The Analysis of the Cost and Quality of Direct Cut Vacuum Silage for the Northeast

Final Report for FNE10-690

Project Type: Farmer
Funds awarded in 2010: $8,442.00
Projected End Date: 12/31/2010
Region: Northeast
State: Maine
Project Leader:
Seth Kroeck
Crystal Spring Community Farm
Expand All

Project Information


Our goal fort this project was to investigate Direct Cut Vacuum Silage as a viable low cost option for small farms to produce high quality silage to feed their livestock during the winter months. We tested this process using rented equipment from the midwest and compared it to round bale wrap systems currently in use in our area. By making many silage piles in several locations with different forages we were able to assess this silage method and understand the variables that make it successful. The low cost of this method both in capital and operational expense are in many ways balanced against a higher degree of complexity is using it to successfully make silage. Having the opportunity with this grant to explore the variables involved in using this system has allowed us to understand and adopt this system for our farm.


Examine vacuum cut silage as a technique to provide a high quality, economical forage for small to medium sized farms in the Northeast.

Farm Profile
Crystal Spring Farm is located in Brunswick, Maine and produces organic vegetables and natural lamb on 17 acres of cropland and 45 acres of pasture/hay land.

Our technical advisor for this project has been Richard Kersbergen, extension professor and forage crop specialist for the state of Maine. In addition we had two other farmers, Joe Grady of Two Coves Farm in Harpswell, Maine and Steve Sinisi of Old Crow Ranch in Durham, Maine who provided us standing forage on their farms to cut and ensile.

Project activities
Equipment for the project was leased from Alpha-Ag in Illinois and we began cutting silage at Crystal Spring Farm on June 8.

Two fields, one of alfalfa and another of mixed grass/legume (primarily perennial ryegrass and white clover) were cut on this day for ensiling. A section of each field was cut with a mower conditioner, wilted down for several hours, baled with a round baler and wrapped to ensile. Another section of each field was cut using the vacuum silage technique with the flail-type “lacerator”, blown into a forage wagon and transported to a site either in the field or at the farmstead to be piled covered with plastic and ensiled. Sugar was added to the cut forage as it was blown into the forage wagon to help ensure a quick fermentation. As the piles of forage were made a 4”perforated pipe that was connected to a high-volume vacuum pump was placed into each pile. Once the pile was complete it was covered by 2-ply white on black silage plastic and the sides of the plastic were sealed with coarse sand. Once the piles were sealed the vacuum pump was run for 25 minutes and turned off. The vacuum was run a second time 2 hours later in the alfalfa pile. This was the first pile we made and there was some confusion about vacuum process. After running the pump in the piles the pipe was quickly pulled from the pile and the edge of the plastic sealed with more sand. Forage quality samples were taken by our technical advisors at the time of cutting and frozen for transport to the analysis lab.

This process was repeated at both Two Coves Farm and Old Crow Ranch. The forage cut at these farms was of moderate quality and cut from fields that had not been renovated and seeded or many years. Conventional round bale silage as controls were not made at these farms.

Later in the season at Crystal Spring Farm two more cuttings were made using the same two fields and forage crops. This later alfalfa cut was made with a mower conditioner mid-morning and allowed to wilt before being blown into the forage wagon using the “lacerator”. This change was made in the process after silage analysis on the first alfalfa cutting showed it to be unsuccessful. Our technical advisors recommended using a few hours of sunlight to wilt down the moisture laden stems of the alfalfa, thus increasing its sugar percentage and improving he likelihood of successful ensiling.

Time/cost records were only kept during the first day of cutting/ensiling at Crystal Spring Farm due to time restrictions of the participants.

The vacuum ensiling process worked well with one of the six piles that were made. A combination of “learning process” mistakes and environmental conditions caused five of the piles to either not ensile correctly or become spoiled after ensiling.

The successful pile was made from the late season cutting of alfalfa that was cut with a mower conditioner and allowed to wilt. The high moisture content of the alfalfa appears to make this step necessary. The quality of this forage at cutting was 21.2% protein and after successful ensiling this number was 20.9%. While this pile ensiled successfully and was fed out to our ewe flock in January 2011 several results from the analysis show that the process could be improved.

Both lactic and acetic acid levels were lower than optimum as was the ratio between the two. These acids at proper levels demonstrate a healthy fermentation process. pH is another result that is slightly off optimum, running .9 higher, or slightly more basic. The analysis for butyric acid, an indicator of poor quality silage was low, a good sign that the process used maintained and anaerobic condition during fermentation.

The control silage from both fields that was made using the round bale/wrap ensiling system was successful. Looking at the analysis report from these samples they reflect general guidelines for successful silage. Lactic and acetic acid levels were within parameters individually as was the ratio between these two acids. pH fro these bales was also good, and the levels of butyric and propionic acids were very low, signifying a good preservation process.

Of the five piles that did not ensile correctly, three were damaged by birds, (birds damaged the cover by poking holes which broke the seal, allowing air to enter, stopping fermentation), one was opened accidentally and exposed to oxygen one week into ensiling and the last was our first pile of alfalfa. This pile was both vacuumed an extra time (possibly pulling oxygen into the pile after fermentation had begun) and not allowed to wilt, as we found in the later pile to be helpful in increasing the sugar content, thus speeding up fermentation.

The conditions that affected our results on the farm were birds damaging the plastic and a unknowing farmhand opening one of the piles in mid-fermentation. Five piles of six were lost to these conditions

Time cost 1.75 hours to cut and pile 2 acres alfalfa. Using 2010 Iowa Farm machinery calculator at an average rate of $60/hr. for flail chopping (the closest application to running the vacuum silage “lacerator”) this would equal $105 for 8 tons of forage. Which would put our cost of harvest at $.0875per m/cal.


