Nutritive value of green forage and crop by-products of Cynara cardunculus

The nutritive value of cardoon (Cynara cardunculus L.) green forage (GF), d ry leaves (DL) and straw (S) was studied from chemical composition analyses and from voluntary intake, digestibility and rumen degradability estimatio ns obtained using adult wethers. Aptitude For bring ensiled according to th e wilting period was also evaluated making silages with fresh forage and af ter 24 and 94 hours of wilting. Green forage had a high nutritive value, as shown by low levels of fibre and lignin and its very high digestibility (8 6 % for OM). Nevertheless, its voluntary intake was relatively low (64 g DM .kg(-1) LW0.75), although very variable among animals. Fermentation charact eristics of the GF silages were good and wilting reduced silage losses and improved the duality of silages. Nutritive value of DL was high, but limite d only by a moderate crude protein content. Supplemented with urea, it had an OM digestibility similar to a medium-good quality hay (65.9 % average) a nd a voluntary intake equivalent to a good quality grass (75.9 g DM.kg(-1) LW0.75). Finally, S was a typical fibrous and low protein forage, but when supplemented with urea, it had an intake and a digestibility higher than th ose of cereal straws. Variations in digestibility for OM and energy among t he different non-preserved Cynara cardunculus forages showed close relation ships with fibre fractions, especially with the acid detergent lignin conte nt." ((C) Elsevier / Inra).