Expected progeny differences (EPDs) have been an integral part of cattle buying and breeding since before McDonald’s introduced the Angus burger. Though not without flaws, they have changed the cattle industry.
Now, those same tools are finally coming to the sheep world.
Why not sheep?
The comparatively small size of the sheep industry in the U.S. is one reason that genetic tests for sheep have received less attention until now. “We’re not as big as the dairy industry or [beef] cattle industry,” says Dr. Brenda Murdoch of the University of Idaho (UI).
She is well acquainted with both, as the first portion of her career involved developing and using genetic tools to help the cattle industry. Since coming to Idaho, Murdoch has seen the importance of sheep to the state and the U.S., and she has shifted focus – but her work is still in the same vein. “A lot of what I do is I look for genetic variations that are associated with traits that we want to select for or against,” she says.
Another reason sheep producers may not invest in genetic testing is that sheep themselves are smaller than cattle. “The cost is so high relative to the cost of a single animal,” Murdoch says. Ross Blattner, of Blattner Suffolks in Kuna, agrees. “You have to consider how will it return your investment,” he says.
An Idaho innovation
Typically, single-trait genetic tests on the market are cost prohibitive at $10 or more per test. Such an expense adds up quickly, says UI Sheep Center Manager Dino Vinci – particularly if the producer is interested in more than one question.
Enter the Flock54 genetic test. “We decided to change technology and change platforms to do it through sequencing technology,” Murdoch says. She is the lead researcher who worked on developing Flock54, named for a sheep’s 54 chromosomes. Researchers used data from animals at the Sheep Center in Moscow and information gleaned from scientific literature.
As it stands now, sheep producers anywhere in the U.S. can send a blood or tissue sample to Superior Farms, a large Dixon, California, meat processing plant. Murdoch chose to work with Superior Farms in developing the test because they were interested in helping producers and because they were buying a lot of Idaho lambs. “They take all the orders and handle the samples,” says Murdoch. “I don’t run a service lab out of the university.”
Superior Farms uses a company to extract DNA from the samples, sequences them and sends back the marker data in an Excel spreadsheet. The test has been available to the public for about three years for $20 per animal, or $16 for Superior Farms members. The cost savings are significant if the producer is interested in two or more different traits, which would otherwise require separate tests.
“It’s neat that it’s available to the public,” Vinci says. “There are a lot of other tests that are not approved [for scrapie testing] that cost per gene. … We used to pay 12 to 18 dollars per gene.”
Scrapie and beyond
One of the reasons Flock54 may be gaining traction is because of national requirements for scrapie-resistance testing when selling breeding stock across state lines – requirements that affect both Blattner Suffolks and the UI Sheep Center. Scrapie is a fatal neurological disease in sheep and goats. It causes degeneration in the brain and spinal cord and can reside undetected in a host animal for two to five years without visible symptoms. However, a genetic test can determine whether a sheep is susceptible or resistant to the disease.
Flock54 is one of the few tests certified by the USDA Animal and Plant Health Inspection Service (APHIS) for scrapie-resistance testing. At the Sheep Center, Vinci is also interested in whether his Polypay and Suffolk sheep are carriers for spider lamb syndrome or the dwarf gene; Flock54 provides information about both.
With so much information available from the test, Vinci says, the UI Sheep Center is starting to use Flock54 results to consider more than disease resistance. The ability to pinpoint parentage, for example, is a useful tool for large producers. Flock54 also gives some information on carcass and growth traits, though Blattner still finds the usefulness of these data points to be somewhat limited.
“There are a bunch of markers, but we don’t really use them,” he says. “There’s lots of potential with it, but you still have to walk out into the pen for picking replacements.”
For Blattner Suffolks, the information that would make the test more helpful for improving herd genetics would be milking ability and (related to that) weaning weight. “Milk is probably the number one thing,” Blattner says. Close behind those factors is breeding ability, particularly the likelihood of giving twins.
Such information may be on the way. Just because the test is available to the public doesn’t mean work on it has stopped. “If we find new markers, next time we remake the panels we add in that new information,” Murdoch says. With panels made in batches of 10,000, she updates the test every year or so with current knowledge from her own work or the literature.
Next step: Carcass quality?
Those updates may make the test more applicable for both commercial and purebred breeders as time passes. “We’re working on trying to validate carcass-quality markers,” Murdoch says.
In Blattner’s view, access to carcass information – and the relevance of that information to the bottom line – is what will make the test invaluable to sheep producers. “We need to be able to put together carcass data with [pedigree] lines,” he says, “and then get a premium for improving them.”
Although Blattner sees limits to the test in its current form, Blattner Suffolks continues to send in samples for all ram and most ewe lambs. “I think it’s really important – that’s why we’re doing it,” he says.
They’re in on the ground floor for a transition that will give sheep producers tools similar to those cattle producers already enjoy. “The sheep industry is going to have to go to this,” says Blattner. “It’s just in its infancy stage.”
PHOTOs: Photos by Emily Blattner.
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