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Effects of endosperm vitreousness and kernel processing of corn silage on fiber and starch metabolism
Abstract
Three corn hybrids with different endosperm types (flinty, intermediate, floury) were chopped (nonprocessed: 0.95 cm or processed: 1.91 cm chop at a 1-mm roller clearance) for silage. Kernel processing eliminated whole kernels. Processing reduced the medium particle fraction (0.95 to 1.91 cm) resulting in an increased small particle fraction (<0.95 cm). Floury compared with flinty silage resulted in a greater small particle fraction. Processing numerically increased starch content of small particles, and NDF and ADF content of medium particles. Flinty compared with floury silage increased in vitro and in situ NDF digestibility of small particles. Ruminal digestion kinetics of processed versus nonprocessed, and flinty versus floury silage were compared using a standard and a new macro in situ procedure. The standard procedure showed a reduction in NDF digestibility for floury compared with flinty silage. The macro procedure resulted in an increased DM digestibility for processed compared with nonprocessed silage, and an increased DM digestibility and decreased NDF digestibility for floury compared with flinty silage. Eight cannulated, multiparous (BW = 649 kg) and four primiparous (BW = 638 kg) Holstein cows were used to evaluate effects of kernel processing and endosperm type of corn silage on digestibility and milk production. A replicated 4 x 4 Latin square with a 2 x 2 factorial arrangement of treatments was used. Processing improved daily milk production (9.9%), 4% FCM (8.3%), efficiency of 4% FCM produced (12%), and starch digestibility (8.9%), while reducing (14.7%) NDF digestibility. Floury endosperm corn silage improved efficiency (5.1%) of 4% FCM production, and DM (7.5%), OM (8.3) and starch (6.4%) digestibilities. Milk production and feed efficiency can be improved by kernel processing corn silage. Furthermore, selecting floury verses flinty endosperm hybrids can increase milk production efficiency. Changes in physicochemical characteristics of particles result in improved ruminal and total tract digestibilities with processed and floury endosperm silages. Therefore, when formulating lactating dairy cows diets, endosperm type and processing method need to be considered.
Subject Area
Livestock
Recommended Citation
Fanning, Ki C, "Effects of endosperm vitreousness and kernel processing of corn silage on fiber and starch metabolism" (2002). ETD collection for University of Nebraska-Lincoln. AAI3056689.
https://digitalcommons.unl.edu/dissertations/AAI3056689