An article in today's New York Times (www.newyorktimes.com - search on mad cow disease) reports a new theory has immerged which blames the start of mad cow disease, not on scrapie in M&BM, but rather on a single antelope imported for a Safari Park in England. When the animal died, it was processed into M&BM, which was then fed to a herd of cattle, whose brains were themselves processed into M&BM and fed to other cattle. The researched examined around 30 scenerios and found this one to be the most likely cause.

Certainly not much consolation for the Vermont dairy sheep farmers.

-- Ken S. in WC TN (scharabo@aol.com), April 19, 2001

Answers

That's really sad. Exactly when did they start that practice? Seems years ago when I was around Texas A&M, and had students working for me on the ranch, they didn't do this thing of feeding dead animals. I can't say for sure though. I wonder who's bright idea it was in the first place.

I would think that nature would make the carnivores immune to things like this, and the herbivores just aren't equiped to handle the weird protein being fed to them. Even I studied the food chain in science class, we all did. That's so sad and it should never have happened. Did you ever find out if it is passed to the calf? And so on and so on. Maybe there's allot more cattle that have it than we even realize.

I've always wondered what would happen to the ecosystems if the animals in the zoos should all get loose, like earthquakes or something along those lines. The whole continent would get out of wack.

-- Cindy in Ky (solidrockranch@hotmail.com), April 19, 2001.

The process of making meat and bone meal (M&BM) basically started after WW-II. When livestock is processed everything which has a market is used, such as cattle lips and cheeks from the U.S. are sold to processors in Mexico who chop them up for taco filling. Only parts for which there is no market are processed into M&BM, which was used as a high-protein animal feed supplement - and is still allowed today for non-ruminant animals, such as swine, poultry, horses, dogs, cats, rabbits, etc.

The attribution to MCD starting from scrapie in M&BM just doesn't sit right with me, since there is little market for mutton from aged sheep, so often all of the carcass, likely less the pelt, when to a rendering plant. Surely from the start some of those were scrapie infected. Yet, it wasn't until about the mid-80s MCD became known.

The U.S. uses basically the same methods of making M&BM as Britian, but why hasn't either MCD or vCJD shown up here? We have scrapie here also.

Sometime back someone mentioned a mother with vCJD passing it onto her fetus, but have seen no documentation for it. I don't believe it can be passed on from infected cow to calf while a fetus or while nursing, but then few dairy cows, the ones most affected, are allowed to nurse anyway.

Each species, including humans (CJD) seem to have their own form of this disease, which seems to occur naturally in 1:1M. It has been documented CJD can be spread by even sterilized instruments used for brain surgery. It can be spread by eating infected brain and spinal cord tissue (and possibly other organs), yet why is there a pocket of Chronic Wasting Disease, the deer and elk equivalent, in a fairly small area out west when these are not carnivores?

Personally, I don't give much credibility to the antelope with MAD (mad antelope disease) as the cause. I still lean towards there being a separate trigger. Yes, deformed prions may be the transmitting agent, what what causes normal prions to become deformed?

-- Ken S. in WC TN (scharabo@aol.com), April 20, 2001.

I dunno, maybe organophosphates. Maybe spraying all the forests for Pine Beetle infestations was some sort of trigger. Maybe the hunters fed the deer grain that was tainted, but then it doesn't seem there would be as many, unless it is passed on and multiplies. Maybe it's both of them put together.

-- Cindy in Ky (solidrockranch@hotmail.com), April 20, 2001.

Another loose piece of a puzzle. Somewhere in Internet readings, I read some farmer wrote of this in 1906 or there abouts. His/Her theory was it had to do with the conditions under which the cattle were raised. Over crowding, poor food, etc. The article said he/she washed feces off their cattle and kept them clean. Even went further to say her/his herd had "mingled" with a "sick herd", and came away scatheless. To make a comparison, commercial poultry is now raised in crowded conditions. The lights stay on because a chick will eat as long as there is light. Quicker turn over to market. They have to have medicines against diseases because of their living conditions. They digest the medicines in their food, we eat their flesh. Our Fore Fathers never took a chick to a vet or gave them medicines. Of course the chicks were raised in a better setting. So chicken is so healthy?

-- My Story (andIam@sticking.com), April 24, 2001.

Ken, are you sure meat and bone meal only came into use since WWII?. I recall reading a description of a late 19th century (i.e. "1800s") pig slaughtering operation where they made use of "everything but the squeal".

-- john hill (john@cnd.co.nz), April 25, 2001.

John:

You are correct. What chanced was the processing method. From Feeds and Feeding by Morrison, 1948 edition.

Prior to WW-II the method used was the wet-rendered method in which the raw material is thoroughly cooked by steam under pressure in closed tanks. The fat is then skimmed off, the soupy liquid drained off and the solid residue pressed to remove as much of the fat and water as possible. The liquid was then evaporated own until it became gluey, added to the solid residue and the mixture dried and ground. This method was common called digester tankage, meat meal tankage or feeding tankage. (I know on farms with hogs near a processing plant this liquid was fed to hogs as part of their swill.)

After WW-II the method changed to a dry-rendering method. The waste meat by-products are cooked in an open steam-jacketed vessel until the moisture has evaporated. Then the fat is drained off, the solid residue is pressed to remove as much of the fat as possible and the dry residue is granulated or ground into a meat. Originally it was called meat scraps, meat meal or dry rendered tankage, but is widely known today as meat and bone meal when bones are also added.

The dry-rendering method is more efficient than the wet-rendering method. Neither method would kill prions.

-- Ken S. in WC TN (scharabo@aol.com), April 25, 2001.