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Multinutrient blocks as a strategic supplement for ruminants

Supplementation and animal productivity
Practical constraints
Multinutrient blocks
Balancing nutrient supply to the animal
Foliage from legume trees as multipurpose supplements
Implications of strategic supplementation for lifetime productivity
Improving productivity through enhancing digestibility of crop residues
Enhanced digestibility of straw by manipulation of rumen function

R.A Leng T.R. Preston R. Sansoucy and P.J. George Kunju

Dr Leng is a professor in the Department of Biochemistry, Microbiology and Nutrition, University of New England, Armidale, Australia. Dr Preston is Scientific Adviser, Fundación para el Desarrollo Integral del Valle del Cauca, Cali, Colombia. Mr Sansoucy is Senior Officer, Feed Resources Group, Animal Production and Health Division, FAO, Rome, and Dr George Kunju is Senior Project Executive, National Dairy Development Board, Anand 388001, India.

The effects on ruminants of imbalanced nutrient supply, in particular fermentable nitrogen and protein, include low calving, low birth weight, high calf mortality, low weaning weight and reduced milk production. To increase productivity of cattle, alternative nutritional practices should be developed by the smallholder in developing countries. These should include feed supplementation by use of multinutrient blocks containing fermentable nitrogen and other microbial growth factors; the enhancing of digestibility of crop residues; and that of straw by the manipulation of rumen function.

Introduction of such technologies is especially appropriate to smallholders who do not have easy access to extension services.

The major feed resources for large ruminants in developing countries tend to be low in nitrogen and of low digestibility. In South Asia, for example, crop residues are the staple feed all year round, supplemented to a varying degree by grazing and/or harvested grasses, weeds and tree foliage.

In Africa, grazing, usually on communal lands, is the dominant feeding system and nutritive value is not a constraint when there is rain, but during the extended dry season the mature tropical grasses (standing hay) resemble crop residues in their chemical composition and nutritive value.

The principles underlying the efficient use of fibrous crop residues and standing hays by large ruminants are now well understood. The first constraint to their better utilization is the imbalance in the nutrients made available from rumen fermentative digestion and not their low digestibility per se (Preston and Leng, 1984, 1986).

The efficiency with which these feeds are utilized can be markedly increased by a feeding strategy aimed to:

· create an efficient ecosystem for fermentative digestion of fibre in the rumen; and

· balance the products of the fermentative digestion with by-pass (or escape) nutrients of dietary origin in order to optimize the use of the available energy for productive purposes.

1. Effect of continuous supply of urea (150 g/day) on the intake and digestibility of oat straw

Influence d'une fourniture continue en urée (150 g/jour) sur la consommation et la digestibilité de la paille d'avoine

Efecto del suministro constante de urea (150 g/día) sobre la ingestión y la digestibilidad de la paja de avena


Straw + urea

Digestibility of dry matter (%)



Intake of straw (kg/d)



Source: Campling, Freer and Balch, 1962.

2. Response to urea supplements (with/without sulphur) by cattle and sheep maintained during pregnancy on mature pasture hays

Réponse à des supplémentations en urée (avec ou sans soufre) de vaches et brebis nourries de foin provenant de pâturage sec pendant la gestation

Respuesta a los suplementos de urea (con y sin azufre) de vacunos y ovinos mantenidos a base de heno de pasto maduro durante la preñez


Cattle 1

Sheep 2

No suppl.


No suppl.


Birth weight (kg)





1 Source: Lindsay, Mason and Thomas, 1982.
2 Source: Stephenson, Edwards and Hopkins, 1981.

3. Effect of feeding urea/sulphur and by-pass protein on hay intake (45% digestible, 0.4% N), and live weight of growing and pregnant cattle

Influence de la supplémentation en urée/soufre et protéines digestibles au niveau de l'intestin sur la consommation de foin (45% digestible, 0,4% N) et la prise de poids de bovine en croissance et de vaches pleines

Efecto de la administración de urea/azufre y proteína digestible en el intestino sobre el consumo de heno (45% digestible, 0,4% N) y sobre el peso vivo de vacunos en fase de crecimiento y vacas preñadas


Hay intake (kg DM/d)

Live-weight change (kg/d)

Growing cattle (170 kg live weight)







Urea plus by-pass protein (500 g/d)



Pregnant cattle (last 60 days)







Urea/sulphur plus by-pass protein (1 kg/d)



