Livestock Research for Rural Development 8 (4) 1996

Citation of this paper

Effect of housing system (cage versus underground shelter) on performance of rabbits on farms

Nguyen Quang Suc, Dinh Van Binh, Le Thi Thu Ha and T R Preston(1)

(1) Finca Ecologica, University of Agriculture and Forestry, Ho Chi Minh City, Vietnam - E-mail: thomas%preston%sarec%ifs.plants@ox.ac.uk

Goat and Rabbit Research Centre, Sontay, Vietnam

Abstract

This paper reports the results of a preliminary experiment to test the hypothesis that a system of underground shelters would be a way of improving the environment of the rabbit, as compared with conventional raised cages, and thus make it possible to increase productivity in a tropical climate. The study was done with the cooperation of 30 small scale farmers in Ha Tay and Hai Hung provinces in North Vietnam.

All the performance parameters were significantly improved in rabbits housed in the underground shelters compared with the cages. The does in underground shelters were 8% heavier after 2 months in the experiment, they gave birth to 39% more offspring and weaned 60% more than those in cages. Survival rate to weaning of the offspring was improved by 16%.

During the growing-fattening phase, the rabbits in underground shelters were 17% heavier after 1 month and 19% heavier after 3 months with average growth rates that were 20% greater.

It is concluded that the underground shelter system of housing is especially suitable for rabbit production for small scale farmers in tropical regions.

Key words: Rabbits, underground shelters, cages, environment, reproduction. growth, tropics

Introduction

Rabbit breeding is practised in almost all developing countries and contributes to family nutrition and economy, through the availability of a source of animal protein, as well as through extra income by sale of animals. Rabbit production has been developed in Vietnam based on the conventional system of cages raised above the ground. The major constraints of this housing system are low reproduction due to high temperatures in summer (30-35 C) and high mortality of the offspring due to cold (12-15 C) and wet weather in winter. The suitable ambient environment for rabbit production in Vietnam is a temperature range of 18-28 C and humidity between 80 and 86% (Nguyen Quang Suc 1985).

The greatest disadvantage of the cage system is that the rabbits are exposed to high temperatures during the hot season. The impact of temperature rabbits has been studied by various authors. Lebas et al (1986) noted that high temperature affects spermatogenesis, reducing the volume and concentration of ejaculates and also affects sperm motility after 8 hours at 36 C or 14 days at 30C. High temperature also affects growing rabbits negatively due to reduced rates of liveweight gain caused by the reduction in feed intake. When rabbits are raised at 18-20 C they can reach a live weight of 3 kg by 112 days, whereas at 30-31 C they only reach 2.5 kg (Lebas et al 1986).

It has been proposed that the system of underground shelters, developed by Finzi and Amici (1991), would be a way of modifying the immediate environment of the rabbit and thus make it possible to increase productivity in a tropical climate. This paper reports the results of a preliminary experiment to test this hypothesis carried out on small scale farms in Ha Tay and Hai Hung provinces in North Vietnam.

Material and methods

Housing system

Conventional:

The most widespread housing system in Vietnam is the one which utilizes hutches or cages. This was introduced during the colonial period and imitates the hutch models which were developed during the first phase of intensification of rabbit production, and were later superceded by the wire net cages presently employed in large scale operations world wide.

Alternative systems:

Free range

The free range system is obviously the most simple since it respects the rabbit's natural living conditions. In a small group (1 buck and 3-5 does) the rabbits will reproduce without leaving the area if feed and water are regularly supplied and they are kept under control by some form of periphery fence.

Underground shelter

The underground shelter is based on the premise that rabbits under natural conditions live in underground "burrows" dug out from the soil. This can provide a better environment for the rabbits especially if they are free to move in and out according to the climatic conditions.

The simulation of such "burrows" can be done by making a shelter above or under the ground using stones, bricks, clay or concrete, which can be covered by earth. With this system rabbits can choose the place to make their nest for giving birth. They can also modify the shelter by "digging" to enlarge or lengthen the "burrow".

Integrated free range and underground system

The integration of the underground shelter and limited free range appears to be the most feasible way for implementing an improved housing system at household level. This was the housing system chosen for the experiment.

Treatments, design and feeding

Thirty farmers, who traditionally raised rabbits, were chosen to implement the experiment which consisted of a comparison of some form of underground shelter versus the conventional system of raised wire cages. Each farmer was asked to keep 3 females and 1 male for the observation of reproduction and lactation and 5 weaned rabbits for fattening on each of the two housing systems.

For the underground shelter, the farmers themselves decided on the exact form in which the shelters were constructed following the principle of a fenced free area of about 0.5-1 m per adult rabbit and a mound of earth (0.5 x 2 m area and 0.5 m high) in which the rabbits could make their "burrows". The mound area and the immediate points of entry to the burrows were protected with a roof usually made of dry leaves of sugar cane or rice straw to avoid rain entering the shelters.

The conventional housing consisted of cages made of wire or bamboo with 0.6 m area per adult. Nest boxes were introduced into the cage immediately prior to parturition.

