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Centre for Genetic
Improvement of Livestock A Sound Technology
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Selecting sheep
with superior carcass traits will soon be easier, faster and less
expensive, thanks to real-time ultrasound technology, say University of
Guelph researchers...and that means a better eating experience for
consumers.
The technology -- already widely used in the cattle and swine breeding industries to select for sires with an optimal lean meat-to-fat ratio - is being adapted for Ontario's growing sheep industry. Prof. Jim Wilton, Centre for the Genetic Improvement of Livestock, is working with graduate student Tamara Fernandes to evaluate the technology's effectiveness in the sheep industry. They conducted trials on 30 sheep farms across the province to measure the carcass traits of live lambs -- of similar age -- using real-time ultrasound. Ultimately, the researchers hope to give the Ontario sheep industry an edge over competitors from New Zealand and Australia. "There's a tremendous industry interest in this technology," says Wilton. "The technology is simple to use and the cost of sending a technician to the farm is very reasonable." In sheep, genetics play an important role in determining fat content. In fact, about 35 per cent of a sheep's fat content is heritable. That makes it important to select for sires with higher lean muscle-to-fat ratios that will pass on these carcass traits to their progeny. Traditionally, selecting optimal sires depends on post-slaughter carcass trait measurements of progeny from different sires. But waiting for progeny can take time. That's where ultrasound comes in. It measures the fat content of young animals directly and can give a quick estimate of a sire's potential for passing on lean meat traits. That's important to breeding associations which could benefit by using the technology to boost the reputation of their breed and sell more stock. Ultrasound is also non-invasive and less expensive than post-slaughter measurements. Here's how the technology works. Sound waves are generated by a vibrating crystal housed in the ultrasound machine and sent through an animal's body. The waves travel through different types of tissues at different speeds depending on the tissue density. For example, sound waves pass through muscle quickly, but their transit is slower through fat. The waves bounce off different tissues and are picked up by a recorder which displays a complete on-screen picture of the animal's carcass traits. Ultrasound measurements are usually carried out on marketplace lambs, the stage when the animals begin to fatten. A lamb's total fat content is estimated from the amount of fat covering the rib muscle. As part of a validity check on the technology, the researchers are working with the Ontario Lamb Improvement Breeding Strategies Program to compare the accuracy of ultrasound measurements to post-slaughter carcass measures. Live animal ultrasound and carcass measures were carried out on lambs from the New Liskeard Agricultural Research Station and show that while ultrasound isn't an exact science, it's very close. "Real-time ultrasound has the potential to help producers provide consumers with a product that's more uniform," says Fernandes. "That will help increase the retail market for Ontario lamb." This research is sponsored by the Ontario Sheep Marketing Agency through the CanAdapt program (administered by the Agricultural Adaptation Council). Fernandes's position is being partially supported by Ontario Rural Jobs Strategies. |
