Milk production with extensively processed silage for increased forage intake and increased resource efficiency

This research project aims at improving the resource-use efficiency of milk cow feed by extensively pretreating silage. The effects of this pretreatment are a higher rumen passage enabling a higher share of energy to be derived from silage and thereby decreasing the demand for additional concentrate components. This is considered to have the effect of lower dependency on (imported) concentrates, which is seen as an environmental benefit. The faster rumen passage will likely result in manure with a higher energy content. In order for this manure not to lead to a larger environmental impact due to methane losses, the manure will have to be treated, e.g. in anaerobic digestion, in order to fully make use of the feed resource. On the other hand, the higher energy content will likely increase profitability of the biogas production.

In a combined field and systems assessment study, the overall impact of a change from untreated to treated silage will be evaluated. Treatment of silage will be tested using a bioextruder. Data on feeding and rumen digestion efficiency will be assessed for feed based on both treated and untreated silage in an in vivo study. Results of the feeding experiment will be used to study the complete value chain of feed production, manure handling, anaerobic digestion and manure/digestate use as biofertilizer using life cycle assessment. Impact on climate and economic results will be assessed using a stepwise production model.

The outcome of this study has large potential for application in Sweden, where milk farmers struggle to improve economics of milk production. At the same time, anaerobic treatment of manure is likely to be more profitable as it is desired to decrease climate impact from current manure handling.