A focus on pre-lambing feeding

Most ewe flocks in the South Island took advantage of a good autumn flush in March and April and were on a rising plane of nutrition pre-tupping. With a cold and wet May the growth of pasture and crops had stopped. June and July have also been very slow, which means feed on and off farm is limited.

This means the reality will be that many ewe flocks in the two months leading up to lambing will be fed on mainly silage, baleage and hay which have an average quality of 9-10 MJ ME/kg DM and 11-14 % protein.

Most ewe flocks will be scanned by now and split up in singles, multiples and dries to ensure the best quality feed and allowance goes to the flocks having multiple lambs.

Pre-lambing feeding has a major impact on lamb survival and lamb growth rates:

  • The conceptus(embryo) takes up a lot of abdominal space, which compresses the rumen and therefore reduces the feed intake. This is especially true for bulky slower digesting feeds like baleage, silage and hay, or feeds with a low DM content (e.g. below 15%).
  • Although the lamb size at birth weight is mostly set at 90 days in pregnancy, the fat reserves are put on the lamb in the last 60 days of pregnancy. Lambs with more energy stored as fat at birth are better equipped to survive spells of bad weather in spring and maintain their suckling drive.
  • When ewes are having multiple lambs they easily lose condition, which is unseen in the last two months. This can cause sleepy sickness (ketosis/acetonaemia) but this will also reduce colostrum and milk production after lambing. In the first four weeks 80% of the lamb's growth is derived from milk production.
  • Ewes having single lambs can become overweight when they are provided high quality feed which can lead to lambing difficulties. This is best addressed by feeding them less or more bulkier feed between scanning and 120 days of pregnancy, but not in the last month before lambing.
  • Selenium, iodine and the cobalt-containing vitamin B12 are transferred via the placenta to the lambs in the last 4-8 weeks pre-lambing and also after birth through the colostrum. Ensuring the ewe gets the right amount of each enables you to look after the lambs in the first six weeks of their lives and achieve good lamb survival and growth rates.

Best use of supplements

Normal practice is to setstock the ewes 1-2 weeks before expected lambing on good quality pasture. In a situation of low pasture covers and growth it is better to wait as long as possible with set stocking to prevent the ewes with lambs running out of feed in the first month. Otherwise this would undo a lot of good work earlier on. Set your best quality silage or baleage aside for feeding the last 6-8 weeks prelambing to the multiple bearing ewes. Put the bales aside and write on them with permanent marker straight after they have been wrapped, this prevents 'mistakes' later on.

In the South Island, barley is commonly used to supplement ewes in late pregnancy, because of its

  • Higher energy content; 11.5-12.5 MJ ME/kg
  • Economics: lower cost per MJ ME than baleage
  • Less bulk and fibre, hence its intake is not limited by 'rumen fill'

There are however a few issues with barley, the quality can be variable and difficult to effectively feed out in the paddock, mainly in wet conditions. It pays to deal with a reputable supplier who can supply grain with good test-weights and low screenings.

Alternatively you can use a balanced feed like the Reliance Sheep Nut. It contains quality ingredients like barley, wheat, molasses, soya-oil and also the macro-minerals, trace-elements and vitamins. The pelletising process in the feedmill enhances the digestibility and the utilisation in the paddock.

For high performing ewes with triplets or twins, the Reliance Triplet Nut has been developed in the past in cooperation with the researchers at Invermay. Beside the normal ingredients like in the sheep nut, the Triplet Nut contains a high level of balanced bypass protein (3 different sources). This supports the unborn lamb and its mother and also results in more colostrum early on, which is crucial for the survival of triplet and twin lambs.