4. Live weight and conception rates of lactating beef cows grazing native pasture with dry-season supplements

Poids vif et taux de conception de vaches de boucherie en lactation, sur pâturages naturels et recevant un supplément en saison sèche

Peso vivo y porcentaje de concepción de vacas de come en lactación alimentadas a base de pasto nativo con suplementos en la estación seca

Supplement (to 12 cows) 1

Live weight (kg)

Pregnancy (%)




Energy concentrate 2 (1.85 kg)



Cottonseed meal (by-pass protein) (1.5 kg)



1 Source: Hennessy 1986.
2 Molasses 85% cottonseed meal 12.3%, urea 1.7% and mono-ammonium phosphate 1.0%.

5. A comparison of cattle (320 kg live weight) body weight change with treated or untreated rice straw 1 and by-pass protein meal

Comparaison entre les changements de poids de bovine (poids vif 320 kg) selon qu'ils reçoivent de la paille de riz traitée ou non et des tourteaux de protéines digestibles au niveau de l'intestin

Comparación del cambio de peso corporal de vacunos (320 kg de peso vivo) alimentados con paja de arroz tratada o no tratada y harina proteica digestible en el intestino

Supplement (protein meal)

Cattle growth rate (g/d) 2

Fed straw

Fed treated straw













Source Perdock and Leng, 1987 (unpublished).

1 Plus 0.5 kg molasses/urea block (15% urea) to supply fermentable-N and with 0.6 kg rice pollard to supply small amounts of starch and lipids.

2 Means that do not share a common superscript differ significantly (P<0.05).

To achieve these dual objectives, different classes of nutrients are needed. For the rumen ecosystem, the priorities are fermentable nitrogen, together with trace quantities of microbial growth stimulants such as peptides/amino-acids, minerals, vitamins and highly digestible fibre. Correcting the nutrient imbalance usually requires amino-acids, long-chain fatty acids and glucogenic precursors that arise respectively from protein, lipids and starch that by-pass the rumen fermentation.

This two-pronged approach is quite different from the traditional one of supplementing roughage with a balanced concentrate made from cereal grains and protein cakes/meals. While this strategy improved the nutrition of the animal, it ignored the role of the cellulolytic rumen micro-organisms and frequently depressed their activity.

The new strategy also counters the often stated assumption that fibrous feeds are energy-deficient. Optimizing the rumen ecosystem leads to increased rate of fibre digestion and increased rumen outflow of microbial protein, both of which stimulate the intake of the basal feed, with beneficial effects on the animal's energy status.

Supplementation and animal productivity

Animal response to supplementation is a function of the productive status of the animal and the nature of the supplement.

Improving the rumen ecosystem will raise the potential nutritive value of the ration and will bring about some improvement in animal performance, for example, increasing birth weight and reducing weight loss. However, it is the synergistic effect of combining rumen supplements with by-pass nutrients that leads to dramatic improvement in animal performance, especially for demanding traits such as milk production.

In promoting productivity of ruminants dependent on fibrous feeds of low digestibility and low nitrogen content, the key role of urea - to supply-fermentable nitrogen - and that of by-pass protein (Leng, Nolan and Kempton, 1977) - to supply amino-acids directly to the animal - are illustrated by research findings reported in Tables 1, 2, 3, 4 and 5, and in Figure 1.

Supplements providing only fermentable nitrogen, with or without sulphur, were effective in increasing digestibility and feed intake (Table 1) which is reflected in increased foetal growth (Table 2) and reduced live-weight loss in growing and pregnant animals (Table 3).

More demanding productive states such as conception (Table 4), growth and fattening (Table 5) and milk production (Figure 1) require by-pass nutrients as well as rumen activators. The responses to supplements providing nutrients for rumen micro-organisms are mediated-via increased rates of fibre digestion and an increased proportion of microbial protein in the digestion end-products. By-pass nutrients have their origin in dietary sources of protein, starch and fat, which give rise respectively to amino-acids, glucose and long-chain fatty acids. Amino-acids have a direct role as building blocks for tissue and/or milk proteins, and indirectly as glucogenic precursors. Glucose and/or its precursors are the sources of lactose in milk.

Fat is synthesized either from acetate, a process requiring the concommitant oxidation of glucose and/or its precursors, or directly from long-chain fatty acids. Since glucose and/or its precursors are always limiting nutrients in the end-products arising from fermentative digestion of low nitrogen fibrous feeds, there are obvious advantages in having a source of long-chain fatty acids available, such as rice polishings and oil-seed cakes, which effectively spare both glucose and amino-acids.

