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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Dairy Forage Research » Research » Publications at this Location » Publication #310258

Title: Effects of silo type on ensiling alfalfa

Author
item Muck, Richard
item Brink, Geoffrey
item Broderick, Glen

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2015
Publication Date: N/A
Publication URL: https://handle.nal.usda.gov/10113/62450
Citation: N/A

Interpretive Summary: When farmers are exploring different options for making silage, capital costs are at the forefront of those deliberations. However, a thorough evaluation must consider the losses and changes in quality that take place in the silo because these may be equally important in determining the true cost of silo storage. Unfortunately there have been no direct comparisons of silo types. For two consecutive years, we simultaneously filled a bag silo, a bunker silo and an oxygen-limiting tower silo, three of the most common types in the U.S., with alfalfa. The following year we emptied all three silos simultaneously over the summer. The losses varied by silo type: bag silo, 11%; bunker silo, 17%; and oxygen-limiting tower silo, 4%. Quality of the silage was affected adversely by losses so that silage quality was highest coming from the oxygen-limiting silo. These results will help farmers and their consultants more accurately evaluate different silo types when they are contemplating adding or replacing silos.

Technical Abstract: Various silo types are used on dairy farms, but there is uncertainty as to how silo type affects losses and silage quality. The objective of this study was to compare three silo types, filled with alfalfa from the same fields and emptied simultaneously, relative to filling rates, dry matter (DM) losses and silage quality. Similar trials were performed in two consecutive years where second cutting alfalfa was harvested in late June and ensiled in three silos: a bunker (4.9 m x 21.3 m x 3.5 m), a bag (2.4 m dia. x 52 m) and an oxygen-limiting tower (4.3 m dia. x 15.2 m). Approximately half of each field in each trial was ensiled in the bunker silo, and a quarter was allocated to the bag and tower silos. All three silos were filled over approximately a 24-h period with target DM concentrations of 35 to 40% for the bag and bunker silos and 45 to 50% for the tower. For each load, weight and times for filling and packing were recorded; a sample of each load was taken for analysis. The following summer, all three silos were emptied over approximately the same dates. Daily silage samples from each silo were composited weekly for analysis, and the weights of all silage removed were recorded whether fed or not. Filling rates (Mg DM per h) were similar across the bag, bunker and oxygen-limiting silos using the established management practices and equipment at the research farm. Over the two trials, average DM losses from the bag, bunker and oxygen-limiting silos were 11, 17 and 4%, respectively, for 14 to 15 months storage. There were few effects of silo type on nutritive characteristics such as CP and fiber fractions of the alfalfa silages in the first year when invisible DM losses varied over a narrow range across silos. In the second year where the bunker silo had the highest invisible losses, CP was reduced and fiber fractions were increased in the bunker silage compared with those in the silages from the other two silos. Small effects in silage fermentation due to silo type were observed in the first year where the DM concentrations were similar across the three silos. In the second year, the best fermentation occurred in the oxygen-limited silo whereas the bunker silo with the greatest losses had evidence of a beginning clostridial fermentation.