Troubleshooting concerns associated with direct long cut vacuum grass silage

View the project final report

• 2006 annual report

Commodities

• Animals: bovine, sheep
• Animal Products: dairy

Practices

• Animal Production: feed/forage, winter forage

Direct long cut vacuum grass silage is a technique for forage preservation that is of increasing interest to grass based producers. A one-pass system requiring minimal investment in equipment or infrastructure and minimal manpower it is well-suited to small farms. Popularized in the farm press, there has been limited formal research investigating the process or resultant silage product. Farmers first formed a farmer research group in 2002 to evaluate the equipment and technique on their farms. They and several followers are now adopting the technique. Outstanding questions remain. The grass silage is unusual in its composition and apparently undergoes an atypical fermentation which may indicate an environment for growth of potentially toxic bacteria in the silage. This may be attributable to the use of vacuum rather than mechanical packing to eliminate air at ensiling or to the direct cut that results in higher moisture. Farmers have questions about the importance of the type vacuum technique to the resultant silage. Consensus is that these two inquiries are best answered in a controlled and replicated study which would be at the New England Small farm Institute. The current farmer group evaluating the technique on their own farms for their own operations will provide oversight to this trial.

To determine:

1. Does the type and amount of vacuum applied effect forage quality? Does it affect a. nutritive value? and b. Potentially dangerous microbial growth in wet grass silage?

2. Are there any environmentally harmful silage nutrients lost either as leachate or runoff from silage piles, associated with this technique? Farmers have not observed exudates from their test piles, but it is important to understand if there are significant losses before widespread promotion of the technique.

Answering these questions will address the risks to profitability that have been identified theoretically with grass silage, because Clostridia can be toxic to livestock. It will also validate observations made by farmers that the DLCVGS process results in minimal silage exudates and runoff, making it benign for the environment, particularly surface waters, which are most likely to be contaminated by runoff of silage exudates (biological oxygen demand (BOD) and consequent eutrophication). This will be important to siting of the piles in the farmstead. Resolving these concerns will allow promotion of an effective means to harvest surplus pasture in the spring, contributing to a source of better quality grass nutrients year round and the success of grass-based farming.
3. Our solution is to have the farmers who have had experience with the DLCVGS consult on a replicated study of the technique. The study will be conducted on the grounds of the New England Small Farm Institute. It will measure forage quality changes including clostridial contamination and growth under two vacuum systems. It will also assess runoff, and leaching from the silage piles.

Performance targets:
Between fifteen and fifty farmers will have better information when making decisions about DLCVGS

Milestones:
Consult with experienced farmers
Implement the study
Collect data
Conduct field day
Report