Meeting pregnant ewes' dietary needs in winter
Published 12/01/2010 | 05:00
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.