Abstract

This experiment compares the nutritive value of New Zealand native flax, Phormium tenax, by-products i.e. leaves (L), butts (B), thrash-stripped fibre (F) and green matter (G), with white clover (WC) via digestion kinetics derived from in vitro and in sacco incubations. The WC had a high nutritive quality (11.1 MJME/kg DM, CP 28% DM), G a moderate (10.1 MJME/kg DM, CP 9% DM), and L, B, F were of very low nutritive quality (< 8 MJME/kg DM, CP < 6 % DM). After 24 hours, 96, 76, 47, 47, and 30 % of the DM was degraded for WC, G, L, B and F, respectively (P < 0.001). The degradation rates (%/h) of digestible DM were faster (P < 0.001) for WC (13) and G (11) than B (3.8), L (4.6) and F (2.7). Flax by-products had a net loss of ammonia after 2 (B), 4 (F and L) and 8 hours (G). The proportion of DM converted to VFA by 8 hours was 21 %, and 14 % for WC and G respectively, but only 9-10 % for the other flax by-products (P < 0.001). The feeding model BestFeed™ predicted that G could grow a 500 kg bull at 0.8 kg/day and had potential as a supplement for pasture-fed animals. KEYWORDS: flax; Phormium tenax; in sacco; in vitro; digestion kinetics; nutritive value; forage ration, BestFeed.

AJ, Litherland, DL Layton, JL Burke, DC Corson, and JS Peters

Proceedings of the New Zealand Society of Animal Production, Volume 65, Christchurch, 367-371, 2005