An earlier ACIAR project on this topic (No. 8203) successfully promoted the use of urea and other rumen activators to aid fermentative digestion of cereal crop residues by cattle and buffalo on Indian smallholdings, and showed that development of a multinutrient block is a useful first step in such supplementation. Research in India and Australia has also demonstrated the vital role of catalytic bypass protein and other nutrients, particularly oil-seed meals, in increasing ruminants' productivity.

The present project will further develop this approach - through research to maximise the efficiency of rumen fermentative digestion by manipulating the rumen ecosystem together with investigations of the critical nutrients needed, in terms of animal response and cost effectiveness. It will include field testing, validation and evaluation of the resulting strategies before these are packaged for use by the target group of Indian smallholders. Its goals will include increases in: growth rate (with consequent earlier sexual maturity); conception rate; calf birth weights and hence survival rates; milk yields per cow; and mature body size (with major implications for draught animal power).

To this end, scientists at Hissar will conduct feeding trials on strategic supplementation combined with cost-benefit analyses, and develop related rumen studies in collaboration with Haryana Agricultural University. Those at Izatnager and Karnal will undertake rumen metabolism studies on factors that increase digestibility of cereal crop residues as well as the balance of nutrients - also with feeding trials and cost-benefit analyses - and longer-term studies into manipulation of the ruminal bacterial, fungal and protozoan populations. Concurrently, scientists at Armidale will carry out parallel studies of microbial interactions, define nutrient requirements, examine feed factors that reduce digestibility and find means of overcoming these adverse effects.

Investigations of critical nutrients will cover supplementation, assay of bypass proteins and acetate clearance. Scientists manipulating the rumen ecosystem will use nylon bags and isotope dilution procedures to study the rumen's efficiency and its microbial populations and use fistulated animals for intensive studies of defaunated buffalo. They will identify anti-protozoal feeds and monitor these for their potential toxic effects. Digestibility studies will also utilise the nylon bag as the major technique for investigating the effects of various supplements such as urea, sulfur and soluble proteins on the digestibility of straw-based diets.

Close exchange of information among the four institutes will co-ordinate the research, and the National Dairy Development Board will take part in field testing under village conditions. Tesing and validation will be undertaken at both institutional and village levels.

Since the vast majority of large ruminants in India are owned by smallholders, even moderate increases in productivity per head should lead to large increases in national milk production, with advantages for both rural and urban populations.