Nematodirus and Coccidiosis risks in youngstock


Nematodirus is a particularly nasty disease in lambs, which can strike quickly causing high lamb mortalities and stunting the growth of many others. It can be seen in cattle but is less commonplace. The battus worm causes the infection which can pass from lamb to lamb and has a different lifecycle to other sheep worms. Fecal Egg Counts (FEC) may not identify the risk initially, as mass hatchings can occur after cold weather followed quickly by a warm spell. This is because non egg producing immature larvae cause most damage. So instead on relying on FEC in this instance, consider if lambs are grazing pasture that carried lambs last spring and if they are now consuming a significant amount of grass -if they are then, they are at risk. The SCOPS Nematodirus Forecast https://www.scops.org.uk/forecasts/nematodirus-forecast/ is based on temperature data from 140 weather stations across the UK and should be utilised to predict risk in a particular region. However, nematodirus eggs can hatch earlier in warmer, more sheltered fields and it is important to consider potential variations from field to field and farm to farm. The class of white (1-BZ) drench is still effective and several treatments at different times may be required, particularly if a longer lambing period results in groups of lambs beginning to graze and inject larvae over a longer period. It is essential to drench correctly and follow all the basic steps as with any oral treatments.


Coccidiosis is another concern particularly for grazing lambs and calves resulting in diarrhoea, poor weight gain, and sometimes death. Coccidiosis is caused by a single celled microscopic Eimeria parasite that multiplies in the intestine of infected animals bursting the cells open damaging the inside lining of the gut reducing the absorptive capacity and causing distress to an animal.


Not all Coccidiosis species are harmful, and many strains exist. The disease causing Eimeria species in cattle or sheep are spread in faeces or by oral contact. They are host specific so calves can be turned out on pasture that held infected lambs or vice versa. Eggs or oocysts can remain though and are very resilient and many disinfectants are ineffective if cleaning sheds so the formulation and dilution rates should be checked. On pasture, oocysts can remain over winter even so if the field was contaminated the previous season pasture rotation the following year should be followed.


Infection therefore can occur in contaminated housing often observed amongst dairy calves. Beef calves or young cattle recently turned out onto pasture can also be at risk. In particular, water courses can become heavily contaminated if the flow of water lessens or only pools remain. These areas where possible should be fenced off and water supplied via mains pipes into a drinking trough. Areas around feeders where ground becomes poached can also become heavily infected especially during warmer weather and should be moved where possible. It is also important to prevent creep feed becoming soiled with animal waste which also applies to housed youngstock too.


Due to the similar symptoms in grazing lambs, it is important to determine if Eimeria or Nematodirus infection is present. Concurrent infection with both parasites is not uncommon, potentially leading to even greater disease severity.


Preventative treatment for both Nematodirus and Coccidiosis is commonly done by oral drench.

Look at your equipment before you start

  • Weigh-crates need to be accurate, remove any build-up of woolly dags -even consider changing to a digital weighing system upgrading the faithful and well used dial scale.

  • Drench guns need to deliver the correct dose and chambers and valves need to be clean and lightly lubricated. Tubes also need to be securely in place and clean. Fit non kink springs when attaching to a drench pack if possible. All factors that can cause air bubbles to form. Regular cleaning with warm soapy water after use assists the longevity and accuracy of drench guns.


Drenching correctly