|Galloway Sr, D|
Submitted to: Animal Feed Science And Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/1995
Publication Date: N/A
Citation: N/A Interpretive Summary: Objectives of our experiment were to determine influences of dietary inclusion of broiler litter and level of forage in litter-based diets on feed intake, digestibility and particulate passage rates at different body weights of growing cattle. Rates at which particulates passed from the rumen for broiler litter diets were not influenced by dietary forage level and were greater than for the hay-based control diet at all live weights. Regardless of live weight, increased total organic matter intake compensated for low organic matter digestibility of litter diets, although digestible organic matter intake increased linearly as hay level in litter diets was raised from 0.3% of live weight to 0.6 and 0.9%. Optimal forage level in broiler litter-based diets for high digestible organic matter intake by growing steers did not appear to vary with live weight and may have been 0.6% live weight (i.e., 15% of dry matter intake) or greater. That digestible organic matter intake was only slightly less with the lowest level of forage compared with higher levels implies that as long as a minimum level of dietary roughage is employed, differences in forage level in broiler litter-based diets should not greatly alter digestible organic matter intake. Hence, stringent control of dietary forage level would not appear necessary. Accordingly, the absence of significant interactions between live weight and dietary forage level in digestible organic matter intake indicates that it is unnecessary to alter roughage level as live weight of growing cattle increases. Changes in digestible organic matter intake with increasing live weight should be the same for diets high in broiler litter as with more typical forage-based diets.
Technical Abstract: 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-wk periods 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 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<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 0.55 kg/d for control, L, M and H, respectively). Digestible OM intake did not differ between control and litter diets but increased linearly (P<0.05) as level of hay in litter diets increased (3.91, 3.81, 4.05 and 4.06 kg/d for control, L, M and H, respectively; SE 0.067). Particulate passage rate for Yb-labeled hay was greater (P<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 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 0.6% BW (i.e., 15% of dry matter intake) or greater.