2 days Ago By By The Newsroom
Sign up to our daily Farming Life Today newsletter Did you know with an ad-lite subscription to Farming Life, you get 70% fewer ads while viewing the news that matters to you. Farmers work tirelessly over lambing to ensure they achieve the best crop of lambs despite many challenges from weather to diseases. Thankfully this spring we have had good weather and for many farmers they will have got ewes and lambs turned out to grass quickly.
Farmers will now be considering what animal health planning will be required for their lambs to ensure they achieve their required growth rates. Firstly, the most major risk to lambs turned out to grass is the internal parasite worm Nematodirus. It can strike very quickly with little warning causing high mortalities in lambs and stunting growth and therefore farmers need to act swiftly to deal with it.
Advertisement Advertisement Unlike other worms Nematodirus has a different lifecycle where the development of the effective larvae takes place within the egg and the infection is passed from one crop of lambs to another grazing the same field. As a result, faecal egg counts (FECs) are not a reliable indicator for Nematodirus. Lambs at most risk are generally lambs from 6 weeks of age and over that are grazing (may be younger if ewe has low milk supplies), lambs grazing fields that had lambs present last spring and lambs under other stresses e.
g. triplets, disease etc. Nematodirus hatches occur when there has been cold weather followed by warm weather of 10°C or more.
If avoiding pastures grazed previously by lambs is not possible, farmers should watch the SCOPs Nematodirus forecast and should treat lambs accordingly with a white (1-BZ) drench. Gut worms start to effect lambs around 4-6 weeks of age when the lambs start eating grass and ingesting worm larvae. Due to an increase in anthelmintic resistance farmers are advised against blanket dosing.
When deciding to worm lambs farmers should carry out a FECs through collecting a represented sample of faeces from the group and sampling. The FEC will give approximate measure of the severity of the worm burden present in lambs. Farmers are advised to discuss the results with their vet or SQP to determine a treatment plan.
Farmers should also monitor lamb weight gain through observation or regular weighing. Lambs that are not meeting their daily liveweight gain can be an indication of a worm burden. Farmers when monitoring lambs should also check for cleanliness of back ends and condition of lambs.
There are five worm classes including Group 1 BZ, white drench, Benzimidazoles, Group 2 LV, yellow drench, Levamisole, Group 3 ML, clear drench, Ivermectin, Doromectin, Moxidectin, Group 4 AD, orange drench and Group 5 SI, purple drench (Group 4 and 5 are recommended for a quarantine dose and one-off dose for lambs in the later grazing season). When selecting which wormer to use farmers must be aware of which wormer is effective on farm and what wormers there is resistance to. Advertisement Advertisement To reduce resistance farmers are advised to rotate wormers classes within a season to ensure worms are not repeatedly exposed to the same wormer drug.
When dosing lambs farmers are advised to avoid treating all lambs in the group and to leave around 10% untreated (lambs that are clean and growing well). This leaves a normal population of resistant and susceptible worms which helps to reduce selection pressure for resistance. It is good practice to return lambs to the previous field for 48 hours after worming before moving to clean grass.
Coccidiosis in lambs effects lambs aged 4-8 weeks old. Symptoms in lambs include diarrhoea containing mucus or blood, straining, pain, weight loss and lamb death. Growth rates can also be effected in older lambs due to the damage to the gut which reduces the ability to absorb nutrients.
Coccidiosis is a single celled microscopic parasite that lives and reproduces in lamb gut cells. When a lamb ingests coccidia oocysts, the oocysts hatch within the gut and invade the gut cells and multiply dramatically. The coccidia emerge by bursting the cells open and damage the lambs’ guts.
The oocysts are then shed in the faeces. Faecal samples can be taken to identify oocyst count however sometimes oocysts are not present in faeces. Farmers are advised to send lambs to postmortem for further diagnostics.
If a farmer identifies there is coccidiosis issue on farm there is preventive and treatment products including Decoquinate which can be added to commercial lamb creep feeds or farmers can dose lambs with diclazuril or toltrazuril drench from 3 weeks of age. Vaccinations on farm are extremely important to prevent diseases such as Clostridial diseases e.g.
lamb dysentery, pulp kidney, braxy, blackleg etc. and pasteurellosis (pneumonia). If ewes were vaccinated for clostridial diseases and pasteurellosis prior to lambing a level of immunity will be passed to the lambs in the first few weeks.
Advertisement Advertisement However, after a few weeks this level of immunity declines and farmers are advised to vaccinate lambs against clostridial diseases and pasteurellosis. Lambs can be vaccinated from 4 weeks of age and receive a booster injection if required 4-6 weeks after. Farmers are advised to speak to their local vets and SQP’s to create a health plan suited to their individual farm.
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