Factors affecting the freezing point stability of milk from individual cows

Abstract

The effect of breed, parity, lactation stage, interaction of year and period, rumen protein balance (RPB) group and somatic cell count (SCC) on the freezing point (FP) of milk from individual cows was estimated. One hundred and thirty cows of the Estonian Holstein, Estonian Red, Red-and-White Holstein and Estonian Native breeds were sampled once or twice a month for 2 years for the measurement of test-day milk yield, milk composition, urea content, SCC and FP of milk. Of the factors examined, parity and SCC did not influence milk freezing point. Maximum FP differences for each of the factors studied were as follows: 0.0022 °C for breed, 0.0032 °C for lactation stage, 0.0053 °C for interaction of year and period and 0.0062 °C for RPB group. Interpreting the milk freezing point data, primarily the possible effects of season and diet, and the combined effect of them should be considered.