Effects of forage level in broiler litter-based diets on feed intake, digestibility and particulate passage rate in Holstein steers at different live weights
Rossi, J.E.; Goetsch, A.L.; Patil, A.R.; Kouakou, B.; Park, K.K.; Wang, Z.S.; GallowayD.L.Sr.; Johnson, Z.B.
Animal Feed Science and Technology 62(2-4): 163-177
ISSN/ISBN: 0377-8401 DOI: 10.1016/s0377-8401(96)00967-4
Sixteen Holstein steers were used in a split-plot experiment to determine influences of dietary inclusion of broiler litter and level of forage in litter-based diets on feed intake, digestibility and particulate passage rate at different body weights. Body weight (BW) at the end of four 3 week periods, separated by periods of 3 weeks or more, was 151 +- 2.3, 190 +- 3.1, 252 +- 3.7 and 298 +- 3.8 kg in Period 1, 2, 3 and 4, respectively. All steers consumed approximately 1% BW (dry matter) of ground corn; bermudagrass (Cynodon dactylon) hay (76% neutral detergent fiber) was consumed ad libitum (Control) or at 0.3 (L), 0.6 (M) or 0.9% BW (H; dry matter); and L, M and H steers consumed ad libitum deep-stacked broiler litter (29% crude protein, 19% ash and 43% neutral detergent fiber). Intake of organic matter (OM) was increased (P lt 0.05) by dietary inclusion of litter in each period (Period 1: 4.20, 4.93, 4.75 and 4.92; Period 2: 5.63, 5.97, 6.43 and 6.64; Period 3: 6.92, 8.05, 8.15 and 8.58; Period 4: 7.89, 9.60, 9.58 and 9.55 kg day-1 for Control, L, M and H, respectively). Digestible OM intake did not differ between Control and litter diets but increased linearly (P lt 0.05) as level of hay in litter diets increased (3.91, 3.81, 4.05 and 4.06 kg day-1 for Control, L, M and H, respectively; SE 0.067). Particulate passage rate for Yb-labeled hay was greater (P lt 0.05) for diets with than without litter, and changed quadratically (P = 0.05) as hay level in litter diets increased (3.45, 5.42, 4.31 and 4.85% h-1 for Control, L, M and H, respectively). In conclusion, optimal forage level in broiler litter-based diets for high digestible OM intake by growing Holstein steers appeared to be at least 0.6% BW (i.e. 15% of dry matter intake).