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Danish Environmental and Pig Housing Trends
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Larry D. Jacobson, Minnesota
Extension Engineer
Each year I receive an annual report from the Danish National Committee
for Pig Production, which summarizes the applied research activities
of the research and development arm of this influential producer organization.
Ever since I started getting this report in 1995, I have viewed it as
a window into the future for issues and policies that the United States
pig and livestock industries will be dealing with in the coming years.
The 2001 report raises several key environmental and animal housing
issues that Minnesota and other states have begun to address and others
that are only being discussed. Here is a quick summary of the items
in the environment and housing sections of the report:
New feed and manure assessments for pig production
The Danish Institute of Agricultural Sciences and the National Committee
have teamed up to produce a new feed assessment system that will go
into effect this summer (2002). This includes new energy factors for
individual nutrients in feedstuffs for growing pigs and a separate set
of values for lactating sows. Along with this change, new calculations
of animal units went into effect on August 1, 2002 to better account
for the amounts of nitrogen and phosphorous in the manure produced by
sows, weaners, and finishing pigs. The amount of cropland needed for
utilization of the manure by pig producers has also been adjusted to
reflect these feed and manure nutrient value changes.
Outdoor and Indoor Air Quality
Ammonia emissions from pig production units remain a major concern
in Denmark and other European countries. Odors near these farms are
also a concern to nearby neighbors and communities. Recent research
effects have focused on reducing the surface area of manure gutters
by using V-shaped gutters or channels under slatted floor pens. A 16%
reduction in ammonia concentrations has been measured using the V-shaped
vs. the flat bottom gutters. Odor control technologies are being investigated
in Denmark just as they are in the United States. Two technologies being
studied are biological air scrubbers (passing building exhaust air through
filters that are sprinkled with water) and ozone treatment of exhaust
air. Mathematical dispersion models are being used to predict concentrations
of airborne contaminants downwind from pig production sites. One study
has looked at ventilation stack heights from barns (most exhaust fans
are mounted in the ceiling of Danish pig buildings) to determine if
they affected the dispersion of odor from the barn. Results showed that
for distances under 100 meters (330 ft), the calculated odor intensity
was lowered when the stack was raised 6 meters (20 ft) above the barn’s
roof line, but there was no stack effect for distances over 100 meters
from the source. Worker health remains an important issue in Danish
pig production. Respirators for dust are being investigated in cooperation
with health care personnel at several hospitals. Technologies to reduce
dust concentrations in pig facilities are being practiced, such as using
fat in the feed and using pelleted instead of ground feed. The use of
bedding in pig housing system provides more animal comfort but is a
source of airborne dust in these types of housing systems.
Water sprinkling guidelines for finishing pigs
Sprinkling of water in the pen dunging areas to provide pig cooling
and to promote cleaner pens is common in Denmark and many countries
including the United States. However, in practice, many sprinkler systems
do not work properly or fail to accomplish their intended goals. Danish
studies suggest that water flow rates should vary depending on the type
of ventilation system. For ventilation systems with diffuse or low velocity
air inlets (perforated ceiling) water flow rates should be 0.5 to 1
liters/min (1/8 to 1/4 gal/min). Systems with high velocity inlets (normal
ceiling or slot inlets) or natural ventilation systems should have water
flow rates of 1 to 2 liters/min. (1/4 to 1/2 gal/min). It is critical
that water is only delivered to the dunging area of the pen and not
in walk and alleyways.
Group vs. individual housing of gestation sows
Animal welfare concerns are forcing many European pig producers to
consider group housing of gestation sows. Producers in the UK can no
longer use individual stalls for “dry” sows. Although this
requirement is for the well-being of the sows, many timid sows can be
injured from fights with other sows in the group over feed or a resting
space. Of particular concern is having a non-skid floor, which is most
easily obtained by providing large amounts of bedding. But deep-bedded
systems are labor intensive and need to be managed properly. Also, pen
designs where each sow has permanent access to a feeding stall, with
a deep-bedded open area at the rear of these stalls are being evaluated
at the present time.
Housing and feeding systems for nursery and finishing pigs
Starting on July 1, 2005, pigs in Denmark will need to have access
to some form of “rooting” material during the first 9 weeks
of their grow-finish phase. The following rooting materials have been
studied and, in order of pig preference, are: alfalfa hay, ropes and/or
straw, and wooden “beams.” Typically the hay and straw are
placed in a “dispenser” that the young pigs can reach to pull
out individual strands, while the rope and “chain” type of
materials are using hung in the middle of the pens at pig shoulder height.
On July 1, 2000 it became mandatory in Denmark to have at least a third
of the pen area either solid or “drained.” Drained flooring
is defined as material with a maximum open area of 10% (standard slatted
floor area is about 20% open). Studies are ongoing with different flooring
materials to meet these requirements and maintain pig performance while
minimizing labor and maintenance costs. Finally, wean to finish (WTF)
pig facilities are being investigated for use in Denmark, and the National
Committee has assessed the operation of “tube” feeders, troughs,
and covered (or hovered) areas for use by pigs in wean to finish facilities.
There are numerous problems with adapting feeders (both liquid and dry),
waterers, and pen arrangements for pigs as young as a few weeks to 5-1/2
month-old finishing pigs. Many of the same issues are being raised by
wean to finish facilities in this country.
As is apparent in this brief summary of activities by the Danish National
Committee for Pig Production, there are many challenges facing pig producers
in Denmark. The livestock production industry in the United States has
a number of similar issues that need to be addressed through research
and development that will require investments of money and time to find
acceptable solutions.
You can view the annual report on the web at http://www.danskeslagterier.dk/view.asp?ID=539