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Maximise performance by tailoring nutritional requirements of in-lamb ewes

To maximise flock performance, it is important to feed ewes according to their needs at different stages of production, as good ewe nutrition impacts on lamb survival and growth rates. Formulating rations based on forage will help optimise health and welfare in mid to late pregnancy.

In order to feed ewes efficiently and without spending too much money, it is important to maximise the use of forage in the diet, as grazed grass and silage are the cheapest feed sources available for sheep in terms of cost per unit of energy. Maintaining intakes from forage helps to optimise rumen health, but many people believe ewes in late pregnancy - particularly those carrying multiples - are unable to maintain high intake levels of forage because there is less space in the abdomen for digestion. However, the rumen is able to adapt in the later stages of pregnancy and maintain its efficiency.

“In late pregnancy, the space for the rumen is so much smaller, but instead of slowing down, the turnover rate increases and intakes go through much quicker,” sheep specialist John Vipond told farmers at a progression event at Rhiwgriafol, Machynlleth, a Farming Connect Demonstration Farm.

“When feeding in-lamb ewes, we’ve been concentrating on feed tables that are out of date and forgetting about the animal itself. I’m trying to meet the needs of the animal and make progress on reducing lamb losses by moving to high-quality forage topped up with Dietary Undegradable Protein (DUP) and cutting out readily available starch.”

DUP helps correct the deficit between an animal’s protein requirements and the rumen’s ability to produce microbial protein. With a higher turnover rate in late pregnancy, around 12-15% of material escapes degradation in the rumen, reducing the ability to produce microbial protein. Formaldehyde treated soya products contain about 48% crude protein, of which 85-90% is undegradable, helping to meet protein and energy requirements.

In order to use forage effectively and ensure protein and energy levels are being met, it is important to have silages and hay analysed. For the system advocated to work it does need silage with an ME of at least 10.5 so analysis of forage is vital to provide a clear picture of the type and amount of supplementation required.

Dr Vipond also discussed all-grass wintering, explaining that rotational grazing systems can offer a cost-effective alternative to housing.

“It’s a fantastic system if you can grow grass during the winter and you’ve got land that will keep stock without getting poached up,” he added. “If you can’t grow enough grass throughout the winter or there’s a bad spell of weather, you have to have a plan B, such as feeding silage or housing them. But once they’re housed you get the extra costs of straw, feed, energy and labour.”

Dr Vipond recommended a system based on a 100-day rotation, starting 25 days after the tup goes in with the ewes. The minimum total cover target at the beginning of the rotation is 1,700-2,000kg DM, with ewes allocated 1.1kg-1.2kg DM a day.

“If you’ve got a field with 2,200kg DM, graze down to 1,000kg at the start of the rotation, so they’ve got 1,200kg DM available to eat. 1000 ewes would get a hectare, 500 ewes get half a hectare. You have to work out how much feed there is and vary the paddock size according to sward height.”

To maximise grass utilisation, ewes should be moved every 24 hours, and after scanning they may need to be split into different groups.

“Twins will need a bigger allowance of grass, so lift them up to 2kg DM per day, but singles can be managed as a separate mob a couple of paddocks behind. If you left 1,200kg there will be enough grass for them to have a pick at. Otherwise it will be difficult to manage their body condition going into lambing.”

The importance of body condition scoring was also highlighted, with farmers urged to score their ewes regularly and adapt feeding regimes to help meet their nutritional requirements, in order to maximise lamb output.

In-conjunction with Farming Connect, Rhydian is carrying out a project comparing three systems of wintering sheep: housing, swedes and sending ewes away on winter tack. Each will be fully costed, to find out about these results and for information on a planned open day in May, please contact Technical Officer Catherine Nakielny on  01970 631 406 or email catherine.nakielny@menterabusnes.co.uk

Did you know that there is an e-learning module available which covers the topic of ‘Preparing a winter feed budget? The bite-sized interactive module aims to help you to better manage your feed over the winter, and takes around 15 – 20 minutes to complete. You can access the ‘Preparing a winter feed budget’ module along with modules covering a variety of other topics on the BOSS website https://businesswales.gov.wales/boss/lms/login.