Concern about mimosine toxicity and its management has contributed to the restricted adoption of leucaena as a forage for ruminants. The toxicity is a function of the antimitotic effects of mimosine, which is rapidly converted to isomers of hydroxypyridone (DHP), also toxic compounds, by plant and microbial enzymes. Work by R.J. Jones and colleagues (1960-1994) identified a rumen bacterium (Synergistes jonesii) capable of degrading DHP, and rumen fluid containing this bacterium was subsequently made available in Australia as a commercial inoculum for cattle producers.Research by University of Queensland and CSIRO over 15 years, commencing in 2003, found evidence for another pathway of toxin management in Indonesia, where hundreds of Balinese farmers had fed uninoculated Bali bulls (Bos javanicus) up to 100% leucaena without experiencing toxicity symptoms, apart from an initial 1-2 week period while their cattle became adapted to the new diet. Tests showed that the Indonesian cattle were not degrading all DHP, as it appeared in high concentrations in urine samples, predominantly as 2,3-DHP and almost all (>97%) in a conjugated form. The conjugating compounds (glucuronic acid and sulfate compounds), produced in the liver, appeared to be the major pathway for neutralizing the toxicity of DHP. Other work revealed that S. jonesii was a ubiquitous organism in the rumen fluid of animals in all countries but always as a minor population, just detectable using new PCR-based assays, and sometimes not detected in all animals studied.Since the Indonesian cattle fed leucaena suffered symptoms of mimosine toxicity for only a short time before quickly recovering, we hypothesize that conjugation of DHP by the liver was the major detoxification pathway for these animals. This detoxification pathway is also operative in Australia and other countries but further studies are needed to determine its significance.

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An update on leucaena toxicity: Is inoculation with Synergistes jonesii necessary?

In tropical and subtropical regions, as well as in the internal and/or marginal Mediterranean areas, one of the most important problems related to animal production is represented by the inadequate nutritional supplies. The low productivity of the animals, often connected to reduced annual growth, is, in fact, not infrequently attributable to the low nitrogen content and the high fiber content of the local plant species and crop residues that constitute the base ingredients of the rations commonly adopted by farmers. The use of the supplementation with arboreal and shrub fodder, although often containing anti-nutritional factors and toxins that limit its use, could be a profitable way to alleviate the nutritional deficiencies of the basic diets. Leucaena leucocephala (Lam.) De Wit is native to Central America and widely naturalized in the majority of Latin American countries. It is a legume suitable for tropical and subtropical environments including the countries of the Mediterranean area. Moreover, its spread is desirable if we consider the multiple uses to which it is suitable, the considerable amount of biomass produced, and its role in preserving the environment. The aim of this work was to highlight the characteristics of Leucaena that can justify its wide diffusion. A structured analysis of strengths and weaknesses was performed accordingly. Being a good protein source for feeding livestock, it could be a species to be introduced in the inland areas of the Mediterranean countries as an alternative protein source; the limit represented by the presence of anti-nutritional factors could be overcome by feed processing and by launching targeted research programs.

A Multipurpose Leguminous Plant for the Mediterranean Countries: Leucaena leucocephala as an Alternative Protein Source: A Review

Research and government agencies in eastern Indonesia have identified 2 systems with potential to increase productivity and incomes of small-holder cattle producers: improved cattle feeding practices through forage tree legumes (FTL); and the development of more efficient and specialized cattle-fattening systems. Extensive research has been conducted on production and technical aspects of FTL-fattening systems, but there is a gap in research on economic incentives for households to adopt the systems. This paper provides an economic analysis of a leucaena-fattening system in a village in West Timor. It draws on trial data from associated technical research projects and detailed semi-structured interviews with farmers and other stakeholders to populate a bio-economic model built for the research. Under all measures of profitability, leucaena-fattening systems in representative households are profitable in the wet season. Importantly, 'returns to person days' are higher than off-farm incomes. The activity generates cash income, increasingly required to meet cash expenses in modern rural Indonesian society. However, returns vary considerably between households, are considerably lower in the dry season and, as would be expected, are sensitive to relative prices of feeder and finished cattle.

Economic analysis of cattle fattening systems based on forage tree legume diets in eastern Indonesia

A review on bioenergetic applications of Leucaena leucocephala

Poster presented at the International Leucaena Conference, 1‒3 November 2018, Brisbane, Queensland, Australia.

Seasonal growth of Leucaena leucocephala cv. Tarramba in dry land of west Sumbawa, Indonesia

Leucaena has been fed to cattle by the Balinese community in Sumbawa and West Sumbawa districts on Sumbawa Island since the 1980s. However, prior to 2011, this practice was not adopted by the local Sumbawanese farmers. Since then, a model leucaena-based cattle fattening system was developed in Sumbawa and West Sumbawa districts in a collaborative research project between the Assessment Institute for Agricultural Technology (BPTP), University of Mataram and The University of Queensland (UQ) funded by the Australian Centre for International Agricultural Research (ACIAR), followed by a scaling-out project involving collaboration between the University of Mataram and CSIRO (Applied Research and Innovation Systems in Agriculture - ARISA project) funded by DFAT (Department of Foreign Affairs and Trade) promoting public-private partnerships. Further promotion of leucaena-based fattening systems occurred in Dompu, Sumbawa, through a project with the University of Mataram and Massey University funded by the New Zealand Ministry of Foreign Affairs and Trade (MFAT). By the end of October 2018, more than 2,500 farmers on Sumbawa Island were practicing leucaena-based cattle fattening. The main drivers of adoption of cattle fattening with leucaena were: (1) The high growth rates achieved (0.4-0.6 kg/d for bulls fed 100% leucaena and 0.66 kg/d when maize grain was added to the leucaena basal diet) compared with 0.16 kg/d for the traditional system, combined with high profitability; (2) the needs of farmers being met in terms of relevance and cultural appropriateness; (3) field extension staff being well trained and mentored, and respected by the farmers; (4) the local government being highly supportive of leucaena-based cattle fattening; and (5) additional benefits being increased dressing percentage and high carcass quality. The rapid increase in the use of leucaena for cattle fattening in eastern Indonesia is expected to have a significant positive impact on household incomes as well as on regional economic growth.

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Steve T. Morris

Papers

Adoption of leucaena-based feeding systems in Sumbawa, eastern Indonesia and its impact on cattle productivity and farm profitability