GreenFeed is Online!

Advanced technology for the cow of
the future
US Patent number 7966971
What is GreenFeed?
The patented (additional patents pending) GreenFeed system
quantitatively and unobtrusively monitors methane (CH4 ), carbon
dioxide (CO2), and other selected trace gas mass fluxes emitted from the
mouth and nose of cattle during eructation and respiration.
CH4 is a powerful greenhouse gas that is produced by anaerobic
digestion in the rumen, and CH4 production represents an energy loss of
two to ten percent of a cow’s gross energy intake. Rumen CH4 and CO2
fluxes are also sensitive to rumen function, diet, behavior, health, and
genetics. In addition, respiratory CO2 fluxes can be used to estimate
energy balances, and efficiency, for individual cattle.
The GreenFeed system makes automated, periodic measurements of
CH4 and CO2 fluxes for many individuals several times each day while
each animal visits a feeder-station. The periodic daily data, when
aggregated over time, allows the user to track and compare emissions
for large groups of individual animals. The individual animal data can
also be aggregated as totals for the herd.
Overall, the GreenFeed system is unobtrusive to the animal, userfriendly, and simple to maintain and operate. Compared to “classical”
methods such as calorimetric chambers or the SF6 tracer method,
GreenFeed is inexpensive to acquire and operate. In contrast to
alternative techniques, GreenFeed is portable, standardized, and does not
require intensive animal or technician training. GreenFeed systems can
be used in tie-stalls, free-stall barns, feedlots, or pastures. GreenFeed
has also been retro-fitted into robotic milking machines and can be
adapted to operate with a wide range of watering , feed and dairy
How Does GreenFeed Work?
The operation of GreenFeed is analogous to a highly instrumented
portable “fume hood”. Field-operation consists of the following
(1) A target animal approaches the unit and is identified by an
integrated RFID reader.
(2) User-specified “bait” is delivered to a specially-designed feed tray
and gas intake manifold. Bait can consist of feed pellets, minerals
or water.
(3) The animal inserts its head to consume the feed.
(4) Simultaneously, a fan pulls air at a specified mass flow rate over
the animal’s head and nostrils, through the intake manifold, and
into the air-flow handling and monitoring system.
(5) A proximity sensor detects and documents the position of the
animal’s nose in relation to the air-sampling manifold inlet.
(6) Continuous measurements of CH4 and CO2, and airflow are
recorded at a resolution of about one second.
(7) A tracer is periodically released into the feeder near the animal’s
nose, and then measured to determine the “capture rate” of gases
emitted from the animal that enter the manifold.
(8) The data is stored and periodically transmitted to a server, where it
is processed and the mass fluxes of gasses from each animal are
directly calculated for each feeding period.
Patented Technology
GreenFeed can measure Methane and
Carbon Dioxide emissions in any cattle system!
Portable, Push-Cart
GreenFeed for Tie-Stall use
GreenFeed Fitted into a
Milking Robot
Portable, solar-powered GreenFeed trailer for use in Pastures.
Layout of the GreenFeed Stand-Alone Feeder
Portable, trailer
mounted GreenFeed
How Mass Fluxes are Calculated Using GreenFeed
The mass fluxes of CH4 and CO2 (or any other measured gas) are
directly monitored and calculated from measured trace gas
concentrations, airflow, and other supporting data collected by
GreenFeed. Basically, the measured increase in concentrations
compared to the background (ambient) levels are multiplied by the
measured airflow rate. Then the ideal gas laws are applied to convert
the data to mass fluxes. The math is similar to that used in most
chamber studies. However, unlike chamber equations, an additional
“capture” rate adjustment factor is applied using data from the
GreenFeed tracer release. The correct dimensional conversion factors
are also used.
4 volume
 Fc * C R *
* ( CH
4 avg
 CH
4 bkgrnd
) * Q air
CR = Capture rate adjustment, determined using the tracer
t = Time period over which emissions are measured (1 second)
CH4avg = Average concentrations during the measurement period (%)
CH4bkgrnd = Background concentrations of CH4 (%)
Qair = Airflow rate during the measurement period (flow per unit time)
Fc = Dimensional factor
Once the volume of CH4 or CO2 emitted by the cow per unit time is
calculated, it is straight-forward to convert the data into mass fluxes for
each trace gas of interest using ideal gas laws and the molecular masses
of the gasses. The fluxes can be plotted second-by-second, as shown on
the opposing page for one five-minute feeding period.
Then, for each feeding period, the mass of methane and total time of
each measured eructation is calculated. The sum of all of the eructations
measured during a feeding period is then divided by the time length of
the measured eructations to calculate a mass flux per unit of time.
