Dr Eileen McCloskey, Sheep Technologists CAFRE, Greenmount
GOOD ewe nutrition is vital for successful flock performance.
The feed requirements of the ewe will vary significantly throughout her pro-ductive cycle.
Offering the correct amount and type of feed at key times is essential to ensure best performance and good health. Nutrition during late pregnancy (day 90-145) influences lamb birth weight and viability, colostrum supply, lambing difficulty, mothering ability, ewe mortality and subsequent lamb growth rates. Therefore appropriate feeding dur-ing the final six-eight weeks pre lambing is vital.
Feed requirements will depend on a number of factors such as litter size and ewe body condition. In late pregnancy energy and protein requirements will increase rapidly potentially doubling for ewes carrying twins.
However, as the lambs grow, rumen space is reduced and appetite can be reduced by 30 per cent making it difficult for the ewe to meet all the nutrient demands from forage alone.
Supplementary feeding will greatly
depend on the availability and quality of forage and the system, for example outdoor or indoor lambing. Where ewes are housed and fed silage, hay or straw they will need some level of concentrate feeding because the forage will not be balanced in terms of energy, protein, minerals and vitamins and also because in the latter stages of pregnancy foetal growth will inhibit their ability to consume sufficient levels of bulky forage.
The data in Table 1 highlights the significant range in concentrate feed levels required for a 70kg twin bearing ewe offered a ranged of forages.
Offering precision chop silage with a high energy and protein level will greatly reduce concentrate feed requirements. Big bale silage of similar quality to precision chop silage will require higher feed levels as the physical nature of the forage will reduce intake.
Concentrate feed quality
Concentrate feed quality is also critical. While energy is a very important component of the ration, it’s not stated on the label, discuss with supplier and be aware of the difference between fresh and dry matter. In the absence of this information, look for a ration which contains high energy ingredients such as barley, wheat, maize, citrus/beet pulp, soyabean meal and distillers (be cautious with the levels of distillers as certain breeds are more susceptible to copper toxicity).
Protein is also very important, especially in the final three weeks of pregnancy. Most feeds will be sold with a declaration of crude protein percentage which should be at least 16-18 per cent in a pre-lambing ration.
Protein quality is extremely important so ensure that the ration contains good quality ingredients, ideally soyabean meal, as the main protein source followed by rapeseed meal. Avoid feeds with high levels of poor quality proteins. The rate of inclusion of ingredients will be listed in descending order with the highest levels first. Ensure the ration contains appropriate mineral and vitamins for your stock and feeding regime.
It is important to have adequate trough space to avoid competition and aggression when sheep are given concentrate feed and all animals are fed together to ensure that all ewes receive an adequate amount. Recommended feed space requirements for manually-fed ewes are stated in Table 2.
When feeding ad lib (within a total mixed ration) trough space can normally be provided within the range 10-12cm per ewe, dependent upon ewe size.
A good grass-based system has the potential to meet all the demands of the pregnant and lactating ewe without offering supplementary feeding. Like housed systems it will depend on ewe condition, litter size and grass quality while taking into account lambing date, weather and ground conditions. Spring grass can provide a food source with 10-12MJ of energy and 16-22 per cent crude protein per kg/DM. Target swards heights at 4-5cm and stock appropriately based on grass quality, growing conditions and litter size. Ewe condition should be regularly monitored and additional feed offered if required.
Correct management of the ewe during the last six to eight weeks pre-lambing is critical as 75 per cent of lamb growth occurs during this time as well as udder development and colostrum production.
The level of supplementary feeding will depend on the body condition of the ewe, litter size, type and quality of forage available.
Silages should be well fermented, have a good energy, protein, dry matter and D value and be free from soil contamination. This will improve intake values, reduce the need for supplementation and avoid issues such as listeriosis.
It is essential to know the quality of the forage offered to ensure appropriate concentrate levels which meet the demands of the ewe but are also economic, ask your nutritionist or feed supplier about forage analysis.
Understand the quality of the concentrate feed; check energy, protein and mineral and vitamin levels as well as the quality and inclusion of individual ingredients.
If ewes are housed, appropriate feed space is essential to avoid under feeding and aggression. Always ensure a good supply of fresh water, especially where high levels of concentrate feed are offered.