Effect of supplementation of dried distillers grains with solubles on forage intake and characteristics of digestion of beef heifers grazing small-grain pasture.
Sixteen ruminally cannulated, English-crossbred heifers (378 ± 28.4 kg) grazing small-grain pasture (SGP) were used in a completely randomized design to evaluate effects of supplementing different amounts of corn dried distillers grains with solubles (DDGS; 0, 0.2, 0.4, and 0.6% of BW; as-fed basis) on forage intake, digestibility, and rumen fermentation characteristics. The experiment was conducted from April 6 through April 20, 2007. Heifers grazed in a single SGP with supplements offered individually, once daily at 0700 h. Forage and total OM, CP, and NDF intake were not affected (P ≥ 0.21) by DDGS amount. Digestibility of NDF and ether extract (EE) increased linearly (P < 0.001) when heifers consumed more DDGS. Intake of DM (kg/d and g/kg of BW), ruminal volume (L), fluid dilution rate (%/h), fluid flow rate (L/h) turnover time (h), and particle dilution rate (SGP and DDGS) were not affected (P ≥ 0.32) by increasing DDGS supplementation amount. In situ DDGS CP kinetic parameters were not affected (P ≥ 0.25) by increasing DDGS supplementation amount. Forage masticate in situ soluble CP fraction and CP effective degradability increased quadratically (P = 0.01) with increasing DDGS supplementation amount. However, amount of DDGS did not affect forage masticate CP slowly degradable fraction (%; P = 0.39) or degradation rate (%/h; P = 0.63). Rate of in situ disappearance (%/h) for DDGS DM (P = 0.94), forage masticate DM (P = 0.89), and NDF (P = 0.89) were not affected by DDGS supplementation amount, nor was rumen undegradable intake protein (% of CP) for DDGS (P = 0.28) and forage masticate samples (P = 0.93). Ruminal concentration of VFA and ammonia and ruminal pH were not affected (P ≥ 0.21) by increasing DDGS amount. Results indicated that DDGS can be used in SGP supplements without negatively affecting forage intake, digestibility, or ruminal fermentation.
Islas
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Department of Animal and Range Sciences, New Mexico State University, Las Cruces 88003, USA.
Soto-Navarro
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SA
D000641:Ammonia / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000254:growth & development / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004063:Digestion; D004435:Eating; D005260:Female; D005285:Fermentation; D009516:New Mexico; D011897:Random Allocation; D012417:Rumen / Q000502:physiology; D003313:Zea mays
D000641:Ammonia