Simplified method for alkali treatment of low-quality roughages for use by small-holders in developing countries

Abstract

The method described is a modification of the soaking procedure of Beckmann and of Torgrimsby. As the effluent NaOH solution is successively replenished and re-used many times before being discarded, pollution is minimised. Furthermore, the amounts of water and alkali consumed are smaller than with the Beckmann method, and the same container is used for all treatments and washing. The method is adaptable to small-scale farming. In Experiment 1, Cynodon hay was treated with 0, 50 or 100 kg NaOH/tonne dry matter (DM), by a modification of the Beckmann method. Significant ( P < 0.01) improvements in digestibility of dry matter (DM), organic matter (OM), and cell wall constituents (CWC) were obtained, and voluntary feed intake was raised significantly ( P < 0.01). In Experiment 2, both NaOH and Ca(OH) 2 treatments at 0, 50, 100 and 150 kg alkali/tonne DM of maize stover, significantly ( P < 0.01) increased DM and OM digestibility, but the response was greater with NaOH. A combination of NaOH and Ca(OH) 2 treatments had no consistent effect on digestibility, but the trend was a decline in digestibility when Ca(OH) 2 was applied at high rates of 100 and 150 kg Ca(OH) 2/tonne DM. The recovery of DM increased with Ca(OH) 2 treatment, but decreased with NaOH. In Experiment 3, the treatment of maize stover with 0, 25 or 50 kg Ca(OH) 2/tonne DM, in combination with 0, 100 or 150 kg NaOH/tonne DM, significantly ( P < 0.01) decreased DM, OM, and CWC digestibility below that achieved by NaOH alone. It is concluded that with the modified method an initial allowance of 100–150 kg NaOH/tonne DM of stover and replenishment of 40–60 kg NaOH/tonne DM is optimal.