UTILIZATION OF AGRICULTURAL BY-PRODUCTS IN TAIWAN

UTILIZATION OF AGRICULTURAL BY-PRODUCTS IN TAIWAN An-Kuo Su Heng-Chun Station Taiwan Livestock Research Institute Taiwab ABSTRACT An abundance of agricultural by-products have been used to feed dairy and beef cattle in Taiwan, in order to reduce the cost of livestock production. Most farmers are not concerned about the nutrient value of agricultural by-products. They need to be educated on how to utilize by-products properly. Research to improve techniques of preservation and the efficiency of utilization of agricultural by-products also needs to be carried out. In future, extension will be directed toward the establishment of agricultural by-product supply centers, and adjusting formulas for feeding rations which will include indigenous feed resources in Taiwan. INTRODUCTION Taiwan is a subtropical island, most of which is mountainous. The production of crops is just enough to meet the needs of human consumption. In developing the dairy and beef industries in Taiwan, it has been difficult to reduce production costs, because of the high cost of feed and the limited land area. According to the available research data, the cost of feed is around two-thirds of total cost of milk and beef production. Fortunately, there are many agricultural by-products which can be utilized as feed. The history of utilizing such by-products in Taiwan can be traced back more than half a century. A series of experiments have been conducted over the past 20 years by the Taiwan Livestock Research Institute to provide a model to farmers of how they might utilize agricultural by-products. Also, extension classes have been held by the Institute to educate farmers in how to use various kinds of agricultural by-product properly, and how to preserve them successfully. OBJECTIVES There are two main reasons for small-scale livestock farmers in Taiwan to use agricultural byproducts. One is to replace concentrate feeds and reduce the cost of production, and the other is to solve the problem of environmental pollution which results from the accumulation of agricultural byproducts in the field. Decreasing the Cost of Animal Production A great deal of grain is imported into Taiwan for feed concentrates. Total digestible nutrients (TDN) from agricultural by-products may substitute for those from concentrates and forage without affecting animal production. Solving the Problem of Pollution Most agricultural by-products are discarded in the field as organic fertilizer. This can result in pollution in the soil and groundwater (Chung 1976, Table 1). TYPES OF AGRICULTURAL BY-PRODUCTS IN TAIWAN Agricultural by-products utilized by farmers include farm by-products and processing resi- Keywords: Agricultural by-products, bagasse, brewers' grain, farmers' education, livestock production, Taiwan, tofu wastes 1

Table 1. The utilization of farm by products in Taiwan dues. Farm by-products, the residues of crops after harvest, have a high dry matter and fiber content. Most of them are discarded in the field as fertilizer, but some are dried and stored as a forage supplement for ruminants in winter. Processing residues, after crops have been processed for human consumption, have a high water content, good palatability and are rich in nutrients. They also have a high fiber content, and are easily spoiled and fermented. Unless they are dried or ensiled, they must be used while they are still fresh (Chi 1984, Table 2). Although some by-products may become scarce if cropping patterns change, in general the production of agricultural by-products in Taiwan remains constant from one year to another (Chen 1977, Table 3). Those which are used by small-scale dairy and beef farmers in Taiwan are shown in Fig. 1 (Su and Yun 1995). Farmers often use different types of by-products at different times of the year. If there is a seasonal shortage of certain by-products, sometimes farmers need to preserve a small quantity to cover the period of deficit. 2 FEEDING AGRICULTURAL BY-PRODUCTS Tomato pomace and bean vines are used as feed for dairy cattle, but only a few farmers use them because the supply is limited. Some by-products may have harmful effects: for example, hairballs accumulated from the fibrils in bamboo shoot shells have been discovered in the rumen of young calves. These might result in the loss of the calf. Similarly, aflatoxin has been discovered in peanut vines when these have been stored badly. Bamboo shoot shells and peanut vines should therefore be fed to beef cattle only during the fattening period. Currently, brewers grain and soybean cake pomace (tofu wastes) are the most popular by-products used by smallscale farmers in Taiwan. Bagasse is another important by-product, which is often used together with molasses by large-scale beef cattle farms (Su 1990, Table 4). EFFICIENCY OF USING AGRICULTURAL BY- PRODUCTS A series of experiments have been conducted in Taiwan to evaluate the efficiency of feeding agricultural by-products. One study focused on the nutrient value of agricultural by-products on the production of beef cattle and meat goats. The data showed that there was a wide range in the cost of weight gain between different treatments for both cattle and goats (Su and Yun 1990, 1991, 1992, Table 5). THREE BY-PRODUCTS USED BY CATTLE IN TAIWAN Brewers Grain Spent brewers grain is a by-product of beer making. The production of spent brewers' grain has declined in Taiwan in recent years, due to an increase in the amount of imported beer. In 1994, only 146 thousand mt was available, compared to 187 thousand mt in 1990. Brewers grain contains about 77% water, and also contains 25% crude protein on a dry matter basis. It has been successfully incorporated into dairy cow rations in proportions ranging from 5 to 10%, and incorporated into beef cattle rations at a rate of 20-40% (on a dry matter basis). However, it is limited to less than 5% in the rations of monogastric animals, because of its high content of crude fiber (Table 6). The production of brewers grain depends on the level of beer consumption in Taiwan more in summer, and less in winter. Small-scale farmers can therefore obtain brewers gain more easily in summer than in winter. Brewers grain costs about US$28-40/mt, depending on the shipping distance

