Rabbit Production. James I McNitt
Outlets should not be located so they blow into the prevailing wind. In a naturally ventilated building, the air outlets should be at the ridge (highest point of the building) to draw moist, warm air out of the rabbitry even if there is no wind (Fig. 4.2).
Fig. 4.2. Placement of winter and summer air inlets and outlets for a mechanically ventilated rabbit building (top) and for naturally ventilated buildings (bottom). (Courtesy of James A. Moore)
The economics of commercial meat rabbit production generally does not warrant the construction of environmentally controlled buildings. The returns generated from sale of meat rabbits may be insufficient to pay the interest on borrowed capital for building construction, to say nothing of utility bills for air conditioning. Therefore, it is recommended that naturally ventilated buildings be used.
Evaporative cooling systems may be used in hot, dry climates. This type of cooling uses cold water running through mats or coils. Air is drawn through these and cooled. A properly installed sprinkling system on the roof of an enclosed building will help reduce the high temperatures and, when thermostatically controlled, will be a safeguard when sudden weather changes occur. The thermostat should be set so the sprinkler will be turned on when the temperature in the rabbitry reaches about 30°C. Ideally the volume of water will be just that which will evaporate so there is little, if any, dripping from the eaves. It is the heat used to evaporate the water that produces the cooling, not the cool water flowing over the roof. This system is less effective with roofs that are properly insulated.
In many areas, insulation of the rabbitry is desirable to control environmental temperature. This is important in both hot and cold areas. In hot climates, an insulated building is necessary to complement the action of cooling systems and to minimize radiation of heat from the roof into the rabbitry. Both the walls and the ceiling of an environmentally controlled building should be insulated. With an open building, insulation of the ceiling will aid in control of high temperatures by reducing radiation from the roof into the rabbitry.
Evaporative systems do not work in areas with high humidity. An alternative that might be used in such areas is bringing in cooled air through tubes or pipes buried in the ground. The outside air is drawn through these tubes and cooled to the surrounding soil temperature (about 50°F, depending on the depth). The cooling will result in condensation of the moisture in the air, so it is necessary to slope the pipes to a sump and install a sump pump to remove the moisture.
A solid concrete floor may not be the best type to use in a rabbitry. Concrete floors lead to excessive humidity and ammonia levels, as liquid wastes cannot be readily removed. If solid concrete floors are used, provision must be made for rapid removal of solid and liquid wastes. A better system is to use pits beneath the cages, with concrete alleyways. Concrete alleyways 1 m in width between rows of hanging cages are desirable. Beneath the cages, a porous pit of layers of gravel and sand, with a drainage tile to remove liquids, is a good system. Manure is allowed to accumulate and may be removed semi-annually, quarterly, or as required. As long as the sand and gravel layers remain porous, the urine doesn’t accumulate, and the humidity of the building will not increase. The pits may be cleaned manually or with scraper devices. Gypsum (magnesium sulfate) spread on the sand immediately after cleaning will help keep the soil porous. This works even better if the gypsum is sprinkled with water after it is applied.
Various devices to automatically remove manure have been developed. They include scrapers on a cable, tractor-driven scrapers, and flushing water systems. Most of them share a common characteristic: they generally don’t work very well! Many automatic scraping systems can be seen stacked up outside rabbitries, because they weren’t satisfactory. Rabbitries with these systems usually are characterized by high humidity, a strong odor of ammonia, and many sneezing rabbits with snuffles.
It is desirable that a commercial rabbitry be equipped with lights to provide extra hours of light during the late fall and the winter. This has been shown to increase reproductive performance during this period when a decline in reproductive efficiency is often seen, presumably a result of the shortening days signaling the reproductive system that winter is approaching. The extra lighting should be used to prevent the hours of light from declining. Sixteen hours of light and eight hours of darkness are commonly used in commercial rabbitries. There is recent evidence that extra light needs to be provided in the morning as well as the evening. There is no evidence that fluorescent lighting provides better results than incandescent, although the former is less expensive to operate. The lights should be controlled by a timer like those used in poultry houses. Electrical outlets for other equipment, such as fans, should not be wired through the timer.
A good policy in a commercial rabbitry is to restrict visitors. Other rabbit raisers may bring diseases with them when they visit your rabbitry. Strangers cause stress to rabbits. A compromise policy is to install a viewing window at one end of the building. Visitors can look inside, but disease organisms and noise are kept out.
A commercial rabbitry should have an office area for recordkeeping, etc. It should be equipped with office supplies, including a calculator. A large rabbitry will find a personal computer a good investment to enhance recordkeeping and economic analysis and to produce daily chore sheets. Other components of the rabbitry include bulk feed tanks and a feed storage room. If the volume of feed used is very substantial, bulk tanks are advisable. Bagged feed is more expensive than bulk, and with increasing costs of labor and materials, the relative difference between the two is likely to continue to rise. A screen may be installed between the bulk bin and the feed cart to remove fines from the feed, if necessary. There is little difference in the amounts of fines between bulk and bagged feed of the same formula. Bulk feed may also be delivered in 800 kg nylon bulk feed sacks. They are filled from the top at the feed mill and delivered on pallets. They are removed from the truck with a fork lift or pallet jack. The rabbit raiser empties a sack by dipping from the top with a bucket or by opening a funnel on the bottom. With this system, no expensive bulk tanks are required and, because of reduced condensation, caked feed is seldom seen.
Under certain circumstances, radically different approaches to the housing of rabbits may have merit. For example, it is possible to construct a rabbitry underground in certain locations. The advantages are that control of temperature in a range desirable for rabbit production may be more feasible than with above-ground rabbitries in some climates.
In hot, arid areas raising rabbits in combination indoor/outdoor units has proven effective (Fig. 4.3). The indoor units are constructed of concrete and are connected by a large tube or directly to an outside cage area constructed of wire with slatted floors. In hot areas, the rabbits stay inside during the day and come out into the cages at night to eat. The rabbits are trained to defecate and urinate in the outdoor cages making the units easy to keep clean. Plants can be grown in the areas over the tubes which helps keep the units cool. They also have application in tropical countries, where they can be constructed of clay or other local building materials.
Fig. 4.3. A combination indoor/outdoor rabbit unit with the indoor part constructed of concrete; the outdoor unit is constructed of wire with slatted floors. (Courtesy of consortium “Green Rabbit Leprino of Viterbo,” Italy)
Other innovations include using a flushing manure removal system, with solid:liquid separation and fermentation of the solids in a methane generator. Some rabbit raisers have combined their waste disposal systems with aquaculture (fish ponds) or greenhouse irrigation. Rabbits have been kept in greenhouses, with their body heat contributing to the heating of the greenhouses. For the ingenious person there are many possibilities for using unique housing systems, particularly if only a few rabbits are to be raised.
Hutches and Cages
A