The use of live microorganisms as feed supplements for ruminants is not a new concept.
The use of microbial preparations has been largely based on empirical observations that suggest that some types of live microorganisms in feeds may beneficially influence animal performance in many types of production systems.
Relatively speaking, large-scale applications of live microorganisms in feeds were not common historically.
However, in the two last decades, the potential roles of specific microbial supplements have been better defined and there has been considerable interest in using preparations containing live microorganisms as feed supplements for ruminants (Dawson, 2002).
The original concept of administering microorganisms to animals involved the feeding of large amounts of “beneficial” microbes to livestock when they were “stressed” or ill.
Microbial products used in this manner were originally called “probiotics”, or products “for life.”
However, the term “probiotic” implied a curative nature. In the U.S., claims by a product to decrease mortality, to improve
health, or to increase production (e.g. increased milk production or dry matter intake) cannot be made of any product unless its safety and efficacy have been documented and approved by government regulatory agencies.
Thus, to overcome this requirement, the feed industry in conjunction with regulatory agencies, has accepted the more generic term of “Direct-Fed Microbials” (DFM) to describe microbial-based feed additives.
In addition, a list of accepted microorganisms for use in animal feeds was developed.