QUANTITATIVE ANALYSIS IN MILK CYTOLOGICAL TESTS BASED ON ARITHMETIC AND GEOMETRIC MEANS

The aim of this study was to evaluate mathematical tests allowing a more precise statistical analysis of the SCC values contained in a millilitre of milked milk and measured with an electronic counter. The study was conducted on a herd of 800 hf cows (100%) with an average yield of ~9,500 kg of milk, which were kept in cubicles in a free-stall system. The analyses carried out showed that a comparison of the Nelson Philpot coefficient column values with the values of the other parameters and with the course of their curves suggests that the course of the geometric mean and natural logarithm curves was the most similar – but not identical – to the fluctuations in the height of the linear index columns. It should be pointed out, however, that the values of this logarithm turned out to be ~3.7 times greater than the linear coefficient, and the first of these averages was as much as ~50 times greater than the aforementioned coefficient. Despite the ever-increasing number of electronic counters used for quantitative cytological milk tests, the use of field cellular reaction tests (TOK or CMT) will not decrease at all. It is necessary, though, to sample more precisely and to harmonise the data of the linear Philpot index and the interpretation of the former Drury–Reed index. At the same time, since the dairy industry has already accepted the natural logarithm and the geometric mean in milk assessment, threshold values for SCC should also be established for these by means of an appropriate field trial. As it was noted in the study, each of the averages had its advantages and disadvantages; it would be worthwhile to assess the harmonic and quadratic averages similarly (observation under natural conditions).