What is grass silage?

Silage is a forage crop that has been preserved through the process of ensiling. It involves the fermentation of plant material, such as grass, to create a highly nutritious feed for livestock. Grass silage specifically refers to the ensiling of grass as the primary forage crop.

During the production of grass silage, the grass is mown and then wilted to a suitable dry matter content (percentage dry matter). Grass is then harvested, where it is chopped into smaller pieces, before being compacted tightly in storage structures, such as clamps, silos or bales. The absence of air creates anaerobic conditions that both promote the activity of “good bacteria” to ferment the crop and restrict the activity of other microbes which could be detrimental to the process. Typically in the UK, several cuts of grass silage are taken per year, during the period from spring to late summer.

The fermentation process is facilitated by bacteria that convert some of the sugars present in the grass into organic acids, the most desirable being lactic acid. This conversion is crucial for preserving the forage and inhibiting the growth of spoilage-causing microorganisms. Lactic acid acts as a natural preservative, effectively pickling the forage and maintaining nutritional quality until it is fed.

What is grass silage used for?

Grass silage is commonly used as a feed for ruminant animals, such as dairy cows, beef cattle, and sheep. Grass silage provides a valuable source of energy, protein, minerals and vitamins for these animals, particularly during periods when fresh pasture is limited, such as winter months or dry spells.

Grass silage serves as an important component of their diet, supplying necessary roughage (fibre) and nutrients for rumen microbial activity and overall animal health. It helps maintain their body condition, supports milk production in dairy cows, and promotes growth and development in beef cattle and sheep.