Sources of by-pass nutrients are essential for even a moderate growth rate (300-600 g/d) and milk production (4-6 l/day) on crop residues.

Practical constraints

The feeding of supplements rich in microbial and/or bypass nutrients, although highly beneficial, has not been widely accepted for several reasons:

· a natural reluctance among smallholder farmers and extensionists to feed urea because mistakes in the amount or in the way it is given can easily lead to deaths of animals from ammonia toxicity;

· local research is needed to identify appropriate supplements and to develop technologies for incorporating these in production systems;

· advisers continue to insist that crop residues and standing hays are energy deficient per se and that, therefore, supplements rich in carbohydrates, i.e. cereal grains, should be fed;

· there have been few attempts to prepare a supplement rich in the desired nutrients and to package this in a way that will facilitate its acceptance by smallholders.

There are now encouraging signs that these constraints are being overcome and that the "strategic supplementation" approach is beginning to have an impact at the smallholder level (Leng and Preston, 1983; Leng, 1984).

Multinutrient blocks

The National Dairy Development Board of India has successfully developed and introduced multinutrient blocks based on molasses and urea for dairy buffaloes kept by village smallholders. These blocks-provide, primarily for the needs of the rumen, micro-organisms rich in sources of fermentable nitrogen, minerals, vitamins, amino-acids and peptides. Rates of consumption of blocks are of the order of 500 g/animal/day for adult animals fed on rice straw under conditions of complete confinement. Responses have been apparent in terms of increased milk production at the same level of concentrate consumption, or the same level of production achieved with reduction in concentrate level (see Tables 6 and 7).

1. Milk yield of native and cross-bred cattle fed ammoniated (urea-ensiling) rice straw supplemented with fish-meal - Production laitière de vaches indigènes et croisées alimentées avec de la paille de riz traitée à l'urée et un complément de farine de poisson - Producción de leche de vacunos autóctonos y mestizas alimentados con paja de arroz (ensilaje con urea) amoniacada, complementada con harina de pescado

Source: A. Saadullah 1984

2. Growth rate of weaner cattle increases curvilinearly in accordance with the proportion of legume forage Gliricidia sepium in a basal diet of king grass - Le taux de croissance des bovines sevrés augmente de façon curvilinéaire avec la proportion de légumineuses fourragères (Gliricidia sepium) de la ration, l'alimentation étant à base de lespedeza du Japon (king grass) - La tasa de crecimiento de los vacunos destetados aumenta de manera curvilínea de acuerdo con la proporción del forraje de leguminosas (Gliricidia sepium) en una dieta basal de rabo de ratón

Blocks distributed to transhumant herds Senegal - Distribution de blocs aux troupeaux transhumants au Sénégal - Bloques distribuidos a hatos trashumantes en el Senegal

Photo/Foto: R. Sansoucy

Ingredients commonly used in the formulation of multinutrient blocks in Senegal. From left to right: molasses, common salt, urea, cereal bran and quicklime - Ingrédients communément utilisée pour la formulation des blocs multinutritionnels au Sénégal. De gauche à droite: mélasse, sel de cuisine, urée, son de céréale et chaux vive - Ingredientes utilizados habitualmente en la formulación de bloques de multinutrientes en el Senegal. De izquierda a derecha: melaza, sal común, urea, salvado de cereales y cal

Multinutrient blocks are now finding ready acceptance in Africa by pastoralists as well as by small milk producers (Sansoucy, 1986; Sansoucy and Aarts, 1987).

The data in Tables 8 and 9 confirm the economic benefits of using blocks as a partial substitute for, or as a complement to, protein-rich oil-seed cakes. Positive effects of multinutrient blocks on the performance of grazing sheep have also been reported from Ethiopia (Negussi and Anderson, personal communication, 1986).

Balancing nutrient supply to the animal

The practical application of the second component of the supplementation strategy is less advanced, at least in its intended restricted format.

Traditional concentrates are usually based on cereals and the by-products of the cereal and oil-seed milling industries. Therefore, they provide the required range of by-pass nutrients - protein, long-chain fatty acids and glucogenic precursors. However, they frequently contain excessive proportions of readily fermentable proteins and carbohydrates which can depress the activity of cellulose-digesting micro-organisms, the consequence of which is usually the partial substitution of the basal fibrous feed by the concentrate. Thus, the benefits of by-pass nutrients are counteracted by the negative effects of a less efficient rumen fermentation.