The feeding system was the same for both types of housing and consisted of free access to a molasses block, by-products from the kitchen as available (eg: banana peel, jackfruit, soya bean residue), grasses (mostly guinea grass) and tree leaves (from Trichantera gigantea, mulberry, Leucaena leucocephala and bamboo).

The experiment began in January 1996 and continued until July 1996.

A more detailed study of the effects of the housing system on temperature and humidity was done between 5 and 15 July 1996 at the experimental farm of the Goat and Rabbit Research Centre, where the same treatments as on the farms were applied.

Measurements

On all farms the following performance data were recorded:

 

On the experimental farm, the ambient temperature and the humidify were recorded daily at 7:00 , 13:00 and 19:00 hours in the cages and in the underground shelters over a 10-day period from 5 to 15 July.

Results and discussion

Effect of housing systems on reproduction and growth of rabbits

The results from the on-farm trials are presented in Table 1. All the performance parameters were significantly improved in rabbits housed in the underground shelters compared with the cages. The does in underground shelters were 8% heavier after 2 months in the experiment, they gave birth to 39% more offspring and weaned 60% more than those in cages. Survival rate to weaning of the offspring was improved by 16%.

Table 1: Mean values for parameters of reproduction and growth of rabbits housed in cages or in underground shelters in small scale farms

BLGIF.GIF (44 bytes)

Cages

Under-

SE/Prob.

ground

BLGIF.GIF (44 bytes)

Liveweight of doe, g

Initial

1652

1659

20.9/NS

Final

2,137

2,310

11.2/0.001

Litter size at

Birth

4.88

6.68

0.13/0.001

Weaning

3.64

5.81

0.11/0.001

Survival, %

74.1

85.7

0.68/0.001

Weight of growing rabbit, g

1 month

306

360

3.9/0.001

2 month

891

1,055

5.3/0.001

3 month

1,365

1,639

6.5/0.001

Gain

1-3mth, g/d

17.7

21.3

0.095/0.001

BLGIF.GIF (44 bytes)

 

During the growing-fattening phase, the rabbits in underground shelters were 17% heavier after 1 month and 19% heavier after 3 months with average growth rates that were 20% greater.

It was not possible to obtain detailed records on feed intake but most of the farmers observed that the rabbits in the underground shelters ate more than those in cages. More precise experiments are needed to confirm this aspect.

Effect of housing systems on temperature and humidity

The results of the study on temperature and humidity during a 10-day period in July in the two housing systems are shown in Tables 2, 3 and 4. Ambient temperature on average was 3.8 C lower (P=0.001) and humidity was 4.75% higher (P=0.001) in the underground shelters compared with the cages. It seemed that these mean differences were maintained throughout the day from 7:00 to 19:00 hours (Table 3).

Table 2: Mean values for temperature and humidity in cages and in underground shelters (at 00.70, 13.00 and 19.00 hours during a 10 day period

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Day

Temperature C

Humidity, %

Grnd

Cage

Grnd

Cage

BLGIF.GIF (44 bytes)

1

28

32

65

60

2

30

35

65

62

3

28

30

76

72

4

26

28

86

80

5

26

30

83

83

6

26

30

82

72

7

26

30

82

74

8

26

30

83

76

9

27

32

84

83

10

27

31

83

80

BLGIF.GIF (44 bytes)

 

Table 3: Effect of housing on temperature and humidity (mean values)

BLGIF.GIF (44 bytes)

Cage

Grnd

Diff

SE/Prob

BLGIF.GIF (44 bytes)

Temperature,C

29.4

25.9

3.8

0.33/0.001

Humidity, %

75.9

80.4

4.75

0.99/0.001

BLGIF.GIF (44 bytes)

 

Table 4: Mean values for temperature and humidity during the day in cages and underground shelters

BLGIF.GIF (44 bytes)

TemperatureC

Humidity, %

Cage

Grnd

Cage

Grnd

BLGIF.GIF (44 bytes)

07.00

29.6

25.7

77.6

81.5

13.00

30.5

26.9

74.2

78.9

19.00

28.2

25.2

76.0

80.8

BLGIF.GIF (44 bytes)

 

Conclusions and recommendations

 

Acknowledgments

This study was financed through a "Letter of Agreement" with the Animal Production and Health Division of FAO. The authors are grateful to Dr Manuel Sanchez, FAO, Rome and to Dr A Finzi of the Rabbit Research Centre, Animal Husbandry Institute, University of Viterbo, Italy, for their suggestions and advice.

References

Finzi A and Amici A 1991 Traditional and alternative rabbit breeding systems for developing countries. Revista di Agricoltura Subtropicale e Tropicales. Anno LXXXV No 1:103-125.

Lebas F, Coudert P, Rouvier R and Rochambeau H de 1986 The rabbit; husbandry, health and production. FAO Animal Production and Health Series, No 21

Nguyen Quang Suc 1985 The disease situation of improved New Zealand White rabbits raised in Vietnam. Publication of The Animal Husbandry Research Institute, Hanoi

 

(Received 31 August 1996)