Researchers say the process is just speeding up natural selection
Putting a live sheep into a CT scanner looks ungainly, even slightly comical, but the science behind it has serious implications for Britain's national flock.
One by one they are mildly sedated and then strapped to a gurney, complete with head cushion for comfort.
Once loaded on to the machine itself, a slow conveyor takes them through the large white, donut-shaped scanner.
This is not happening because the animal is hurt or injured, in fact the Charollais ram is in tip top condition and his owner wants more like him.
Dr Kevin Sinclair, a professor in developmental biology at The University of Nottingham, is helping farmers pick the best of the best to breed better quality meat into their flocks.
He says: "One argument for lamb becoming less popular as a meat is because people complain about it being too fatty.
"Breeders are increasingly testing their animals for leanness and this does it with pinpoint accuracy."
When asked about the issues surrounding genetics in farming he added: "Genetic modification conjures up all the wrong images in people's minds.
"What we're doing here is a process of selection, akin to natural selection, except we're speeding up the process and selecting for characteristics that we favour.
"This isn't new. Domestication in farm animals occurred 10,000 years ago and we've been doing it ever since.
"By using the technology we can do it with greater precision and accuracy that ever before."
The mobile scanner was brought down to Nottingham from the Scottish Agricultural College in Edinburgh which developed the technique.
Dr. Lutz Bunger, who heads up SAC's Growth Genetics Team, said "We are proud of what our service can do.
"While ultrasound scanning has been used to measure the fat layers on a sheep's back, this latest technology allows us to measure meat and bone as well.
"We can identify the very best sheep to breed from, those with the best genetics for growth rate and meat yield".
The university is the only place it has been used south of the border and it has been such a hit with farmers it is hoped a permanent unit will be set up at its Sutton Bonnington campus by the end of the year.
The system has already improved the yield of some flocks
Virtual cross-section slices appear on a radiologist's screen as each lamb passes through the former NHS scanner.
The images show the animal's fat, muscle and bone content. To improve their stock, farmers are looking for less fat and more muscle.
The information is being put to good use by Charles Sercombe, who has a sheep farm in Leicestershire.
At £85 per animal, he can only afford to scan a hand-picked trailer full, but believes it is a good investment for the future of his flock.
By pinpointing the best of the best, Mr Sercombe says he can achieve better margins and sustainability: "As farmers I think we have a real duty at this moment in time to produce food more efficiently.
"There are obviously finite resources on this planet and I think we have a duty to the general population to produce faster growing, more muscled animals that use less resources and have less impact on the climate."
The superior genes of his fitter, leaner lambs fetch a premium when sold for breeding. The programme is being welcomed by an industry worth £822m a year in Britain.
Mr Sercombe says the breeding programme has already increased his yield per lamb by two kilos. It will take two to three years for that to filter down through his whole flock and longer still to reach the general sheep population.
But as more farmers cotton on to this technology the future of British lamb is looking good.
The story was updated on 27 May 2010 to include a comment from Dr Lutz Bunger after additional information came to light post publication and was added to clarify the nature of the work.