The pressing need is to develop supplements that are predominantly composed of by-pass nutrients either for feeding alone, or in a combined package with a source of rumen nutrients.

The feedmills established by the National Dairy Development Board of India have made some progress in this respect by formulating their concentrate feeds with a high content of cottonseed meal. In Latin America and the Caribbean, and to some extent in Asia, the problem has been tackled by promoting the feeding of limited amounts of rice polishings with chemical and physical properties that make them an ideal source of by-pass nutrients. Rice polishings contain 10-12 percent of lipids, 10-12 percent of protein of high biological value and up to 50 percent of starch.

There are reports that most of the starch and protein escapes rumen fermentation (Elliott et al., 1978a, b), a process facilitated by the protective action of the oil and the fact that much of the starch is present as broken rice grains. The dramatic effects of small amounts of rice polishings on the performance of cattle fed ammoniated rice straw and steam-hydrolysed sugar-cane bagasse are shown in Table 10. As a result, rice polishings are the supplement of choice in commercial feeding systems in Colombia using these feed resources (Preston, personal communication, 1987).

An even better source of by-pass nutrients is the milk taken by suckling. Farmers in developing countries have long recognized its importance, as witnessed by the practice of permitting the calf to have restricted access to the dam throughout the lactations. Suckled milk is converted to live weight more efficiently than milk "from a bucket", which can be explained partially by the stimulating effect of suckling on the closing of the oesophagal groove (Orskov, 1983). This ensures that the valuable fat, lactose and protein in the milk completely escape the rumen fermentation.

The belated recognition of the advantages of dual-purpose systems of cattle production (ICA/CIAT, 1987), in which restricted calf suckling is an integral component, reflects in part an increased understanding by scientists of the extra value of suckled milk to complement the nutrients arising from rumen digestion of fibrous crop residues and mature pastures.

Foliage from legume trees as multipurpose supplements

A recent development in supplementation strategies is the use of foliage from forage trees, particularly the leguminous species, of which Leucaena leucocephala has been most promoted (Jones, 1979). However, recent developments indicate that Gliricidia septum and Erythrina spp. offer even greater potential. Compared with Leucaena, they are more widely distributed, are easier to establish and are more resistant to diseases. Fed at about 30 percent of the diet dry matter, they appear to provide both the rumen fermentable nitrogen and by-pass protein needed to balance a low-protein tropical grass (see Figure 2).

The presence of antinutritional factors, especially phenolic compounds, in tree foliages in general probably enhances their usefulness as supplements since, besides their protective action on proteins, these substances may exert other beneficial effects as natural toxins against parasites, including possible rumen protozoa.

It is expected that the use of forage trees as strategic supplements will increase substantially in the future, in view of their multipurpose role as components of land conservation programmes and as renewable fuel sources.

Implications of strategic supplementation for lifetime productivity

The effects of periods of unbalanced nutrient supply, particularly of protein and fermentable nitrogen, are a low calving percentage, low calf birth weight, high calf mortality rates, low weaning weight, stunted body size, late sexual maturity and reduced milk production in cattle and buffaloes. Part of the problem stems from the demand by humans for the limited milk production, which severely restricts the amount that calves are allowed to consume. Without alternative sources of the by-pass nutrients provided by milk (protein, lactose and fat), the calf uses its basal feed inefficiently and its growth rate is markedly reduced.

Growth and development are further slowed by periods of unbalanced nutrition because of seasonal rainfall and, in the case of cattle in the tethered husbandry systems, dependence on crop residues as the major feed resources. This sets a spiral of events in motion, the most obvious end-effect of which is reduced mature body size. It is also probable that the periods of unbalanced nutrition result in other functions being permanently impaired, including reproductive abilities and mammary gland development and subsequently potential milk production. The reported inferiority of indigenous breeds compared with introduced genotypes is often a reflection of the confounding effect of undernutrition and not simply due to the genotype per se.

