June 19, 2006

 

Canadian authorities believe contaminated feed led to mad cow case

 

 

The mad cow case found in British Columbia in mid April this year was a result of contaminated feed, said the Canadian Food Inspection Agency after concluding its investigation.

 

Investigators believed that vehicles and equipment used to ship and receive a variety of ingredients likely contaminated cattle feed with an agent responsible for causing the disease.

 

The investigation involved 148 animals, including the affected animal's herdmates and recent offspring. 22 live animals were located and all tested negative for mad cow disease. Of the remaining animals investigated, 77 had died or been slaughtered, 15 were exported to the United States and 33 were untraceable.

 

The Agency examined feed to which the affected animal would have been exposed early in its life, when cattle are most likely to develop the disease. Records and procedures were reviewed at the farm, retail and production levels.

 

Investigators also discovered that the same feed ingredient was also involved in Canada's previous case discovered in January this year. This suggests all of Canada's cases fall within the same geographic cluster, which is reflective of feed sourcing, production and distribution patterns.

 

The five major products manufactured in-house by the primary supplier were formulated in a facility dedicated free of ingredients prohibited from use in ruminant feeds.

 

However, the investigation also revealed that the facility shared an ingredient receiving system and bulk feed delivery trucks with another facility that did use prohibited materials in the manufacture of feeds for non-ruminant species. Thus, cross-contamination of feeds could have occurred as a result of either the shared ingredient receiving system or during the delivery of bulk feed.

 

Interviews with staff at the latter facility identified that flushing procedures were used to prevent cross-contamination of ingredients and feeds at these points. However, written procedures at the time did not identify these requirements, and it was also not the practice at the time of production to document when flushing procedures were applied, the report said.

 

The investigation said the risk of exposure of the index animal to a potentially contaminated feed cannot be ascribed to any specific product.

 

The findings of the investigation indicate manufacturing facilities have largely  complied with the1997 feed ban. However, it is evident that opportunities for cross-contamination remained where conveyances and equipment were cross-utilised, the report noted.

 

Since the detection of BSE in Canada in May 2003, the increased testing of animals from the high risk categories was directed at determining the level of mad cow disease in Canada, while monitoring the effectiveness of measures in place.

 

Out of 105,000 targeted tests conducted since 2003, this is only the fifth positive animal detected, indicating an extremely low level of BSE in Canada. Such detections demonstrate the integrity of Canada's surveillance system, the investigation concluded.