A case of mad cow disease in the US may boost New Zealand beef exports, says the industry's association.
The brain wasting disease has been found in a dairy cow in central California, the first reported case since 2006.
Beef and Lamb New Zealand chairman Mike Petersen says there may be opportunities in Asian markets for New Zealand exporters, depending on the reaction.
He said the organisation is keeping a close eye on Japan, Taiwan and Korea - but other countries may also react and that could open up other opportunities.
However, Petersen also said there may be a downside of an overall lack in confidence in beef.
Still the announcement, major export markets for US beef from Canada to Japan have stayed amid assurances that rigorous surveillance had safeguarded the food system.
US live cattle futures were higher today, but only recovered about half of what they lost yesterday when the market posted its biggest drop in seven months.
And shares were little changed yesterday for leading US beef producers Tyson Foods Inc and JBS-USA
US authorities quickly told consumers and importers around the world there was no danger that meat from the infected California dairy cow would enter the food chain.
The cow tested positive for bovine spongiform encephalopathy (BSE), commonly called mad cow disease.
Mexico, Korea, Japan, Canada and the European Union said they would continue to import US beef, although two major South Korean retailers halted sales.
In 2011, Canada, Japan, Mexico and South Korea combined took 65%, or 1.82 billion lbs, of US beef exports.
"This finding will not affect trade between the US and Canada," the Canadian Food Inspection Agency said in a statement
"Both countries have implemented science-based measures to protect animal and human health."
Japan already only allows imports of US and Canadian beef from cattle aged 20 months or less.
Samples from the infected cow have been sent to laboratories in Canada and Britain for final confirmation, Paris-based World Organization for Animal Health (OIE) said in a statement, adding that the case was unlikely to affect the current USDA "controlled risk" categorisation for mad cow disease.
"According to USDA statements, the steps taken so far are consistent with OIE standards," it added.
Russia's health watchdog said it could consider restrictions on US imports but that it was waiting for more information on the outbreak and the planned US response before taking a decision.
Korean retailer Lotte Mart, a unit of Lotte Shopping, said it had suspended sales due to what it said was "customer concerns", as did Home Plus, a unit of Britain's Tesco PLC.
Vietnam, which suspended US beef imports between December 2003 and September 2011, said it had not changed its policy on US beef in response to the latest news.
Beef exports hit after 2003 case
Three previous cases of mad cow disease were confirmed in the Unites States between 2003 and 2006. Memories were still sharp of the first case in 2003, which caused a $US3 billion drop in US exports.
It took until 2011 before those exports fully recovered.
Experts said the latest case was "atypical", meaning it was a rare occurrence in which a cow contracts the disease spontaneously, rather than through the feed supply.
They said the dairy cow had not been eaten by other animals and there was no risk of the disease being spread and estimated the chance of an animal spontaneously contracting the disease at about one in a million.
There are nearly 91 million cattle and calves in the United States, according to a USDA report released in January, of which about a third are beef cows and 9.2 million are milk cows. Mad Cow generally occurs in animals that are several years old, and beef cattle are generally slaughtered at 18 months.