A. Djajanegara and M. Rangkuti
Animal Husbandry Research Institute, Agency for Agricultural Research and Development, Ministry of Agriculture, Ciawi, Bogor, Indonesia
A detailed description identifying the specific by-products or waste materials in Indonesia that could be used for animal feeds, with or without processing, should preferably be based on a survey. The survey should then aim to quantify, describe, and determine the quality of each potential by-product or waste and place it in proper perspective as to amount available, location, and possible problems that might be associated with its application.
The typical small land holders in Indonesia generally use almost all agricultural residues they generate, and an improved export marketing system has provided an outlet for those by-products not used on the farm. There are times, however - such as just after harvest - when the residues are in excess of the farmers' needs and disposal becomes a problem. Proper processing could turn these by-products into an asset, particularly in the feeding of animals. This paper presents a broad view of potentially useful byproducts and wastes that might be used as animal feeds in Indonesia.
The Republic of Indonesia lies within the tropical zone (between 6°N and 11°S latitude) and consists of a spread of water dotted with islands in an area as large as the whole of Europe. The average yearround temperature is 28° C (23°-35° C), and humidity is high except in the cooler, mountainous area. Rainfall is heavier in the west than in the east, averaging 4,000 mm per year in Bogor (West Java) and only 60 mm per year in the Nusa Tenggara Islands, The population is now about 135 million, with a 2.3 per cent yearly growth rate.
The GNP in 1978 was US$850 million, with agriculture accounting for about half of this amount. Unfortunately, there are few processing centres for agricultural products, so much of the food raised is exported. Because of uneven distribution in local production, this often means that some areas have food shortages. This is exacerbated by an unbalanced distribution of population, with 60 to 70 per cent of the people living in Java, which makes up only 6 per cent of the total land area of Indonesia. This means that any extension of agriculture in Java is limited by land constraints. Furthermore, 75 per cent of all Indonesian livestock is raised in Java.
Except on a few dairy farms and beef cattle ranches, animals are raised in small numbers (one to five head of cattle or five to ten sheep per farmer). There are some medium-sized cattle ranches in Sulawesi and on the Nusa Tenggara Islands. Only 10 per cent of all poultry is raised on medium-sized poultry farms; the rest is family owned.
Rice is by far the main staple crop and occupies the largest agricultural area. Most food is produced by small land-holders who individually sell any excess produce to nearby markets. Most of Indonesian land is dominated by forests, with agriculture covering only 6 per cent of the total land area. Constraints to land ownership and the resulting small-farm system means that small-scale agricultural production is the rule. For this reason, agricultural wastes and by-products are few and widely dispersed, so that collecting enough to make it economically feasible to process it for use as feed will require many farmers to work co-operatively.
Fish comprises most of the animal protein in the Indonesian diet because it is cheap. Beef and poultry are also consumed; pork is not as popular. Fresh dairy products are not readily available because the cows are raised only in the mountainous areas of East, Central, and West Java. The government is expanding the beef and poultry industries through schemes (BlMAs and PUTP) that provide credit and some technical input for small-scale production.
Cattle. Most of the 10 million head of cattle and buffaloes in Indonesia are in Java and Madura, and are generally kept as draught animals or as investments. Farmers do not usually feed their cattle protein concentrates. Grass and agricultural by-products and wastes are the main feed supplies; the latter are used to the extent that a farmer can produce or find them near his farm. These cattle are therefore sold when the farmer needs money, and no particular live weight is attained before they are taken to market. Old and unused animals are the ones slaughtered at abattoirs. The domestic price of beef is at present around Rp 2,500/kg (US$4) in cities and is not related to quality.
Pigs. The raising of pigs in Indonesia is restricted to certain areas. Data from 1978 showed a population of 4 million pigs, of which 1.3 million are concentrated in North Sumatra and around 1 million in Bali and the Nusa Tenggara Islands. The major limiting factor in expanding pig development (besides feed supply) is religion. The pig competes with humans for the limited amount of grains available; therefore, another source of feed is required. Most pigs are kept as scavengers rather than on a commercial basis.
Poultry. Like pigs, poultry require a high-protein feed; however, "kampung" chickens (estimated at around 97.5 million in 1976) are all kept as scavengers. Kampung hens produce about 30 to 40 per cent of all eggs consumed in Indonesia, and an estimated 80 per cent of all poultry meat is supplied by these birds. The preference for the kampung chicken and its abundant numbers ensure the primary place of this bird over broilers and better-laying breeds for many years to come. The poultry industry is growing, although not as fast as in other ASEAN countries.
