Frozen and snow-covered ground has made grazing conditions difficult for sheep that are outdoors. At this stage many mid-season flocks will be entering the final third of pregnancy. It is during this period that 75pc of foetal growth takes place and this places huge demands on the heavily pregnant ewe.
Sheep are unusual animals insofar as their ability to consume enough food decreases as their requirement for extra nutrients increases. This is due to the space that the rapidly growing lambs take up inside the ewe, and this has the effect of reducing the space into which the rumen (stomach) can expand into.
It is up to the shepherd to take steps to ensure that the ewe's nutritional requirements are met. Failure to meet these will, at best, result in undersized and weak lambs at birth and ewes with little milk to rear these lambs. In more extreme cases the ewes will succumb to twin lamb disease (pregnancy toxaemia), which can result in the death of the ewe and her unborn lambs.
In situations where ewes are housed, the diet being fed is completely under the control of the shepherd. During the last six or seven-week period the amount of energy and protein required by the ewe increases sharply. As the roughage in the diet will not be able to meet these requirements (because the sheep is not able to consume enough), some of these extra nutrients have to be supplied as concentrate feed.
The accompanying table (right) outlines how much concentrate feed should be given and when feeding should start. It is important to note that many winter forages this year are low in digestibility (due to delayed harvesting) so concentrate supplementation may have to start earlier than the traditional six or seven weeks pre-lambing.
When selecting your concentrates, aim for one which has good quality ingredients. Cereals (oats, barley, maize and wheat) and pulps (citrus and beet) are good energy feeds. Protein sources that are high in energy should also be chosen. Soya is the product of choice when it comes to protein but it is somewhat expensive. Distillers' grains, peas and beans are also good on both protein and energy.
Rapeseed meal -- restrict levels to a maximum of 15pc -- and maize gluten are also high in protein, but tend to drag down the energy value somewhat. Don't forget the minerals and vitamins as these are important for pregnant ewes. Over-feeding of minerals can do more harm than good so stick to the manufacturer's recommendations.
In situations where there is not sufficient winter roughage available to supplement the ewes or where ewes are not normally housed but have been housed due to snow, for example, it is possible to get away with just concentrate feed alone.
The trick is to make sure that you have at least 8pc crude fibre in the diet. Good sources of fibre are: pulps (citrus and beet), soya hulls, oats, rapeseed, grass meal. Your aim should be to supply the ewes with about 1kg of concentrate (0.9ufl energy value), which should be fed in two feeds.
Ewes will have to be built up gradually to this level of meal feeding to avoid acidosis. In the final six weeks of pregnancy this feeding level needs to increase gradually up to about 1.5kg concentrate feed at lambing (for twin bearing ewes). At these high feeding levels check with the suppliers that the mineral inclusion level in the ration is suitable for longer-term feeding.
On hill/rough grazing supplementing ewes with high energy/protein blocks or feeds can greatly increase the digestibility of the natural roughage that is available. This should be considered in areas where sheep are under nutritional pressure and cannot be housed or moved to grass.