title: Effect of forage level and replacing canola meal with dry distillers grains with solubles in precision-fed heifer diets: Digestibility and rumen fermentation.
abstract: Objectives of this study were to determine the effects of feeding differing forage-to-concentrate ratios (F:C) and inclusion rates of corn dry distillers grain with solubles (DDGS) on digestion and rumen fermentation in precision-fed dairy heifer rations. A split-plot design with F:C as whole plot and DDGS inclusion level as sub-plot was administered in a 4-period (19 d) 4 × 4 Latin square. Eight rumen-cannulated Holstein heifers (12.5 ± 0.5 mo of age and 344 ± 15 kg of body weight) housed in individual stalls were allocated to 2 F:C [50:50, low forage, or 75:25 high forage; dry matter (DM) basis] and to a sequence of DDGS inclusion (0, 7, 14, and 21%; DM basis). Forage was a mix of 50% corn silage and 50% grass hay (DM basis). Diets were fed to allow for 800 g/d of body weight gain and fed 1×/d. Rumen contents were sampled at -2, 0, 2, 4, 6, 8, 10, 12, and 20 h after feeding for rumen fermentation measures. Low-forage rations had greater DM and organic matter apparent digestibility. We detected a quadratic effect for DM, organic matter, acid detergent fiber, and neutral detergent fiber apparent digestibility, with the 14% DDGS inclusion level having the highest values. Nitrogen retention decreased with increasing levels of DDGS. Molar proportions of acetate tended to be greater for HF and decreased as DDGS increased; propionate increased as DDGS increased, resulting in the opposite effect on acetate to propionate ratio. Rumen protozoa count decreased as DDGS increased. Moderate levels (14% of DM) of DDGS appear to enhance nutrient utilization and fermentation in precision-fed dairy heifers fed different F:C diets.
authors: Department of Animal Science, The Pennsylvania State University, University Park 16802.
authors: F X
authors: FX
authors: Suarez-Mena
authors: Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634.
authors: G J
authors: GJ
authors: Lascano
authors: Department of Animal Science, Université Laval, Quebec, QC, G1V 0A6, Canada.
authors: D E
authors: DE
authors: Rico
authors: Department of Animal Science, The Pennsylvania State University, University Park 16802. Electronic address: ajh@psu.edu.
authors: A J
authors: AJ
authors: Heinrichs
mesh_terms: D000821:Animal Feed / Q000145:classification* / Q000592:standards; D000818:Animals; D029688:Brassica napus; D002417:Cattle / Q000502:physiology*; D003612:Dairying; D003890:Desiccation; D004032:Diet / Q000662:veterinary*; D004043:Dietary Fiber / Q000378:metabolism; D004063:Digestion; D002523:Edible Grain; D005260:Female; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D012417:Rumen / Q000378:metabolism; D012820:Silage / Q000032:analysis; D003313:Zea mays
keywords: canola meal; dried distillers grains with solubles; heifer diet; precision feeding