Indonesia's duck population is the largest in the ASEAN region (15.2 million in 1976). Duck eggs are widely consumed, often in salted form, but there is little demand for duck meat. In Java ducks are generally kept in small flocks of 40 and are allowed to graze in the paddy fields that supply them with small fish, snails, etc. for their protein needs. The feeding system for ducks in Alabio (South Kalimantan) is more advanced and is based on sago, rice bran, water snails, fish, and coconut pressmeal. These ducks also have a higher laying capacity than the Javanese ducks.
Agricultural By-products and Wastes
Rice, as the largest crop, has a potential by-product in the form of rice straw. A common practice in East Java is to burn this straw in the field and return the ash to the soil, whereas in West Java the straw is left in the field and ploughed in later during cultivation. The use of rice straw for animal feed is already practiced, although not maximally. The yield is about 2.3 tons of dry matter per hectare, and production varies all over Indonesia. Several rice mills are in operation in Java, generally in the vicinity of the large cities, and there are also mills on the other islands. Products such as rice bran, rice polishings, and hulls are available in various quantities, depending on how much the mills produce. Rice bran (dedak) and rice polishings (bekatul) are used as feed for poultry, pigs, and some dairy cattle because they are relatively cheap and do not require processing. Recently, doubts have arisen concerning their value for animal feed because of a high phytate and phosphorus content. The main drawback to using rice milling by-products is that mills are widely scattered and it is difficult to collect them continuously from many mills in large quantities, thus making central treatment impractical. For instance, a rice bran oil factory in Krawang (near Jakarta) is at the moment not operating because of a lack of a fresh supply of bran.
Except in some areas such as Lampung and South Sumatra, corn (maize), like rice, is generally produced in small quantities by individual farmers. Corn stover (about six tons of dry matter per hectare) is already fed to cattle, but is not used if there is no livestock near the place of harvest. Corn cobs are generally burned.
Sweet potatoes and cassava are also commonly grown in rural areas. Their leaves are fed to cattle, sheep, or goats. Sweet potato and cassava have no waste products of any significance because their byproducts are known to the farmer as good-quality roughages. Cassava is primarily a food and export commodity, and no waste is available in large quantities. The export price determines the amount of cassava available for local use. The potential production of the leaves is, however, about 1 ton of dry matter per hectare for cassava and about 1.5 tons of dry matter per hectare for sweet potatoes.
Legume straw from peanuts, soybeans, mung beans, bush beans, and other beans is not wasted in Indonesia, but its nutritive value could be increased by better drying methods. The decreasing number of livestock in rural areas may result in some accumulation of legume straw. The yield of peanut and soybean straw is approximately 2.7 tons of dry matter per hectare.
Banana trees are found all over Indonesia, but banana plantations are rare. The stems and leaves, containing about 80 per cent of the total weight, are not usually fed to cattle, except in Timor during the dry season. They are used to supply water to the animals, with Leucaena leaves as the major source of protein. Leucaena is also often used as a cover crop for young plants on coffee plantations, but there are indications that in future it will not be used for this purpose because its growth is difficult to control. The high mimosine content is a limiting factor to its use as feed, and the new low-mimosine Leucaena from Peru is more promising. It has been introduced to Indonesia but is still not widely used.
Heretofore the availability of rubber seeds has been overlooked, and they are now collected by hand. Considering the large rubber plantations in Indonesia, this by product is worth looking into as an animal feed. However, the raw seeds are unpalatable and can cause diarrhoea in animals.
Animal Industry By-products and Wastes
The abattoirs located in large cities are the main source of animal wastes. Rumen contents and manure are the major residues, and in Java some abattoirs slaughter 250 head per day. The wastes are generally used as fertilizer. Hooves and horns are both exported and used as raw materials for handcrafted items, as are the bones. Animal blood, although not completely collected at the abattoirs, provides a protein source for human consumption after the application of simple processing treatment. Blood meal is also available in the market as animal feed. Organs such as the gall bladder, pancreas, thyroid, uterus, etc. are wasted but could be useful for the production of hormones. No gut residue is available from abattoirs.
Manure is the main waste product from the pig and poultry industries. Of the 95 million or so birds in Indonesia, fewer than 10 per cent are raised commercially in units ranging from 200 to 1,000 birds per farm. There is no indication of available feather meal, and recycling of poultry manure to feed ruminants is in the initial stages. In the pig industry, conversion of waste to biogas is practiced, but is limited to a few medium- and large-sized pig farms. The majority of pigs in Indonesia are raised in small numbers as scavengers.
