From the State Vet's Office
by Dr. Terry Slaten
There have been two particular cows (possibly more) that have, through no intentional effort, become part of the history of the United States. Those two cows probably didn’t have much in common. They were both of the genus and species Bos Indicus. They were both dairy cows. Most importantly, they both caused significant economic impacts. Also, both received a great deal of media attention. In contrast, one was made famous (or infamous) by the actual negative damage she caused. The other gained notoriety because of the perceived damage she caused. The first cow is Mrs. O’Leary’s cow that, according to legend, kicked over the lantern in the barn that started the Chicago Fire of 1871. The second is the Washington State cow that was the first cow to be confirmed as BSE positive in the United States.
According to legend, and it may be more speculation than fact, the Great Chicago Fire was started by the O’Leary cow and her unfortunate interaction with a lit lantern. Certainly, according to history, the fire did start in the area of the O’Leary barn. Most accounts of the event do not vary too widely in the details of the damage done by the fire. The fire burned over 3 and a half square miles in some of the more populated areas of the city. There were over 100,000 people left homeless and 300 deaths as a result of the fire. Whether the cow was responsible for the fire or not, she was blamed for it…. and so the legend goes.
The second cow moved into the United States from Canada in a group of 81 Holstein cows that were part of a dispersal in Alberta, Canada. As a bred heifer, she became part of a dairy herd in Washington State. While part of the herd, she calved three times. The first calf was a stillbirth, the second was a heifer and the third, a bull. Incidentally, paralysis from calving difficulty was the reason the cow went to slaughter.
As a "downer" cow, she fit the criteria of a target animal to be tested for BSE. A target animal is a cow (or bull) over thirty months of age that is showing nervous signs such as abnormal gait, stiffness, incoordination, down, dying, or dead from an unknown cause. As a tested target animal, her brain tissue became one of the samples on the way to the USDA’s goal of 40,000 samples for fiscal year 2004. That number of negative tests would have given a 95 percent confidence level that BSE existed in the United States at a rate less than one in one million However, when she tested positive, life changed drastically for the beef industry, including the export market, the rendering industry and for certain, the way beef is processed.
In early 2004, in response to the positive BSE cow, USDA’s Food Safety Inspection Service took measures to make sure that Specified Risk Material (SRM) are removed from all cattle over thirty months of age that are slaughtered. SRM’s include the brain, spinal cord, retinas, and the entire small intestine. These are the tissues where the prion that causes BSE could be found. It is accepted that animals under thirty months of age do not get the disease; therefore, the SRMs only become a concern after the animal reaches 30 months. Also, downer cows were no longer allowed to be slaughtered and enter the human food chain. And finally, if an animal is tested, before the meat or by-products enter either the human food chain or are rendered for animal food, the carcass is held until the test comes back negative. These measures were in addition to measures put in place during the latter part of the twentieth century, including banning the import of cattle from countries known to have BSE and the banning of ruminant by-products in cattle feed.
By June 1, 2004, USDA kicked off an intensive testing program that had a goal of testing 268,000 target animals in one year. According to a Harvard University study, that many negative tests would yield a 99 per cent confidence level that BSE would show up if it existed at a level greater than one in one million. At the one year mark, there had been well over 350,000 samples. That year of intensive testing proved the extremely low incidence of the disease. Although the positive retest of a sample that had been called negative in November 2004 was announced in late June, the disease is getting more and more difficult to find. And we are looking diligently. Someone recently commented that finding BSE has gone from looking for a needle in a hay stack to looking for a needle in a hay field.
The producers from the State of Alabama have participated well in the BSE Surveillance Program. At the one year point (June 1), over 1,300 samples had been submitted from target cattle from Alabama farms. By mid-August, the number of samples submitted from the state was 1,785. Nationally, the number of samples has surpassed 430,000. We continue to look for a disease that continues to make an exit.
So what about the two cows? The O’Leary Cow will forever live in legend and the history of Chicago. The BSE cow? We continue to deal with trade issues, testing, and maintaining consumer confidence. The bottom line is that BSE is an animal health issue and not a food safety issue. Since 1996 when a casual link between BSE and new variant Cruetzfeldt-Jacobs Disease was mentioned, less that 150 people worldwide have died from new variant CJD. That is far short of the thousands of cases predicted to have been present in humans by now.
As we continue with the enhanced BSE Surveillance Program, we ask that anyone who thinks he or she may have a target animal to call the USDA’s BSE hot line at 1-866-536-7593 or call our office at 1-334-240-7253.
Dr. Terry Slaten is the Associate State Veterinarian.