The Control and Manipulation of Rumen Fermentation

The loss of energy which occurs in the rumen fermentation can be very appreciable (Czerkawski, 1969) and it is therefore not surprising that efforts are being made to find ways of manipulating the fermentation to minimise this loss. The area has been reviewed by Marty, (1972), Demeyer and Van Nevel (1975) and Czerkawski (1969). In addition to the energy consideration a number of conditions exist, where the pattern of the major fermentation products, the short chain fatty acids. are unbalanced in terms of animal needs. In the high producing dairy cow a fine balance obtains between the needs for glucose and consequently glucose precursors for milk production (Blaxter, 1967) and the effects of excess of these on milk fat content (Jorgensen, Schultz & Barr, 1965; McCullough, 1966). Very high rates of growth in ruminants have generally been associated with rumen fermentations giving elevated proportions of propionate. Ishaque, Thomas and Rook (1971) have obtained an augmented flow of microbial protein at the level of the duodenum associated with high propionate proportions in the rumen. The rumen fermentation through the production of microbial protein constitutes a major source of essential amino acids to the animal. Possible objectives in altering the fermentation may be: