PART II (Contd.)

CHAPTER 8
THE UTILIZATION OF AGRO-INDUSTRIAL BY-PRODUCTS IN ASIA AND THE FAR EAST

by

C. Devendra

Malaysian Agricultural Research and Development Institute,
Serdang, Selangor, Malaysia

Resumen

En Asia y el Lejano Oriente los subproductos agroindustriales que abundan y son muy variados constituyen una fuente importante de alimentos para el ganado. El interés por su empleo ha aumentado con el desarrollo de la agricultura, con el aumento del volumen de producción obtenido gracias a la “Revolución Verde” y últimente con la crisis de la energia.

Los subproductos que hay actualmente se pueden dividir en dos categorías: subproductos primarios, que constituyen la base principal de un sistema de alimentación, y subproductos secundarios, que se usan como suplementos de la dieta. Con respecto a los primeros, se concentra la atención particularmente en la utilización de los subproductos del arroz, de la caña de azúcar, de la palma de aceite y de la de coco. Otros subproductos de este grupo son los del trigo, el caucho, la yuca y el sagú. Entre los subproductos secundarios figuran, entre otros, la cáscara de arroz, los desechos de la piña y el cacao, la paja de legumbres, las hajos de yuca, las tortas de semillas de algodón, de soja y de maní, la harina de semilla de “sal” y de guar, la semilla de mango, la harina de carne y de huesos, la de sangre y de plumas y el estiércol de aves. En un cuadro se dan a conocer aproximadamente las tasas de extracción de ciertos subproductos.

Se estudia la utilizacion de ambos grupos de subproductos en relación con su valor para la alimentación de rumiantes y no rumiantes en varios países de la región. El valor aparece en cuadros separados. De acuerdo con estos resultados, hay enormes posibilidades de ampliar la aplicación de determìnados subproductos en la alimentación intensiva del ganado.

Entre los subproductos primarios que constituyen el ingrediente principal de la dieta, se presta especial atención al afrecho de arroz, a la melaza, a la borra de aceite de palma, a la fibra de palma presada y a las tortas de coco. Excepto la melaza, se llega a la conclusión general de que la utilización de cada subproducto y el rendimiento óptimo de cada animal se logra con tasas de incorporación del 30 a 40 por ciento. En este rendimiento se incluye el valor de la melaza agregada a la dieta (20 a 30 por ciento) para hacerla más apetitosa, la que sirve de vehículo a fuentes de nitrógeno no proteínicas tales como la urea y es un suplemento energético. Para una utilización más intensiva de estos subproductos, si hay disponibilidades, se recomienda que del 50 al 70 por ciento de la dieta total consista en subproducto y melaza.

Con respecto a los subproductos secundarios, que se usan como suplementos de la dieta, se dan ejemplos de su valor. Como los suplementos proteínicos tienen particular valorse insiste en la necesidad de conservarlos y de administrárselos a los rumiantes y no rumiantes de manera más racional. En relación con lo dicho, se obtienen beneficios si las fuentes de nitrógeno no proteínicas de la dieta de los rumiantes satisfacen del 60 al 70 por ciento de sus necesidades totales de nitrógeno.

Se estudian los beneficios potenciales de la utilización máxima de los subproductos agroindustriales en relación con el aprovechamiento total de las especies animales y con la búsqueda de un potencial realista y de un nivel económico de productividad.

Introduction

Agro-industrial by-products in Asia and the Far East are varied and abundant, due to the emphasis on crop cultivation. In most countries in the region, there has been an increase in the volume of production of cereal straws due to the “Green Revolution” By-products represent an important source of feedingstuffs for ruminants (cattle, buffaloes, goats and sheep) and non-ruminants. Interest in their utilization is stimulated by their potential value for feeding farm livestock and, more recently, by the energy crisis. However, it is doubtful that the bulk of these by-products are incorporated efficiently into feeding systems which ensure maximum livestock response and therefore productivity. The purpose of this paper is to identify these agro-industrial by-products and give a comprehensive review of the level of utilization by livestock in Asia and the Far East.

