Does chop length really matter?

Chop length is a critical factor in producing successful silage. Mistakes made during this initial stage can have lasting, irreparable effects.

- Richardt Venter

A high-quality silage mower is essential. The optimal particle length generally falls between 10 and 20mm. Shorter chop lengths allow animals to consume more fodder, but if the silage is too fine it may not adequately stimulate the rumen, causing digestive issues. Conversely, overly long particles can reduce feed intake.

Particle length is one of the most important physical characteristics influencing how efficiently ruminants ruminate, digest, and utilise feed. It affects fermentation, animal performance, rumen function, passage rate, and even silage stability.

Rumen function and rumination

Ruminants require optimal amounts of effective fibre to stimulate key physiological processes, including rumination, saliva production, and rumen motility.

Longer particle lengths increase the amount of effective fibre, helping maintain optimal rumen pH and preventing acidosis. If silage is chopped too finely and fed on its own, ruminants cannot chew adequately, producing less saliva to buffer the rumen. Depending on the intake of other feeds, this can lead to subacute rumen acidosis and reduced fibre digestion.

Density and fermentation