4. Silage additives.
In the past decade it has become increasingly common to use silage additives to improve the ensiling process. The choice of additives appears to be sheer limitless if one looks at the large number of chemical and biological silage additives that are commercially available. The UKASTA Forage Approval Scheme of the UK for example lists more than 80 products (Rider 1997). Fortunately, the choice of a suitable additive is less complicated than it seems, because the modes of action of most additives fall within a few categories (Table 1).