Forage particle length affects many aspects of rumen function as
well as dry matter intake (DMI). Regardless of current milk
prices, input costs or other variables, milk production remains
a dairy producer’s highest priority, and DMI is fundamental to
achieving high milk production. Maximum DMI can only be reached
by maintaining optimal rumen fermentation through proper diet,
mixing and feeding. To understand how forage particle size
impacts rumen health and DMI, it’s helpful to understand how the
rumen works.The rumen acts as a fermentation vat. The rumen
microbial population is responsible for fermentation and is
sensitive to changes in rumen pH. Proper pH is needed to
optimize the number of microbes and increase digestibility.
Rumination or “cud chewing” produces saliva, which helps
maintain rumen pH. Consumption of too-finely processed forages
decreases rumination. Diets with too many small particles result
in feed spending less time in the rumen and less microbial
digestion. This can reduce digestibility