Breeding ewe lamb replacements
• Remove rams from ewe lambs after 21 days.
Well grown replacement ewe lambs (48kg plus) that have been teased for 14/17 days before ram turn out should have over 70% mated in the first cycle. The general advice is to take rams out from ewe lambs after 30-35 days. There is now some evidence that overall flock fertility can be improved by selecting replacements only from those ewe lambs that go in lamb after one service, i.e., rams are removed after 17 days. This practice will result in a flock with higher fertility with more ewes holding to first service and fewer repeat or barren ewes. To be able to do this you need to keep 25/30% more replacement ewe lambs than is needed for flock replacements and cull those that don’t prove in lamb. Like mature ewes, ewe lambs should not be subjected to any undue stress for the first 30 days of pregnancy. Keep them on an even plane of nutrition for the first third of pregnancy. Trials in Northern Ireland and at SAC Scotland have shown that overfeeding ewe lambs at this stage will result in lighter lamb birth weights and higher lamb mortality at lambing. The target live weight gain is 80gm/day or 0.6kg per week. Good to medium-quality grass will be sufficient to achieve this rate of gain.