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Pre-mating Management

19 August 2022

Ram sales are well in progress and early lambing pedigree flocks are already preparing ewes for mating in the next few weeks, meaning it is time again to start preparing the bulk of ewes for mating to lamb in the main lambing season (March – May).  Ensuring ewes have sufficient body reserves and are on a good plane of nutrition pre-mating is essential to promote ovulation.  The assessment of body condition score post weaning is important to identify under conditioned ewes that may need supplementary feeding to promote optimum ovulation pre-mating. Ideally at mating we are aiming for a BCS of 3.5 – 4.0 in a 70kg lowland ewe and 2.5 – 3.0 in a 50kg hill ewe. Ewes that are overfat before mating should ideally be separated from over thin ewes to allow for separate management pre-mating. Ideally ewes >4.0 should be maintained on current grazing with the best available grazing reserved for leaner ewes.

With many areas of the country now struggling for grazing following the prolonged dry spell we have been experiencing, availability of good quality grazing to flush thin ewes could be an issue, if pasture does not to recover in time. In the absence of good quality autumn grazing (10 MJ/kg ME and 90 g/kg MP), we need to that ensure thinner ewe’s additional nutritional requirements are met to increase nutritional reserves promoting ovulation for a successful mating. It is thought that a reduction in one unit of BCS can account for a 0.45 reduction in ovulation rate. For a lowland flock of 100 ewes scanning normally at 180% this would mean a reduction of 8.1 lambs if 10 ewes were to be under target by 1 BCS, reducing lambing percentage to 172% highlighting the importance of management of under conditioned ewes pre-mating on the success of the future lamb crop.

Alternative methods of flushing thin ewes include:

  • Provision of supplementary forage either silage or hay.
  • Concentrate feeding typically no more than 400g/d of a high energy 16% protein feed reducing to 250g/d at mating.
  • Supplementing forage with a high energy pre-mating blocks aiming for around 300g/d intake depending on block provided.
  • Sourcing additional grazing away from farm allowing mating fields to rest.

Now is also the time to start planning to manage grazing available over mating. Either by resting pasture, reducing stocking density of land required and considering the application of adequate fertiliser to promote growth of forage for sufficient grazing to ensure we can minimise movement and therefore stress to stock over mating to further enhance potential success of the next lamb crop.


Lorna Shaw,


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