Despite what can only be described as a difficult spring weather-wise the lowland flocks in the Teagasc BETTER farm sheep programme still recorded excellent lamb performance throughout the pre-weaning period.

This was particularly evident in the first seven weeks of life (Figure 1) when lamb performance is largely driven by the milk production of the ewe. Twin lambs across the flocks averaged 284g/hd/day during this period. This performance was somewhat surprising as previously when weather conditions have been difficult post-lambing flock performance has suffered, such as in the spring of 2024.

Ewe body condition

So, what was different this spring compared to spring 2024? This question could potentially be answered in numerous ways depending on the farm but the main difference this spring across the flocks has been ewe body condition score (BCS), particularly the number of ‘thin’ ewes in the flocks. As shown in Figure 2, the percentage of ‘thin’ ewes at mating in October 2023 (lambing spring 2024) was significantly higher compared to October 2025 (lambing spring 2026).

Once a ewe lambs she is reliant on having enough BCS to mobilise in the first weeks after lambing to meet her nutrient demands, regardless of the diet offered as the ewes feed intake ability will take time to recover post-lambing. Where ewes are thin and unable to mobilise body reserves, milk yield will be below potential and anything that negatively affects ewe milk production will negatively affect lamb performance.

Unfavourable weather

The unfavourable weather this spring seems far removed from the current conditions, but the preparation for next spring needs to start now for sheep flocks. Building ewe BCS takes time and needs to happen during the dry period before mating when the ewe’s energy demands are at their lowest and she has no other demands such as from the time the ram is introduced to the moment her lambs are weaned the following spring.

Ewe BCS is recorded on the Teagasc BETTER sheep flocks at three key time points across the year; pre-mating (late July/early August), mating time (October) and pregnancy scanning (January). During the year farmers also handle the ewes to identify thin ewes, such as at lambing time. While assessing BCS accurately to one-quarter scores does require training and practice at farm level the goal can simply be to be able to identify thin and non-thin ewes.

Body condition in sheep is assessed through using your hand to feel along the sheep’s lumbar region (back bone) between the last rib bone and the hip bone. The level of fat and muscle cover on four areas is assessed: the spinous process, the transverse process (horizontal bones below the eye muscle), over the ends of the transverse process and the fullness of tissue between spinous and transverse processes.

Flock goals

From mating through to lambing the goal should be to have as few ewes as possible less than BCS 3.0. If this is achieved the average BCS of the flock will usually be OK and most of the ewes will have sufficient BCS to mobilise during lactation. A ewe at BCS 3.0 is generally described as a ewe where you can feel the spinous process with firm pressure, and the transverse process are smooth but can still be identified. The easier it is to pick out the individual spinous and transverse processes (sharper they feel) the less body condition the ewe has.

‘Fat’ ewes are generally found in small numbers in grass-based commercial sheep flocks and are not a big issue due to their small numbers. Thin ewes are the problem ewes and the ones more likely to not go in lamb, have a lower litter size, not raise good lambs, become lame etc.

Previous work on BCS data from the Teagasc BETTER farm sheep flocks observed that across five years of mating BCS data there were three times where there was more thin ewes than fat ewes on average in the flocks with only 4% of ewes being considered fat at mating time.

BCS targets

The ideal situation for ewes is being at BCS 3.5 at mating, maintain all (or most) of this BCS up to lambing time and then utilise her body reserves to meet nutrient demands in early lactation. That has been a big focus for the Teagasc BETTER sheep farmers in recent years and as already discussed, there has been a big improvement in this performance metric.

So, what does that mean and how do we achieve it? The first step for these flocks in managing BCS is weaning on time, so they have enough time to recover the lost BCS before mating. Once ewes are dried off post-weaning it can take eight to 10 weeks to put on one full BCS so starting preparation early is vital.

Once the lambs are 14 weeks of age (on average) they should be weaned. Where grass supplies are tight or ewes are very thin and ewes would benefit from more time to recover BCS, lambs can be weaned at 12 weeks of age without negatively impacting the performance of the lambs.

Once weaned, ewes are given two to three weeks to dry off fully. When dried off ewes are assessed for culling faults (eg mastitis) including checking mouths – as broken mouth ewes will struggle to graze properly and will struggle to regain and maintain BCS.

Two categories

The remaining ewes are then assessed for BCS with ewes divided into two categories – thin and the rest. Thin ewes are marked clearly and given access to preferential grass – if by mating time they have failed to regain BCS they are culled from the flock as this usually indicates an underlying issue that is potentially going to cause further issues during pregnancy or lactation.

Just because a ewe is thin now does not necessarily mean she is a problem ewe. She may be the best ewe in the flock and has put all her reserves into her lambs. It is the ewes that fail to regain BCS by mating time that are the problem ewes.

Where the number of thin ewes is very high then obviously not all thin ewes can be culled and, in this instance, the worst ewes that fail to regain any condition are culled.

The remainder of the flock (not marked as thin) are still used to graze out paddocks etc, but not forced to spend too long grazing poor-quality forage, so they also have a chance to regain BCS pre-mating.

From mating time on, BCS is managed so that ewes maintain BCS up to lambing. While inevitably there will be some slippage at scanning time this should be kept to an absolute minimum as BCS on the ewes at this time is usually the maximum she will have at lambing time.

Conclusion

If you want to improve performance in your flock now is the time to act. There can be big gains achieved in terms of ewe reproductive performance, even through a simple practice of splitting ewes in to a batch of thin ewes for preferential treatment and a batch that can be fed to maintenance.

In short