Table 2. Types of livestock which use agricultural by products in Taiwan Table 3. Chemical composition of agricultural by products Fig. 1. Seasonal availability of agricultural by products in Taiwan 3

Table 4. Consumption of agricultural by products by cattle in Taiwan Table 5. Daily gain and feed costs of beef cattle and meat goats fed with agricultural byproducts 4

from the factory to the farm (Table 7 Table 8). Brewers grain is used in the rations of milking cows, each cow receiving about 5 kg fresh brewers grain daily. Dairy farmers use a mixer truck to mix concentrates, forage and brewers grain together, to save labor and time. The only limiting factor in using brewers grains is the season. Although brewers' grain is sometimes preserved to use during the winter, the percentage of spoiled grain is very high, and some nutrients are lost along with the water. The surface layer is also attacked by molds. A successful technique of using plastic bags to store brewers grain mixed with whole corn has been developed (Su, Pen and Yun 1994). The corn kernels absorb water from the brewers grains, thus becoming reconstituted corn. In this way, spent brewers grain can be stored easily, so that the utilization of both corn and brewers grain is improved (Table 9 Table 10). Tofu Wastes Tofu wastes, also known as soybean cake pomace, come from the processing of tofu (soybean curd) and its by-products. Tofu factories in Taiwan are always close to cities. Customers prefer to consume tofu in summer rather than in winter, so that the production of tofu wastes tends to be seasonal (Fig. 2). Tofu wastes ferment quickly, and are always fed fresh to cattle. In some parts of Taiwan, dairy farmers feed 2-5 kg of fresh tofu wastes daily as a protein supplement for milking cows. Table 6. Composition of silage made from corn and brewers grain Table 7. The cost of ingredients in corn brewer s grain silage (US$) Table 8. The cost of silage made from corn and brewers' grain (US$) 5

Table 9. Nutrient composition of silage made from corn and brewers grain Table 10. Growth performance of beef cattle fed with corn and silage made from brewer s grain Bagasse Sugarcane has been one of the most important agricultural crops in Taiwan for several decades, and produces one million mt of bagasse per year as a by-product of sugar making. Its production is affected by seasonal factors, but usually bagasse is used at times when other forage sources are less readily available. Bagasse contains a low percentage of crude protein (CP) and a high percentage of acid detergent fiber (ADF). Therefore, it is only used on cattle farms at a rate of 15-20% of total rations. The Taiwan Sugar Corporation owns several large beef cattle farms, and uses a large amount of bagasse with molasses in beef production (Tabale 11). The nutrient value of bagasse can be improved by chemical treatments (Shimabukuro and Otagaki 1959), or microbial treatments (Su and Yun 1993). Chemical treatments are complicated, and their odor reduced the appetite of the animals. After treatment with cellulolytic bacteria taken from the gastrointestinal tracts of yellow cattle (Table 12), acid detergent fiber (ADF) in bagasse fell by 6.7%, while total digestible nutrients (TDN) increased by 70% (Tabale 12). IMPORTANT CONSTRAINTS TO USING AGRI- CULTURAL BY-PRODUCTS IN TAIWAN There are eight important factors which affect the use of agricultural by-products. Production Region Processing or crop residues are most convenient to use when the distance from the field or factory to the farm is short. If suitable by-products 6

are produced far from livestock farms, high transportation costs will reduce any economic benefits. Production Season Most agricultural by-products have a short production period in Taiwan, and when they are finished farmers must search for alternative byproducts. This means changing the livestock rations, and if farmers do this too often, rumen ecology and the performance of cattle will be affected. Pesticide Residues There are many insect pests in Taiwan which affect the production of crops. Farmers often use large amounts of pesticide to kill these insects. Pesticide residues are a big problem when agricultural by-products are used as feed. Price The price of agricultural by-products depends on what profit the manufacturer expects, the broker s charges, and the transportation fees. Generally, the cost of transportation is at least 50% of the total cost. The greater the distance of delivery, the higher the cost. Nutritional Balance The nutrient content of each agricultural by-product is completely different from that of the others. Before by-products can be used as feed, their chemical composition has to be determined. Farmers also need to be educated through short extension Fig. 2. Monthly production of soybean cake pomace Source: Chi 1984 Table 11. Bagasse production* in Taiwan, 1990 1994 7

