Laboratory analyses of the nutritional value of western Queensland browse feeds

Abstract

Seventy samples of browse feeds, collected during late autumn and spring of 1971 from 42 western Queensland shrubs and trees, were subjected to laboratory analyses of the proximate fractions and in vitro digestibility. Crude protein, crude fibre and nitrogen-free-extract fractions ranged between 65 and 242, 55 and 353 and 425 and 71 1 g kg-1 dry matter, repectively. The in vitro dry matter digestibility coefficients ranged between 0.22 and 0.86. Comparisons of 15 browse feeds collected in April-May and October indicated a higher crude protein content (P < 0.05) and in vitro digestibility (P .= 0.01) and lower crude fibre (P < 0.01) and ash (P < 0.01 ) content in spring samples for most species. Nine browse feeds of known in vivo dry matter and organic matter digestibility were subjected to in vitro digestibility analysis. Whilst the in vitro and in vivo dry matter digestibilities were similar (0.43 and 0.45, respectively) the mean in vitro organic matter digestibility was substantially lower than the corresponding in vivo digestibility (0.40 and 0.46, respectively).