Effects of urea, bermudagrass hay and molasses additions to and covering of deep-stacked broiler litter on nutritive value

Broiler litter was deep-stacked with bermudagrass hay (Cynodon dactylon) or molasses added singly at 0, 5, 10 or 20% (dry matter; DM;) or in I:I (DM) mixtures at 0, 10 or 20% (DM). Urea was included at 0, 2.8 or 5.6% (DM) and substrates were placed in duplicate dacron bags in the center of deep-stacks of broiler litter with the same levels of urea either covered with plastic or left open. Recovery of neutral detergent fiber (NDF; ash-free) was decreased more (interaction; P<0. 05) by urea with open than with covered litter and was less (P<O.05) for 5. 6 vs 2.8% urea (67, 58 and 54% with open litter and 75, 60 and 56% with covered litter for 0, 2.8 and 5. 6% urea, respectively; SE 1.2). Molasses addition decreased (P<0.05) and 10 or 20% bermudagrass inclusion increased (P<0.05) NDF recovery (62, 56, 56 and 55% with molasses and 62, 62, 68 and 73% with bermudagrass at 0, 5, 10 and 20%, respectively; SE 1.4). Recovery of neutral detergent soluble organic matter (NDSOM) was not affected (P>0.05) by treatments with covered litter and with open litter NDSOM recovery was similar between bermudagrass and malasses substrates. Overall, increases in 12-h in situ ruminal DM disappearance due to urea inclusion coincided with changes in concentrations and recoveries of NDF and NDSOM regardless of air exposure treatment and carbonaceous feedstuff source and bevel and treatments other than urea had relatively small effects. Treatment effects on 48-h DM disappearance were small in magnitude. Mixtures of bermudagrass and molasses added to broiler litter resulted in expected changes based on additive effects of singular additions. In conclusion only urea improved nutritive value as assessed by chemical analyses and in digestibility, although changes appeared restricted to solubilization. Source and level of added carbonaceous feedstuff and air exposure treatment did not appreciably alter urea effects.