Abstract: This study systematically analyzed the differences in 38 fatty acids (FAs) composition between Jersey and Holstein cow milk using gas chromatography (GC), and built a breed traceability model by integrating principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). The results revealed that the total FA content and the contents of 36 individual FAs in Jersey milk were significantly higher than those in Holstein milk (P < 0.05), with 51%, 22%, and 39% increase being observed in the contents of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA), respectively. Additionally, the contents of n-3 and n-6 FAs in Jersey milk were elevated by 58% and 39%, respectively. PCA identified 21 FAs as markers to discriminate between Jersey and Holstein cow milk using the cut-off of variable importance in projection (VIP) score > 1 with a P value < 0.05, among which C6:0, C8:0, C10:0, C12:0, and C14:0 exhibited the greatest differences between the two milks. Furthermore, Jersey milk demonstrated a lower n-6/n-3 ratio, higher essential fatty acid (EFA) content, and a more favorable linoleic acid (LA)/α-linolenic acid (ALA) ratio compared with Holstein milk. This study provides a scientific basis for discriminating between milk from different breeds of cows and evaluating the nutritional quality of milk.

Key words: Jersey milk; composition analysis; fatty acids; breed authentication; nutritional profiling; milk lipid nutritional evaluation