The discussion in Chapter 3 highlights the areas and suggest priorities for application and continuing research for improving animal production from the available feed resources for livestock in developing countries. The targets are:—
Maximisation of P/E ratio in Nutrients Absorbed from the Rumen
Some methods/techniques to do this are listed below:—
by combinations of minerals, non-protein nitrogen and protein supplementation to support high efficiencies of rumen fermentation
improve microbial growth efficiency by manipulating the microbial populations
to obtain more efficient microbes
to remove protozoa
to adjust the P/E ratio with feed additives
to alter the genetic capacity of the microbes to synthesise protein or to produce higher biological value proteins
improve dietary protein bypass. Where protein is fed, to decrease protein and/or peptide and/or amino acid degradation in the rumen and allow a greater flow of amino acids, peptides and protein to the intestines from dietary origin
development of sources of supplements of protein meals that have natural protection or are manipulated to escape rumen fermentation. This includes the need to:—
identify protein sources that are protected naturally or in processing
identify soluble protein sources and find economic and viable mechanisms for protection of the proteins
develop protein crops or by-products that can be grown and processed at the site of ruminant population densities in countries where protein meals are scarce
develop rumen manipulation studies to enhance the bypass of soluble proteins.
Maximisation of Digestibility of Fibrous Feeds
This is achieved by:—
providing supplements of essential nutrients required by microbes
manipulating microbial populations in the rumen to increase digestibility
promote populations of selected, highly fibrolytic fungi in the rumen
defaunation
treatment of crop residues prior to feeding to enhance their digestibility
altering the physiology of the digestive tract (e.g. rumen mobility, turnover etc.) e.g. through the use of immunisation of somatotropin release inhibiting factor (SRIF).
Optimising the Partitioning of Nutrients into Product
This includes:—
by breeding more efficient animals
chemical intervention—hormonal implants or injections
injections of compounds such as B-agonists, bovine growth hormone
development of transgenic animals with particular characteristics e.g. high circulating BSt or enzymes complements previously not present in animals.
Assigning priorities within this list is a most important aspect of this report. Clearly the research requires a differing level of sophistication of technology and different priorities will need to be assigned to different resource bases. Simply stated, the priority ratings for research emphasis are in order of priority:—
to ensure an adequate P/E ratio in nutrients absorbed
to improve the extent of digestion of low digestibility feeds that require microbial fermentation for digestion
to improve the partitioning of available nutrients for product synthesis (meat, milk, wool etc.) or drought power generation.
It is clear that an inadequate nutrition will not allow the expression of any manipulations in priority (3). It is also obvious that a super bug cannot be successful in the rumen that is deficient in critical nutrients (for example, ammonia).
