Influence of stage of lactation on the chemical composition and physical properties of sheep milk

摘要

The aim of research was to determine the influence of stages of lactation on the chemical composition and physical properties of sheep milk. The analysis involved a total of 202 milk samples in various stages of lactation (beginning, midpoint, end). Milk analyses included determination of the contents of dry matter, fat, protein, lactose, solids-non-fat, degree of acidity, pH values and freezing point. Data was statistically processed in accordance with the SAS statistics package (1990). Sheep milk contained on average 19.11% total solids, 7.52% fat, 5.90% protein, 4.55% lactose, 11.45% solids-non-fat, Titratable acidity of milk amounted to 9.30degreesSH, ionometric 6.78, and freezing point was -0.566degreesC. In the middle and at the end of the lactation period the contents of total solids, far, protein, and pH value were significantly higher (P < 0.01) than at the beginning. In the same period lactose content and titratable acidity values were significantly lower (P < 0.01).