For dairy farms, it is of great importance to insure the appropriate hygienic status of milk and to examine it regularly. Escherichia coli, belonging to the coliform bacteria type of, is a good indicator of contamination, and therefore suitable for characterising the hygienic condition of milk production.
The aim of our research was to examine the connection between the Escherichi coli count in bulk tank milk and housing and milking technologies of different-sizes farms. We examined the relation using various statistical methods.
Analysing the connection between the E. coli count and the farm size we found no significant difference between the farms. On the basis of the mean values of the E. coli count, we can say that the hygienic conditions are appropriate for mid-sized farms, and tolerable for large farms. We found differences in the hygienic status among the small farms. Half of the eight small farms, had no adequate hygiene. The results of the analysis of the quality categories show that the probability of inadequate quality milk was the largest on small farms (37.5%).
Comparing the various housing and milking methods with each other, there were numerical differences in the E. coli count, but these differences were not significant. We got higher E. coli count values on those farms using tied stall barn and bucket milking installation. The reason for this could be that in cases of farms using bucket milking installation, it is harder to meet the requirements.
After forming groups by farm size, housing and milking methods, we found that the E. coli counts are adequate on mid-size farms using various housing and milking methods; and tolerable on those large farms using loose housing stable and a milking parlour. At the same time, we found inadequate E. coli counts on the smaller farms using tied stall barns and bucket milking installation.
The results show that if there is suitable attention, independent of farm size, housing and milking procedure, it is possible to produce milk with low E. coli counts, and to insure appropriate hygienic conditions.
Further detailed examinations are needed to decide which factors of housing and milking technologies influence the E. coli count of bulk tank milk.