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From: hall@vice.ICO.TEK.COM (Hal Lillywhite)
Newsgroups: sci.physics,sci.bio
Subject: Re: cow magnets
Message-ID: <6642@vice.ICO.TEK.COM>
Date: 10 Jan 91 23:03:36 GMT
References: <1991Jan10.210958.14351@xn.ll.mit.edu>
Followup-To: sci.physics
Organization: Tektronix Inc., Beaverton, Or.
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In article <1991Jan10.210958.14351@xn.ll.mit.edu> rp@jupiter.ll.mit.edu (Richard Pavelle) writes:
>
>A recent Edmund Scientific catalog (#11N1), Page 149, lists
>Cow Magnets. These magnets.. "allow farmers to trap metal in the 
>stomach of cows". Can someone explain why/how these are used?

Yes, I was raised on a dairy farm and remember when these first came
out and what a difference they made.  The problem is that a cow's
taste is not very discriminating, they will eat *anything* which
happens to be in their feed.  This includes barbed wire, baling
wire, and lots of other things which damage their innards.  We used
to regularly have the vet out to do a rumenotomy on some cow
(rumenotomy is the operation to remove the offending whatever).
With modern farming cows are exposed to a lot more of this than a
ruminent in nature would be.  This ailment is called hardware
disease.

The idea of these magnets is that the wire (the usual offender)
attaches to the magnet and is held parallel to it so it can't
puncture the stomach lining.  It works very well.  I only remember
one case of hardware disease after we started using them.  I
watched that operation and the problem was a piece of barbed wire
about an inch longer than the magnet.  As long as the magnet is 
longer than the wire they are very effective.

As long as we're on the subject the following  told to me by a
vet is good for entertainment.  Colorado State University once
decided that for a Christmas program they would invite each college
to demonstrate something they did.  All went well until it came the
turn of the College of Veterinary Medicine.  Then some students
hauled a cow out on stage and proceded to perform the above
mentioned operation (which involves cutting into the cow's stomach).
There were 2 results:

1.  The immediate, almost total evcuation of the auditorium.

2.  One certain college was not invited to participate the next
year.