Increasing the interest in agro-industrial by-products, consistent with their more effective utilization in the region, necessitates keeping in perspective three broad objectives:

1. full exploitation of the animal species;

2. the availability of dietary ingredients; and

3. a realistic potential and economic level of productivity.

All three factors are important in determining the level of exploitation and therefore productivity from the livestock resources as a whole. The first lies outside the scope of the discussion, but the second and third form the basis of this paper. For purposes of coverage, the “region” under consideration includes India, Pakistan and all countries to the east of these.

Value of agro-industrial by-products

Agro-industrial by-products for feeding livestock present a number of advantages, including inter alia:

1. availability in substantial quantities
2. relatively low or no cost
3. low feeding value of tropical forages
4. justification for supplementation
5. feed shortage during periods of scarcity and uneven distribution
6. scope for import substitution
7. improved efficiency of the stall feeding system.

Of these factors encouraging increased byproduct utilization, great importance is attached to the first: availability. In turn, this key factor is associated with at least three other considerations: extent of present utilization, potential value for livestock and precise guidelines for effective utilization. An understanding of these considerations is therefore essential, since they influence in varying degrees the extent and effectiveness of present usage. For the area under consideration, these factors also represent the main constraints concerning their use in the diet.

Perhaps the most challenging aspect of the utilization of agro-industrial byproducts in Asia and the Far East, and the potential prospects for their increased use, is associated with the scope for import substitution. Quite often awareness of the value of these by-products has made it possible to replace imported feedingstuffs, reducing the cost of livestock production. The case for import substitution is justified by two reasons:

1. the high cost to the economy assotiated with imports of animal feedingstuffs, and

2. the increased efficiency of feeding to stimulate high animal-product output.

Import substitution in this sense implies more than merely replacing an imported feedingstuff, since it includes inter alia development and expansion of the market, productive capacity, rate of growth for animal products and also creation of further resource use.

The support for import substitution is evident in a recent ESCAP report on the compound feed industry in Sri Lanka, Thailand, Indonesia and Malaysia (Halliday and Exeter, 1975), which suggests that there are considerable opportunities for increased utilization of raw materials in these countries. A corollary of this is the recognition that a low-cost feed manufacturing industry is vital in the development of efficient animal production, consistent with quality standards.

Availability of agro-industrial by-products

A variety of agro-industrial by-products are available in Asia and the Far East, some abundant and more useful, others available only in small quantities and therefore of secondary importance. For purposes of convenience, the available by-products can be grouped into two categories:

A. Primary by-products: major ingredients forming the base of a feeding system

B. Secondary by-products: minor ingredients supplementing the diet.

The distinction is by no means absolute, as some by-products, e.g. oilcake meals, may be considered secondary, but can also form the base of feeding systems for non-ruminants. Likewise, major by-products such as molasses are important in enhancing the palatability and feeding value of the diet. The major by-product feeds derived from tree and field crops in the region, together with approximate extraction rates, are listed in Table 7.1. Table 7.2 gives similar information for minor by-products; data for Thailand (Smith and Payne, 1974) and Malaysia (Devendra, 1975 a) have been published.

Utilization in feeding systems

Large-scale utilization of agro-industrial by-products in the region is dependent on optimum inclusion of chosen by-products in the diet, onsistent with their efficient utilization. Efficiency in this case implies not only feed efficiency but also economic efficiency, i.e, the cost of the by-product should be such that its inclusion is economically justified.

Although the inclusion of a by-product in the diet is most valuable when it is economic, periods of feed shortage, due for example to drought or uneven distribution of feeds accentuate the true value of the by-products. The use of agro-industrial by-products under these circumstances considerably reduces weight loss and poor condition of livestock. Comprehensive reviews of the value of agro-industrial by-products in feeding systems have been reported for India (Mudgal, 1973), Malaysia (Devendra, 1973; 1974; 1975 b) and the Philippines (Perez, 1976).

A. Primary by-products in a feeding system

1. Rice by-products - Rice bran

Rice bran is an important by-product of padi production; on average it constitutes approximately 10% of the weight of unpolished rice. It has a high fat content, and unless the fat is extracted or antioxidants used, rancidity is rapid in hot humid environments. Rice bran quality varies, and in Malaysia three categories are identifiable.

¹ implies equivalent weight to grain yields.

