And here's something else to ponder regarding the food chain: line breeding, prions and mad cow disease.

It is my hope that this article will bring about further investigation by the scientific community and much dialogue on the subject of prion-related diseases.

Theories, like opinions, are all over the place. There have been many theories that after much scientific research were proved to be unsubstantiated. I believe that I have found the common denominator to the various diseases the science has determined to have been caused in part by what has been termed the "prion," the prion being made up of protein. Once the prion reaches the mutated stage, there is no way to destroy it as of this date. The prion has been blamed for causing Bovine Spongiform Encephalopathy (BSE or Mad Cow Disease) and its human equivalent, Creutzfedlt-Jakob disease (CJD) and variant Creutzfeldt-Jakob disease (vCJD). This class of diseases are called Transmissible Spongiform Encephalopathy's or TSE's. Also included is Chronic Wasting Disease (CWD) found in wild game and scrapie in sheep. It is believed that one of the methods of contracting TSE's in cattle is the consumption of animal byproducts as a feed additive which has been outlawed in most countries.

Science has determined that in some human cases of CJD that there may be a genetic predisposition for the prion to mutate. I believe that I have found one of the common denominators involving prion related diseases. It is common knowledge that consumption by humans of tainted meat and the consumption by animals of by-products in their feed is definitely a method by which the disease can be transmitted. The common denominator in this disease, I believe, will eventually be found to be line breeding. Some examples are CWD in wildlife, in most instances found in domesticated herds, and also in areas of the country where herds have been mismanaged and allowed to over populate. In cattle, most BSE has been found in dairy cattle that have been line bred for decades. The same holds true in sheep with scrapies. I do not know, but in theory, this could also be true of the indigenous tribes that were discovered in the 1950s in New Guinea and were the subject of a book called Deadly Feasts, by Richard Rhodes.

Most dairy cattle breeds have been maintained as purebreds, quite the opposite is found in beef cattle, of which the majority found in feedlots today are crossbred. This is also true in sheep, most of which are genetically pure breeds. This line breeding has been going on for decades, even in species such as canines. I believe that the practice of line breeding has come full circle and created a genetic predisposition for the mutation of prions. Most of the dairy cattle that are slaughtered for human consumption have reached an age of maturity where the prion has had ample time to mutate. Beef cattle usually reach the kill floor before 24 months of age and, again, are primarily crossbred.

I believe as science progresses in the search for answers that they will discover that line/inbreeding will be determined to have played a major role in the progression of prion related diseases. I believe that it is extremely important to not only ban all animal by-products fed to ruminant animals, but also to re-think the issue of line breeding. It is a proven fact that cross breeding produces a healthier, heartier animal. I would urge all herdsmen and wildlife managers to rethink their breeding programs and pay close attention to wildlife management practices to prevent herd overpopulation.

In conclusion, I would like to recognize my late father, E. A. "Dink" Robart for having taught me about line breeding in his efforts to find the perfect racehorse. Line breeding has been practiced in numerous species over the years in an attempt to develop what man perceives to be perfect conformation and to increase milk production and many other traits that are deemed beneficial. This is not to say that all genetically predisposed diseases came from line/in-breeding. In the case of a prion related disease it appears that it is most prevalent in ruminant animals with the exception of man. We must be extremely careful when attempting to improve upon God's creatures, for the potential exists for creating a genetic trigger that could destroy mankind.

DINK ROBART

ALPINE, AZ