Keeping any foreign animal disease out of the United States requires action by the federal government, which has the authority to inspect goods at ports, to monitor imports and to negotiate with foreign governments over trade matters. Wisconsin, and other states, work cooperatively with the federal agencies.
In the United States, we take a multi-pronged approach to preventing BSE.
In 1989, the U.S. Department of Agriculture (USDA) banned imports of these products from countries where BSE had been found in cattle:
- Live ruminants (cud-chewing animals including cattle, sheep, goats and deer)
- Meat from ruminants
- By-products from ruminants, including bonemeal, bloodmeal, fats, and glands (milk does not carry the abnormal BSE proteins, so dairy products are not included in the ban)
In 1997, the USDA broadened the ban to cover all of Europe. In 2000, the USDA broadened the ban again to cover by-products from all animals in Europe. In 2001, Japan was added to the list and in 2002, Israel was added. In 2003, Canadian imports were banned, but because only one case of BSE was found despite an exhaustive search, some were reinstated.
BSE apparently arose from including by-products from infected animals in feed as a protein supplement. First, the feed contained parts from sheep that had scrapie, a related disease. After the disease infected cattle as BSE, parts from those cattle went into feed before anyone knew about BSE. This practice has now been prohibited in much of the world and has been effective in slowing the epidemic in the United Kingdom. Cases still being found were probably infected prior to the prohibition, because BSE has an incubation period of 2-8 years.
In 1997, the U.S. Food and Drug Administration (FDA) prohibited U.S. manufacturers from using almost any by-products from mammals in animal feeds for ruminants. To enforce this "prohibited protein" ban, the FDA and state agriculture departments inspect feed mills, feedlots, dairy farms, rendering plants, distributors and other businesses involved in animal feeds.
Wisconsin has over 1,200 firms with commercial feed licenses, distributing nearly 3 million tons of feed products. Our department along with our federal counterparts inspect and monitor feed manufacturers to ensure their continued compliance with state and federal feed rules. The few Wisconsin firms that handle prohibited animal proteins are inspected annually. Although banned in ruminant animal feeds, these animal proteins are permitted in pet foods, poultry feeds or industrial uses. Most rendered animal-by products produced in Wisconsin are shipped out of state. You may find cattle or deer feed listing "animal protein" as an ingredient; this is allowed if the protein source is certified as bieing purely from horse or swine by-products. Also, fats, oils, grease, tallow, blood, blood products, milk and milk products are permitted even though they come from animal sources.
State or federal inspectors examine all cattle before they are slaughtered. No animal with symptoms of a central nervous system disease can be used for human food, and its brain is examined for BSE. Also, cattle slaughtered because of rabies-like symptoms are tested for BSE if they test negative for rabies. "Downer” cattle – those slaughtered because they are unable to stand up – are also tested for BSE.
Nationwide, from 1986 through 2003, the brains of more than 48,000 cattle have been examined. In December 2003, one positive sample was identified in a Washington state dairy cow born in Canada prior to the feeding prohibitions. Beginning in June, 2004, USDA began an intensive testing program designed to provide a snapshot of the U.S. cattle population to determine if BSE is present in this country and if so, at what level. The program is designed to test as many cattle from the high-risk population as possible within a 12-18 month period. Through mid-November 2004, more than 120,000 cattle have had samples tested. In Wisconsin we have submitted brain tissue samples of more than 25,000 cattle.
Nonambulatory cattle, often called "downers," are no longer permitted to go to slaughter. These are cattle that are unable to walk. Most often this is because of an injury such as a broken leg, or paralysis caused by a difficult calving. Sometimes it is because they have a disease. In the past, those cattle that had disease symtoms were condemned and not used in human food, but injured animals could be used for meat. Nonambulatory cattle have been the largest source of BSE test samples. After humane euthanizing, these animals must now go to rendering, or be buried on farm, composted, or landfilled.
Specified risk materials
Specified risk materials are now banned from human foods. These "SRMs" are the parts of cattle most likely to contain prions, believed to cause BSE or the human disease new variant Creutzfeldt-Jakob disease. They include the skull, brain, eyes, and spinal column and cord from cattle 30 months or older, and tonsils and small intestines from all cattle.
State and Federal Responsibility
Here is a detailed account of state and federal actions to prevent and detect BSE.