M. Banzira
Institut des Sciences Agronomiques de Burundi (ISABU)
B.P. 795, Bujumbura, Burundi
Natural grazing lands are becoming scarce and more degraded every year because of the population explosion. Since the livestock production methods practiced today no longer enable the animals to realize their full production potential there is a need to adopt other methods such as the cultivation of fodder grasses and legumes. The fodder types would be sufficiently productive and adapted to each of the country's natural regions. The rational use of field-crop residues and processing of agro-industrial by-products will also be important in increasing livestock productivity.
An improvement in animal feeding and the livestock breeding environment are basic conditions for the intensification of animal production. The improvement of animal feeding means rational management of natural pastures, the establishment of fodder crops and the availability of concentrates in sufficient quantities. The traditional method of livestock production is based on extensive grazing where animals feed exclusively on the natural grazing lands. The traditional system may be improved by ranching. In this system seasonal fluctuations in quality and supplies adversely affect livestock productivity. In fact, it is recognised that food problem is most responsible for poor animal performance. The genetic factor is only of secondary importance. Therefore, adequate and good quality feed supplies should get first priority genetic improvement. This presentation will deal with the rational exploitation of natural pastures, agro-industrial byproducts and concentrate supplements.
Natural Pastures
The natural pastures of Burundi, even though they are subject to continuous deterioration, will remain the mainstay of animal feeding for a long time to come. In order to make some improvement in our pastures, and especially to avoid further deterioration of cover vegetation and soil, we recommend the practice of very late bush fires in October after the commencement of the long rains 50 to 100 mm of rainfall. In cases where there is a possibility of mowing (on the commercial farms) three-year burnings followed by grazing restriction and then mowing, would be advisable. In order to apply this method, the grazing lands are sub-divided into paddocks whereby about one-third is mown annually and another one-third is burnt. Burning should be done in paddocks which were mowed the previous year.
Some experiments have also been carried out to determine the potential grazing capacity, which varies according to the type of vegetation in each natural region of the country and according to the season of the year. The grazing capacity also depends on the quantity of the fodder produced and the quality available to the animal so that they can support satisfactory animal performance.
The most precise method consists in determining the value of the pasture through estimates of the recorded animal-husbandry performance of a given grass, that is the weight of livestock that the grass can sustain and the performances realized by the animals.
The agro-industrial by-products produced in Burundi include brans from cereals, oil meals and brewer's wastes. For a long time cottonseed cake was the only by-product offered on the market. Lately others have been introduced including rice bran, plam-kernel cake and wheat and maize brans. With the exception of wheat bran, the amount of the by-products available each year depends exclusively on the national production of cotton, palm kernels, rice and maize. Recent production statistics are shown in Table 1.
Table 1. National concentrate production and prices
|
Concentrate
|
Production |
Maximum factory capacity (tons)
|
Price per kg (FBu)
|
|
|
1982 |
1983 |
|||
|
Wheat bran |
595 |
1,554 |
2,000 |
7 |
|
Maize bran |
194 |
42 |
1,200 |
9 |
|
Rice bran |
770 |
1,000 |
1,500 |
7 |
|
Brewer's waste |
- |
4,050 |
- |
- |
|
Cotton-seed cake |
1,520 |
800 |
3,000 |
10 |
|
Palm-kernel cake |
1,475 |
1,500 |
1,500 |
7 |
|
Groundnut cake |
- |
17 |
- |
- |
What bran is produced by the Muramvya Flour Mills, the major part of the wheat being imported. Intensification in what growing will make it possible to increase the production of wheat bran that is so essential for food and animal production. The extraction yield is about 23%. The maximum production capacity is 2,000 tons per year, of milled wheat depending on the demand for wheat flower for bread making. Maize bran is also produced at Muramvya Flour Mills, the milling yield being 17% bran. The maximum annual capacity is 1,200 tons. The production of maize bran is almost exclusively dependent on the purchases of the Brarudi (Burundi's brewery) the availability of maize bran is, therefore, erratic. It is also very dependent on the maize offered on the market and sales are limited to only a few months in the year. The rice bran is produced at the rice fields of the Imbo Societe Regionale de Developpement (SRDI). These are residues resulting from the polishing of rice grain produced in the Imbo Valley.
Brewer's wastes are produced by the Brarudi Breweries. The present installations only allow for delivery of wet wastes to each brewer. The setting up of a pressing and drying machine will make it possible to deliver the wastes in bags and consequently to widen the geographical area from which they can be collected. The recent opening of the Gitega Brewery will make it possible to increase the availability of fresh brewer's wastes, and particularly make them available in the areas surrounding Gitega. Cottonseed cake is produced by RAFINA, from cotton grains delivered by COGERCO. The extension of cotton cultivation to other areas (Move) will make it possible to increase the amounts of cotton-seed cake produced. Sunflower-seed cake is also produced by RAFINA, using sunflower seeds from the Kivoga plantations. Production is, however, limited to about 30 tons per year. Palm-kernel cake is produced by several small factories whose main final product is soap. The extension of palm-kernel cultivation undertaken in the Rumonge Region by the Societe Regionale de Developpement will increase the production of palm-kernel cake.