Fishing industry residues are often abundant in fish markets. Unsold fish are generally preserved by salting and sold for human consumption; they are relatively cheap and serve as a major protein source in the daily diets of most people. But fish meal is also produced by a drying process using the free solar energy source of the tropics. Small fish-meal operations exist in Java and South Sumatra. Fish trimmings, heads, intestines, and trash fish are sometimes available and often appear to be wasted or infficiently preserved. This is largely because fishing is scattered over a wide area and ice is not available in remote areas for preserving small, local catches. The possibility of ensiling these after either microbial or acid preservation is promising.
There are many coconut plantations in Indonesia, but waste is not available. The stems are used as building material in the rural areas. Copra is collected, dried, and sent to coconut oil factories that produce coconut oil cake as a by-product. This is already used as a feed for animal production, but over two-thirds of Indonesia's production is exported. The protein content is 17 to 20 per cent, with an energy value of 2.5 kcal ME/g dry matter. On occasions the capacity of the factories to extract the oil may be overloaded, so the oil cakes can vary widely in oil/fat content.
Peanut oil cake is also available as a by-product from this oil extraction industry and is also an animal feed. This by-product, in the form of fermented peanut, has a market for human consumption. Palm kernel oil industries exist in Java and Sumatra, but 90 per cent of the palm kernel oil cake is at present exported, leaving no residue in Indonesia.
Wheat milling by-products. Although all wheat is imported, substantial quantities of bran and pollard are available. There are only two companies (in Jakarta and Bali) with a production close to 0.5 million tons annually. The nutritional value of bran is well known; however, again, 95 per cent of the total by-product is exported.
There are 19 small-scale and 3 large-scale fruit canning industries in Java, Sumatra, and Sulawesi, but no information is available on the waste potential from these canning operations.
A by-product from the forestry industry that might be used is sawdust There are about 29 million ha of forestland with a capacity of 43 million m³ of logs per annum. The big saw mills are located in Kalimantan and Sumatra, but unfortunately in areas carrying few livestock. About 10 percent of the total wood residue in a saw mill is sawdust, and about 54 percent is total waste (trimmings, chips, etc.). These percentages depend on the type of wood, type of saw, etc. The use of sawdust for animal feed is not practiced, and these products are at present used mostly as raw materials for building materials such as hard-board. In the plywood industry, about 0.7 to 1 per cent of the total by-product is sawdust and 6.5 per cent plywood trimmings with a total recovery of only 39 to 40 per cent.
Sugar cane provides a potentially useful waste, and the increasing demand for sugar will increase the size of sugar plantations. These, in turn, will produce more tops. About 150,000 hectares of land are at present planted with sugar cane, and about 16 tons of top material per hectare are available at harvest. Sugar cane top composition is: 6 per cent crude protein, 37.4 per cent crude fibre, 42 per cent nitrogenfree extract, 2.4 per cent fat, and 29.4 per cent dry matter.
Bagasse, available after extraction of cane juice, is at present not efficiently used. It is available in large quantities, concentrated to some degree near sugar factories. Some of this material is used in the paper industry, but most is used as a cheap energy source for people who live near sugar factories. Molasses is a high-energy feed for animals that is at present fed only to horses. Most of it is used for alcohol production.
Alang-alang grass (Imperata cylindrica Beauv.) has been shown to have at least the same nutritive value as elephant grass (Pennisetum purpureum) when cut at 30-day intervals. Its cultivation for feed is not recommended, however, and its present use is as roofing material for houses in rural areas. The rest of it is burned off. Alang-alang grass covers an estimated 20 million ha, and this is increasing because of shifting cultivation practices over the years. It might have some value as a feed and at the same time this might help to control the spread of the grass.
Although Indonesia is an oil-producing country, oil residues are not at present available. This is because Indonesia exports crude oil instead of refined oil, and therefore no refinery from which hydrocarbon fractions could be obtained is operating. Costs of single-cell protein production from oil residues are unattractive at present, but might become more feasible under certain circumstances at some future date.
Material known as "pasar" waste - consisting of anything from cellulose to plastic and metal scraps - is generated primarily in urban areas and is constantly accumulating. Recycling has been investigated but is not yet being carried out; separation of heavy metals is a problem. Its disposal is essentially a problem of urban sanitation. It does not seem possible to convert it into animal feed, and, even if it were, the process would have little relevance to rural community conditions.
The potential as animal feed materials of the by-products and wastes we have discussed can be fulfilled only if they meet the following criteria:
Given these considerations, the major by-products and wastes that might have a potential and be worth looking into are:
Most of the residues available in Indonesia are already used, although not efficiently. Research to increase their digestibility and nutritive value is important, because these products are at present fed "as is" and have a low feeding value for animals. The major residues that will have a feed potential in the future are presented, as these have potential use as animal feeds because they are not in competition with products for direct human consumption.