Improved ruminant production through the efficient use of tannin containing shrub legumes

• Balai Penelitian Ternak, Indonesia
• University of Adelaide, Australia

In many tropical regions of Australia, Indonesia and other parts of Southeast Asia, animal production is greatly restricted by the lack of protein in the animals' diets. A lack of protein rich feed in the wet season limits weight gain and reproductive potential and a lack of sufficient quality and quantity of feed in the dry leads to significant weight losses. This feed problem results in longer times for animals to reach marketable weight, a lower quality product and reduced reproductive efficiency.

Rapid growth rates have been sustained in dry tropical regions, without the use of expensive supplements or crop fertilisers, using the shrub legume Leucaena leucocephala. The high feed value of this plant appears to be due to its moderate tannin content (3-6%) which is thought to protect the protein from digestion in the rumen making it available for digestion and absorption the animals' small intestines.

To meet the rapidly rising demand for beef, Indonesia needs to produce an extra 400,000 cattle by the turn of the century. This project will assist in meeting this demand, improving growth rate and reproductive efficiency in village beef production in Eastern Indonesia through the use of tannin containing shrub legumes in feed.

There is a need to identify shrub legumes which can replace leucaena as a nutritious feed supplying rumen-protected protein, due to attack by the leucaena psyllid and the unsuitability of this plant to more acidic soils.

The methods used in this project include:

develop tannin-containing shrub legumes as components of pastures to increase the growth rates of young cattle and the quality of the meat, and to improve the cattle's reproductive performance;

characterise the tannin profile of a range of shrub legumes most suitable for animal production under the cut-and-carry feeding strategy common in the region and to extrapolate this information to other plant species;

understand the interaction between tannins and micro-organisms in the rumen;

manipulate the microflora in the rumen of animals to increase the availability of proteins by controlling the tannin-protein interactions. Micro-organisms isolated from the rumens of a range of animal species will be characterised and evaluated for their ability to improve animal production;

assess co-feeding of shrub legumes Gliricidia and Acacia/Calliandra as an alternative strategy for maintaining high quality feeds while minimising the effects of high tannin content. The effects of high tannin levels will be reduced by addition of poly ethylene glycol, by co-feeding with non-tannin-containing shrub legumes and by transferring tannin-active organisms from the rumens of a range of animals with high tannin diets.