Influencing lamb survival
Now that ewes are pregnant, the focus turns to maximising lambs' survival.
Placental development influences lamb birthweight, which in turn strongly determines survival rates post birth. The development of the placenta between 30 to 90 days has the greatest effect on subsequent birthweights of lambs.
Ewes need to eat approximately 1.3 to 1.5 kg of good quality dry matter to maintain body condition through the early to mid-point of pregnancy.
Ultrasound scanning occurs between days 60 to 90 of pregnancy. This gives important information on pregnancy status and helps identify multiple carrying ewes who have higher energy demands. Scanning also provides an opportunity to physically Body Condition Score (BCS) ewes. Separate light ewes with a BCS of less than 3 and preferentially provide energy dense, high protein feed over the next 30 days before the rumen fill is restricted by the rapidly growing foetuses in the last month of pregnancy.
If quality feed is short in supply, consider supplementary feed such as sheep nuts or dehydrated molasses blocks containing bypass protein.
Foetal growth in the last 50 days of pregnancy is rapid and coincides with significant udder development by the ewe for subsequent colostrum production and lactation. Rumen space is restricted resulting in an inability to physically eat enough energy/protein for the demands of the foetuses. Feed restriction at this stage of pregnancy increases metabolic problems for the ewe and results in poor milk quality and quantity for the lactation. With severe feed restrictions, ketosis (sleepy sickness) or hypocalcaemia (milk fever) occur and result in higher rates of lamb deaths and even ewe deaths. These problems are preventable through identifying at risk ewes early and feeding them a highly nutritious diet.
For more information on the types of supplements suitable for your ewes pre-lambing, contact your local PGG Wrightson Technical Field Representative.