14 June 1996

Scanning helps eye muscle depth count

EYE muscle depth in hill breeding ewes varies between 14mm and 34mm.

Ultrasound scanning for the same trait in stock rams shows a range of 23mm to 44mm.

The results, recorded last autumn by Signet, were used to demonstrate how carcass conformation could be improved by breeding from leaner sheep.

Signet representatives stressed that a ewe with a high eye muscle depth as a lamb would retain that advantage throughout its life.

Breeders taking the initiative from this message by scanning for the trait can hope to see eight-week weights increase by 3kg within 10 years, predicted Robin Thomson, Signets southern Scotland consultant.

"This means producers will be able to market lambs earlier or, if they choose, take them to heavier weights as they will be genetically leaner," he explained.

Signet is also aiming to improve lambing percentage in these breeds by 25% over the same period. Mothering and milking ability are two other traits researchers are targeting. Trial results from the Scottish Agriculture College on the latter two characteristics are now being applied on farm to ensure meatier sheep do not lose these traits which are the mainstay of these hardy breeds.

"Most producers have not concentrated on genetic improvement in the past few years. They have had no incentive to improve breed quality as lambs were sold so young on to a lucrative export market. But we are focusing on improving carcass conformation, for the hill ewe constitutes a third of a finished lambs genes. Therefore we are aiming to make improvements at the top end of the stratification to ensure the quality is from the beginning."

Signets Jim Stark and Mervyn Stone scanning hill sheep to determine eye muscle depth.