Forages and Pastures: Harvested Forages and Forage Quality

Ferulate-mediated lignin/hemicellulose cross linking in grasses reduces in vitro NDF digestibility (IVNDFD). Impact of ferulate cross linking on animal performance was examined in lamb digestibility and dairy cow performance trials using the seedling ferulate ester (sfe) corn mutant that reduces cross linking and improves IVNDFD. Digestibility of control (W23) and 2 near-isogenic sfe (M04–4 and M04–21) silages was determined with lambs fed ad lib and restricted. Each silage was fed to 4 lambs as the sole ingredient. The same silages were fed to lactating cows in 37% corn silage diets formulated for 29% diet NDF and 70% of NDF from corn silage. A 28-d lactation trial was conducted with 14 cows per diet. Feed intake and milk production were determined. Both trials were analyzed as a randomized complete block using PROC MIXED. Orthogonal contrasts were used to compare W23 to sfe lines combined and M04–21 only. The sfe silages had fewer ferulate cross links than W23 (0.96, 0.86, and 0.81% of NDF in W23, M04–4, and M04–21, respectively), but the sfe mutants had higher NDF and ADL, and lower starch concentrations than W23. The IVNDFD of MO4–21 silage after 24-, 48-, and 96-h was greater than W23, while M04–4 IVNDFD was only greater after 24 h. Lamb ad lib silage intake was greater (P < 0.05) for W23 than sfe lines combined, but M04–21 did not differ from W23. Digestibility of DM was greater (P < 0.05) for W23 than sfe at ad lib but not restricted intake, whereas silages did not differ for NDF or starch digestibility at either intake. Lambs were less selective against NDF when fed sfe silages ad lib (P < 0.05) or restricted (P < 0.10). Intake (21.8, 23.4, and 23.3 kg/d for W23, M04–4, and M04–21, respectively) and milk production (38.9, 39.3, and 41.6 kg/d for W23, M04–4, and M04–21, respectively) were greater (P < 0.01) for cows fed the sfe containing diets. Diet refusals indicated cows selected less against NDF in the sfe diets than for W23 diets. The data suggest reduced ferulate cross linking in corn silage had a small positive impact on ruminant performance.