Tracing of Cohorts 1996 - 1998 - Diagram Descriptions

This diagram shows the tracing of the cohorts from 1996 to 1998. The diagram is dated as of March 11, 2004.

The notes at the bottom of the page are:

• Index case born April 9, 1997 in Alberta.
• Cohorts are those animals born one year before and one year after the birth of the index case. Thus, animals born during the period of April 1996 to April 1998.
• The symbol of the blue triangle indicates tested negative for BSE.
• The symbol of the red line indicates possible scenario for route of feed exposure. A small amount of feed was transferred from Farm A to neighbouring Farm B.

The diagram is divided in half horizontally by a dotted line. Above the dotted line, in the centre is a red circle that states Birth Herd Farm A - Dairy 57 Cohorts, Alberta with a red arrow that points below, past the dotted line to Farm B. Farm B is a yellow circle outlined in red which states Farm B - Beef 57 Cohorts, Alberta. The red arrow indicates possible scenario for route of feed exposure. From Farm A, there are 6 arrows pointing to 6 blue circles.

Starting from the blue circle on the right and moving counterclockwise the text reads:

• first circle: 27 cows traced and confirmed dead
• second circle: moved September 2001, 1 cow born November 1996, located in Alberta, with a blue triangle symbol (which indicates tested negative for BSE)
• third circle: moved January 1998, 1 cow born May 1996, untraceable
• fourth circle: moved September 4, 2001, 25 cows exported to US (including index case)
• fifth circle: moved August 1997, 1 cow born November 1996, untraceable
• sixth circle: 2 beef/dairy cross bred cows born September 1997 and October 1997, located in Alberta

Then there is an arrow from the sixth circle to a light blue circle which is on the horizontal dotted line. The light blue circle states moved 1998 from Farm A to Farm B, with a blue triangle symbol (which indicates tested negative for BSE).

From Farm B - Beef 57 Cohorts, Alberta, the yellow circle outlined in red, there are two arrows pointing to two blue circles. Starting from the left and moving counterclockwise the text reads:

• first circle: 9 cows located at Farm B, with a blue triangle symbol (which indicates tested negative for BSE)
• second circle: 48 cows

From the circle with 48 cows there is one arrow pointing to one blue circle which states 48 cows sold among 86 head. From this circle, there are three arrows pointing to three circles. Starting from the top and moving clockwise the text reads:

• 4 cows traced to a herd of 150 cows
• 2 cows untraceable
• 80 cows traced and confirmed dead