Body condition score ewes to optimise scanning rates

Farmers are being advised to get ewes in the correct condition before tupping to avoid a second year of poor scanning rates. Grass growth rates stunted by lack of rain during May and June have largely returned to normal following the warm, wet summer. But a close eye still needs to be kept on ewe body condition score, says Wynnstay national sheep and beef adviser Bryn Hughes.

Scanning rates were down 15-20% on some farms in 2022/23 – highlighting the importance of ewes being in the right condition before tupping, explains Mr Hughes. Producers who have not yet done so should body score now to identify any thin ewes sooner rather than later, he adds.

“When identifying thin ewes, it’s important to ask yourself why they are thin – is it down to late lambing, poor health or grass availability? Once this has been agreed, take corrective action.”

One body condition score equates to 10-12% of body weight,| explains Mr Hughes. For a 75kg ewe, this is about 7.5kg. Ewes typically gain 300g/day, so this means will take at least 25 days for a ewe to regain condition.

“This requires very good grazing, so farmers will need to consider if they can achieve this or if ewes need supplementary feed. Depending on their score, good grazing with flusher buckets is often enough to put ewes in good condition for tupping.”

 Why is scoring important?

Lamb growth rates were significantly impacted by ewe body condition, according to a 

large study of 2,516 ewes carried out over three consecutive years in four New Zealand flocks.

Ewes with high scores that lost condition during rearing were using energy reserves to feed lambs which led the researchers to conclude that “adequate feeding is required to achieve high BCS at lambing.”

Triplets were at the highest risk of low lamb growth compared to singles and doubles, which indicated that increased energy demands during gestation and rearing were insufficient.