Sheep Genetics Expanding in the US
By John Wilkes
Some United States sheep breeders dedicated to breeds from the United Kingdom are concerned about shrinking gene pools. Throughout American history, British settlers introduced breeds such as Lincoln, Leicester Longwool, Shropshire, Suffolk, and Hampshire. More recently, some U.S. sheep breeds have morphed into anatomically larger versions of their British counterparts, arguably leading to a decline in meat and overall carcass quality.
The average weight of a U.S. lamb carcass in 1980 was 55 pounds. In recent years, U.S. breeders have produced lamb carcass weights at 67 pounds on average — an additional 12 pounds over the past 37 years. By contrast, a U.K. lamb carcass weighs just 44 pounds.
And U.S. sheep breeders of U.K. breed-types are in need of fresh genetics. After a six-year embargo, the ban on British ovine semen was lifted in May 2016 by USDA Animal Plant Health Inspection Service (APHIS). The opportunity to import fresh genetics is now possible, though the pathway is challenging for U.K. sheep breeders.
Stringent health protocol, lengthy quarantine requirements, and logistics for compliance are major hurdles for the U.K. sheep industry. Extensive health screening of U.K. donor rams is mandated by APHIS. Donor rams must prove to be scrapie-free at the onset. Scrapie-free donor rams then undergo on-farm quarantine, before semen collection. Tests for brucellosis, bovine tuberculosis (TB), border disease, and Schmallenberg virus are taken two to three times. Rams that pass all tests can be moved to U.K. government licensed semen collection centers for U.S. export. A final Schmallenberg blood test, post semen collection, must also be conducted.
Bovine TB is a problem for U.K. cattle herds, although failure of the bovine TB test carries significant ramifications for sheep breeders. Failure of any ram’s TB test means all sheep on a breeder’s farm must be TB tested, and a 5-mile movement-restriction zone established. Despite almost no recorded instances of bovine TB in the national sheep flock, many breeders are not willing to take this risk.
The U.K. freely exports ovine genetics globally to countries like New Zealand that have TB but require no such test. The New Zealand government follows biosecurity measures closely and adheres to many of the most stringent livestock world health standards.
In 2017, positive Schmallenberg virus test results eliminated some rams from the collection program. Impact of the midge-borne virus that causes fetal abnormalities in cattle and sheep varies annually. Livestock in southern England are more susceptible to being bitten by vector midges blowing in from northern Europe.
Despite concerns, one group of U.K. rams’ semen was successfully harvested in 2016. An application was made for a U.S. import certificate. However, the application was denied because of noncompliance with APHIS regulations. Requirements for export caused confusion, and many breeders chose not to participate. Negotiation talks were held between APHIS and U.K. veterinary officials to clarify rules on ovine semen export. Ultimately, they agreed to subject donor rams to a 120-day quarantine period.
Only one British sheep breeder endured, Darrell Pilkington, former President of the U.K. Teeswater Sheep Breeders’ Association. Pilkington is determined to help fellow American breeders source genetics that offer a lifeline for their flocks. “While all the officials threw their toys out of the pram, I just kept my sheep in isolation,” Pilkington says. He continued to quarantine rams from his heritage fine wool flock on his own farm in Lancashire, England, from July 2016 until March 2017. American sheep breeders held their breath.
“Previously, there have been a very limited number of Teeswater rams exported, and many were related, so I purposely selected three unrelated rams for the U.S.,” says Pilkington. Ultimately only one of three met all criteria for semen collection. This ram was quite literally the last ram standing for U.S. export in 2016.
On April 11, 2017, after months of quarantine and multiple negative test results, U.S. breeders finally received the results of the last Schmallenberg virus test that guaranteed U.K. export status. Unfortunately, the last ram standing tested positive for the Schmallenberg virus. This left U.S. sheep breeders heartbroken. Pilkington says, ”The rules and regulations they are insisting on are nigh on impossible.”
The demand for fresh U.K. sheep genetics remains strong, and U.S. breeders have not given up hope. In fact, APHIS proposed legislation in July 2016 that would allow the importation of U.K. ovine embryos. If passed, this would promote rapid genetic improvement of both older heritage and modern commercial sheep breeds.
After the U.K. BSE crisis in 1989, the U.S. imposed a blanket ban on all British beef and lamb products entering the U.S., including ovine embryos. APHIS’s new position is the result of a wider global change in perception of risk associated with transmissible spongiform encephalopathies (TSEs) that include scrapie. The World Organisation for Animal Health (OIE) agrees that TSEs no longer pose a significant risk to human health.
This allows APHIS to urge reinstatement of imports from the U.K. including embryos, lamb (meat), and live sheep. APHIS advocates U.K. ovine genetics to help bolster the American sheep industry while implementing regulations that ensure health protection of the U.S. national sheep flock.
Pedigree ovine embryos are genetic silver bullets. For commercial U.S. lamb producers, high performance from British Texel, Suffolk, and Charollais breeds can improve overall lamb carcass conformation and meat yield. If embryos can be imported by U.S. lamb growers, this will be a boon to the industry. Until such a decision is reached by the U.S. government, ovine semen remains the only option for fresh genetics.
One Scottish breeder with rams presently in quarantine represents the best of British genes — Texel, Suffolk, and Bluefaced Leicester. Bruce Ingram of Logie Durno Farm and his flock may evade both TB and the Schmallenberg virus because of their location near Aberdeen in northern Scotland. Vector midges are not present that far north, and Scotland is officially TB-free. Ingram says, “It’s a great opportunity for U.K. breeders to get genetics out there. We’ve put a lot of effort into high-quality sheep that perform well. Hopefully we can make an impact in the U.S.”
John Wilkes is a former U.K. livestock farmer who now resides in the Washington, D.C. metro area. He is an analyst and consultant for the international livestock industry, and he writes for a variety of trade publications in both the U.K. and U.S. He is a Board Member of The Livestock Conservancy and a member of The American Sheep Industry Association.
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