Biomedical Engineering Reference
In-Depth Information
Types of Group Enclosures
Commonly used outdoor enclosures are corn cribs, runs,
field cages, corrals, and islands.
joined together to provide a smooth interior surface that
cannot be climbed. The pipes supporting the panels should
be set in a concrete footing. A small gap (2 inch) at the
bottom of the panel wall will allow airflow but prevent
escape by young animals. In some warm climate locations,
the bottom half of the wall can be constructed of chain link
wire to allow for better circulation of air and prevent the
wall from being damaged by strong winds.
Enclosures that are sometimes called field cages may be
built entirely of chain link fencing material. This type of
construction includes a chain link fence roof constructed to
prevent the escape of animals. The galvanized walls of
outdoor enclosures whether sheet metal, chain link, or
welded rod will eventually rust and require refurbishing or
replacement. Preventing moisture, soil, organic debris,
rocks, and gravel from prolonged contact with the galva-
nized surfaces of the enclosure may delay rusting.
Although considerably more expensive, enclosures con-
structed of aluminum or stainless steel will not rust. In areas
prone to hurricanes, chain link is preferable to solid sheet
siding, to allow passage of high winds.
Corn Cribs
Small outdoor enclosures such as circular galvanized wire
“corn crib” structures have proven effective for housing
primates (
Bohm and Kreitlein, 2009
, figure 21-6). Origi-
nally, corn cribs used for animal housing were in fact metal
mesh structures fabricated to store ears of corn. In the USA,
more modern housing of similar construction is still
referred to as a “corn crib.” Corn crib enclosures are usually
circular, hexagonal, or cuboidal structures constructed with
welded galvanized or aluminum rod walls with approxi-
mately 130 ft
2
of floor area and covered with a sheet metal
roof. Corn crib enclosures may be placed on concrete or
cement block footings with cement or gravel floors. They
can also be constructed with elevated metal or plastic grid
floors, reducing animal contact with waste material and
moisture. Some corn cribs are designed to be movable.
Corn cribs may be equipped with removable panels to
block the wind in the cooler months and may have heat
sources in the cone roof or sides of the units. Such modi-
fications may not be sufficient to provide the warmth
needed for cold-intolerant species during cold spells.
Islands
Islands serve as outdoor facilities in locations with warm
climates (
Foster, 1976; Weed and Cheslak, 1984; Rawlins
and Kessler, 1986; Kyes, 1993; Kyes et al., 1997
). The
water barrier limits the number of animals that escape from
the island; however, macaques are good swimmers and can
escape from islands that are located near other land.
Chimpanzees do not swim; therefore, islands and water
barriers are potentially more dangerous. The use of islands
limits control of nutrition, health surveillance, and pedigree
management, and managers should assure adequate
supplies of appropriate food, water, and shelter (
National
Research Council
Runs or Pens
Indoor/outdoor type enclosures referred to as runs can be of
various shapes and sizes; see figures 21-7 and 21-8, in
Bohm and Kreitlein (2009)
. Like corn cribs, runs may have
cement or elevated grid floors. The inside portion should be
of sufficient size to adequately house all of the animals
simultaneously. Runs should be large enough to prevent
dominant or aggressive animals from keeping others from
food, water, and access to shelter. This type of housing
should be monitored by behavioral observations to ensure
that
(Institute
for Laboratory Animal
Research), 2011
).
subordinate
individuals
are
not
systematically
Ground Surfaces and Floors
Ground surfaces in the outdoor facilities may be concrete,
rock, gravel, soil, natural vegetation, or elevated wire. US
Federal regulations require that floors in outdoor enclosures
be raked and cleaned frequently enough to prevent the
accumulation of feces and organic debris (
US Department
of Agriculture, 1991
;
National Research Council (Institute
for Laboratory Animal Research), 2011
). Excessive accu-
mulation of waste material may create a health hazard to
the animals.
excluded from the interior section.
Corrals and Field Cages
Outdoor group enclosures may be configured as open top-
ped corrals or totally enclosed field cages; see figures 21-9
and 21-10 in
Bohm and Kreitlein (2009)
. These enclosures
vary in size from less than an acre to several acres in size.
To prevent escape, open-topped corral enclosures for
macaques and baboons should be surrounded with solid
galvanized panels that are 11 feet tall and tilted inward at
a15
angle. At this inward angle, the height of the slanted
wall from the ground to the top is approximately 10 feet 8
inches. Corral walls that are 10 feet high without the inward
angle must be capped at the top of the corners with a metal
panel to prevent animal escape. The wall panels must be
Soil Surfaces
Large enclosures with soil surfaces must have adequate
slope and/or drain tiles to assure drainage of excessive
surface ground water. In some areas,
local regulations