Chemical Analysis of Agro-Industrial By-Products
The chemical composition of the agro-industrial try-products given in Table 2 are averages for five years for the cakes and three years for the brans. In general, the composition of the various concentrates does not differ substantially from that reported in the literature.
However, the cotton-seed cake produced in Burundi has traces of gossypol in it and the fat content of the local palm cake is about 20% of dry matter. The high level of fat in the palm-kernel cake is due to the method of extracting the palm oil. The high rate of fat is a disadvantage as it greatly reduces the preservation period of the feed. All the byproducts have imbalances in the phospho-calcium ratio. It is, therefore, advisable to rectify the mineral balance by adding some chalk.
The palatability of the different by-products is variable, both within each species and between different test animals. Cotton-seed cake and the brans are the most relished by all classes of livestock, while the palm-kernel cake is the least accepted, with the exception of pigs. In order to avoid dustiness in brans it is advisable to feed it wet, although humidity somewhat modifies the smell.
The storage of the agro-industrial by-products does not pose serious problems if they are used within a short period. Storage of palm-kernel and groundnut cakes and of rice bran is limited to one month: beyond that, there is a serious risk of it becoming rancid.
How can these agro-industrial by-products reach the livestock farmer? While livestock keepers in the vicinity of the factories can obtain the concentrates directly from the factories, those farther away buy them from veterinary centres. As is to be expected the prices are higher at these centres being one franc more per kilo than the factory price.
Table 2. Chemical composition of agro-industrial by-products
|
Composition (% DM) |
Cotton-seed |
Palm-kernel cake |
Wheat bran |
Rice bran |
Maize bran |
Brewer's wastes |
Groundnut cake |
Rice straw |
|
Dry matter content (% of total) |
90.8 |
91.1 |
88.5 |
88.9 |
87.6 |
91.5 |
91.7 |
91.5 |
|
Protein |
45.2 |
14.6 |
15.5 |
11.1 |
11.6 |
4.5 |
41.6 |
4.5 |
|
Cellulose |
7.3 |
27.3 |
9.3 |
12.1 |
6.1 |
33.5 |
6.5 |
33.3 |
|
Ash |
6.5 |
3.5 |
5.2 |
11.8 |
2.9 |
11.2 |
3.6 |
11.2 |
|
Fat |
8.2 |
20.2 |
4.3 |
13.1 |
5.1 |
0.8 |
21.1 |
0.8 |
|
Non-azotic extract |
32.8 |
34.4 |
65.1 |
51.3 |
13.1 |
- |
- |
- |
|
Calcium (mg/kg) |
1,703 |
1,825 |
898 |
5,511 |
390 |
2,900 |
375 |
- |
|
Phosphorus mg/kg |
11,589 |
4,948 |
10,439 |
9,519 |
3,135 |
4,800 |
4,648 |
- |
|
FBu/kg |
1.0 |
0.1 |
0.75 |
0.75 |
0.8 |
- |
- |
- |
Burundi is faced with an ever increasing population resulting in an increase in the amount of arable land at the expense of grazing land. Intensive animal production can only develop through a really intensive farming system based on the use of fodder crops. According to a 1970 SEDES study there were 1,477,000 ha of pastoral land in Burundi. That area is now reduced to 810,000 ha (1983-1987 Five-Year ISABU Development Plan).
The intensification of fodder-crop cultivation is already a subject of study at ISABU and is a practice which is starting to spread here and there in the country. But there is still a long way to go. At present 1,708 ha (1982 agricultural census) of fodder crops have been established in the rural areas, made up as follows: 463 ha started by the development projects (for demonstration), 1,129 ha started by the livestock farmers themselves, and 116 ha through community development works using stem cuttings and root fragments produced by ISABU and given to the various extension centres in the rural areas. These fodder crops are mainly Tripsacum laxum and Setaria sphacelata in the low- and medium-altitude regions and Setaria splendida in the high-altitude regions. Pennisetum purpureum is grown in all regions.
ISABU is carrying out research on improvement of the grazing lands, the development of artificial pastures (with the emphasis on fodder-crop cultivation), the preservation of fodder, and the collection of agro-industrial by-products with the aim of integrating agriculture with livestock breeding. We must choose the most adaptable and productive of the available fodder-crop species, whether local or imported.
