Bred for meat as well as wool, sheep have been part of the American landscape since colonial times. Now, advances in genetic research are changing breeding procedures, leading to faster, cheaper and more accurate techniques.
New research is making it easier to predict the future-at least as far as lamb products are concerned. At the U.S. Sheep Experiment Station in Dubois, Idaho, research leader Greg Lewis and his colleagues have shown that ultrasound can be used to accurately predict characteristics that indicate carcass yield and value in live sheep.
This could significantly improve the speed and accuracy of selective-breeding methods. Since carcass data is difficult for producers to obtain, many of them currently rely on visual appraisals to predict carcass traits before choosing which sheep to breed. Ultrasound provides a faster, more accurate alternative.
To assess the reliability of the technology, scientists captured ultrasound images of 172 lambs before slaughter. At Ohio State University, assistant professor Henry Zerby coordinated the collection of carcass-trait data for the lambs. Lewis collaborated with Agricultural Research Service scientists and Dave Notter, a geneticist at Virginia Tech, to analyze the data.
Results showed that a trained technician can capture an ultrasound image in about 30 seconds with reasonable accuracy. Scientists can use the images to estimate traits that influence the carcass value of market lambs-such as loin muscle area, loin muscle depth and back-fat thickness.
Ultrasound is initially more expensive than visual appraisals, but the technique's superior accuracy may translate into better economic returns through improved evaluation and selection of breeding stock.
"Ultrasound is a great way for breeding-stock producers to get the data they need to make selection decisions," Lewis said.
The full article is available at www.ars.usda.gov/is/AR/archive/oct09/.
Reprinted from ARS