Location: Dairy Forage Research2012 Annual Report
1a. Objectives (from AD-416):
To determine if ensiling and storing treatments applied to corn stover or the whole corn plant modify the endproduct compostion or in vitro fiber digestibility of this crop residue, and thus, affect its utility for use as a feed for ruminants.
1b. Approach (from AD-416):
Corn stover of 2 different moisture contents and whole corn plant will be ensiled in 3 separate bag silos. Treatments applied to material in each silo will include control (no amendments), inoculant (Lactobacillus buchneri 500), or the L. buchneri inoculant and an enzyme treatment to give a total of 9 treatments, with 3 replicates of each treatment in each silo bag. Corn stover will also be stored aerobically in 4 bales per treatment of control, yeast, Bacillus exotherm inoculant, or wrapped bale treatments. Previous experiments sponsored by ADM suggest that treatments may improve fiber digestibility and increase the feeding value of corn stover to ruminants. The University of Wisconsin-Madison has performed the ensiling and baling in a separate experiment and will provide initial and ensiled samples to ARS. Single composited samples from each treatment replication will be analyzed singly for dry matter, ash, nitrogen (crude protein), neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) composition, one time point for NDF digestibility (e.g., 24 hours) replicated in two in vitro fermentation runs with mixed ruminal microbes, and starch on whole corn plant samples. Ensiled and baled samples will be analyzed for fermentation acids, mold, and yeast counts. Data will be analyzed as a randomized complete block design within silo; bales will be analyzed as a randomized complete block. The unensiled or unbaled material will be analyzed by treatment. The same initial stover and whole-corn plant material used in the bag silos will also be subject to ensiling in experimental silos and analyzed for lactic acid bacteria. The same analyses will be used on the materials from the bag silos, except for NDF fermentability.
3. Progress Report:
This project relates to the following objectives of the parent project: Objective 1: Identify and measure plant chemical and physical characteristics and dietary interactions that may alter nutrient digestibility and excretion by lactating dairy cattle. The project evaluated the interaction of physically effective fiber (peNDF) and fermentability of starch, and their effects on ruminal fermentation and animal performance. In this project, ensiled corn stover and whole-plant corn silage: 1) left untreated, 2) treated with microbial inoculum, or 3) treated with microbial inoculum and enzymes were evaluated for compositional changes, fermentation profiles, and fiber digestibility. Treatments affected corn stover composition, with inoculum and enzymes increasing fiber digestibility. A similar increase in fiber digestibility was not noted in the whole-plant corn silage, but the increased starch content with inoculum and enzymes suggested a better preservation of ensiled organic matter. In a separate study, effects of treatments (untreated, treated with yeast or microbial inoculant, or wrapped in plastic) on aerobically stored bales of corn stover were evaluated. The microbial inoculant and plastic wrapping preserved the organic matter best, though no differences in fiber digestibility were detected. A final report was submitted to representatives of the cooperator.