6. Effect of multinutrient blocks on straw intake and buffalo milk production

Influence des blocs multinutritionnels sur la consommation de paille et la production de lait de bufflonne

Efecto de los bloques de multinutrientes sobre el consumo de paja y la producción de leche de búfala







Block (±)





Cottonseed cake





Straw DM intake





Fat-corrected milk





Source: George Kunju et al. 1983 (personal communication)

7. The effects of introducing molasses/urea blocks on milk and fat production by buffalo 1

Influence de l'introduction de blocs de mélasse/urée sur la production de lait et de matière grasse des bufflonnes

Efectos de la introducción de bloques de melaza/urea sobre la producción de leche y de grasa de las búfalas


Average milk yield (kg/d)

Average milk fat (g/d)

No block 2

With block

No block 2

With block































1 In smallholdings in villages of the Kaira District, Gujarat, India (George Kunju, 1986).
2 Prior to blocks being made available in the village.

8. Effect of supplementary multinutrient blocks and oil-seed cake on milk yield and live-weight change

Influence de l'introduction dans l'alimentation de blocs multinutritionnels et de tourteaux oléagineux sur la production de lait et la prise de poids

Efectos de la administración de bloques de multinutrientes y de torta de semillas oleaginosas sobre la producción de leche y el cambio de peso vivo de vacas mestizas


Cross-bred cows fed basal diet of low-N mature grass hay


Oil-seed cake





Block (±) (700 g/cow/d)





Milk yield





Live-weight change





Source: Preston and Mean, 1986.

9. Mean values for live-weight change feed intake and feed conversion in diets of old draught oxen

Variations moyennes de poids, consommation de nourriture et conversion alimentaire chez de vieux bœufs de trait recevant une ration à base de paille de blé et des suppléments

Valores medios del cambio de peso vivo, consumo de pienso y transformación de piensos en dietas de bueyes de tiro viejos

Oxen fattened on basal diet of wheat straw and supplements


Urea/molasses block



Live weight (kg)






Daily change 1





Feed intake 2 (kg/d)


























Feed conversion 2





Source: H. Soller, ILCA (unpublished). Data refer to 55-day trial.
1 SE of mean = ±0.065.

10. Effect of dietary supplementation with rice polishings on growth rate of cattle

Influence de la complémentation en farine basse de riz sur le taux de croissance de bovins

Efecto de la dieta suplementaria con salvado de arroz sobre el ritmo de crecimiento de vacunos

Cattle fed basal diet of bagasse/bagasse pith predigested with high-pressure steam


Rice polishings


Live-weight gain

Bagasse pith


400 1



500 1

Ammoniated rice straw


550 2

Source: CIPAV, 1987.
1 300 g/d rice polishings.
2 500 g/d rice polishings.

The key to increasing the productivity of cattle under smallholder management in developing countries is to develop alternative nutritional strategies which take account of:

· the nutrients available in local feed resources and seasonal effects on these;

· the competition for milk from humans and calves;

· the need to provide supplements to correct the nutrient imbalances brought about by the effects of the two preceding points.

Improving productivity through enhancing digestibility of crop residues

Once the upper level of improvement in the efficiency of feed utilization has been reached by supplementation, any further increases in production can only be achieved by raising the digestibility of the basal diet and increasing the turnover rate in the rumen.

It is known that some 80 percent of even mature, dry roughages and crop residues are potentially fermentable. However, a considerable proportion is protected from microbial fermentation by the formation of ligno-cellulose bonds or by physical exclusion of microbes by the lignin that covers the fermentable substrate. With sorghum straw, the presence of high levels of phenolics apparently reduces digestibility.

Physical and chemical treatments are available for improving the potential rate and extent of digestion of crop residues. Ammoniation, through the use of anhydrous ammonia or urease-induced hydrolysis of urea, appears to be the most practicable. Strategic supplementation is equally, if not more, important when ammoniated straw is the basal diet (see Table 10).

Enhanced digestibility of straw by manipulation of rumen function

Increasing the digestibility of straw by ammoniation requires relatively expensive inputs in materials such as urea, anhydrous ammonia and plastic sheets, as well as human resources. Up to now, relatively small numbers of smallholders in developing countries have used these methods. However, there is a growing use of multinutrient blocks by farmers in India and great interest in these is being shown in Africa and Latin America. FAO has in fact received requests for assistance in this technology from about 50 countries.