¹ Based on a daily faecal production of 110 g/adult bird.
² Of live weight.
³ Of the weight of wet offal.

In India, replacing rice bran (polish) with the deoiled by-product in chick diets had no significance on performance. However, the efficiency of metabolizable energy utilization was reduced as the level of deoiled rice polish in the diet increased beyond 30% (Table 7.3). The inclusion of 30% of this by-product in the starter diet adequately met the energy requirement of chicks. More recently, Datta and Bose (1974) have shown that a 20% level of rice bran in the diet with either an all-vegetable protein (ground sesame cake plus groundnut cake) or animal protein source (fishmeal) had no significant effect on the laying performance of White Leghorn or Rhode lsland Red pullets. More recently, rice bran up to 15% for weaners and 30% for growing-finishing pigs have been shown to be suitable with no effect on performance (Campabadal et al., 1976).

II. Sugarcane by-products - Molasses

Of the by-products of sugarcane, molasses is the most important, and is widely used for feeding livestock in the region. Its greatest value is associated with the fact that it enhances palatability, acts as an energy supplement to roughage by-products such as rice straw, often as carrier of these, and also of non-protein nitrogenous (NPN) sources like urea. Because of the content of mainly soluble sugars, it is also an excellent substrate for microbial growth (Preston, 1972).

In consideration of these features, the utilization of molasses in the region has followed three main paths:

1. relatively low levels (5–10% DM in mixed feeds and pelleted diets to improve palatability and reduce dustiness;

2. liquid feeding for grazing ruminants, molasses providing part of the dietary energy and also acting as a carrier of NPN;

3. relatively high levels of feeding to provide the main energy source.

Of these, the first two are by far the most common for feeding practical diets to livestock in the region. They also reflect traditional molasses utilization practices. However, with a view to increasing the utilization of agro-industrial by-products, and more particularly considering the significant advances that have been demonstrated concerning the utilization of molasses as a major source of energy, notably by Preston and his colleagues (Preston and Willis, 1969; 1970; Preston, 1972; 1974), more attention is also being directed at the third aspect. In digestibility studies with rice straw (20% level) diets, with 20 to 59% levels of molasses in the diet, digestibility of dry matter was maximum for the 59% level of molasses.

III. Oil palm by-products

Oil palm by-products are becoming increasingly important, mainly because of the expanding acreage under this crop in some countries in the region, especially Malaysia. The three main by-products are palm press fibre (PPF), palm kernel cake (PKC) and oil palm sludge (OPS). In Malaysia alone, the total production of these in 1974 was quite considerable. Their chemical composition is given in Table 7.4. PKC has been used quite extensively as a protein supplement in pig and poultry diets, but very little is known about their value in diets for ruminants.

In order to stimulate interest in these potentially valuable by-products, with particular reference to ruminants, studies have been recently reported on the value of OPS and PPF in feeding systems. The initial approach was to seek efficient utilization of optimal levels of these when combined in the fresh form in molasses-urea diets. The digestibility results are presented in Table 7.5.

Since the intake and feeding value of the oil palm by-products used was considerably enhanced by the presence of molasses, it was of interest to examine the pattern of utilization in relation to the level of molasses in the diet (Table 7.6). This consideration, with reference to the digestibility of organic matter (DOM), suggests that the optimum rations of OPS, PPF and OPS plus PPF to molasses were 1 : 1.2, 1 : 1.4 and 1 : 1.2 respectively; optimal levels of inclusion of the by-products in the diet, based on digestibility, were 40, 30 and 40% respectively.

The acceptability and feeding value of these by-products has also been demonstrated in ongoing feeding trials with pigs, beef cattle and buffaloes. More recently, OPS has been combined with palm kernel cake and/or cassava before drying into a produce that appears to have potential as a cheaper feedingstuff compared to maize (Webb, Hutagalung and Cheam, 1976). More extensive use in situ of these by-products, especially in large oil-palm estates and plantations, is favoured by a number of practical considerations, inter alia, increased palatability of the fresh by-products, difficulties in transport due to bulkiness, and low storage life. Furthermore, feeding the by-products overcomes problems of effluent disposal and pollution. The moist and oily nature of PPF, for example, although it can be overcome by partial sun-drying, causes the product to mould very rapidly.

IV. Coconut by-product - Coconut cake

Coconut cake or copra cake is an important by-product for animal feeding in all areas where coconuts are cultivated extensively, notably India and countries to the east, including the Pacific region. The importance of the by-product is associated with the fact that it is used as an energy and a protein source, and can therefore be classified under both the broad categories mentioned above.

Although it is used by both non-ruminants and ruminants, its deficiency in the amino acids lysine and histidine and a relatively high fibre content make it more suited for feeding ruminants. With non-ruminants, early studies in the Philippines showed that a 20% level was optimal in the performance of pigs (Fronda and Mallonga, 1935) and poultry (Eamilao, 1938); levels higher than this were associated with high mortality in chicks and poor performance in pigs. Confirmation that the 20% level was optimal also appears in a number of studies on pigs in the West Indies (Grieve, Osbourn and Gonzalez, 1966; Jeffers and lton, 1966; Devendra and Clyde Parris, 1970; Clyde Parris and Devendra, 1971); the value of coconut cake for feeding pigs has been reviewed (Devendra, 1971). Much higher levels (up to 40%) can be used in diets for pigs and poultry if lysine and methionine supplements are provided (Thomas and Scott, 1962; Momongan et al., 1964). Thomas and Scott, for example, have shown that a 40% level is suitable in poultry starter rations when combined with fishmeal, alfalfa meal, meat and bone scraps, torula yeast and blood meal, plus lysine and methionine supplementation.

For ruminants, coconut cake is used extensively and especially in rural areas. It is often fed intact after soaking for cattle, especially lactating cows and buffaloes, or mixed with one or two other dietary ingredients, for example with citrus meal in a 1 : 1 ratio. In ruminant diets, therefore, it can be used at fairly high levels. In the Philippines, 35, 45 and 55% coconut cake in the diet of lactating cows gave significant differences (.P 0.01) in the butter-fat percentage, which increased with increasing levels of inclusion. It was significant that the cost of the diet decreased with increasing amounts of coconut cake inclusion (Castillo et al., 1961). Much higher levels, of up to 92% in the total diet have been reported to give between 0.39 to 0.40 kg daily live weight gain in the growth of Local Indian Dairy calves in Malaysia (Devendra and Slvarajasingam, 1975).

¹ All diets included 16% groundnut cake and 10% meat meal as protein supplements.
² Supplemented with 5% groundnut oil.

Source: Malik, Lodhi and Ichponani, 1973

Table 8.4. Availability of oil palm by-products and their chemical composition in Malaysia (1974)

I. Availability (Tonnes of air-dry material)

II. Chemical composition (% DM)

¹ Expellar and solvent extracted.

Table 8.5. Apparent digestibility of oil palm by-products (oil palm sludge and palm press fibre) in Malaysia

I. Diets fed

II. Digestibility (%)

¹ Mixed in equal portions on dry matter basis in iso-nitrogenous diets.
² Providing the following minerals and vitamins when added at the rate of 5 000 000 IU vitamin A; 1 250 000 IU vitamin D; 1 330 mg cobalt; 250 g calcium; 22 570 mg copper; 41 730 mg iron; 44 180 mg manganese; 38 200 mg zinc and 113 400 mg magnesium.
³ Least significant difference.
⁴ Determined from bomb calorimetry of feed and faecal samples.

Note: Each DOM value is the mean of four sheep in trials 1 and 2 and three sheep in trial 3.

Source: Devendra and Muthurajah, 1976

Although attention has been focused on these main rice, sugarcane, oil palm and coconut by-products, the list is by no means complete. To them can be added the by-products from such other very important crops as wheat in India (wheat straw and wheat middlings), rubber in Malaysia, Sri Lanka and Thailand (rubber seed cake), taploca in South India, Malaysia and Thailand (tapioca waste) and sago in Sabah (sago waste). In general, inclusion of these in the diet and the development of effective feeding systems remain to be explored, and emphasizing again the potential of by-product use in tropical animal production.

B. Secondary by-products that supplement the diet

The secondary by-products that supplement the diet can be grouped into three categories:

1. those that are produced in small quantities
2. those that are produced in large quantities
3. proteins and concentrate supplements.

