308. The freezing-point of milk: II. The influence of various factors and their bearing on the detection of added water

Abstract

The results of a series of determinations of the freezing-point depressions of the milk of the individual cows of a Shorthorn herd over a period of 16 months are reported.The relative constancy of the freezing-point was confirmed, all but two values deviating by less than 4·5% from the mean Δ values.Significant seasonal trends were observed, especially during the spring when the supply of ample amounts of young grass may cause the production of milk with somewhat smaller freezing-point depressions.Systematic trends in the differences between the Δ of morning and evening milk were found, the evening values being generally higher, except for the winter period, during which the cows were housed at night, when the morning Δ values became the higher. The differences appear to depend on the changes in the temperature of environment to which the cows are exposed. These observations provide an explanation for the discrepancies reported in the literature.