EN
On the basis of reviewed literature it was stated an existing relationship between the amounts of Listeria monocytogenes bacteria and the reaction (pH) of ensiled green fodders. At pH below 4, the silages are mostly free from these microorganisms that may cause different diseases in farm animals and in the people. The silages produced in form of big cylindrical bales are of ten the source of Listeria, because of less convenient fermentation conditions in comparison to ensiling in properly designed silo. Anaerobic fermentation condition are an effective factor eliminating Listeria monocytogenes in final product. The silage of poor quality (high pH value, infested by moulds and fungi) may contain large numbers of Listeria microbes bading to listeriosis in fed farm animals. These bacteria are pathogenic conditionally, their pathogenic propeties are being revealed in the individuals of weak condition, resulted from im proper feeding or negative influence of the environmental factors. The listeriosis in sheep may conduce to serious economic problems in the regions of numerous sheep population.