It is important, especially in early cut forage, where moisture levels in the plants are high to use a mower conditioner and wilt for at least 3 hours before lacerating. This allows forage to wilt, increasing its sugar concentration. The higher plant sugar concentration supports early fermentation and the production of lactic and proprionic acids needed to produce high quality forage

The success of the control bales made with the round bale/wrap system support this conclusion as well. They were allowed to wilt for several hours before baling and wrapping

Higher early fermentation rates can also be achieved by adding common sugar at the time of laceration. The lacerator has a device attached to it that meters sugar into the forage as it is being blown into the forage wagon. All of this is work towards a plant sugar content in the silage pile that will support rapid and significant formation of lactic and proprionic acids.

It is also important that silage piles, which are covered with plastic, are protected from bird damage. The piles we made by the barn had no damage, while the pile we made in the field had significant bird damage letting air into the fermenting piles, which resulted in spoiled silage. So either make piles where there is activity or cover piles with a second protective covering to prevent bird damage.


While our success rate was not high this first season we feel that the process was successful and we understand better the variables that will allow us to make silage successfully this coming season. The ease of using this system, combined with the low capital and operating costs we feel work well for our farm scale. As we move forward and try to increase the profitability of our forage based livestock system, we expect vacuum silage to play a vital role.

To make this system work we will cut and wilt forage before lacerating and ensiling it and we will provide protection for the silage piles by locating that at the farm and/or putting additional cover over them to protect them from damage from birds.


Outreach for this project was two presentations of the vacuum silage process.

The first was a field day on October 2nd at Crystal Spring Farm in Brunswick, Maine. There were 15 attendees at this event in addition to our technical advisors and the equipment supplier, Alpha-Ag. We spent 30 minutes looking at the equipment and talking about the process. We then went to the field and cut a few thousand square feet of forage and made a pile.

The second presentation was done by our technical advisor Rick Kersbergen at the Maine Agricultural Trades Show Augusta, Maine on January 12th. The powerpoint document for this presentation is attached.

Project Objectives:

For this project, equipment to produce direct cut vacuum silage will be leased from an equipment supplier- the closest available equipment is in Illinois. In order to better evaluate the direct cut process, our “control” will be to hire a local farmer to make round bale silage from the same fields at the same time the direct cut silage is harvested.

The process involves cutting with a unique simple heavy-duty flail style chopper designed in New Zealand called a “lacerator”. The forage is cut and blown directly into a forage wagon. The filled silage wagon is transported to a silage storage area (can be a close mowed location in a field). Thirty to fifty feet long piles, twenty feet wide are made by dumping the wagons and pushing the material into the long rows. When the plies are approximately half the final height (approximately 4’ to 5’) a four inch perforated PVC pipe is placed the long way on the pile. The pipe is plugged at one end and the pile is completed. A silage grade plastic sheet large enough to cover all of the silage is pulled over the pile and the edges of the plastic are made tight to the ground using soil, sand, lime, etc. A large vacuum pump is attached to the open end of the PVC pipe and air is removed from the silage to create a “shrink wrap” appearance to the pile. Under these conditions fermentation begins creating organic acids that act to lower the pH in the silage pile and preserve the forage as high quality feed.

Forage material to be harvested will come from several different fields, each representing a different mix of grass/legumes. By harvesting from several fields growing different grass/legumes mixes we will be able to describe whether forage type has an influence on quality in the direct cut /round bale silage comparison.

Samples of the material will be taken at harvest time and at time of feeding from the direct cut material and the round bale silage. The samples from the direct cut will be taken as the material is dumped where the piles are being formed. Samples will be taken from the round bale silage using a hay auger at times silage is baled. All samples will be put into airtight containers and placed in a freezer until shipped for analysis. The samples will be shipped for overnight delivery to the testing laboratory, Dairy One Forage Testing Laboratory, Ithaca, New York.

Samples of both types of silage will also be collected at time of feeding, 6 to 8 months after the silage has been made. These samples are crucial and need to be taken carefully to assure we are testing properly collected materials. They will be collected with the advice and suggestions of our technical advisors (Brzozowski, Kersbergen, Stokes). The samples will be placed in airtight containers and stored in a freezer until shipped overnight to the testing laboratory. We will use a wet analysis package along with a fermentation profile to evaluate the types of acids produced. Using the results of the silage analysis a summary of overall quality and feed value will be developed.

The total cost of producing silage is important. By calculating labor, equipment costs and other expenses involved in producing the respective silages a cost per pound of protein and unit of energy will be calculated. This will provide one way to evaluate how important direct cut vacuum silage may be to the small and medium sized farmer. Other observations will be noted such as how convenient is direct cut silage to feed, what is the general acceptance of the animals of the product, what are ways the process could be improved.

We have asked 3 individuals to be our technical advisors and they include:

Richard Kersbergen, Extension Professor, University of Maine (Richard will be our primarily advisor)with input and help from:

Richard Brzozowski, Extension Professor, University of Maine
Martin Stokes, Professor and Chair, Animal And Veterinary Sciences Department, University of Maine
Mr. Kersbergen and Dr. Stokes will provide advice and direction regarding our silage making processes, sampling techniques and review the information we collect.

Mr. Brzozowski will help primarily with the organization of field days and handouts, videos and other outreach efforts we will use to share the results of this project.


Click linked name(s) to expand/collapse or show everyone's info
  • Dick Brzozowski
  • Joe Grady
  • Rick Kersbergen
  • Tom Settlemire
  • Steve Sinisi
  • Martin Stokes


Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.