Ewe nutrition during this period has a direct effect on lamb performance, as well as ewe health and performance. By following a few key principles for feeding pre-lambing ewes, we can ensure rumen health and optimise outcomes for both ewes and lambs.
Why the pre-lambing period matters
During the last six weeks of pregnancy, ewes experience a surge in energy requirements due to the rapid growth of their lambs. Foetal weight increases by 70%, 50% and 20% in the last six, four, and 2 weeks before lambing, respectively. This growth reduces rumen capacity, limiting the ewe's ability to eat just as nutrient demands for colostrum and lamb development peak.
Failing to meet these needs can result in issues such as:
- Twin lamb disease (pregnancy toxaemia)
- Poor maternal behaviour and mismothering
- Weak lambs with reduced growth rates
- Lower milk yield and colostrum quality
Conversely, overfeeding can lead to ewes becoming too fat, increasing the risk of prolapse, lambing difficulties, and immune suppression. Striking the right balance is essential.
Below are some basic management and nutrition principles to help meet nutritional needs as efficiently as possible and ensure ewes lamb down in adequate condition.
1. Group Ewes Based on Nutritional Needs
- Scan ewes and divide them into groups based on the number of lambs they are carrying. The differences in nutritional requirements between single, twin and triplet bearing ewes are significant, which makes feeding by lambs carried an absolute priority. (see Figure 1)
- Body condition scoring (BCS) helps identify under-conditioned or over-conditioned ewes, allowing tailored feeding strategies.
- Base feed requirements on mature ewe body weight, as nutritional needs scale with size.
Figure 1: Relative nutritional requirements of pregnant ewes
2. Balance the Diet with Forage and Supplements
Forage is the largest single feed source for ewes, so understanding its quality and making decisions accordingly is key. Start by analysing forage to determine nutrient content, then balance the diet to supplement deficiencies with concentrates.
When energy levels are too low, the ewe is required to mobilise excess energy from her fat reserves, potentially leading to twin lamb disease when the energy gap is too large. Provide a mix of energy sources to support rumen health and meet metabolic demands, including:
- Long fibre (e.g., hay, silage) to maintain rumen structure.
- Digestible fibre (e.g., beet pulp, soya hulls) for sustained energy release.
- Starch and sugar (e.g. cereals) for quick energy and to support colostrum production.
- Plenty of feed access – 15cm/ewe for ad lib forage or 45cm/ewe for concentrates (approximately 30 ewes per standard 15ft6 bay for ad lib forage or 11/ bay for concentrates)
The amount of microbial protein made available to the ewe is crucial, as is optimising rumen function to ensure its uptake. In late pregnancy, ewes need more bypass protein, meaning sources like high-quality soybean meal or rapeseed meal become critical for supplying amino acids.
Did You Know? A 70kg ewe carrying twins requires 60% more metabolizable protein in the final seven weeks of pregnancy.
3. Choose the Right Concentrates
High-quality concentrates, combined with plenty of good-quality forage, reduce the amount of feed needed while improving ewe health and lamb vitality. Key attributes of an effective concentrate include:
- High cereal content to stimulate rumen function.
- Highly concentration of bypass protein such as Soya
- Fortified with vitamin E (150mg/kg) and selenium (0.5mg/kg) to enhance ewe and lamb immunity.
The table below demonstrates how forage quality and pregnancy stage affects concentrate requirements, using a 70kg ewe carrying twins as an example.
Supporting Rumen Health for Optimal Feed Efficiency
Feeding a pre-lambing ewe is about supporting the microbes in her rumen, as they ultimately provide the majority of her nutrients. These microbes convert feed into nutrients that drive lamb performance and ewe health. However, their efficiency declines with sudden diet changes, meal feeding and higher levels of starch and sugars. This is especially true for the fibre digesting microbes, who are sensitive to the resulting changes in rumen pH.
Gradually transition ewes onto pre-lambing diets over 7–10 days to give the rumen microbes time to adjust and avoid a reduction in feed efficiency.
Adding Actisaf® Sc47 live yeast probiotic to ewe diets to support the growth of beneficial microbes that digest fibre and convert lactic acid to propionate, as well as stabilises rumen pH. Other benefits include:
- Increased feed intake
- Improved fibre digestion and more propionate to supply glucose.
- Up to 20% more milk for lambs
- Smooth dietary transitions
- Reduced risk of acidosis
Boosting Immunity and Colostrum Quality
Additionally, ewes prioritize nutrients for their lambs later in pregnancy, which will naturally reduce their immune system’s effectiveness. This leaves them pre-disposed to higher worm burdens and a poorer response to disease, which is especially true for under-conditioned ewes.
Postbiotic Safmannan® premium yeast fraction can support immunity and improves colostrum quality, giving lambs the antibodies needed for a healthy start and ensuring stronger performance later in life.