Sheep farmers are being urged to stay vigilant for signs of twin lamb disease (pregnancy toxaemia) this winter, with cold weather and variable forage quality increasing the risk in late-pregnant ewes.
Twin lamb disease occurs when a ewe goes into negative energy balance, meaning she is using more energy than her diet provides. As a result, levels of compounds called ketones in the blood start to rise. This leads to clinical signs such as:
- Dullness
- Weakness
- Loss of appetite
- Muscle tremors
- Disorientation
- In severe cases, abortion, stillbirths or ewe deaths.
Who’s most at risk?
Nettex Commercial and Technical Manager Nia Williams says certain groups of ewes are particularly vulnerable.
“Ewes carrying twins or triplets in the final six weeks of pregnancy are at greatest risk,” explains Mrs Williams. “But those that are under or over-conditioned, have underlying disease or parasite challenges, or are on rations that don’t meet their energy demands are also highly susceptible. The latter is a particular concern this year, with forage quality and quantity being so variable on farms across the country.”
Body condition score management (BCS) is pivotal to prevention of twin lamb disease. Target BCS at lambing is 3.0-3.5 for lowland breeds and 2.5-3.0 for hill breeds. Studies have shown that ewes in BCS of 2.0 or below are at significantly higher risk of suffering from twin lamb disease1.
The condition can strike flocks of all types, especially when weather or management changes — such as regrouping or moving ewes — reduce feed intakes.
Research has shown the impacts can be devastating, with up to 80% mortality in untreated cases¹. It is also reported that only around 12% of lambs born to affected ewes survive¹. Difficult lambings and higher rates of mastitis are also common.
“Due to the devastating impact twin lamb disease can have, prevention is a must — and that hinges on accurate nutrition and monitoring in the run-up to lambing,” says Mrs Williams.
Nutrition and prevention
“Body condition scoring and ultrasound scanning are two simple but powerful tools,” adds Mrs Williams. “By grouping ewes according to litter size, you can feed them appropriately and avoid both under- and overfeeding. Also, knowing exactly what you’re feeding and balancing rations appropriately is important.”
Blood testing for ketone levels as part of a pre-lambing metabolic profile can also help monitor the energy status of pregnant ewes, allowing for ration adjustments before problems escalate. Ewes should be sampled 3-4 weeks before lambing is due to start, ensuring that the earliest lambing ewes in average body condition are selected.
“Where trace elements may be lacking, for example on forage-only diets or where unmineralised home-mixes are fed, ensuring they’re balanced using something like Nettex Sheep Conditioning Drench or an Endurabol Sheep bolus is important,” she says.
However, Mrs Williams adds that stress, sudden dietary changes or extreme weather can all trigger cases in late pregnancy, so any dietary changes should be introduced gradually.
“Even small disruptions – moving or mixing groups, or a few days of poor appetite due to bad weather – can tip high-risk ewes into trouble,” she warns.
Acting quickly
Early detection is vital. Ewes may initially appear slightly dull, reluctant to feed or ‘twitchy’ – all signs of rising ketone levels. Treatment at this stage will have the greatest chance of success.
“When energy levels crash, every hour counts. Ewes simply don’t have the reserves to recover without intervention,” says Mrs Williams.
That’s where Nettex’s Multi Lamb Rapid can play a key role. The high-energy, concentrated liquid is formulated for the reduction of the risk and recuperation from Ketosis.
Each 495ml bottle contains enough for 11 feeds, making it a practical on-farm option for dealing with at-risk animals.
“Energy means life,” says Mrs Williams. “Multi Lamb Rapid provides an immediate energy lift, helping ewes regain appetite and strength while rebalancing essential nutrients. Used promptly, it can be the difference between losing and saving both ewe and lambs.”
“By keeping an eye on ewe condition, feeding according to litter size, and acting quickly with an energy drench if needed, farmers can safeguard ewe health and give lambs the best possible start,” adds Mrs Williams.
References:
¹ Crilly, J., Phythian, C., & Evans, M. (2021). Advances in managing pregnancy toxaemia in sheep. In Practice. Advance online publication. https://doi.org/10.1002/inpr.17
