The general concept of inoculating ruminants with beneficial microorganisms
is not a new practice.
For example, many producers and veterinarians have been inoculating sick ruminants (especially those that have been off feed) with rumen fluid
from healthy animals in hopes of stimulating normal rumen function and improving dry matter intakes.
However, there are no controlled research studies that document the efficacy of this practice and there are no commercial products based on this concept.
In contrast, there are many bacterial based DFM that are sold for use in ruminant diets with more specific applications.
These products often contain Lactobacillus spp. being one of the most common microorganisms used.
Other commonly used bacteria include various species of Bifidobacterium, Enterococcus, and Bacillus (Denev, 1996).
Most bacterial-based DFM are probably beneficial because they have effects in the
gut and not in the rumen (Denev et al., 2000; Denev, 2006).