IN VIVO UTILIZATION OF WILTED GRASS SILAGES PREPARED IN THE MARITIME PROVINCES OF CANADA

Abstract

Voluntary intakes and apparent digestibilities of wilted grass silages produced under humid climatic conditions of the Maritime Provinces of Canada were determined from feeding trials with wether lambs during two 24-day periods. The silages included seeding year Italian ryegrass (Lolium multiflorum Lam. ’Lemtal’), and first-cut perennial ryegrass (L. perenne L. ’Norlea’), meadow fescue (Festuca pratensis Huds. ’Trader’), orchardgrass (Dactylis glomerata L. ’Tardus’), and quack-grass (Agropyron repens (L.) Beauv.). Second-cut quackgrass was also included. Dry matter and digestibile energy intakes were not different among the first-cut silages (58.8–65.7 g and 746–848 KJ/kg.75BW, respectively) but were higher (P < 0.05) in comparison to the intakes of the nutrients contained in the second-cut quackgrass silage (49.6 g and 467 KJ/kg.75BW). The two-stage in vitro dry matter disappearance, but not the acid-pepsin solubility determinations on the silage samples dried at 55 °C, were closely correlated with the intakes of silage dry matter (r = 0.90, P < 0.05) and digestible energy (r = 0.98, P < 0.01), and with the apparent digestibilities of these respective nutrients (r = 0.92 and 0.96, P < 0.01). Silage content of acid detergent fiber, in comparison with in vitro dry matter disappearance, was less closely correlated with the apparent digestibilities of dry matter (r = −0.82, P < 0.05) and digestible energy (r = -0.75, P < 0.10).