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Air quality in the rabbit house has a direct effect upon the health and
well being of rabbits housed in a building. Proper ventilation
as well as maintaining low ammonia levels can have a positive impact
upon the overall health of the respiratory tract of rabbits.
Most rabbitries are built inside of a building of some kind. A balance
of plenty of air flow and closed off enough to be able to heat as needed
in the winter will be the dilemma for all indoor rabbit
AMMONIA AND ITS IMPACT ON PET RABBITS
Ammonia is generated as a result of the breakdown of urine. The rate at
which ammonia develops is dependent upon the rabbits diet (higher
protein, more ammonia), as well as ambient air temperature (higher the
temperature, the faster the development). Ammonia is a heavy gas and
will settle to the floor of a building. If there is no air flow in the
building to remove it, the concentration of ammonia will rise up in the
building.
Ammonia has a detrimental impact upon the health of rabbits. Once
damage occurs you will need to get new rabbits.
In comparison to rabbits, the human sense of smell is rather poor. Once one is able to detect
ammonia vapors, the level of ammonia is already too high in the
building.
PET RABBIT - BUILDING DESIGN
Many times a breeder will utilize an existing building or may wish to
design a building specifically for the rabbits. The optimum elements in
any rabbitry building is the establishment of passive ventilation.
Passive ventilation is established by the proper location of inlet and
outlet air openings in the building. There are two problems that need to
be dealt with in the rabbitry: Hot air (especially in summer) and
ammonia vapors that develop as a result of the breakdown of urine. Hot
air rises to the top of the building, whereas ammonia is a heavy gas
that drops down to the floor. In summer, the breeder does not want hot
air to build up (reaching the floor), nor does one want to have ammonia
build up to move up in the building. In winter, this becomes a balancing
act because we want the heat of the building (if heated) to drop down
more to keep rabbits warmer.
Passive ventilation also relies upon the prevailing wind of the area.
Air from outside the building must enter in order to get the percolating
effect that passive ventilation offers. That means, inlet openings
should ideally be on the windward side of the building at a minimum.
This means, thought must be given to the orientation of the building.
The longest wall of the building should ideally be oriented to the
prevailing wind side (in most areas, this is to the west).
Inlet openings should be located, evenly spaced near the floor of the
building on the windward side and on the opposite wall, should be
staggered. In other words, not in direct line with the ones on the
windward side. If they were located directly opposite the ones on the
windward side, on a windy day, air would pass horizontally and out the
other side. The passive ventilation would not occur correctly. The goal
is to move cool air from the floor to the ceiling, where the outlet air
would be located. This is especially important for the winter, since
this type of air flow would force warm air out of the building by
drawing it down from the ceiling. It is also important to have openings
the full length of the building so that corners of the building do not
become dead air spaces where no air can flow or be drawn from.
The size of the openings is also important. The TOTAL square foot area
of the inlet air should be slightly less than the TOTAL square foot area
of the outlet. The outlet area being larger will work to remove hot air
faster. If the total square foot area of inlet is more than the outlet,
air will move much more slowly or not at all on calm days. On winter
days, passive ventilation needs to be adjusted to keep more heat in the
building. Inlet air opens on the windward side of the building should be
equipped with a means to close some of them off to slow the air
movement. Because air flow is slower, it will be necessary to implement
other measures to reduce ammonia levels (discussed later).
Since many breeders start out utilizing an existing building, not all of
the elements of the passive ventilation system are possible, either
because of the building orientation or other factors. By implementing as
much of the system as possible, one can generally establish some level
of air flow which can be supplemented with other measures to reduce
ammonia.
NEGATIVE AIR SYSTEM
This system is similar to the passive air system in that inlet and
outlet openings are still necessary but the air is forced out of the
building by mechanical means, such as exhaust fans. Again, the openings
need to be located the same but the TOTAL outlet air opens can be less
than the inlet. It is also important to locate the outlet openings as
well as the number of outlet openings to ensure that there are no dead
air spaces in the building. In summer, ideally, the outlet air should
exit the building near the floor since ammonia levels will be at the
highest this time of year. In winter, one can either switch to the
passive system completely or reduce the number of inlet openings by
closing some of them to prevent excessive cooling of the building and
establishment of drafts.
CONCENTRATION OF PET RABBITS
Air quality also depends upon the number of rabbits housed in the
building. Many breeders utilize stacking cages to keep the number of
rabbits they need for their breeding programs. One must keep in mind
that keeping large numbers of rabbits in a small unventilated building
will cause an increase in the ammonia levels that will be difficult to
manage.
