The Volume of the Cream Layers Forming on Holstein and Jersey Milk

Abstract

Summary 1.The comparative creaming properties of milk may vary according to the procedure followed in making the tests. For greatest uniformity and the exclusion of unknown factors the milk was set for creaming within a few minutes after milking in ice water at 2.8° to 4.4°C. The cream layers of different samples showed variations in the cream layer volume and the distinctness of the cream line after two or four hours which were less pronounced after twenty-four hours. 2.The mean depth of the cream layers forming on normal milk from Holstein and Jersey cows was directly proportional to the percentages of fat which they contained. The percentage which the cream layer represented of the total volume of milk was about 4.1 times the percentage of fat. 3.The variations in the cream layer volumes forming on individual samples of Jersey milk were greater than those for Holstein milk. This difference was especially noticeable after two and four hours of creaming. 4.The milk from an individual cow did not possess uniform creaming properties from milking to milking although there was a tendency for the milk from certain cows to give either large or small cream layer volumes or a high percentage of no layer cases. 5.The cream layer volumes on the samples of milk used in these tests were not affected by the season of the year in which the milk was produced. The milk from Holstein cows remained most uniform throughout the year. 6.Variations in specific gravity of milk were not related to changes in creaming properties.