Traces of PED found in pig feed
Wednesday, February 12, 2014
by SUSAN MANN
The Ontario Ministry of Agriculture and Food has found genetic material of porcine epidemic diarrhea virus in some pig feed samples from farms with confirmed cases of the disease, but Canadian researchers must do a lot more work to determine if the virus is transmitted through feed.
Greg Douglas, Ontario’s chief veterinarian, says the agriculture ministry’s finding of PED genetic material in swine feed samples on some of the 12 Ontario farms confirmed to be positive for the virus is interesting. The Canadian Food Inspection Agency has offered to do work in “determining whether those samples are infective or not at their laboratory in Winnipeg.”
PED is a viral disease causing vomiting and diarrhea in pigs. The virus doesn’t affect food safety and poses no risk to human health or other animals besides pigs. On farms, the virus wipes out almost all nursing piglets while older animals get widespread diarrhea but can recover. Ontario’s first case was confirmed on Jan. 22 at a Middlesex Country farm.
Douglas adds that it’s too early to say what conclusions can be drawn from the ministry’s finding. Others in the industry are equally cautious about linking swine feed to PED virus transmission. One scientist says there’s no link whatsoever.
Robert Harding, executive director of the Canadian Swine Health Board, says the caution is understandable because a scientific link between feed and PED virus transmission hasn’t been determined yet.
Ontario Pork chair Amy Cronin says the ministry’s finding “will help us learn more about PED and the transmission of the virus.” But more research needs to be done about PED and feed and the possible transmission of the “virus that way.”
University of Guelph swine nutrition Prof. Kees De Lange says “the fact that you find some genetic material of a virus doesn’t mean the virus is active.” The finding also doesn’t mean “it represents a risk.”
Lisa Murphy, CFIA spokesperson, says by email the agency verifies that livestock feeds manufactured and sold or imported into Canada are effective and are appropriately labelled.
About the finding of PED genetic material in feed from Ontario farms, she says “since heat treatment is used to render pathogens in feed inactive, DNA findings are not indicative of live virus.”
She further notes the U.S. Department of Agriculture and the U.S. Food and Drug Administration have been exploring PED risk factors, including feed, “and have not confirmed the linkage.”
So far, the risk of swine feed as a transmission source of PED virus is unknown, according to a Feb. 9 written statement by the Kansas State University swine nutrition team posted on Ontario Pork’s website. The team “believes at this time it is prudent for pig producers to be knowledgeable of feed ingredients that are in their swine rations.”
Prior to the weekend posting of the press release from Kansas State University’s swine nutrition team, Steve Dritz of the university said in a Feb. 4 notice they had been getting “a multitude of questions about PED and feed.”
The concern about feed as a possible PED transmission source and the Kansas State University swine nutrition team’s statement prompted the Cambridge-based feed manufacturer, Grand Valley Fortifiers, in a news release on Sunday, to urge its customers to stop using three of its nursery feed products sold from Jan. 1 because they contain “porcine origin blood plasma."
The company says in the release it’s recalling the entire remaining inventory of these feed products, Bionic, BioForce and BioPrime, and “will credit the account of producers accordingly.” Grand Valley Fortifiers recommends its customers switch to its product, called Natures Blend, which doesn’t contain animal byproducts.
Grand Valley Fortifiers CEO Ian Ross couldn’t be reached for comment.
The association representing the companies manufacturing blood plasma, the North American Spray Dried Blood and Plasma Producers, has weighed into the debate saying in a Feb. 11 press release that based on current scientific evidence, properly sourced, collected and processed porcine blood and porcine blood products are safe “and do not contribute to the spread of PED virus.”
De Lange says feeding porcine blood plasma to pigs is very common and it’s used as part of the first phase of a pig starter diet. “It’s most effective within the first one to three weeks after weaning,” he says, noting pigs are usually weaned around three weeks of age.
Most of the diets for just-weaned pigs have blood plasma because the product contains quite a bit of highly digestible protein along with bioactive compounds that are also in sows’ milk, such as antibodies to boost a piglet’s immune system. “I would say more than 50 per cent” of just-weaned pigs are fed the blood plasma, De Lange says. It is generally fed as a processed, pelleted product.
Prof. Robert Friendship, a swine health management specialist with the University of Guelph, says starter rations for pigs contain other proteins from various sources in addition to blood plasma. But the blood plasma is included because it is easy for pigs to digest, they “like the taste” and it helps them fight diseases.
De Lange says in the first week after weaning, the pelleted feed would contain four to eight per cent of plasma but the exact composition of the feed isn’t divulged because the feed companies consider that “proprietary” information. “The plasma is very expensive.”
The blood plasma itself can come from the United States, he notes, adding there may also be some production of it in Canada.
The use of blood plasma in the just-wean pigs’ diets began 20 years ago and made early weaning possible, he says. BF
UPDATE: Thurs. Feb. 13, 2014
by SUSAN MANN
Kansas State University’s advice to farmers concerned about their feed being a possible source of PED virus, even though the risk of that is currently unknown, includes:
• Testing all porcine products for PED before using them in diets and only using them after they test negative for the virus.
• Replacing all porcine-based products in diets with bovine products, such as bovine plasma instead of porcine plasma.
• Removing all animal proteins, except milk products, from the diet.
The Kansas State University swine nutrition team also advises talking to your herd veterinarian, nutrition adviser, feed manufacturer and ingredient supplier to help make the best decisions for your operation.
In Ontario Susan Murray, provincial agriculture ministry spokesperson, says they’ve been hearing some farmers are assuming that if it’s confirmed PED virus is being spread through feed ingredients other biosecurity measures are irrelevant. But ministry officials are urging farmers to not relax their biosecurity protocols.
The possible spread of PED through feed hasn’t been proven. This is “one potential avenue and there are lots of other known avenues so people really need to continue to work on their biosecurity,” she says.
As for the results from Winnipeg on the PED genetic material in Ontario feed samples and whether the material is infective, Murray says it will take two to three weeks for the ministry to get results. The samples were sent to the Canadian Food Inspection Agency lab at the beginning of this week. BF