ARRANGEMENT OF CAGES FOR PET RABBITS
The cage system in use will dictate some of the necessary steps one must
take to ventilate the building. Stacking cages that rest on the floor of
the building will require different measures than cages set up as
suspended runs (single level). Rabbits closest to the floor will be
exposed to higher ammonia levels than those closer to the ceiling
whereas those closer to the ceiling will be warmer than those near the
floor. The temperature of the building differs at different levels. In
summer, it is often necessary to house bucks in the lower levels to help
offset summer sterility due to high temperatures. However, this also
exposes them to higher ammonia. Those who use stacking cages need to
adjust the ventilation system for summer and winter. Those who utilize
single level suspended cages may not need to make major adjustments from
summer to winter.
HUSBANDRY METHODS
Husbandry methods can supplement the ventilation system and reduce the
need for fast airflow to remove heat and/or ammonia from the building.
These methods should be utilized extensively to reduce the need to make
major adjustments in airflow or ventilation.
For those that utilize stacking cages with drop pans, cleaning and
rinsing of the pans on a regular basis will greatly reduce the ammonia
levels. Ideally, this should be done at least every 3-4 days, depending
upon the concentration of rabbits in the building. It should be done
more often in winter if a heating system is used and/or the ventilation
system is not optimal as well as in the summer where the hot days can
increase ammonia levels.
Additives to the drop pan can help absorb some of the ammonia generated
between cleaning. One excellent product, zeolite, can be used in the
bedding in the drop pan to help absorb the ammonia. Zeolite can also be
used in solid floored cages since the product is non-toxic to rabbits.
They can ingest the product with no adverse health effects. (In fact,
the product can be used to help absorb toxins in the GI tract of
animals.) Some breeders also claim that adding vanilla to the drinking
water of the rabbits helps to reduce ammonia as well as deter flies.
There are also sprays that can be applied to the drop pan between
cleaning that contain enzymes that break down the ammonia.
Another aspect of ammonia development is the diet. A higher protein
level in the feed will generate more ammonia. Rabbits should be fed the
lowest protein which produces the desired quality of animals. This is
not always advisable in winter however. It is best to feed whatever
level protein is necessary for the stage of life of the rabbit and to
utilize other means to reduce ammonia production.
For those who utilize single level suspended cages, manure drops to the
floor. Since rabbits are up off the floor at a comfortable working level
for the breeder, ammonia tends to stay closer to the floor and rabbits
are not exposed to high levels unless the manure is allowed to build up
in a closed building with little ventilation. Most suspended cages are
utilized in a large barn that generally breathes very well so it is
often not as much of a problem to allow the manure to remain on the
floor for several months. Many who use this caging system do not remove
the manure for 6 months to a year. Some breeders may establish worm beds
under the cages, which greatly reduce the ammonia generated since the
worms are “cultivating” the manure. The only problem that does exist
with this system is when urine becomes concentrated in one location on
the floor. The worms tend to avoid these areas unless the breeder
“turns” the manure or adds peat moss or old wood sawdust to the area.
HEATED BUILDINGS for PET RABBITS
In winter, some breeders heat the building to just above freezing to
keep the water bottles or automatic watering system working and to make
for a more comfortable work environment for the breeder. Heating is not
absolutely necessary for rabbits themselves since they do exceedingly
well in cold weather. It is intended more as a convenience for the
breeder. But heating does pose a problem with the generation of ammonia.
Ammonia development increases with increased temperatures, thus, in a
closed building, this can cause a problem since one needs to keep the
building more closed in to keep the heat in the building. More frequent
cleaning of pans and the use of zeolite can help. Many breeders who heat
can often shut down the heating system on warmer winter days and open
the building during the day to ventilate, closing it up later in the
day.
HUMIDITY
Humidity plays a role in ammonia generation as well as the level of
damage it can cause to both the respiratory system of rabbits and the
cages. High humidity reduces a rabbits ability to remove moisture from
the respiratory tract, whereas low humidity does the opposite. Both are
not good for the mucous membranes of the respiratory tract of the
rabbit. High humidity also increases the rate at which ammonia eats away
at the galvanizing on cages.
Humidity if often very difficult to manage. Ventilation can help but
when the outside air is humid, there isn’t much that can be done except
to use dehumidifiers, which is not always practical. Moving the air more
quickly will remove the ammonia from the building, which is the most
important thing. Cleaning cages more often than normal will also help.
Conclusion - Have a good fan or have lots of air ventilation for
your pet rabbits.
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