7 September 2001

Use ultrasound to select rams with better carcasses

ULTRASOUND scanning has proved to be an invaluable on-farm technique to select rams for improved carcass composition, according to SAC research.

The research by student Jenny Macfarlane looked at how closely on-farm ultrasound measurements of carcass lean and fat weights, compared with the extremely accurate method of CT scanning.

Between 1997 and 1999, about 3000 lambs from the Texel, Charollais and Suffolk breed sire referencing schemes were CT scanned in Edinburgh, a few weeks after Signet technicians ultrasound scanned them on-farm.

In each breed, carcass lean and fat weights were predicted with more than 75% accuracy from ultrasonic scans and liveweight. Although not as accurate as CT scanning, SAC sheep geneticist Ron Lewis says producers using ultrasound benefit from increased revenues by improving carcass attributes.

"Ultrasound is a dependable on-farm tool to identify stock with a tendency towards lean muscle growth and is a relatively inexpensive, non-invasive and quick technique."

He expects ultrasound to provide similar predictions of lean and fat content in other terminal sire sheep breeds. &#42