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IN TEMPERATE CLIMATES
In countries with temperate or cool climates, rabbits are reared in buildings that are more or less closed in order to ensure year-round production. Traditional rabbit production in Europe and North America used to be out of doors in hutches, and the animals stopped breeding from the end of summer until early spring. More regular or even nonstop production has been made possible by putting the cages inside.
Temperature and lighting can be controlled to suit the animals. Now the use of wire-mesh cages makes the rabbits more susceptible to the temperature and air flow in their environment, and these cannot really be controlled fully except inside a building. More and more, therefore, European rabbits are being reared in wire-mesh cages inside closed buildings, with controlled ventilation, artificial lighting, winter heating and possibly summer cooling. Such solutions are costly and the producer needs substantial initial capital to house all his animals.
In France, for example, the total outlay (building, caging, other equipment) is figured in terms of the "mother-cage". This reference unit corresponds to the total investment necessary for housing does, bucks, fattening young and future breeders, divided by the number of does. In France the outlay per mother-cage corresponds to the value of the young rabbits produced by the mother-cage in about 18 months.
Technically speaking, the buildings are like those used for battery chickens, with similar insulation, heating, ventilation and lighting. The standards for rabbit production, described at the beginning of this chapter, are, of course, different, but for the rest the rabbit breeder can make convenient use of descriptions of buildings designed for chickens. The many instances of old stables, barns and similar buildings being converted for rabbitries is worth mentioning. Some work is usually needed-sometimes insulation, nearly always ventilation, even for flat-deck systems. Unlike compact batteries, the flat-deck system does not need a very long building, and can therefore usually be installed in any existing construction.
IN VARIABLE HOT CLIMATES
In such climates the rabbits must be reared either on litter in hutches out in the open, or in cages placed inside a building which will serve as a buffer against the heat. Very satisfactory results have been obtained in Burkina Faso with buildings constructed with local materials: laterite bricks, frame made from a hardwood such as palmyra (Borassus arthiopium), and a straw roof. The temperature in a building like this is more constant than in a more costly one made with concrete perpend.
At the Irapuato National Rabbit Centre in Mexico, solid buildings are generally left open in the front during the day and at night the shutters are closed to offset the drop in outside temperature. A daily temperature range of 20°C is common in the region. These shutters also make it possible to ventilate the interior during the daytime; they can be opened to suit the wind direction and regulated to respect the air flow standards mentioned at the start of this chapter.
In some dry tropical regions of Africa where wood is scarce, producers have made satisfactory housing by building small round huts of unbacked earth bricks covered with straw, used for both cage and housing. Litter changing is often quite a problem with this sort of construction, however. The floor should slope slightly and be well off the ground. Parasitism can be partially controlled by demolishing the hut every year and rebuilding it a few metres away. Such housing is thus only suitable for backyard rabbitries in which labour is not a problem.
IN CONSTANT HOT CLIMATES
In countries where the climate is hot but fairly constant (mean minima and maxima between 20 and 30°C) closed buildings are not really necessary. All that is needed is to protect the rabbits against the weather. If the cages are of wood or concrete (solid walls) it may be enough to roof each hutch, as shown in Figure 30. A roof should keep off rain and also heat from direct sunlight. The hutches can also be placed under trees big enough to shade them all day long. A roof should overhang enough to keep water out on rainy' windy days. The hutches should be placed facing away from the prevailing winds.
Wire-mesh cages can be grouped under a common roof. This system, illustrated in Figure 31, was first tried out in California. It is satisfactory provided the roofs overhang far enough at the sides to protect the animals properly. A hedge or fence around the roof structure is useful in protecting the rabbits from strong winds, and from predators.
The problem of predators differs greatly from region to region. The first step is to build cages sturdy enough to withstand the rabbits themselves and the numerous dogs and cats found in many villages. The rabbitry should be fenced to keep out children and large predators like dogs. This also helps provide the quiet surroundings that rabbits need. According to needs, the building or complex of cages making up the rabbitry should be fenced with wire netting, a living thorn hedge or sturdy pickets.
Rats, mice and other rodents are also dangerous predators; they attack the young and carry diseases. Any rats in the rabbitry should first be exterminated, then the legs of the cages and the poles holding up the roof can be fitted with tin plates at a height that will prevent rats from climbing them. Wire-mesh or concrete cages are more effective in keeping out rats than are wooden ones.
These pests can sometimes get into the feed racks or hoppers. Where such a risk exists the openings of these accessories have to be protected too, because a mother rabbit does not usually guard her young as a dog or even a mother rat would do. Snake control, in countries where this is a problem, is a far more difficult matter. Breeders get used to paying a certain toll to snakes. Fortunately, this is a small percentage of the rabbits.
FIGURE 30.-Example of an outdoor wooden cage. Note insulated roof to protect the rabbits from the heat, and feed hopper (1) and forage rack (2) on the side of the hutch
FIGURE 31.-Wire-mesh cages sheltered under a common roof
Table 50.-Average composition of excrement ender wire-mesh cages of rabbits receiving balanced concentrate feed
|Breakdown of crude product||From Varenne et al., 1963||From Franchet, 1979|
|Total minerals||14- 18||5-11|
|CaO||0 9-3 4||0.4-2.0|
Apart from the danger of predators, the risk of escape must also be considered. If the cages and buildings are not properly closed the rabbits can get out: either during handling operations or if the rabbitry is attacked by dogs or other large animals. A well-made outer fence usually ensures that the escaped rabbits can be recaptured quickly. If they do get away, they may well be irremediably lost.
There is no risk that escaped domestic rabbits will adapt to living wild and multiply, as they did in Australia and New Zealand. In almost every other country, escaped domestic rabbits have been unable to adapt to the wild. There are numerous predators of animals the size of rabbits (dog and cat families, birds of prey). which soon destroy them. The only risk is on certain islands where potential predators do not already exist, as was the case in Australia in the last century.
Uses for waste
In every type of rabbit production unit the producer has to remove the excrement and waste from the rabbitry (straw litter and droppings which pile up under cages). These can be put to good use on the farm. The amounts and composition of waste, however. vary according to housing and feeding conditions.
TABLE 51.-QUANTITIES AND COMPOSITION OF EXCREMENT PRODUCED BY DIFFERENT CATEGORIES OF RABBIT
|Origin||Content of fresh product|
|Weight produced per day||N||P2O5||K2O||CaO|
|Nursing doe||250-300||1.0-1.3 1||0.02||0.7-0.8||0.15|
|Resting adult||100||1.0-1.3 1||0.08||0.9-1.2||0.6-0.7|
Rabbits eating balanced concentrate feeds and raised on mesh floors produce about 250-400 g of faeces and 0.5-0.8 litre of urine per mother cage a day, depending on how intensive production is. This waste is much richer in fertilizing elements than average farm manure (Table 50). In fact, farm manure contains only 0.4-0.6 percent of each of the major fertilizer components-N, P2O5 and K2O.
The composition of the waste varies with the type of rabbit (Table 51). A comparison of the figures in Tables 50 and 51 shows that there is a greater risk of nitrogen and phosphorus losses during storage than of the other elements.
The average composition of the manure produced by animals reared on litter depends partly on the kind of feed but mostly on the kind and amount of litter used. If well preserved, the waste collected weekly will contain the fertilizing elements in the faeces and part of those in the urine, plus those in the litter. Fertilizer 'production" is therefore at least equal to that in a rabbitry not using litter.
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