A note on the issue of composting animals. One of the other dangers
with it--as we discussed in the avian botulism/limberneck thread--is
that some pathogens are killed only at high heat, which the compost
cycle does not produce.
/Clostridium botulinum/, for instance, requires 250 degrees F.
(remember that from when you were learning to can vegies? low-acid
fruits go in the pressure cooker because of this....) to ensure
killing the microbes. And unless the composted animal tissue were
very carefully protected, the possibility of it serving as host to
/C. botulinum/ and life forms that concentrate that would seem likely.
Below, I've clipped and pasted some stuff from that earlier
discussion as an example I think may apply in the present discussion.
It applies to avian botulism, but I'd think the principle could be
the same for other pathogens. Not to say that this composting CAN'T
be done--just that I'd think there'd need to be a set of safe
practices developed, and taught, in doing so.
BTW, I think a distinction needs to be made about whether we're
talking about composting as a waste-management method, or as a way of
producing something to put back into the land/life cycles. I can't
imagine composting animals for the latter use. Read on.
In Wisconsin we had a vicious heat wave in the summer of '95, still
referred to by some folks as The Summer of Exploding Cows. That
summer, a dairy farmer friend in the coulee told me that a number of
his neighbors who'd lost livestock were concerned because the offal
truck couldn't keep up with the deaths. And when the temps are at
100+ for x days, you really don't want dead livestock hanging around
the place. I remember seeing that, just driving through rural areas
that summer--bloated livestock. Very painful. And also weirdly
surreal.
So, he said, some were staying quiet about their stock deaths, and
reviving (he used that word; I don't know whether it was reviving, or
creating) a technique for disposal--"pit composting." I said, you
mean burial? He looked distressed and said, "I don't think it's the
same, but I don't know how others might view it." He said it wasn't
just plopping the animal in a hole in the ground, which is burial.
The idea was to excavate a pit, thickly line the pit with and
surround the animal snugly with compostable and
compost-organism-containing residue--bedding, spoiled hay or silage,
etc., top off the pit with that, then replenish it regularly as the
pit-fill sank. I can't remember what he had to say about how to
aerate the pit--posts or pipes would be the simplest solution. After
some period of time (WHY didn't I take notes on this!?), the animal's
tissue would be completely consumed, and the pit would be refilled
with excavated soil. The resulting pit-fill would not be spread on
crops/land for the reasons I mention above and below, but the
disposal would happen organically (in the sense of within living
cycles). In a conventional burial, there wouldn't be nearly as much
microbial activity, in the subsoil, to consume the animal's tissue,
as with this system, which aimed to build an soil-type aerobic
composting cycle in the subsoil.
That same summer or fall, I read Laurie Garrett's /The Coming Plague/
while flying to Madison from San Francisco. And I wondered whether
this animal-disposal system, if widely adopted, wouldn't select for
populations of soil-borne flesh-eating /Strep./ bacteria and other
pathogens. It seems to invite them. Also, in the case of prions,
composting would not break those down--even the heat of an autoclave
can fail to destroy them. Neither of these are very pretty thoughts.
peace
misha
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--U.S. Fish and Wildlife service info:
http://www.emtc.nbs.gov/http_data/nwhc/factshts/avian.html
The authors are at the National Wildlife Health Laboratory, in Madison.
"Avian Botulism affects the nervous system, causing muscle paralysis.
Depending on how far the disease has progressed, various levels of
paralysis will be
observed. An early sign in birds is the inability to fly. Once the
ability to fly is lost and leg muscles become paralyzed, ducks
suffering from botulism often propel
themselves across the water and mud flats with their wings. This
sequence of signs is in contrast to that of lead-poisoned birds,
which have difficulty flying but
remain able to walk and run.
"Paralysis of the inner eyelid and neck muscles follows. These are
the two most easily recognizable signs associated with avian
botulism. The inability of the bird to hold its head erect is the
reason this disease is called "limberneck." Frequently, birds will
drown once they reach this stage in the disease. Those that do not
drown will eventually die from respiratory failure as paralysis
spreads.
"Favorable environmental conditions occur in the tissues of decaying
animal and insect carcasses. The decomposition process uses up all
available oxygen in the
carcass, creating anaerobic conditions. Bacterial spores ingested
during the life of the animal germinate after death. As the bacteria
multiply and die, the toxin is
released.
"The cycle of avian botulism
"Outbreaks of avian botulism occur when the toxin is taken in by
birds. The die-off may begin as birds feed directly on invertebrate
carcasses that contain the toxin, or as a result of feeding on live
maggots of flesh-flies and blowflies. Flies lay their eggs on dead
vertebrates, and the resulting maggots store botulinal toxin in their
bodies as they consume the carcass. More than 5,000 maggots can be
produced by a single bird carcass; consumption of just two to five
toxin-bearing maggots is
often enough to kill a duck!"
Note that the difference between this and Kate's situation is that
the source of the botulinal toxin is dead vertebrates and
invertebrates. Kate is decomposing/composting vegetables. Which is
what I was thinking when I suggested laying the heap open to the air
for city birds to pick at.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Michele Gale-Sinex
Communications manager
Center for Integrated Ag Systems, UW-Madison
http://www.wisc.edu
UW voice mail: 608-262-8018
Home office: 415-504-6474 (504-MISH)
Home office fax: Same as above, phone first for enabling
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Nature bats last, and Mitch Williams is pitching.
--motto of the Center for Integrated Ag Systems, UW-Madison
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