We are all delighted to see the weather picking up, with the last 10 days or so being very mild. However, the warm weatheris creating the perfect conditions for problems with nematodirus in lambs in certain flocks. This is a gut worm affecting mostly lambs but also sometimes calves that can cause profuse watery scours, sometimes deaths and severe lack of thrive.
It has a different life cycle than most of the other gutworms. The eggs will survive over winter and on the ground and the larvae will hatch out following a change of temperature for a period of weeks. The eggs can survive up to two years in pasture and this creates a problem where lambs are grazing the same pastures each spring.
With the right conditions, this will lead to very high levels of infective larvae on certain pastures at certain times of the year. The hatching of the eggs and release of larvae usually coincides with older lambs being out and starting to consume grass. The affected lambs are usually 6-12 weeks; younger lambs are suckling while older lambs tend to develop immunity after 12 weeks. The risk period is from late April to early June in most farms.
Due to the fact that it can be sudden outbreak faecal egg counts are sometimes low. However, if found on dung samples, it is recommended all lambs should be dosed. Nematodirus risk assessment can be done on each flock, past history means a routine dose is often given on those farms. I will often see it in conjunction with coccidiosis or sometimes it is mistaken for coccidiosis.
The risk factors
A sudden change in the weather with warm conditions following a cold spell.Lambs grazing the same pasture annually leading to a build up of the parasite.Age group of 6-12 weeks but it can affect younger and sometimes older lambs later on in the summer.Where coccidiosis is also an issue it can contribute to the problem.Pet lambs or triplets that are grazing more or weaker lambs have less resistance.The treatment thankfully is quiet straightforward. A white dose or benzimidazole will work well and is all that is needed; there is thankfully no reported resistance. I usually recommend a cheap white dose and repeat if nesscessary in 4-6 weeks if there is spread in lambs age and groups or heavy grazing.
In most flocks one well timed dose is enough, so talk to your own vet about dosing lambs. I also have seen this in the last two years occasionally causing scours in calves on pasture. With young calves being turned out and scouring it is one of my differentials. This is not about scaring farmers but more about being aware of the risk and certain flocks might not have an issue. Certainly with scour in lambs from now on, this parasite would be one of my main differentials along with coccidiosis.
We are all delighted to see the weather picking up, with the last 10 days or so being very mild. However, the warm weatheris creating the perfect conditions for problems with nematodirus in lambs in certain flocks. This is a gut worm affecting mostly lambs but also sometimes calves that can cause profuse watery scours, sometimes deaths and severe lack of thrive.
It has a different life cycle than most of the other gutworms. The eggs will survive over winter and on the ground and the larvae will hatch out following a change of temperature for a period of weeks. The eggs can survive up to two years in pasture and this creates a problem where lambs are grazing the same pastures each spring.
With the right conditions, this will lead to very high levels of infective larvae on certain pastures at certain times of the year. The hatching of the eggs and release of larvae usually coincides with older lambs being out and starting to consume grass. The affected lambs are usually 6-12 weeks; younger lambs are suckling while older lambs tend to develop immunity after 12 weeks. The risk period is from late April to early June in most farms.
Due to the fact that it can be sudden outbreak faecal egg counts are sometimes low. However, if found on dung samples, it is recommended all lambs should be dosed. Nematodirus risk assessment can be done on each flock, past history means a routine dose is often given on those farms. I will often see it in conjunction with coccidiosis or sometimes it is mistaken for coccidiosis.
The risk factors
A sudden change in the weather with warm conditions following a cold spell.Lambs grazing the same pasture annually leading to a build up of the parasite.Age group of 6-12 weeks but it can affect younger and sometimes older lambs later on in the summer.Where coccidiosis is also an issue it can contribute to the problem.Pet lambs or triplets that are grazing more or weaker lambs have less resistance.The treatment thankfully is quiet straightforward. A white dose or benzimidazole will work well and is all that is needed; there is thankfully no reported resistance. I usually recommend a cheap white dose and repeat if nesscessary in 4-6 weeks if there is spread in lambs age and groups or heavy grazing.
In most flocks one well timed dose is enough, so talk to your own vet about dosing lambs. I also have seen this in the last two years occasionally causing scours in calves on pasture. With young calves being turned out and scouring it is one of my differentials. This is not about scaring farmers but more about being aware of the risk and certain flocks might not have an issue. Certainly with scour in lambs from now on, this parasite would be one of my main differentials along with coccidiosis.
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