Minnesota/Wisconsin Engineering Notes

May 2003 Should You Be Your Own General Contractor? Bunker Silo Facer—Why Invest? Making Educated Decisions to Keep Children Safe on Your Farm Sustainable Agricultural Program Calls for Grant Preproposals Checking Frozen Septic Systems to Prevent Future Problems Odor Issues with Onsite Sewage Treatment Systems Daily Crop “ET” Info Available on the Internet Computer Spreadsheet Available for Irrigation Scheduling Resources Calendar

Bunker Silo Facer—Why Invest? Brian J. Holmes, Wisconsin Extension Engineer Bunker silo facers are a form of silage unloader which remove silage from the bunker leaving a smooth face with a relatively low exposure to oxygen. The facer is an alternative to the commonly used front-end loader. Even with good management, it is difficult to leave a relatively smooth face with a front-end loader. Too often, you end up with a rough face with deep fissures in the silage, leading to major dry matter losses (up to 10%) from exposure to air. The difference in loss between that obtained by the front-end loader and the facer is influenced by many factors, including how the forage was ensiled, and how it is removed. An estimate of dry matter loss differences based on silage management is listed in Table 1. These estimates assume that the fewer the recommended practices for silage management are followed, the higher the dry matter loss differences become. TABLE 1. Dry matter loss improvement by using a silage facer versus a front-end loader. Dry Matter Loss Improvement (%) Storage Management Characteristics 1 •Harvest forage in the 60-70% moisture range •Short chop length •Pack forage densely (> 16 lbs DM/cu ft) •Remove 12 inches per day from silo face •Good face management with front-end loader 3 •Harvest forage in the 55-65% moisture range •Long chop length •Pack forage to average density (14-15 lbs DM/cu ft) •Remove 6 inches per day from silo face •Moderate face management with front-end loader 5 •Harvest forage in the 50-60% moisture range •Long chop length •Pack forage to below average density (< 14 lbs DM/cu ft) •Remove less than 3 inches per day from silo face •Poor face management with front-end loader So, can a producer justify the investment in a bunker silo facer? To answer this question, a spreadsheet has been developed to establish the break-even cost that one can use to compare to the actual cost of a facer. Table 2 shows results from the spreadsheet. A producer can afford to spend less than the break-even cost and maintain profitability. The break-even cost of the facer when converted to an annual cost equals the sum of improvement in dry matter loss value, additional labor, additional equipment, and additional fuel use costs. The labor, equipment, and fuel use could actually be savings if the facer operates at a faster rate than the front-end loader. In Table 2, the front-end loader and facer are assumed to remove silage from the bunker at the same rate. There will be no additional cost or savings for labor, equipment or fuel use. A small facer may cost between $3,500 and $5,000. From Table 2, a producer with a small amount of forage using good management (1% DM loss difference) will break-even with the cost of a smaller facer. Larger producers or those using fewer good management practices will have significant profits by investing $4,500 for a facer. For example, a producer with 2,050 T DM stored who improved dry matter loss by 3% would have a $29,667 ($34,167 – $4,500) profit over a 10-year period, or about $2,967/year. TABLE 2. Break-even cost with no additional time required by the facer for forage removal compared to a front-end loader. Increased DM Loss Using Front-end Loader (%) Quantity Stored (TDM) 820 2050 4100 6150 8200 No. of Cows with Heifers 100 250 500 750 1000 - - - - - - - - - - - - - - Break-even Investment ($) - - - - - - - - - - - - - - 0.5 2,278 5,694 11,389 17,083 22,778 1 4,556 11,389 22,778 34,167 45,556 2 9,111 22,778 45,556 68,333 91,111 3 13,667 34,167 68,333 102,500 136,667 4 18,222 45,556 91,111 136,667 182,222 5 22,778 56,944 113,889 170,833 227,778 Other Benefits Benefits of a bunker facer that may be difficult to quantify monetarily include: Elimination of silage chunks which are difficult to meter into a feed mixer from a loader bucket and sometimes don’t blend in the mixer Blending of the forage before placing into feed mixer Particle size is not reduced To access the spreadsheet referenced above or a more extensive discussion of this subject, visit the Wisconsin Team Forage, Harvest and Storage web site at http://www.uwex.edu/ces/crops/uwforage/storage.htm

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