Canada’s 13th case of BSE, a Fraser Valley dairy cow from B.C., likely picked up the disease from its heifer ration, according to the Canadian Food Inspection Agency.
In its report Thursday on the investigation into Case 13, CFIA said the five-year-old Holstein cow, which was confirmed in June as BSE-positive, ate feed from a commercial manufacturer that also used ruminant tissue to make rations for non-ruminant species.
To prevent BSE from entering the feed or food supply, ruminant-to-ruminant feeding has been banned in Canada since 1997, well before Case 13 was born.
Parts of the feed mill in question were specifically dedicated to ruminant feed not containing the prohibited material, but CFIA said the plant had “cross-utilized” some bulk ingredient receiving and finished feed handling equipment.
“Written procedures and production records were insufficient to rule out possible contamination with prohibited material at these points affecting both (heifer ration and some dry cow ration) delivered to the case farm,” CFIA wrote, but also said it could not completely rule out dry cow ration or lactation ration from other manufacturers as a BSE source.
Nevertheless, CFIA wrote Thursday, “the detection of this case does not change any of Canada’s BSE risk parameters. The location and age of the animal are consistent with previous cases. Surveillance results to date, including this case, reflect an extremely low level of BSE in Canada.”
Canada and the U.S. both currently have “controlled-risk” status for BSE. The World Organization for Animal Health (OIE) gives that status to countries that have sufficiently advanced controls in place to prevent specified risk materials (SRMs, the tissues known to harbour the protein that causes BSE in infected cattle) from entering food or feed.
Case 13, born in April 2003, was destroyed June 2 this year after a brief illness; its carcass was later tapped for sampling by CFIA under Canada’s national BSE surveillance program. No tissue or SRMs from the cow entered the food or feed supply, CFIA said.
The 79 surviving animals from Case 13’s “feed cohort” of 207 Holstein cows have been quarantined and will be destroyed, CFIA said. The rest of the 207 have long since died or been slaughtered, or are presumed to be dead or slaughtered, except for 13 that were deemed untraceable due to limited record-keeping, CFIA said.