Antibiotics rumen additives

In addition to improved, growth responses in young rats, birds, and pigs, it is claimed that supplementing the diet with an antibiotic benefits young calves. As the commensal microorganisms of the rumen play an important role in older animals, it is not unexpected to find evidence that an antibiotic such as aureomycin interferes with the pattern of the normal flora sufficiently to alter the course of microbial digestion in these older animals. ... 

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