvae that cause the damage.

"This is a good opportunity to use Group 1 white wormers for nematodirus control, since it is one of the few parasites not resistant to this group of wormers.

"However, care should be taken if lambs are being treated later in the nematodirus season as this may overlap with a potentially wider worm spectrum, which will not be as susceptible to white wormers."

Pasture management provides a real opportunity to reduce the infection pressure from nematodirus on sheep, and reduce the reliance on wormers.

"If lambs are turned out onto clean grazing (pasture that was not grazed by lambs the previous year) there is virtually no risk from nematodirus infection," says Mr Hume.

"If however, they are turned out onto paddocks that are used every year, there will be a high risk of nematodirus infection, and lambs will almost certainly need worming in spring."

Parasitic gastroenteritis (PGE) is the next potential disease to cause illness in growing lambs. PGE has the potential to slow growth, increase finishing times and risk further pasture contamination with worm eggs.

Faecal egg counts (FECs) pooled from susceptible lambs can help identify infection and determine the need to drench. Post-drench FECs, taken at an appropriate time after treatment can also help monitor the efficacy of the product used.

Depending on the individual on-farm risk factors, including any known resistance to specific wormer groups, farmers should employ a range of control measures, including pasture rotation and strategic dosing to effectively manage PGE.

Wormers from Group 3 (clear drenches) such as Oramec®, which contains ivermectin, will remove damaging worms and thereby prevent and treat PGE and associated scouring in affected animals. It will also reduce the number of worm eggs passed out to re-infect pasture.


Oramec 1 Oramec 2


Merial-Sanofi_Logo_rgb Oramec® Drench contains ivermectin. Oramec® and the Ramshead® logo is registered trademark of Merial Ltd. ©Merial Ltd 2016. All rights reserved. Legal category: POM-VPS (UK), LM (Ireland). Advice on the use of these or alternative medicines must be sought from the medicine prescriber. For further information refer to the datasheet, contact Merial Animal Health Ltd CM19 5TG, or call the Merial Customer Support Centre on 0800 592699 (UK), 1850 783 783 (Ireland).

Use medicines responsibly.