Despite the existence of regulatory requirements for the sanitation of milking equipment, the variability of microbiological contamination throughout the year remains insufficiently studied, particularly under conditions of industrial dairy production. Systematic analysis of swab test indicators across different seasons makes it possible to identify patterns in microbial load dynamics caused by changes in environmental conditions and equipment operation, and to substantiate adjustments to sanitation practices. The aim of the study was to assess microbial contamination of milking equipment under different animal housing systems – tie-up and free-stall housing. To objectively evaluate the sanitary condition of the equipment, microbiological analysis of swabs taken from teat cups was carried out in both housing systems. It was established that the level of microbial contamination was consistently higher under free-stall housing conditions in all seasons, exceeding that of tie-up housing by an average of 1,9–2,2 times. The highest total microbial counts were recorded in the summer period (up to 7,2×10³ CFU/cm²), while the lowest were observed in winter. A similar trend was identified for Staphylococcus spp., Enterobacteriaceae, as well as yeasts and molds. It was shown that seasonal changes in microclimatic parameters (temperature, humidity, gas composition, and air movement) have an indirect effect on microbial load formation through changes in the level of primary contamination of animals and the environment. Thus, the housing system is a key factor determining microbial contamination of milking equipment, with freestall housing being associated with higher contamination levels. The obtained results substantiate the need for a differentiated approach to sanitation procedures for milking systems, taking into account housing conditions and seasonal factors.
microbial contamination, milking equipment, seasonal factors, tie-stall housing, free-stall housing, microbial load, sanitary condition
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