Lamb losses are very costly and reducing losses by just 1 per cent could help boost returns this season. They can occur at any stage of lamb development and knowing where you are losing lambs is essential to be able to put management decisions in place to address the issue.
Katie Brian, Eblex Better Returns Programme project manager, says: “Effectively managing ewes to ensure they are at their optimum body condition score throughout the year will help minimise the risk of both ewe and lamb mortality.
“But there is a lot to be learnt from what has happened before and the first step in reducing lamb losses is keeping a record of them. Only when a problem is identified can changes be made to improve.”
At this busy time, it is often a low priority to document this information, but it is difficult to identify problems without it.
Miss Brian says: “Farmers should aim to keep total losses below 15 per cent. The Stocktake Report 2014 highlighted the top third of farmers had losses of seven per cent in their flock [lowland breeding], so this target is achievable.”
Lamb losses will affect many other key performance indicators, such as lambs reared per 100 ewes to ram, the weight of lamb reared per ewe to ram and, in the early stages of pregnancy, the scanning percentage.
A key activity prior to lambing is to scan ewes and segregate them using scanning results and body condition score (BCS). Nutrition requirements can then be matched to each group – this is important because during the latter stages of pregnancy, 70 per cent of foetus growth occurs and the udder develops.
A project in New Zealand has shown lamb survival decreases by five per cent for every half BCS lost in the four weeks prior to lambing. And during lambing, every half BCS below three equates to a further five per cent reduction in terms of lamb survival. Therefore optimum management of BCS will decrease the risk of lamb losses and improve the daily liveweight gain to weaning.
Miss Brian says: “Alongside preparing the ewe in terms of nutrition, BCS, health and stockmanship, regular monitoring should ensure any problems are dealt with quickly before they spread within the flock. There is a lot to be said for getting sheds and equipment prepared to ensure you are totally ready before lambing starts.”
At lambing, it is essential to regularly observe the behaviour of ewes and assist them if they have not given birth to a lamb within one hour for experienced ewes and two hours for ewe lambs. Hygiene is important and you should always wear gloves and use plenty of lubrication to assist ewes.
Small or weak lambs will often not take in sufficient colostrum, which can result in starvation, hypothermia and disease. Colostrum is vital to the newborn lamb, as it contains energy, protein and essential immunoglobulins to protect against disease. Lambs need at least 50ml/kg of colostrum in their first four to six hours of life and they will need 200ml/kg within the first 24 hours.
Miss Brian says it is essential lambs are checked to ensure they have suckled sufficient colostrum within the first few hours of life.
“Triplets or lambs from ewes lacking milk may require a supplement of colostrum. But if they are weak or unconscious, a glucose injection will be required first.”
Mismothering will lead to increased losses, as penning the ewe and lambs can help them bond with their offspring. Helping them to start suckling may make them more accepting.