SILAGE BAGGER IMPROVES CSPS, BUT WHAT ABOUT peNDF?
In a recent study we had the opportunity to determine the effect of a silage bagger on the Corn Silage Processing Score (CSPS) of two corn silage hybrids. We bagged BMR and non-BMR (conventional) corn hybrids for a silage feeding trial last fall (2012). We packed fresh chopped whole plant corn in two- gallon buckets at a density of 42 lbs/ft3 as fed at the same time as filling the silage bags. Both silages fermented for over 150 days before being sampled for CSPS and peNDF. The effect of fermentation solublizing and softening the kernel fragments in the silage should have been similar between the buckets and silage bag samples. In other words we were not comparing green chopped corn kernels to fermented ones.
The CSPS is the percentage of starch in particles smaller than 4.75mm upon dry sieving. A score of >70% is optimal, 50-70% is average and <50% is inadequate kernel processing for good starch digestion. The CSPS results are shown in Table 1. The action of the silage bagger fingers packing corn silage into the bag definitely reduced kernel particle size, thereby improving the CSPS scores from “low” average to nearly optimal. We also looked at the effect of the bagging process on the pef of each silage, the proportion of DM larger than 1.18 mm upon dry sieving, used to calculate peNDF. (See Table 2.) Surprisingly, the silage bagger only slightly reduced pef of the silage for both hybrids, from 0.93 and 0.94 to 0.92 each. However, the proportion of DM larger than 3.35mm was reduced by the bagging process, from 0.70 to 0.62 for the BMR and 0.67 to 0.63 for the conventional corn silage.
The silage bagging process definitely reduced kernel particle size of fragments larger than 4.75 mm, resulting in increased and improved CSPS, and in theory improving starch digestion in the cow. Regarding the forage particles, technically the silage bagging process did not affect the pef value of the silages; it did not increase the proportion of fine forage particles smaller than 1.18mm. However, it did reduce the percentage of particles larger than 3.35mm, creating smaller particles. This could possibly result in decreased chewing behavior, which is really the true measure of peNDF.
Fermentations and silage pH were similar between the bagged and bucket (non-bagged) silages. Action of the silage bagger mashing silage into the bag definitely reduces particle size of both corn kernels and forage fiber.
Table 1. Corn silage processing scores, % starch less than 4.75 mm,
of bagged and non-bagged corn silage.
Table 2. Percentage of DM larger than 1.18 and 3.35mm upon dry sieving,
(physical effectiveness factor; pef)
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