Metabolisable energy fermentable

Microbial protein contributes towards satisfying this demand. The yield of microbial crude protein is related to the energy available to the rumen microorganisms in terms of fermentable metabolisable energy ... 

There is some evidence (Fig. 16.4) that the efficiency of utilisation of metabolisable energy for milk production is influenced by the proportion of acetate in the fatty acids produced during rumen fermentation. 

The protein requirements of the rumen microorganisms are stated by AFRC (1993) in terms of effective rumen-degradable protein (ERDP). The requirement for ERDP may be calculated relative to the dietary intake of fermentable metabolisable energy (PME) and is defined as follows ... 

The application of the system to the formulation of rations is rather more complicated. The ration must first be formulated to meet the requirement for metabolisable energy. This allows the fermentable metabolisable energy content to be calculated. Only then may the requirement for ERDP be calculated. The ERDP and DUP status of the ration has then to be assessed and brought into balance. This is most simply done by formulating a supplement having the same FME concentration as the basal ration and the necessary ERDP and DUP concentrations. This is not an uncomplicated procedme. 

The daily requirement for degradable protein (ERDP) is given by (FME X 11) g, where FME (MJ/day) is the fermentable metabolisable energy intake. The contribution of dietary ERDP to satisfying metabolisable protein demand may be calculated, as for the cow, as 0.6375 X ERDP. 

ME = metabolisable energy, MP = metabolisable protein, N = nitrogen, NF = nitrogen fraction, NFF = non-fermentable fraction, PFF = potentially fermentable fraction, UDN = undegradable nitrogen, VFA = volatile fatty acids, WSC = water-soluble carbohydrates. 

Foods with high ME values tend to have higher k values because they are digested and metabolised with less energy expenditure. Ruminants have lower k values than do non-ruminants, mainly because of the heat arising from microbial metabolism (heat of fermentation). 

Cohen, D.C., C.R. Stockdale and RT. Doyle, 2006. Feeding an energy supplement with white elover silage improves rumen fermentation, metabolisable protein utilisation, and milk production in dairy cows. AusL J. Agric. Sci. 57, 367-375. 

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