The first category includes those by-products that are too localized in production within any one country. Proteins and concentrate supplements, although they may be produced in small quantities, are important components of the diet of all livestock.

Examples of agro-industrial by-products that fall into these categories are numerous. The first category includes pineapple waste, cocoa waste and pulse straws (e.g. cowpeas (Vigna catiang)) and vines (e.g. from sweet potatoes (Ipomoea batatas)). A good example of a by-product in the second group is rice husk. In view of its very low nutritive value, only small levels (about 5%) can be included in the diet of ruminants (Devendra, 1976b). Paddy husk has been reported to be extensively used to feed cattle and buffaloes in Andhra Pradesh and Orissa in India (Amble et al., 1965).

The third category includes such crop wastes as cottonseed, soybean and groundnut cakes, guar and sal seed meals, and mango kernels. From the abattoir, a variety of animal by-products are available, such as blood meal, rumen contents, meat and bone meal, tallow and feather meal. Poultry litter is also a valuable by-product for feeding ruminants, and is a useful NPN source (see for example Devendra, 1976a). Industrial by-products relate, for example, to the use of barley in breweries: brewers yeast, dried brewers grains and spent hops. This list is again by no means complete, and recycling of waste materials from urban areas is also being given attention. In many countries in the region, notably India, exhaustive efforts are being made to evaluate the feeding value of various such by-products The approach, motivated essentially by scarcity of feedingstuffs, is commendable since it generates efficiency in feeding and management, minimum loss of potentially useful feedingstuffs and economic production. In the Indian context, tremendous pressure on the use of land, and the shortage of feedstuffs, has accentuated the value of various crop by-products as feeds; the magnitude of this problem has been discussed by Panse, Amble and Abraham, 1964, and by Amble et al., 1965. Consideration has also been given to the types of feedingstuffs that are useful during scarcity periods (Jayal, Ranjhan and Sawhey, 1973).

The main value of these secondary by-products are as supplements to the diet. A most valuable contribution is that of protein supplements, replacing the more expensive imported types.

In Malaysia, for example, the advanced pig and poultry industries are very dependent on imported soybean meal, groundnut meal and fishmeal. In order to offset this dependence, increase the use of local sources, and thereby enhance the economic efficiency of feeding, a programme of research has demonstrated that locally-produced fishmeal, groundnut meal and blood meal can be profitably used in the diet of growing pigs without loss of performance (Hew and Devendra, 1975, 1976a).

In India, attempts have also been made to replace maize, the main energy source in pig diets, with deoiled sal seed cake, a by-product obtained after the extraction of oil from sal seeds for industrial use. It has been demonstrated (Pathak and Ranjhan, 1972) that replacing 50 and 100% of the maize in the diet had no significant effect on performance (Table 7.7). Of particular significance was the finding that the inclusion of deoiled sal meal reduced the cost of pig production by between 6 to 22%. With growing heifers, Sonwany and Mudgal (1974) have suggested that a 30% level can be used, with or without 2% urea.

¹ M - Maize, DSM - deolled sal seed meal.

Source: Pathak and Ranjhan, 1973

With ruminants, attempts have also been made to include guar meal in the diet, and no significant differences in body weight gains were noted compared to performance with groundnut cake (Sadagapon and Talapatra, 1967). It led to no digestive disorders. More recently, it has been used as the sole source of protein in the growth of calves (Sagar and Pradhan, 1975) and its performance also found to be not significantly different to that of groundnut meal. Neem seed cake has also been used effectively as a protein supplement to feed buffaloes (Bedi, Vijian and Ranjhan, 1975).

Agro-industrial by-products and economic feeding

The most important benefit associated with the increased utilization of agro-industrial by-products in the region is the possibility of decreasing the cost of feeding without lowering the performance of livestock. While this applies to all categories of livestock, probably the most note-worthy impact is with those species whose demand for nutrients is high. The dairy cow and buffalo are prominent in this respect, and since concentrate supplementation is necessary for high production, meeting needs will call for skill in covering the higher nutrient demand from available feedingstuffs.

