Wisconsin dairy farmers may soon have to find a replacement for meat and bone meal in their rations. A proposal by the U.S. Food and Drug Administration would ban most meat and bone meal from ruminant diets. Ruminant-derived meat and bone meal in cattle diets is blamed for the outbreak of bovine spongiform encephalopathy (BSE, or “mad cow disease”) in Great Britain. The FDA has not set a date for implementation of the ban.
The proposed regulation, announced Jan. 2, would prohibit using ruminant tissues in the manufacture of ruminant feeds and feed supplements. The rule, which would also ban mink tissue from ruminant feeds, is designed to protect livestock from transmissible degenerative neurological diseases, and to minimize any potential risk that such diseases could be transmitted from animals to humans.
Researchers and regulators are concerned about a possible link between BSE, a fatal brain disease of cattle, and Creutzfeld-Jakob disease (CJD), a fatal brain disease of humans. Recent studies suggest that beef containing nervous-system material from BSE-infected cows could have led to a new British variant of CJD, which so far has killed 12 people. Many observers have called for the United States to ban the feeding of ruminant protein back to ruminants.
Meat and bone meal, produced from rendered animals, is a common ingredient of Wisconsin dairy rations because it has been an inexpensive source of protein, calcium and phosphorus, according to Randy Shaver, extension dairy nutritionist at the College of Agricultural and Life Sciences. Consisting of the cooked and ground-up remains of processed carcasses, it contains 50 percent protein, 10 percent calcium and 4.5 percent phosphorus.
“There are a lot of options on the protein side,” Shaver says. “The major economic impact for farmers involves purchasing inorganic mineral supplements to replace the phosphorus supplied by meat and bone meal.” He points out that the protein from meat and bone meal actually isn”t all that good from a digestibility standpoint, compared with other protein sources. Alternative protein sources include soybean meal, roasted soybeans, blood meal and many commercial protein feeds.
Producers would have to purchase more calcium carbonate and dicalcium phosphate to make up for the minerals supplied by meat and bone meal. Shaver calculated the additional cost of these supplements to be about $15 per cow for the lactation. This would be in addition to the new protein source chosen. There would be no additional labor since farmers are already feeding minerals it”s just a matter of feeding more, Shaver says.
In 1994, 108,473 tons of animal byproducts were distributed in Wisconsin. This figure includes meat and bone meal as well as blood meal, milk products and others according to Eric Nelson of the Feeds Division in the Wisconsin Department of Agriculture, Trade and Consumer Protection. Nelson notes that the numbers are not always accurate because some duplication may occur as commercial feed manufacturers and feed distributors report the same numbers. Wisconsin”s largest producers of meat and bone meal are National By Products, Inc. of Berlin and Anamax Corporation of Green Bay.
BSE may have started as a naturally occurring form of transmissible encephalopathy in cattle that was “amplified” by feeding cattle byproducts back to cattle. Other scientists think that BSE “jumped species,” coming from scrapie-infected sheep byproducts fed to cattle. (Scrapie is a degenerative nervous system disorder of sheep, similar to BSE in cattle.) Most scientists believe that the culprit in BSE and scrapie is a proteinaceous infectious particle, or “prion.” These rogue proteins multiply by changing the shape of normal protein molecules, creating new prions. Eventually they destroy the victim”s brain.
BSE was first recognized in Great Britain in 1986; it has never been found in the United States. Meat and bone meal was banned from ruminant feed in Britain in July 1988. The infective dose is less than one gram of infected material, meaning a 1-kilogram (2.2-pound) cow brain could infect a thousand animals.
CALS veterinary research associate Doris Olander has worked closely with Richard Marsh, a CALS veterinary scientist who specializes in transmissible encephalopathies. According to Olander, BSE moved from primarily an animal issue to a public-health issue on March 20, 1996, with the announcement of the link between BSE and CJD.
“Despite the many implications for agriculture, the ban is appropriate in order to address animal health issues, public concerns about agricultural products, and economic risks posed by BSE. One case in a native-born cow will have the same consequences here in the United States as Britain. In some ways the ban is preventative,” she says. BSE has devastated the British beef industry.
Domestic consumption has plummeted and most countries have banned imports of British beef. “The ramifications of the proposal passing are substantial, just as the ramifications of having a case of BSE in the U.S. are substantial,” Olander says. Farmers, renderers and the feed industry, and the environment will all be affected. After the ban, consumers will probably pay more for dairy products and meat.
“BSE has a long incubation, causing problems with detection and exposure,” Olander says. Still, our chances are good of finding BSE if it exists, she says. “The U.S. knows what cows with BSE look like in the clinical form. Behavioral abnormalities are the hallmark for both BSE and rabies.”
Cattle that exhibit these abnormalities are tested for rabies. If they prove negative for rabies, the cattle are tested for BSE an important part of the U.S. surveillance program. “However, based on research carried out by USDA, a new strain of BSE may not appear rabies-like. Therefore, it is very important to break any BSE transmission cycle by banning ruminant-derived byproducts from ruminant diets,” Olander says.
In 1994, the FDA proposed a ban on sheep-derived meat and bone meal. In April 1996, the USDA called for a voluntary ban on feeding ruminant-derived meat and bone meal to ruminants.
The United Nations World Health Organization has recommended that all countries ban ruminant tissues in ruminant feed. Olander says this is something to consider, as the United States competes in a global economy. Other countries could use a lack of U.S. regulations against us to block imports of U.S. beef or cattle, for example.