Last update: March 26, 2012 12:19:54 PM E-mail Print


Efficient utilisation of Feed Energy


P G Marais

Grootfontein Agricultural College, Middelburg, C.P., 5900.


NOT all the feed energy intake of an animal is available for conversion into the final product; a large proportion is lost in the form of manure and urine. The order size of energy loss through the excretion of manure, urine and methane, etc., varies considerably among the different feeds, but it can generally be said that the sum total of these losses is less for concentrates than for roughage. Further, the metabolizable energy (ME) of concentrates is always utilised more efficiently by the animal for production than the ME roughages. Consequently it is clear that a considerably larger percentage of the feed energy in concentrates in the product (lamb) can be converted than in the case of roughages.

The difference in the efficiency of the utilisation of concentrate-ME and roughage-ME is, however, influenced by the animal's state of production function (maintenance, growth, fat measuring, lactation, etc.). It can be seen in Table 1 that the improvement in ME utilisation, should concentrates instead of roughages be used for maintenance, is only 15 units, while for growth and fattening up it can be as much as 88 units.



It is evident that for the practical application of concentrates and roughages in the mutton sheep enterprise, it does not pay to feed concentrates if the sheep is in a maintenance production function. It does pay if the production function is’ growth and fattening.



Afrino Manual 1986