Is this Hamburger Safe to Eat?
Impact of Bovine Spongiform Encephalopathy (BSE) on the Cattle Industry in the United States — an interview with Dr. John Maas of UC Davis Veterinary School
Daniel Ehrlich

Posted Saturday, May 1, 2004
4 U.C. Davis Bus. L.J. 13 (2004)

Dr. John Maas has been a faculty member of the UC Davis Veterinary School since 1988. Previous to his position at UC Davis, he has taught at Oregon State University and the University of Idaho. He has been involved in research on ruminants for the past 20 years. He received a Doctor of Veterinary Medicine from the University of California and a Master of Science from the University of Missouri in Veterinary Microbiology. He is board certified in both Clinical Nutrition (ACVN) and Internal Medicine (ACVIM). Dr Maas is a member of the National Cattlemen's Beef Association Quality Assurance Advisory Committee and Chair of the NCBA's Animal Disease Research Subcommittee. He is also a cattle producer with ranching interests in Shasta County and Stanislaus County, CA. Dr. Maas is currently Second Vice President of the California Cattlemen's Association.

Q: When was BSE first recognized?

A: BSE (Bovine Spongiform Encephalopathy; Mad Cow Disease) was first recognized in the UK in 1986.

Q: What types of animals are prone to contracting BSE?

A: Beef and dairy cattle, and cattle used as draft animals (like in Southeast Asia), are all susceptible. The most susceptible animals are the ones in the United Kingdom (UK). Over there, dairy cattle are used in beef production. It's a problem because those animals are eating in the pens and are fed the meal, as opposed to grazing in the pastures.

Older animals are the ones most likely to have it. In Europe and the States we've been initiating SRM removal (specified risk material) of the material that has the prion in it. SRM's include spinal cord, tonsils, thymus, brain, eyes, skull, vertebral column, and small intestine. If the animal is over 30 months of age, those materials are simply removed and disposed.

That's not an insignificant cost of removing material; depending on how it's done, it runs from $120 to $300 per animal. Most animals that are slaughtered for profit run about $2500. So the testing cost is two to twelve times the profit of the animals. When you are losing money on every carcass you handle, it's a significant issue.

Q: Is there a genetic component to BSE?

A: It's a Transmissible Spongiform Encephalopathy (TSE). You can take these agents and inject them into the brain of the mice, and they will duplicate there. But in nature the TSE's are species specific. Sheep have scrapie, deer have chronic wasting disease, and humans have Cruetzfeld-Jacob disease. (We're not sure Cruetzfeld-Jacob is transmissible). Cruetzfeld-Jacob disease occurs spontaneously at a rate of about 1-2 people per million worldwide, per year. So when it was described in 1986 in cattle this was a new disease. And yet people had recognized scrapie in sheep for over 100 years and been able to diagnose it. Scrapie is the same sort of disease, but the agent does not jump to cattle naturally.

There is a genetic component to scrapie. We may find some animals that have a resistance to it and some are susceptible. In fact, with scrapie, nowadays there is a live animal test so we can figure out who has it long before it's a problem. There's also a genomic-based test so we can determine which animals are susceptible. My hope is that we can get those similar kinds of live animal tests on cattle because that would make it a lot easier to detect them. You could get rid of the susceptible animals by breeding.

Q: Is there any danger to humans with regard to animal products used in products (such as fat derivatives used in cosmetics).

A: There have been 159 cases worldwide, 149 in the UK. Of the 10 cases outside the UK, half had spent a significant time within the UK at particular times when they would have been exposed the disease. Some have extrapolated that the rate of Cruetzfeld-Jacob (in humans) is 1-2 per million of the cattle population, (saying that BSE occurs spontaneously in cattle just as spontaneous Cruetzfeld-Jacob disease occurs in humans). Therefore, if we have about 100 million cattle in the US, we have 100 to 200 cases of BSE every year. However, there is no basis in fact for this assumption.

Q: What impact has BSE had upon the cattle and beef industry? In particular, what are the short-term affects?

A: Beef markets have gone down 20%. In 2002-2003 we witnessed the first significant increase in cattle prices in a long time, but it still didn't come close to getting back up to inflationary standards. We lost $3 - $4 billion dollars a year in the export market to Japan, South Korea and Mexico. Mexico has since opened to the U.S.

Q: What are the long-term affects?

A: In California, we have had a long-standing industry since the Spanish missionaries came. California still was and in many places still is a natural grazing state because of the way the rain falls, the seasonality of it, and availability of pastures. Grazing has a number of benefits; it gets rid of excess vegetation, decreases brush encroachment, and prevents catastrophic fires from brush that grows up. We also have tremendous population growth which threatens the amount of open space available in the state. Agriculture is the biggest industry in California, and beef cattle is the fifth or sixth largest industry in agriculture, so a disruption of the beef cattle industry by BSE does affect our economy.

Q: Has the impact of BSE upon the cattle and beef industries had a ripple effect on other areas of the economy?

A: Sure, anytime an industry loses 20% of their revenue there is a ripple effect to other industries.

Q: Has the government issued any regulations to protect against BSE?

A: Yes, the government issued regulations to have 40,000 animals tested a year. The USDA is expected to release a statement in March 2004 that the number of tests will go up to 300,000. There are also regulations requiring all the SRM material to be removed, and there is a mandatory animal identification system.

