BHC Newsletter Spring FINAL


Grazing management Animals that are high risk of being affected by worm infestation should be grazed on low contamination pastures. These include: • New or reseeded pastures, • Pastures not grazed by cattle the previous year, • Pastures previously grazed by sheep only for 1-2 months, • Pastures co-grazed by sheep and cattle (note that sheep are also affected by liver fluke), • Pastures that undergo rotational grazing. Appropriate use of anthelmintics Cattle have differing susceptibility to worms depending on their acquired immunity. Adults are at low risk of showing any clinical signs of gut worm infestations. Suckler cows usually do not require treatment for gut worms. Second season grazers are at medium risk as they are not yet fully immune to gut worms and can show poor performance or disease. Animals that were not fully exposed in their first year are at higher risk e.g. late-born calves or beef suckler calves, and these should be monitored. First season grazers initially have no immunity to parasites and are at risk of worm infestations, but the risk differs depending on the type of calves. Beef suckler calves are initially at low risk of gut worm infestations as they have a low grass intake when they are still suckling from their mothers. Around weaning, beef suckler calves become exposed to contaminated pastures and are at much higher risk and should be appropriately monitored. Dairy calves in calf to beef systems are at high risk as they are exposed to infection as soon as they are turned out. They should be grazed on a low contamination pasture and closely monitored. Calf growth rate and body condition should be monitored, and faecal samples taken from 10-15 calves to check the number of worm eggs around 8 weeks after turnout. If nutrition seems appropriate but growth rates are below target (0.6-0.75 kg/ day) or a significant number of worm eggs are seen, then using anthelmintics is justified. Follow-up monitoring will depend on the anthelmintic given, if calves are treated, and the grazing management on farm, and seeking veterinary advice is recommended.

Recent research suggests that treating only those animals in a group with growth rates that fall below target still maintains satisfactory group performance.



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