In Sacco and In Vitro Organic Matter Degradability (OMD) Of Selected Semi Arid Browse Forages

Abstract

Organic matter degradation of Acacia nilotica, Acacia sieberiana, Annana senegalensis, Balanites aegyptiaca, Cassia sieberiana, Combretum leati, Faidhebia albida, Maerua angolensis, Prosopis africana and Vitex doniana using two different techniques: (i) the in sacco nylon bag degradation and in vitro gas production techniques. Samples were incubated in sacco and in vitro for 24, 48, 72 and 96 h. In sacco and in vitro OM degradation kinetics were described using the equation Y=a+b(1-e -ct ). The dry matter (DM) and crude protein (CP) were relatively high ranging from 934.00 to 984.60 g Kg -1 DM and 122.50 to 174.80 g Kg -1 DM in Cassia sieberiana and Acacis nilotica had the highest value (216.60 and 910.30 g Kg -1 DM for as and organic matter (OM) The highest value for neutral detergent fibre (NDF) and acid detergent fibre (ADF) was observed in Vitex doniana. The acid detergent fibre was generally high ranging from 86.40 to 144.70 g Kg -1 DM. The OM disappearance increases with increasing incubation time in all the browse forages ranging from 28.56 in Balanites aegyptiaca at 24 h to 76.53 in Combretum leati at 96 h. The OM degradation constant (a, b, a+b, lag T and ED) were all significantly different (P<0.05) except 'c' values. The cumulative gas production was generally low for all the browse forages Acacia sieberiana and Cassia sieberiana having the lowest (9.66 ml/200 mg DM) and Vitex doniana having the highest value (22.66 ml/200 mg DM) at 96 h incubation. In vitro gas production constant showed significant difference (P<0.05) except for rate of constant 'c'. It was concluded that in sacco OM disappearance parameters of browse forages such as the samples used in this study may be predicted from in vitro gas production parameters.