Eructation data is filtered based on the head position data, therefore not
every eructation during a specific feeding period may be quantified.
The mass fluxes over time for several feeding periods for one cow then
can be plotted and averaged (opposing page).
Flux Calculation Examples
Methane Flux Calculation Example, Average Flux for a Feeding
Each Peak is an Eructation
CH4 mass emitted = 0.23 g + 0.26 g + 0.7 g + 0.31 g = 1.07 g
Total Time = 72 s + 79 s + 76 s + 67 s = 294 seconds
CH4 Flux = 1.07 g/294 s= 0.0036 g/s = 13.1 g/hr
Methane Flux Calculation Example, Average Flux from One Cow for
Twelve Feeding Periods over Four Days
Results from GreenFeed
Methane and Carbon Dioxide Concentrations for Five Consecutive
Feeding Periods from Five Different Cows
Average Monthly Methane Emissions for Several Different Animals
GreenFeed is Online!
GreenFeed includes web-based software tools to control and review
results from any computer in the world with an internet connection.
Individual user login and password is secure.
Allows user to control feeder functions and settings in real-time
Control individual animal baiting schedules and rates
Review real-time data
View webcam, watch the cows visit the feeder
Access and plot real-time data
Access and plot historical data
Many education and training applications and opportunities
GreenFeed’s unique capabilities facilitate many new research and
management possibilities. Monitoring changes in CH4 and CO2
emissions from individual animals over time provides important
information about consumption, health, behavior, and efficiency. Since
GreenFeed directly monitors metabolic gas fluxes, GreenFeed data can
be used to evaluate and understand how management strategies impact
metabolic function and animal efficiency. It is therefore well suited for
animal efficiency research applications.
GreenFeed is an ideal tool to accelerate the rising international efforts
such as “The Cow of the Future” to improve ruminant efficiency and
reduce ruminant methane emissions. GreenFeed measurements are
automated and standardized, therefore allowing the direct comparison of
research results from around the world.
GreenFeed is also ideal for genomics studies related to methane, carbon
dioxide, and ultimately animal efficiency. This research requires quick
screening of many animals for desirable traits. GreenFeed is ideal for
quickly measuring CH4 and CO2 emissions for large numbers of
GreenFeed has been used as the primary measurement system in
experimental trials to determine the effectiveness of specific treatments
that reduce methane emissions. Other researchers are using GreenFeed
to monitor whole herd CH4 emissions that result from varied
management practices.
Once effective ruminant methane reduction strategies have been
identified in research facilities, GreenFeed can be used to document and
quantify actual reductions achieved over long time periods in
commercial production facilities.
Our staff is experienced in writing successful scientific proposals. We
are happy to collaborate with you to develop proposals that include new,
innovative research studies involving GreenFeed.
Dr. Patrick Zimmerman, the founder of C-Lock Inc., has worked
more than 35 years in the environmental research field. Before
founding C-Lock Inc., Dr. Zimmerman was a professor and the
Director of the Institute of Atmospheric Sciences at the South
Dakota School of Mines and Technology. Prior to that, he was a
Senior Scientist and Section Head at the National Center for
Atmospheric Research in Boulder, Colorado. Dr. Zimmerman's
work has resulted in the authorship of more than 100 papers in the
refereed scientific literature, and in seven granted patents with more
Dr. Zimmerman received his Ph.D. in Rangeland Systems Ecology
from Colorado State University. His Ph.D. was mentored by, and he
worked closely for several years with Dr. Paul Crutzen, one of three
co-winners of the 1995 Nobel Prize in Atmospheric Chemistry.
Zimmerman’s research has focused on measuring and understanding
the complex interactions among the earth's biological, chemical and
atmospheric systems. Over his career, Dr. Zimmerman has received
dozens of grants and contracts from many federal agencies and he
has consulted for several NGOs and businesses.
Scott Zimmerman worked in the utility industry for 10 years. He has
a Bachelors degree in Civil Engineering from Washington State
University, and a Master's Degree in Water Resource Engineering
from the University of Iowa. He has significant experience in data
analysis and numerical modeling and has worked on several
different studies related to increasing power generation efficiency
and minimizing ecological impacts of hydro-power generation.
Scott has also worked in the environmental compliance and
reporting field, and has experience in measuring and reporting
pollutant emissions to state and local agencies.
C-Lock Inc.
2951 N Plaza Dr.
Rapid City, SD 57702
N Plaza Dr.
Rapid City, SD 57702
The world’s first online system to
measure Methane emissions

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