PARASITE CONTROL AT TURNOUT
Lungworms Lungworm infection (‘hoose’) can cause clinical signs such as coughing and difficulty in breathing. Cattle which are affected by lungworms are also more likely to develop viral and bacterial pneumonia. Cattle do develop immunity to lungworm infection, but it is short lived (6 months) and without further infection they can lose their immunity. At the start of the grazing season, cattle are usually susceptible to new infections of lungworm but the highest challenge period is in late summer and autumn. Calves that are turned out onto pastures that were grazed by young animals the previous year are at higher risk of infection. Dairy-to-beef calves are at particularly high risk. Calves should be closely monitored for early signs of respiratory disease, such as coughing and if these develop, the whole group should be treated as soon as possible. This limits the severity of the disease and contamination of the pastures. A lungworm vaccine is available in Ireland and the vaccinations should be completed before turnout each year. If adult cattle with partial immunity to lungworm are exposed to a high challenge, for example pastures that were previously grazed by calves, they can develop severe coughing or milk drop (reinfection syndrome). This occurs because the immune system kills migrating larvae. Most of these animals will not have detectable lungworm larvae in the faeces. A diagnosis is then made on grazing history, clinical signs, and a blood test that measures the levels of a particular type of white blood cell (eosinophil). Liver fluke If cattle were treated at housing for liver fluke, it is usually not necessary to treat until later in the grazing season. Cattle which were not treated at housing may have adult parasites which can result in contamination of the pastures with liver fluke eggs. A flukicide that is effective against adult fluke should then be used before turnout to prevent this. First season grazers should not initially carry any liver fluke and should not need treatment until the autumn or housing. However, heavily contaminated pastures may expose animals earlier to liver fluke. Weather and farm history will influence this, and farmers should seek the advice of their veterinary practitioner.
Detailed information leaflets on Liver Fluke and Lungworm are available on the Animal Health Ireland website
BEEF HEALTHCHECK NEWSLETTER SPRING EDITION
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