Manufacture and distribution of multinutrient blocks and their ready acceptance by farmers provide a unique opportunity to manipulate indirectly many aspects of the nutrition and health of animals in smallholdings. For instance, by incorporating a small amount of highly digestible fibre in the block, such as the foliages from leguminous forages and trees, it should be possible to stimulate the digestion of dry matter in the basal diet (Silva and Orskov, 1985; Romulo, Bird and Leng, 1986). This opens up an area of research of great relevance and application to small farmers who have recognized for centuries the benefits of adding small quantities of green forages to crop residue-based diets for cattle and buffalo. Making available to rumen microbes small quantities of amino-acids and peptides, through the addition of some protein in the multinutrient blocks, also appears to have beneficial effects on straw digestibility (Sudana and Leng, 1986).

A simple concrete mixer is used for mixing different ingredients in Burkina Faso - Une simple bétonneuse sert a mélanger les différents ingrédients au Burkina Faso - Para mezclar los distintos ingredientes, en Burkina Faso se utiliza una sencilla hormigonera

Photo/Foto: G.P. Levieux

The production unit for molasses-urea blocks in Burkina Faso. Wooden moulds are shown in the foreground - Unité de production de blocs de mélasse-urée au Burkina Faso. Au premier plan, des moules en bois - Instalaciones pare la producción de bloques de melaza-urea en Burkina Faso. En la parte anterior se observan moldes de madera

Photo/Foto: G.P. Levieux

Metallic moulds are used for the preparation of blocks in the Sudan - Moules métalliques utilisés pour la préparation des blocs au Soudan - En el Sudan se utilizan moldes metálicos pare la preparación de los bloques

Photo/Foto: R. Fuller

Multinutrient block used by small farmers in India - Blocs multinutritionnels utilisés par les petits éleveurs en Inde - Bloque de multinutrientes utilizado por los pequeños agricultores en la India

Photo/Foto: P.J. George Kunju

Rumen function can also be improved by manipulating the microbial population. The elimination of protozoa from the rumen of sheep fed straw-based diets increased dry matter digestibility to the same extent as anhydrous ammonia treatment (Romulo, Bird and Leng, 1986; Bird and Leng, 1985). Theoretically, therefore, control of rumen protozoa could give rise to similar increases in productivity as chemical hydrolysis. Associated benefits when protozoa were excluded from the rumen were increases in wool growth in sheep (Bird and Leng, 1983) and increases in live-weight gain of cattle (Bird and Leng, 1978). In all cases, the responses to defaunation were associated with the feeding of basal diets of low-protein content, suggesting that elimination of rumen protozoa might reduce the need for supplementation with by-pass protein. If and when an antiprotozoal agent is developed, the multinutrient block would be a convenient and perhaps the only way of administering it to ruminant animals on smallholder farms.


The strategic use of multinutrient blocks containing fermentable nitrogen and other microbial growth factors, and feed supplements rich in by-pass protein, lipids and starch, has great application in many developing countries where crop production is the major agricultural activity, or where pastoral economies are subject to prolonged dry seasons. The effects of this two-pronged approach are synergistic, with positive responses being elicited in the rate of rumen digestion, feed intake and on the balance of nutrients made available for metabolism.

Future research may reveal opportunities for using supplements as vehicles for other interventions, such as control of rumen fermentative digestion and of internal parasites. The technology is especially suited to the introduction of improved nutritional practices on smallholder farms which are not easily accessible to conventional extension services.


Bird, S.H. & Leng, R.A. 1978. the effects of defaunation of the rumen on the growth of cattle on low-protein high-energy diets. Br. J. Nutr., 49: 163-167.

Bird, S.H. & Leng, R.A. 1983. The influence of the absence of protozoa on ruminant production. In D.J. Farrell, ed. Recent advances in animal nutrition in Australia, p. 111-118. Armidale, University of New England.

Bird, S.H. & Leng, R.A. 1985. Productivity responses to eliminating protozoa from the rumen of sheep. In Biotechnology and recombinant DNA technology in the animal production industries, p. 109-117. Reviews in Rural Sciences No. 6. Armidale, University of New England.

Campling, R.C., Freer, M. & Balch, C.C. 1962. Factors affecting the voluntary intake of food by cows. 3. The effect of urea on the voluntary intake of straw. Br. J. Nutr., 16: 115-124.

CIPAV. 1987. Informe Técnico. Desarrollo de sistemas alimentarios en base a residuos agrícolas y agroindustriales. Convenio Interinstitutional para la Producción Agropecuaria en el Valle del Río Cauca, Cali, Colombia.

