Palatability to sheep of the Eragrostis curvula complex. 4. Dry matter production, feed value and persistence of a range of taxa

Abstract

Productivity, nutritive value and persistence of a range of taxa of Eragrostis curvula complex were evaluated in experiments at Wagga Wagga, Temora, Condobolin and Orange, N.S.W. No relationships were found between previously determined palatability ranks and nitrogen (N) content, acid detergent fibre, digestible dry matter (DDM) or metabolisable energy. The nutritive value of stem was lower than leaf; however, if stem is well grazed this is unlikely to affect animal performance. Mean digestible dry matter and nitrogen contents of the E. curvula accessions were similar in the Wagga Wagga (a total of 8 determinations) and Orange (4 determinations) experiments (overall means, DDM = 57.48% and N = 1.65%), but digestibility was depressed in summer by 3.38 units (54.85 v. 58.23% in autumn) for leaf and 2.3 units (53.98 v. 56. 28%) for stem in the Orange experiment, and 4.68 units (56.43 v, 61.11% in spring) for leaf and 8.35 units (49.96 v. 58.31%) for stem in the Wagga Wagga Naturalised Accessions trial. In practice, this would be offset by increasing availability of palatable forage. Except for 1 occasion with stem, the nitrogen concentrations of the herbage (leaf N 2.02-1.45%, stem N 0.79-1.95%) were sufficient not to limit intake. Differences in persistence and dry matter yield indicated that, of the palatable lines, accession 4663 was better adapted to drier situations than 4650, and that accession 4660 was intermediate between the two. It is concluded that the palatable accessions were potentially useful pasture plants for south-eastern Australia.