Table 12. Treatment of bagasse in a silo, chemical analysis, and in vivo experimental data* classes about the differences between agricultural by-products. Using agricultural by-products as only one part in the total mixed rations is the best method of balancing all the nutrients. Health of Animals Some agricultural by-products contain toxins which affect the health of animals. When cattle eat too much sweet potato vines or peanut vines, for example, they develop diarrhea. The proteinase in pineapple, and the cyanic ions in cassava, also affect the health of livestock. Preservation Only a few farmers in Taiwan have enough space to build a silo in which to preserve agricultural by-products. Most agricultural by-products are stored in piles, without any covers, near livestock pens. The surface layer soon becomes spoiled, and so loses its nutrient value. Milk Quality Some agricultural by-products have strange flavors which can be transmitted to milk, while their nutrient content may not compete with that of forage. If dairy cattle consume a large quantity of these, the flavor of milk may change, and its quality may decline. POTENTIAL OF USING AGRICULTURAL BY-PRODUCTS IN TAIWAN The area under crops in Taiwan has declined as many rural people have moved out of the countryside into the cities. Some food processing factories have been moved abroad to other Asian countries, because of Taiwan s high labor costs and labor shortage. Therefore, from the viewpoint of using agricultural by-products as feed, we can expect the costs of transportation and processing to be fairly high in future. Since there are also a number of other constraints on the use of agricultural byproducts as feed, it is necessary to establish some scheme for using these resources in ruminant production. It would be best for all agricultural byproducts to be studied routinely by a specific center in Taiwan. The chemical composition and any toxins in agricultural by-products should be analyzed there. Research institutes should pay attention to improving techniques of preservation and efficient use, and adjust the total rations to correct any nutrition imbalance from specific agricultural by-products. Extension staff should routinely visit farmers to discover problems, promote the use of local agricultural byproducts, and adjust rations for farmers (Fig. 3). Some dairy and beef production cooperatives are planning to establish several preservation centers for agricultural by-products. These centers will be near 8

Fig. 3. Constraints to using agricultural by products as feed in Taiwan Fig. 3. Scheme for using agricultural by products as feed in Taiwan 9

farms, and will provide silage to farmers. Farmers will follow appropriate feeding recommendations when they use the silage to feed their animals. REFERENCES Chen, M.C. 1977. The utilization of agricultural by-products for livestock. Agriculture Association of China 100: 34-41. Chi, G.H. 1984. Economical investigation on indigenous feed resources in Taiwan. Department of Agriculture and Forestry, Taiwan Provincial Government. (Unpub. mimeograph). Chung, G.L. 1976. Research on the utilization of agricultural by-products. Department of Agriculture and Forestry, Taiwan Provincial Government. (Unpub. mimeograph). Shimabukuro P. and K.K. Otagaki. 1959. The value of ammoniate bagasse pith in ruminant nutrition. Jour. Anim. Sci. 18: 1175. (Abstract). Su, A.K. 1990. Investigation of utilization of agricultural by-products by Taiwan s farmers. Unpublished data. Su, A.K. and S.S. Yun. 1990. Tomato pomace utilization by beef cattle. Report on the Technique of Agricultural Research. (Unpub. mimeograph). Su, A.K. and S.S. Yun. 1991. Peanut vines' utilization by meat goats. Report on the technique of agriculture research. Taiwan Livestock Research Institute. (Unpub. mimeograph). Su, A.K. and S.S. Yun. 1992. Brewers' grain utilization by beef cattle. Report on the Technique of Agricultural Research. Taiwan Livestock Research Institute, (Unpub. mimeograph). Su, A.K. and S.S. Yun. 1993. Effect of treated bagasse on gain performance of cattle. Report on the Technique of Agricultural Research. (Unpub. mimeograph). Su, A.K., B.W. Pen and S.S Yun. 1994. Corn brewers grain silage and utilization by beef cattle. Report on the Technique of Agricultural Research. (Unpub. mimeograph). Su, A.K. and S.S. Yun. 1995. Investigation on agricultural by-products utilization. Paper presented at Seminar on feedstuffs of ruminants. (Unpub. mimeograph). Taiwan Agriculture Year Book. 1994. Department of Agriculture and Forestry, Taiwan Provincial Government. Taiwan Sugar Corporation Year Book. 1994. Taiwan Tobacco and Wine Monopoly Bureau Year Book. 1994. 10