Elliott, R., Ferreiro, H.M., Priego, A. & Preston, T.R. 1978a. Rice polishings as a supplement in sugarcane diets: the quantities of starch (glucose polymers) entering the proximal duodenum. Trop. Anim. Prod., 3: 30-35.

Elliott, R., Ferreiro, H.M., Priego, A. & Preston, T.R. 1978b. Estimate of the quantity of feed protein escaping degradation in the rumen of steers fed chopped sugarcane, molasses-urea supplemented with varying quantities of rice polishings. Trop. Anim. Prod., 3: 36-39.

George Kunju, P.J. 1986. Urea-molasses block lick: a feed supplement for ruminants. In Rice straws and related feeds in ruminant rations. Proc. Int. Workshop, Kandy, Sri Lanka, 1986, p. 261-274.

Hennessy, D.W. 1986. Lactational anoestrus in first-calf heifers grazing native pastures in the sub-tropics. Proc. Australian Soc. Anim. Prod., 17.

ICA/CIAT. 1987. Memorias del seminario internacional sobre sistemas de doble propósito en el trópico. 1986. Cali, Colombia,

Jones, R.J. 1979. The value of Leucaena leucocephala as a feed for ruminants in the tropics. Wld Anim. Rev., 31: 13-23.

Leng, R.A. 1984. The potential for solidified molasses-urea blocks for the correction of multinutritional deficiencies in buffaloes and other ruminants fed low quality agro-industrial by-products. In The use of nuclear techniques to improve domestic buffalo production in Asia, p. 135-150. Vienna, International Atomic Energy Agency.

Leng, R.A., Nolan, J.V. & Kempton, T.J. 1977. Non-protein nitrogen and by-pass proteins in ruminant diets. AMPC Review, 33: 1-21.

Leng, R.A. & Preston, T.R. 1983. Nutritional strategies for the utilization of agro-industrial by-products by ruminants and extension of the principles and technologies to the small farmer in Asia. Fifth World Conference on Animal Production, Tokyo, Japan, p. 310-318.

Lindsay, J.A. & Loxton, I.D. 1981. Supplementation of tropical forage diets with protected proteins. In Recent advances in animal nutrition in Australia, Abstract 1A. Armidale, University of New England.

Lindsay, J.A., Mason, G.W.J. & Thomas, M.A. 1982. Supplementation of pregnant cows with protected proteins when fed tropical forage diets. Proc. Australian Soc. Anim. Prod, 14: 67-78.

Orskov, E.R. 1983. The oesophagal groove reflex and its practical implications in the nutrition of young ruminants. In Maximum livestock production from minimum land, p. 47-53. Mimensingh, Bangladesh Agricultural University.

Preston, T.R. & Leng, R.A. 1984. Supplementation of diets based on fibrous residues and by-products. In Straw and other fibrous by-products as feed, p. 373-413. Amsterdam, Elsevier Press.

Preston, T.R. & Leng, R.A. 1986. Matching livestock systems to available feed resources. Addis Ababa, ILCA.

Romulo, B., Bird, S.H. & Leng, R.A. 1986. The effects of defaunation on digestibility and rumen fungi counts in sheep fed high fibre diets. Proc. Australian Soc. Anim Prod., 16: 327330.

Saadullah, M. 1984. Studies on utilisation of rice straw by cattle. Copenhagen, Royal Veterinary University.

Sansoucy, R. 1986. The Sahel: manufacture of molasses-urea blocks. Wld Anim. Rev., 57: 40-48.

Sansoucy, R. & Aarts, G. 1987. Molasses-urea blocks as multinutrient supplement for ruminants. Proc. FAO Expert Consultation on Sugar Cane as Feed, Santo Domingo, Dominican Republic, July 1986. Rome, FAO.

Silva, A.T. & Orskov, E.R. 1985. Effect of unmolassed beet pulp on the rate of straw degradation in the rumen of sheep given barley straw. Proc. Brit. Nutr. Soc., 44: abstract 50A.

Stephenson, R.C.A., Edwards, J.C. & Hopkins, P.S. 1981. The use of urea to improve milk yield and lamb survival of Merinos in a dry tropical environment. Australian J. Agric. Res., 32: 497-509.

Sudana, I.B. & Leng, R.A. 1986. Effects of supplementing a wheat straw diet with urea or a urea-molasses block and/or cottonseed meal on intake and live-weight change of lambs. Anim. Feed Sci. and Technol., 16: 15-35.

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