Effect of pre-stimulation on milk flow pattern and distribution of milk constituents at a quarter level

Abstract

The aim of this study was to investigate milk flow patterns and milk composition in relation to pre-milking udder stimulation. The milk of one quarter of each of the sixteen cows was removed separately and in the course of milking it was divided into six fractions (P – cisternal milk during milking without stimulation and the first 300 ml during milking with pre-stimulation, 0−25%, 25−50%, 50−75%, 75−100%, 75−100%, MS-machine stripping) and into five portions (25%, 50%, 75%, 100%, 100% + MS). Two milkings were performed during two consecutive evening milkings with or without manual stimulation. Pre-stimulation resulted in a reduction of milking time, duration of the increase and decline phase of milk flow, stripping yield, but it increased the peak flow rate as compared to milking without pre-stimulation (<i>P</i> < 0.05). In both fractions and portions the content of fat increased steadily during milking and reached a maximum at MS. Lactose increased from P to 50−75% and then it decreased to MS. Significantly higher fat contents at 25% and 50% portions and in both protein and dry matter at 25% portions were found during milking with pre-stimulation as compared to no stimulation (<i>P</i> < 0.05). The content of fat, protein and dry matter were also higher in both P and 0−25% fractions for milking with pre-stimulation (<i>P</i> < 0.05). Pre-stimulation positively influenced the parameters of milk flow and therefore the efficiency of milk removal and contributed to better distribution of components in milk fractions during milking.