Get feed right for pregnant ewes
As ewes enter the final third of pregnancy, it is important to get nutrition right because 75pc of foetal growth takes place in the last seven weeks of pregnancy. This is why getting ewe nutrition right in the last third of pregnancy is so important.
For ewes that are starting lambing in March, now is the time to start thinking about supplementary feeding.
Where ewes are housed and fed a diet of hay or silage there will be a requirement for additional energy, protein and minerals/vitamins to meet the requirements of the growing foetus. This additional supplementation is required for two reasons. Firstly, because the conserved roughage is not balanced in terms of energy, protein and minerals/vitamins, and secondly, because the rapid growth of the foetus inhibits the ewe's ability to consume sufficient roughage.
Where the ewes are not able to consume sufficient nutrients to meet the demands of the unborn lamb(s), there can be serious consequences. At best the lambs will be small (underweight) at birth. These lambs will be weaker, resulting in higher mortality and lower lamb weaning weights and delayed drafting. It's also likely that the ewes will be short of colostrum and that subsequent milk yield will be negatively affected. More severe cases of underfeeding can trigger twin lamb disease (pregnancy toxaemia) where the ewes will die if they are not treated promptly.
In short, the message is that underfeeding the ewe in late pregnancy will compromise ewe/lamb performance, increase your workload and see an increase in both ewe and lamb mortality.
To avoid this happening on your farm you will need to understand how the nutritional needs of the ewe change throughout the last few weeks of pregnancy.
Energy is the most important portion of your ewe ration. Unfortunately, most rations in Ireland are sold on the basis of protein percentage (eg Ewe 16 or Ewe 18). We have a methodology for measuring the energy value of a ration called UFL but it is seldom used by millers and compounders when they are selling a ration. The UFL system is based on a French rating system which rates all ingredients relative to barley. One UFL is the equivalent of one kilogramme of air dry barley. Ideally concentrate feeds for ewes in late pregnancy should have a UFL value of at least 0.95.
Where a concentrate feed contains this level of energy, the ewes' nutritional needs can be met using the recommended feeding rates outlined in the accompanying table, above.