Reports from farmers weaning ewes are variable in terms of ewe condition.

Highly stocked farms that found themselves tight on grass and some farmers operating in challenging land types are reporting a higher percentage of ewes in poor body condition.

This is not surprising as this issue dates back to breeding in 2023. At that stage, some flocks had upwards of 20% to 30% of ewes below optimum condition and conditions have remained difficult since then.

Ewes that are under the greatest pressure are typically younger first crop ewes and aged ewes.

The window for ewes to regain body condition is relatively tight. For an early March lambing flock that starts offering ewes preferential treatment now (around 25 July), there is a period of just 11 to 12 weeks before breeding starts.

It will take ewes in good health eight to 10 weeks grazing on good-quality grass to gain one body condition score (BCS). In practical terms, this is equivalent to a ewe gaining 12% to 15% of mature bodyweight or about 10kg to 12kg liveweight in lowland breeds with a mature body weight of approximately 80kg.

Younger ewes and ewes starting in a relatively good position will regain condition much faster, while for ewes lacking significant flesh it will take time for their system to adjust and to start performing positively. This reinforces the importance of taking swift action.

BCS benefits

The benefits of having ewes in ideal body condition at mating are well documented by Teagasc and other research institutions with a strong relationship between ewe liveweight/BCS and subsequent litter size. Taking lowland ewes first, research shows that each one unit increase in BCS within a range of BCS 2.5 to 4 has the potential to increase litter size by 0.13 lambs per ewe joined.

In many non-intensive flocks, there is as much benefit to be gained by addressing ewe condition and maximising the genetic reproductive performance of a breed type with medium prolificacy as adopting high prolificacy genetics. Addressing the body condition of ewes very short on flesh will also help to reduce barrenness and tighten the lambing spread.

Hill ewe fertility

Research shows reproductive performance in the Scottish Blackface breed of sheep is particularly responsive to achieving target BCS and liveweight at joining with rams.

The potential benefits are significant – increasing from BCS 2 to 3 has the potential to raise the lambing percentage by in the region of 13.5%.

The higher reproductive performance is achieved through a combination of an increased litter size and a reduced barren rate.

BCS and weight targets are intrinsically linked with long-term findings from Teagasc research and more recent results from their BETTER farm sheep programme showing the potential of ewe liveweight (Table 1) and identifying the following weight targets:

Furthermore, having ewes in an optimum BCS of 3 to 3.25 will deliver in tightening the lambing spread as detailed in Table 2.

Weight targets

These are guideline percentage targets as the mature weight varies significantly between different breed strains and the type of terrain on which sheep are raised.

On harder hills with poorer vegetation, the mature weight of smaller-framed Scottish Blackface ewes ranges from 47kg to 52kg. This contrasts to ewe weights of upwards of 60kg to 65kg for larger breed strains run on good-quality lands.

Reports indicate the last two challenging years have exposed some flaws in breeding programmes targeting a larger breed of sheep than is capable of running on the type of hill present.

There is merit in continually striving to improve the production potential of your ewes but this needs to be achieved with a ewe type that suits best.

For example, there is little merit in having larger-framed Lanark or Perth-type ewes that will breed better-quality and heavier lambs running on hard hills if it is being achieved from high volumes of imported supplementary feed.

This especially needs to be considered in flocks which are converting to organic farming.

There is also an equally important aspect to consider of having ewes that are capable of maintaining ground in good agricultural and environmental condition to ensure that area-based payments are not compromised.

The reproductive performance in the flock will also directly influence the direction of the breeding programme.

Where the number of lambs reared per ewe joined is low, the focus will need to be on pure breeding/breeding of suitable replacements to replenish the flock. Increasing the number of lambs produced provides more potential to adopt crossbreeding as detailed in Table 3.

The Teagasc figures have been calculated for a hill flock with a replacement rate of about 24%, while allowing for 10% of potential ewe lambs to be deemed unsuitable for selection.

There may be a tendency at present with grass supplies remaining tight to leave ewes tightened up after weaning on bare pastures for long periods with some sheep at risk of losing condition.

This is a poor use of resources and can have significant repercussions in ewes getting back on track. A significant period of under nutrition greatly interferes with an animal’s metabolic system and can take ewes longer to adjust and recover when energy intake increases.

The ideal strategy is to split ewes into groups based on BCS – ewes which need preferential treatment and ewes which can be worked hard and used to graze out paddocks after lambs.

An intake of 1kg grass DM to 1.1kg grass DM will generally be sufficient to meet maintenance requirements of ewes in optimum BCS at weaning.

The number of ewes requiring preferential treatment should ideally be less than 20% of the flock. Where there is pressure on grazing groups, ewes requiring preferential treatment can be joined back with ewe lambs after a couple of weeks.

Favourable conditions

Given favourable conditions, healthy ewes with a good mouth can gain 1kg to 1.5kg grazing leafy swards.

Ewes that fail to improve condition, despite an adequate period of preferential treatment should be culled from the flock as these will end up being the ewes presenting with issues next spring.

A vibrant cull ewe trade is fortunately providing farmers with options to draft cull ewes at good prices while reducing grass demand.

It also provides a good opportunity to replace any ewes with question marks. Identifying the poorest performing ewes in a flock and targeting this 10% to 15% of sheep to be replaced with sheep of higher genetic potential will ensure continuous gain is achieved.

The lower value of ewe lambs should encourage farmers to adopt this strategy and while replacement hoggets may be more expensive to purchase the higher value of culls should leave the farm in no worse of a position.