Variability in biochemical composition of milk among three representative breeds of dairy cows from Romania

Abstract

Reported here is a comparative analysis of the milk from three representative breeds of dairy cows from Romania – Maramures Brown (Brună de Maramureş), Romanian Spotted (Bălțata Românească) and Black Spotted Romanian (Bălțata cu Negru Românească) - in terms of SDS-PAGE analysis of the protein distribution, total contents of protein, lipids, lactose, dry substance, somatic cell counts, pH and yield of milk. The Maramures Brown displays the highest percentage of proteins and of dry matter, the lowest yield of milk, the highest amounts of α-lactalbumin and β-lactoglobulin (tied with the Spotted Romanian for the latter) and the lowest serum albumin and immunoglobulin. The Black Spotted Romanian shows the highest yield of milk, the highest content of lactose, the lowest content in lipids and protein and dry matter, the highest content of casein and BSA, and the lowest content of α-lactalbumin and immunoglobulin. The Spotted Romanian shows the highest content of lipids, the highest SSC and the highest proportion of lactoferrin. Positive correlations with r values at 0.6-0.8 are found between the relative contents of various components - α vs. β casein, Ig vs. α casein, Ig vs. βLgb, lactoglobulin vs. lactalbumin, β casein and αLac, BSA vs. β casein and αLac, total protein content vs. dry residue, SSC vs. lactoferrin and β casein. A weak negative correlation is seen between the total lipid content and lactose (-0.6).