Pregnancy scanning for multiples every year is strongly encouraged and should be seen as an investment rather than a cost.
Benefits of scanning include:
Allows appropriate allocation of feed for single and twin-bearing ewes.
Allows monitoring of ram performance, and early identification of problems.
Better feeding of twin-bearing ewes to reduce losses from metabolic diseases.
Avoid over-feeding of single-bearing ewes.
Determines early and late-lambing ewes for lambing management and selection.
Allows pre-lamb anthelmintic treatments to be targeted at those ewes that really need it.
Helps ascertain were losses may be occurring so that plans can be put in place to minimise these losses in the future and hence maximise flock performance.
Figure: Ultrasound scan of a ewe carrying twin lambs.
Planning for twins, earlies and lates
Scanning and separating ewes based on condition score and the number of lambs they carry enables better allocation of paddocks and pasture to sheep. It is more efficient to run 3-5 year old ewes together and draft on ewe condition and pregnancy status than age groups.
Ewes that are empty at scanning need to be marked and drafted off. These ewes are not productive and should be culled.
Managing ewes during pregnancy
Ewe condition score targets need to be maintained. When BCS cannot be maintained by grazing management in late pregnancy, supplementary feed should be considered.
Any ewes that fail to hit their BCS targets (see nutrition) should be drafted out for preferential feeding. Ensuring ewes are set stocked prior to lambing in good body condition is essential for optimising lamb survival and pre-weaning growth rates.
Ewes approaching lambing lose their resistance to internal parasites, leading to increased numbers of worms surviving in their gut as well as higher number of eggs being produced per worm, therefore increasing the faecal output of parasite eggs onto pasture. The better ewes are managed at this time, the shorter this parasite contamination of pasture will be.
Four weeks before lambing, draft out multiple and late lambing ewes, and allocate to lambing paddocks. Match expected lamb numbers to paddocks, i.e. put ‘early twins’ in the best paddocks, ‘late twins’ in the second best, ‘early singles’ next, then leave the poorest paddocks for the late single-bearing ewes.
Managing Lactating Ewes
Reducing the loss of ewe condition through the early lactation period is essential to ensure plenty of milk is available for lambs. As peak milk consumption occurs about 3 weeks into lambing, ewes should be fed as much as they can eat at this time.
Additionally, increased parasitic challenge during late pregnancy and early lactation means that FEC should be monitored prior to management milestones such as set stocking and lamb marking, and worming strategies should be practiced to minimise pasture contamination.
Note that lambs born to ewes that are in poor condition and hence lactate poorly, will eat pasture earlier and be subject to the negative effects of parasite challenge earlier.
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