09 July 2022

High quality silage: a must for beef production systems

When compared to grazed grass, grass silage it is quite expensive to produce, usually twice the cost per tonne DM. When taken as part of an integrated grazing system it is good value compared to concentrates and alternative forages.

Grass silage typically makes up around one quarter to one third of total feed dry matter (DM) consumed on drystock farms.

Recent experiences with national fodder shortages have underlined the value of having a good reserve of quality silage available on beef farms. Teagasc national fodder surveys in 2020-21 showed that while the majority of beef farms had adequate silage reserves (i.e. 15-20% relative to winter demand), a cohort of 10-12% of farms are consistently running a significant feed deficit of more than 20% of winter requirements. This is a high-risk strategy, especially during periods of fodder scarcity and high input prices. It is likely to be particularly expensive for these farms to bridge deficits with purchased forage and/or concentrates in the winter of 2022/23.

Early intervention to correct shortages is advised, starting with completing a winter feed budget. While most beef farms have tended to secure adequate supply of silage tonnage in recent years, average silage quality (as measured by dry matter digestibility, DMD) remains consistently poor on drystock farms at 65-67% DMD. The principal challenge for beef producers therefore is to balance the dual objectives of having adequate supply of silage, while meeting feed quality targets for good animal performance.

Defining targets for grass silage production

The three key elements to cost effective grass silage production are:

High grass DM yields for first-cut and subsequent cuts, with high total annual grass yield (>14.0 tonnes DM/ha). Guideline yields are 4.8 t DM/ha and up to 6.2 t DM/ha for silage harvested in mid-May and early June, respectively.
Appropriate feed quality for the category of stock to be fed. This is best measured as digestibility of the crop dry matter (DMD); protein content is also important and is positively associated with DMD. Silage quality is a function of growth stage at cutting (leafy swards have higher DMD than stemmy swards).
Clean, stable feed with good intake potential. This is achieved through good fermentation and can be assessed from silage pH (3.9 to 4.2 for un-wilted crops), ammonia (target less than 9%), and lactic acid (target over 8%) content. High DMD (leafy) swards can be well-preserved with good management.