Addition of carbonaceous feedstuffs to broiler litter before deep-stacking

Different types and levels of carbonaceous feedstuffs mixed with broiler litter were incubated in a broiler litter deep-stack for 3 or 9 weeks to determine effects on nutrient composition, recovery and digestibility. Substrates were ground corn (C), whole corn, ground wheat, molasses (M), bermudagrass hay (B), wheat straw and 1:1 (dry matter) mixtures thereof (excluding whole corn and a B-wheat straw mixture) mixed at 10 or 20% of total dry matter with broiler litter. Broiler litter incubated for 3 and 9 weeks had 110 and 106% (SE 1.2) nitrogen recovery, 98 and 118% (SE 1.0) acid detergent fiber nitrogen recovery, 91 and 85% (SE 0.8) neutral detergent fiber recovery, 132 and 148% (SE 4.1) neutral detergent soluble organic matter recovery and 81 and 75% (SE 1.1) in situ ruminal (48 h) neutral detergent fiber disappearance, respectively. In general, effects of C, whole corn and wheat were similar, as well as were those of B and wheat straw. Nitrogen recovery was increased by singular addition of M; associative effects of mixing M with other carbonaceous feedstuffs occurred; and M effects varied with level of addition and length of incubation (112, 131, 114, 124 and 123% with 10% substrate, and 114, 146, 116, 134 and 135% with 20% substrate (SE 1.50); 113, 133, 114, 124 and 127% with 3-week incubation, and 113, 144, 116, 134 and 131% with 9-week incubation (SE 1.50) for C, M, B, C-M and M-B, respectively). Recovery of acid detergent fiber N was increased by cereal grain inclusion (112, 100, 96, 111 and 107% with 10% substrate, and 125, 106, 84, 110 and 91% with 20% substrate (SE 3.4); 114, 103, 81, 113 and 105 with 3-week incubation, and 123, 103, 100, 109 and 93% with 9-week incubation (SE 3.42) for C, M, B, C-M and M-B, respectively). Molasses inclusion decreased neutral detergent fiber recovery more at 20 than 10% and at 9 vs 3 weeks of incubation (106, 76, 84, 81 and 75% with 10% substrate, and 111, 68, 86, 75 and 70% with 20% substrate; 107, 82, 88, 82 and 80% with 3-week incubation, and 110, 63, 83, 74 and 65% with 9-week incubation (SE 2.13) for C, M, B, C-M and M-B, respectively). Recovery of neutral detergent soluble organic matter generally varied inversely with neutral detergent fiber recovery. Molasses resulted in 48-h in situ ruminal neutral detergent fiber disappearance, greater than expected based on the disappearance of feedstuffs before deep-stacking (3-week incubation: 4, 15, 1, -1 and 4% difference (SE 0.88); 9-week incubation: -12, 3, -13, 1 and 0% difference with 10% substrate, and -10, 9, -11, 0 and 0% difference with 20% substrate (SE 1.21) for C, M, B, C-M and M-B, respectively). In conclusion, molasses addition resulted in a number of changes, suggesting improved nutritive value of broiler litter.