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Science Update
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Making Manure Smell Better
Essential oils—like those traditionally extracted from aromatic plants
such as rosemary and lavender—might one day make even manure smell better
. . . or not smell at all. Odor-abatement research has shown that as little as
1 gram of essential oils from oregano and thyme is sufficient to block
production of foul-smelling volatile fatty acids in a half-liter slurry of
cattle feces and urine. Carvacrol and thymol can be obtained from several
common herbal plants or produced synthetically. In tests, both of the these
chemicals inhibited odors for several weeks—whether used singly or in
combination.
The essential oils have also been shown to reduce fecal bacterial populations
in manure slurries. Pathogen-laden manure is one source of contamination that
can occur during slaughter. So researchers are now going to feedlots to test
the efficacy of carvacrol and thymol against potentially deadly pathogens like
E. coli O157:H7.
Vincent H. Varel, USDA-ARS
Roman L. Hruska U.S. Meat Animal Research
Center, Clay Center, Nebraska; phone (402) 762-4207.
Livestock Like Dining at Twilight
Twenty-four-hour surveillance of feedlots has shown that cattle would rather
feed at sunset—instead of morning, as is usual. Observation has shown that
evening feeding may halve the number of aggressive incidents among disgruntled
steers—which could greatly cut down on producer costs.
Such applied animal behavior research, though fairly new to U.S.
agriculturists, is shedding light on other aspects of cattle behavior, too.
Animal ethologists are looking for markers that will allow producers to
measure—and reduce—stress in their animals. They believe that
lessening stress will improve both animal well-being and food safety.
Julie Morrow-Tesch, USDA-ARS
Livestock Issues Research Unit, Lubbock, Texas; phone (806) 742-2826.
Keeping Tabs on Noxious Weeds
Information about the distribution of these persistent pests is now accessible
online at a University of Montana/ARS web site. To view this wealth of noxious
weed data, go to: http://invader.dbs.umt.
edu/Noxious_Weeds. Researchers have uploaded official federal, state, and
provincial noxious weed lists from the lower 48 United States and 6 Canadian
provinces.
The information can help predict potential future weed problems based on past
trends and occurrences in neighboring states and regions. It should also help
decisionmakers' research and control efforts at both local and national levels.
Kerri Skinner, USDA-ARS
Northern Plains Agricultural Research
Laboratory, Sidney, Montana; phone (406) 433-9484.
Don't Wash Those Dishes—Compost Them!
Given a chance, plates and bowls made of a new biodegradable composite material
will all but disappear in only 4 weeks—and all traces will be gone in 6
months. Made mostly of limestone and starch by EarthShell Corp. of Baltimore,
Maryland, the new tableware could degrade even faster with more intense
composting management.
So far, quickest results have been obtained when the composting was done in a
closed container with the material stirred by a mixing auger. The compost
consisted of the EarthShell plates and bowls, unbleached paper napkins, fiber
trays, biodegradable trash bags, and food from a federal agency's cafeteria,
plus leaves and grass clippings.
Best of all, tests show the compost does as well as commercial potting mixes as
a medium for growing cucumbers, and the limestone in it works as a soil
conditioner. So the waste-disposal problem could result in a product useful to
agricultural producers and home gardeners.
Patricia Millner, USDA-ARS
Soil Microbial Systems Laboratory, Beltsville, Maryland; phone (301) 504-8163.
Assessing B12 Deficiency
A close look at three thousand 26- to 83-year-old men and women in the ongoing
Framingham [Massachusetts] Offspring Study has shown 39 percent to have plasma
levels of vitamin B12 in the "low normal" range—that
is, below 258 picomoles per liter.
Nearly 9 percent of the study population fell below the currently stated
deficiency level of 148 pmol/L. Over 16 percent were below 185 pmol/L, a level
at which many people can also be deficient. Researchers think there may be a
lot of undetected vitamin B12 deficiency in the general population.
The human body requires B12 to make the protective coating
surrounding the nerves. A deficiency can cause walking and balance
disturbances, loss of vibration sensation, confusion, and, in advanced cases,
dementia. It also causes a type of anemia in which there are fewer but larger
red blood cells.
High intakes of fortified cereals or dairy products proved to be good sources
of B12—reducing by nearly half the number of subjects with
blood levels below 185 pmol/L. But researchers found no association between
plasma B12 levels and intake of meat, poultry, or fish—at least
among certain age groups—even though those foods are the major dietary
source of B12. The reasons are not yet understood.
Katherine Tucker,
Jean Mayer USDA Human Nutrition Research
Center on Aging at Tufts University, Boston, Massachusetts; phone (617)
556-3351. |
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"Science Update" was published in the
January 2001
issue of Agricultural Research magazine.
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