Impakt of the Number of Somatic Cells on Milk Quality

Abstract

One of the indicators of the hygienic quality of milk is the number of somatic cells, which is an internationally recognized parameter for the health condition of the udder. The increased number of somatic cells over 400.000/ml causes changes in the secretion and the chemical composition of the milk. In this research, based on the number of somatic cells, the milk is categorized in three categories. In milk from the first category the average number of somatic cells equals 444.780/ml, 825.560/ml in the second and 1,242.220/ml in the third category. In milk from the first category the average contents of milk fat, proteins, lactose, dry matter, casein and whey proteins are 4.206%, 3.268%, 4.723%, 12.127%, 2.910%, 0.8610% respectively. In the second category 4.106%, 3.192%, 4.349%, 11.647%, 2.665%, 0.9680%, and 3.989%, 3.139%, 3.964%, 11.092%, 2.386%, 1.1820% in milk from the third category. The pH value of milk in the first, second and third category is 6.627, 6.799 and 6.897 respectively. Between the three categories of milk, significant differences, at the level of (p<0.01), are determined in the number of somatic cells and average contents of milk components. A positive correlation in all three milk categories exists between somatic cells and the whey proteins, and a negative correlating dependency exists between the other chemical parameters and somatic cells.