By Debbie James

Sheep farmers in west Wales are reporting an improvement in flock performance this season with scanning percentages on some farms up by as much as 25 per cent.

Vet Helen Scott, of the Carmarthen Veterinary Centre, says clients with lowland flocks are consistently scanning at rates higher than 200 per cent.

This, she believes, is down to better management of ewes and good fertility resulting from favourable grazing conditions.

“Scanning percentages are generally up 10-15 per cent, averaging 20.5 per cent, but in some flocks we are seeing a 25 per cent improvement,’’ says Ms Scott.

She puts this trend down to good summer and autumn grazing and to higher uptakes of vaccinations to prevent abortion.

“Farmers have a better handle on some of the diseases that were compromising fertility in their flocks,’’ she says.

For others, a more rigorous approach to culling unproductive ewes has been influential.

“Culling has a big impact on barren rates and barren rates have a big impact on scanning rates,’’ Ms Scott points out.

Predicted litter size from scanning does not always equate to numbers of lambs born but this is more likely to happen if ewes are managed according to the lambs carried.

To achieve parity between scanning and lambing rates it is important to monitor body condition score (BCS).

Check ewes regularly to ensure that they are not getting too thin, or indeed too fat, at any stage.

A thin ewe will be more interested in what she wants to eat, not in feeding her lamb, says vet Miranda Timmerman, of ProStock Vets.

She recommends a BCS at lambing of 3.5 in lowland breeds such as the Texel and 2.5-3 in upland breeds.

When scanned litter size is over 200 per cent, a high percentage of ewes will be carrying three lambs so the immediate priority for these ewes is an appropriate feeding regime to ensure birth weights in the region of 4kg for each lamb.

Supplementary feeding of triplet-bearing ewes should commence eight to ten weeks before the expected lambing date – in practice this is immediately after scanning, unless ewes are fit and have plenty of good quality forage when supplementation can start later.

Depending on ewe body condition and the quality of forage available, the level should rise to around 1kg per head per day – split into two feeds – in the weeks before lambing.

However 1kg is not the recommended rate across all forages.

Diets should be worked out from forage analysis with some of the very best forages needing relatively low levels of supplementation even for triplets.

Silage and hay analysis will inform the level of supplementation.

A pregnant ewe will rapidly break down her own body fat reserves due to a high demand for glucose; in late pregnancy this happens if the diet is lacking in energy and results in the release of toxic chemicals called ketones, which rapidly build up in the blood.

Check levels with a ketone meter two-three weeks before lambing or ask your vet to do a metabolic profile at three-four weeks before lambing, to check if energy and protein intake is adequate.