Without exception, meeting the energy needs of the high-producing dairy animal from maize is not only expensive but, even more important, competes with human needs and consumption. The situation is such that in India, high-energy feeds such as maize, wheat and barley are more expensive than high-protein concentrates.

The justification for concentrate supplementation, especially for dairy production (Devendra, 1975c), is associated with four factors:

1. scarcity of nutrients from the quantitative and qualitative standpoints;

2. restriction in energy uptake imposed by bulky forages;

3. relatively low prices of alternative mixed feeds from agro-industrial by-products and/or home-grown feeds;

4. increased milk yield, of a monetary value greater than the cost of the feed required to produce it.

Since concentrate supplementation is a must for lactating ruminants, judicious feeding and skilled manipulation of the feed ingredients is essential. The extent of this supplementation also dictates to a very large extent the margin of profit from the enterprise. India again illustrates the considerable opportunities that exist for increased use of agro-industrial by-products in the feeding of lactating animals: for example Cassia tora seeds (Patel, Patel and Shukla, 1971), tapioca waste (Menon, 1972) and alkali-spray treated wheat straw (Jackson and Agarwal, 1974). Mudgal (1975) has given various examples of diets formulated from local ingredients and the opportunities for economical feeding to meet the nutritional requirements of cows and buffaloes in India, and Devendra (1975c) for feeding dairy cattle in Malaysia.

Feed efficiency and exploitation of livestock resources

A prerequisite for the obtention of more animal proteins from livestock is feed efficiency, whose improvement is important in increasing the contribution and potential productivity of livestock. The opportunities for improved feed efficiency and animal performance are enormous, and from the long-term viewpoint developments in this direction are associated with a number of factors, inter alia:

1. Increasing the yield of feedingstuffs including agro-industrial by-products, and reducing nutrient wastage;

2. Improving through genetic upgrading, the quality of animals with an inherent capacity to utilize feed nutrients more efficiently;

3. more efficient and economic management systems;

4. Improved methods of evaluating and using feed ingredients;

5. increased availability of information on feeding patterns of various animals for specific productive functions;

6. suitable feeding standards.

Implicit in improved feeding efficiency is the need for Judicious use of the feed ingredients in relation to the special attributes inherent in individual species of farm animals. The particular abilities of ruminants, for example, need to be kept in perspective, since they are commensals of man, converting feedingstuffs of a mainly fibrous nature and nitrogen-containing materials into products (meat and milk) important to his nutrition. The potential for a greater contribution of animal products is associated with promoting increased efficiency of livestock production, intensive methods of production and expansion of the sector as a whole.

Recapitulation

Agro-Industrial by-products constitute an important resource base for feeding livestock in Asia and the Far East. These by-products are varied, increasing in volume and found quite abundantly in most countries in the region. Their availability has in recent years been substantially increased by the “Green Revolution” and also more intensive methods of crop cultivation. Some form major ingredients within a feeding system, while others are only supplements to the diet. Their potential value is linked with increasing the contribution from, and stimulating further expansion in, the development of the components of the livestock industry.

Progress in their utilization for feeding farm animals indicates that opportunities in the region for their even wider and more efficient utilization, consistent with more intensive systems of nutritional management, are enormous. The case for stimulating greater interest in them, and the potential benefits of maximizing their use, is associated inter alia with thorough assessment of the availability and value in the diet, full exploitation of the animal species and the economic level of productivity. Economic production is probably the most important single justification for increased utilization of agro-industrial by-products, in view of the possibility of obtaining animal products profitably. The advantages of this approach are reduced dependence of imported feeds, identification of feedingstuffs suited for efficient utilization by individual species, and in the case of cereals, avoidance of competition with human requirements.

The future for increased use of all available agro-industrial by-products is clearly associated with taking full advantage of the available dietary ingredients, development of appropriate feeding systems, the aim for a realistic potential level of production of individual species and identifying the objective clearly in terms of production and profitability. Improved feeding efficiency is especially important in increasing the contribution and potential productivity of farm animals in the region. The search for this efficiency has as its, cardinal objective to increase the availability of animal proteins which would be of great benefit to the nutrition, health, productive capacity, and therefore to the future economies of the countries in Asia and the Far East.

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