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Workshop-seminar "Making better  use of local feed resources" SAREC-UAF,  January , 2000.

 

Feeding systems for tropical rabbit production emphasizing root and bananas

 

Nguyen Quang Suc, Ly Thi Luyen and Dinh Van Binh

Goat and Rabbit Research Centre, Sontay, Vietnam

 

Abstract

In Vietnam molasses, rice bran, cassava root, sweet potato and bananas are available and are potential alternatives to use of cereal grains for rabbits. Novel sources of protein include leaves from trees such as Mulberry (Morus indica) and Trichantera gigantea and the vines of sweet potato (Ipomoea batata).

 

Two experiments were carried out to determine the productivity of rabbits fed leaves of Mulberry, Trichantera gigantea and sweet potato as protein sources, with comparisons of roots of cassava, tubers of sweet potatoes and green bananas as sources of energy-yielding nutrients.

 

Unprocessed sweet potato tubers were comparable to cereal concentrate for growth of fattening rabbits (9.99 and 10.0 g/day) and 34% better than bananas and dry cassava roots. The milk yield of does fed sweet potatoes was 21% lower than on the control treatment, but higher than on cassava roots or bananas.  A combination of  carbohydrate sources (equal parts of banana fruit, cassava roots and sweet potato tubers) mixed with rice bran and molasses in the form of a mash, and supplemented with the tree foliages and sweet potato vines,  gave as good reproductive performance as the concentrate / grass control. 

 

Key words: Rabbits, growth, milk yield, bananas, cassava root, sweet potato, mixed  mash-type concentrate, protein-rich foliage.

 

Introduction

The conventional feeds for rabbits made from cereal grain, oil seed byproducts and fish meal are becoming more expensive due to competition with human or other animal consumption. Earlier work showed that a molasses block could replace the cereal component in conventional diets for reproduction and lactation in rabbits (Dinh van Binh et al 1991); and that leaves from tress and shrubs could be a substitute for the protein meals (Le Thi Ha et al 1996). Cheeke (1992) drew attention to other tropical energy sources including roots and tubers (cassava, sweet potatoes) and fruits (bananas), which have potential for feeding rabbits. Omole (1990) has reviewed the use of cassava in rabbit feeding. Both cassava root meal and cassava peel meal have supported adequate performance when used at levels up to 30-40% of the diet. Gidenne (1986) fed whole green bananas to rabbits as a supplement to a commercial pelleted diet and reported that intakes of fresh bananas reached 120 g per day, equal to about 32% of total dry matter consumption. Raharjo (1987) and Mutetikka et al (1990) showed that the forage and tubers of sweet potato were very palatable to rabbits and could be a useful source of nutrients.

 

In Vietnam, molasses, rice bran, cassava roots, sweet potato tubers and bananas are readily available and cheap agricultural products. This study aimed to determine the productivity of rabbits fed combinations of these energy-rich feed resources, supplementing them with leaves from Mulberry (Morus indica) and Trichanthera gigantea and the vines from sweet potato.

 

Materials and methods

Two experiments were carried out at the Goat and Rabbit Research Centre, Sontay, Vietnam during the summer of 1999.

 

Experiment 1 was done with 60 weaned rabbits at 30 days of age which were allocated five per cage and fed one of the following treatments:

·        Control: Concentrate and guinea grass (Panicum maximum)

·        BF: Banana fruit and forages free choice

·        SWF: Sweet potato tubers and forages free choice

·        CRF: Dry cassava root and forages free choice

The bananas, sweet potatoes and cassava root were sliced and fed on a free choice basis. The weaned rabbits were started on the test diets 10 days before weaning and continued for a period of 60 days.

 

Experiment 2 was a study of dietary effects on reproduction and lactation with 40 does in individual cages. The fresh fruits / roots / tubers were made into a “mash” by pounding.  A mixed “mash” was also studied in which equal parts of banana fruit, cassava roots and sweet potato tubers were mixed in equal proportions (fresh basis) together with rice bran and molasses to make the mixtures more palatable and to retard mould growth.

 

The composition of the cereal concentrate (control) and the experimental mixtures used in experiment 2 is shown in Table 1.

 

 

The does were started on the test diets after pregnancy examination and continued until weaning in order to complete one cycle of pregnancy and lactation.

In both experiments the forages were mixtures of leaves from mulberry (Mora alba), sweet potato (Ipomoea batatas) and Trichanthera gigantea offered on a free-choice basis.

Measurements

Records were kept daily of feed offered and refused. The growing rabbits were weighed at the beginning of the experiment and then at 10 day intervals until 90 days of age. The does were weighed at parturition and at weaning. The litters were weighed at birth, at 21 days and at 30 days (weaning). Milk production of does was calculated from the formula proposed by Labas et al (1986):

 

Milk yield (g/day) = 1.18*[Live weight of litter at 21 days - Litter weight at birth].

 

Results and discussion 

Growing rabbits

 

Growth rates did not differ between the control and sweet potato treatments but were 34% less (P=0.001) on the banana and cassava root diets (Table 2).

 

Intakes of dry matter, protein and fibre were lower on all the experimental diets compared with the control (Table 3).  However, dry matter feed conversion tended to be best for the sweet potato diet.  Feed costs per unit liveweight gain were highest for the control and banana diets and lowest for the sweet potato and cassava diets.

 

Reproduction and lactation

 

Conclusions

·        The unprocessed roots of sweet potato supplemented with mixed foliages from mulberry, Trichanthera gigantea and sweet potato supported the same performance in growing rabbits as the conventional diet of concentrates and grass, but at less cost for feed.

·        A mash composed of equal parts of banana fruit, cassava root and sweet potato tubers (17% of each) with 33% rice bran and 15% molasses, with the same protein-rich foliages as for growing rabbits, supported the same reproductive performance (size and growth rate of the litters; body weight change of the doe) as the conventional concentrates / grass diet, with savings in cost of feed.

 

References

Cheeke P R 1992 Feeding systems for tropical rabbit production. Root, tubers, plantains and bananas in animal feeding, No. 45

Dinh van Binh, Bui-van-Chinh and Preston T R 1991 Molasses-Urea Blocks as supplements for rabbits. Livestock Research for Rural Development  (3) 2:13-18

Le Thi Ha, Nguyen Quang Suc, Dinh van Binh, Le Thi Bien and Preston T R 1996 Replacing concentrates with molasses blocks and protein-rich leaves for reproduction and growth of rabbits. Livestock Research for Rural Development  (8) 3:33-37

Omole T A  1990 The use of cassava in rabbit feeding;  A review. Journal of Applied Rabbit Research 13:

Mutetikka D B and Carles A B 1990 The effect of level of supplementation to diets of Rhodes grass (Choris guyana) hay, of maize (Zea mays) leaves and sweet potato (Ipomea batatas) vines on performance of grower rabbits. Journal of Applied Rabbit Research 13:

Raharjo Y C, Cheeke P R and Patton N M 1988 Evaluation of tropical forages and rice by-products as rabbit feeds. Journal of Applied Rabbit Research 11: 201-211

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