A couple of senators have talked about issuing California legislation. The problem with that is it's such a big issue if we do something unilaterally it has complications across the country, and we don't have the money or resources. If we go off and do something on our own it could disadvantage our consumers and producers. Our producers are disadvantaged anyway because California is such a difficult economic environment. Furthermore, it still may not have any impact on the disease, because there is no evidence it would do anything.

Q: Do you think current government regulations represent a good balance for protection of consumers and the beef and cattle industries at issue?

A: It's always hard to know. We have to keep in mind that this kind of a disease and the programs required to eradicate it are very expensive. In France, for example, the programs are 13 times more expensive than those for eradicating tuberculosis. In livestock we have been much more successful in eradicating tuberculosis than we have in humans. In California, we have 3,000 new cases of tuberculosis every year and we don't even test food servers because of lack of resources. On the livestock side, tuberculosis is almost eradicated. In Europe, the passport system is more complicated for animals than it is for people. This kind of a disease is not cheap. There is no live animal test and the incubation period is extremely long. An animal doesn't often get it till its 10 years old. In France the average age of animals infected was 98 months. In Europe the preferred beef animal is a 5 or 6 year old and the early cases of BSE are at 62 months. Over here our cattle are slaughtered at 12 or 15 months of age and even if they got infected it would only be in the terminal small intestine, which is thrown away anyhow. It starts in the ileum, disappears, and starts replicating in the brain. The kind of cattle here are quite different.

Q: Do you have any particular suggestions about how government regulations could be changed to increase protection for the beef and cattle industry?

A: We're all in this together. It's a big problem for our industry and economy. My suggestions are we should all do our part. Government, consumers, and industry should all do their part.

Q: What is the current understanding of the cause of BSE?

A: BSE is caused by Prions which is an abnormally folded protein that does two things: (1) stimulates cell replication which takes up space in the central nervous system so that the neurons then cannot function, and (2) cause resistance to degradation. They are folded in such a way that heat will not even degrade the 3 dimensional chains of amino acids. If they didn't have the resistant properties they would be much easier to deal with. One could heat or freeze them to disrupt their shape.

Q: Can BSE be eliminated in the US?

A: We haven't had a native animal infected yet, so hopefully we can continue that and keep it out of here. In Europe they are well on their way to eliminating it, and for those countries that have good programs, I would guess they would eliminate it within 20 years. The main thing is to keep animals that might have it out of the country. Since 1986 we've had laws keeping cattle out of our country from countries that have it. The dairy cow that came to Washington from Canada entered before regulations took effect, and we had thought Canada was low risk at the time.

The meat and bone meal ban was started in 1997 and has been extended, and we've had a good surveillance program that exceeds OIE (international office of epizootics- world organization for animal health) standards.

We've been lucky in the United States. We're the 24th country to have a case of BSE on our soil, but we imported that case from Canada. We don't feed our animals meat and bone meal to speak of, because we have protein sources from plant materials that have always been a lot cheaper. Soybean meal, linseed meal, cottonseed meal, and alfalfa hay grows here easily and cheaply and is relatively high in protein (15-25%). We have fed meat and bone meal to poultry and swine, but never cattle. That's quite different than in developing countries where protein sources are scarce, or European countries where meat and bone meal feeding has been part of recycling.

Q: Is there a danger to household pets by feeding them beef products?

A: We don't know. There doesn't appear to be any inkling of problems for dogs. There has been some TSE's in cats in the UK. These appeared around the same time as the BSE's so it may have been a non-transmissible form of BSE from the cattle. There have also been llamas that came down with TSE's. The FDA is looking hard at these things, but there is currently no evidence of transmission to household pets.

Q: Are punishments for violations of the existing codes adequate?

A: I sure hope so. We don't want to have a system that rewards risk taking in public health.

Q: How much will diagnostic testing for BSE cost and who will bear the burden of them?

A: The testing costs are $50 per head for healthy animals that are slaughtered. For at risk animals, the cost is from $150 to $200. It costs a lot more for at risk animals because those animals will have to be specially moved and other additional charges.

I'm not sure who will bear the burden of those costs. If the cow producer bears all the costs of these diseases, there will be no cattle industry. Most of the producers are in the real estate business. Most are working very hard, trying to make ends meet, and are sitting on a gold mine of real estate. So hopefully they won't have to pay at all, because it would totally disrupt our economy and lifestyle. We'd run out of asphalt. Hopefully there will be some incentive, because we don't want people to be afraid of getting a diagnosis, and hiding out.

Q: Where will the testing be done?

A: Independent laboratories must do the testing. You can see the difference in the effectiveness of approaches in France as opposed to Germany. In France they developed a centralized diagnostic lab system that was very effective. In Germany they first denied they had a problem, and when they finally admitted it, they let everyone do their own testing. As a result, their whole industry was disrupted because they had an inadequate and unaccountable system of testing. They actually had less BSE than France, but they were totally disrupted. The rapid tests are quick, but they are not easy. You need all the codes in place and technicians must be certified and trained, it's not just a mill.

Q: How does globalization and increased international trade affect this issue?

A: Globalization certainly does affect the beef and cattle industry. Ultimately, it's most effective to control what's coming in the country than to try to do surveillance on all our cattle. But the negative factor is that you have to kill them to test, since we don't have a live animal test.

Q: What do you think the future of the post-BSE beef and cattle industries look like?

A: BSE is potentially devastating for the industry and pretty tough on the economy. You need science to solve these kinds of problems. We need new methodologies to detect BSE. Hopefully we can learn some lessons out of this and improve prevention.