Corn Stover Replacement with Quercus rugosa Woody Biomass: Growth Performance, Carcass Characteristics, and Meat Quality of Finishing Lambs

This study evaluated the growth performance, blood metabolites, carcass characteristics, meat quality, and economic responses of finishing lambs fed diets in which condensed tannin-containing woody biomass (CTWB) from Quercus rugosa partially or completely replaced corn stover (CS) in the fibrous fraction. Forty-eight intact male Dorper × Katahdin lambs (initial body weight: 33.01 ± 1.23 kg), housed in 24 pens with two lambs per pen, received diets containing 0, 8, 16, or 24% CTWB (CTWB-0, CTWB-8, CTWB-16, and CTWB-24, respectively) for 42 d during 2013–2014. The 24% inclusion level replaced all the CS and supplied a calculated contribution of 6.29 g of condensed tannins/kg dry matter (DM) from CTWB. Dry-matter intake (DMI) was greater with CTWB-24 than with CTWB-0 and CTWB-16 (1.34 vs. 1.17 and 1.18 kg DM/d, respectively; p = 0.021). Growth and gain-to-feed ratio did not differ among treatments (p ≥ 0.240). Blood urea nitrogen concentrations were lower with CTWB-24 than with CTWB-8 (p = 0.014). Carcass weights did not differ (p ≥ 0.779), nor did cooling loss or dressing percentage (p = 0.459 and 0.060, respectively). An overall treatment effect was observed for muscle a* (p = 0.049), without differences between individual treatments; dorsal fat b* did not differ (p = 0.051), nor did water loss, pH, or shear-force measurements (p ≥ 0.103). Calculated diet cost decreased from 0.301 to 0.282 USD/kg DM between CTWB-0 and CTWB-24, but this reduction did not translate into lower total feed cost per lamb (p = 0.150). Carcass income and income over feed cost (IOFC) also did not differ (p ≥ 0.895); IOFC was 205.56 and 202.21 USD/lamb, respectively. Complete replacement of CS with 24% CTWB was accompanied by greater DMI, while no significant differences were detected in growth, carcass weight, or IOFC in this trial with six pens assigned per treatment. These findings do not establish equivalence among diets, and the limited replication means that biologically relevant differences cannot be ruled out.