COMPARISON OF LIPID-COMPOSITION OF MILK FROM HALF-DANISH JERSEY COWS AND UNITED-STATES JERSEY COWS

We studied differences in lipid composition of milk from Jersey cows w ith US sires and from Jersey cows with Danish sires. Milk samples were obtained on DHIA test day from 32 cows with Danish sires and 32 herdm ates with US sires in two herds, The Jerseys with US sires were paired with those with Danish sires by parity and stage of lactation. Mean p ercentage of milk fat was 5.7% for Jerseys with Danish sires and 4.8% for Jerseys with US sires, Total fat per day was the same (.91 kg) for both groups. Detailed analysis of milk lipids indicated that lipid co mposition of milk was similar for cows with US sires and those with Da nish sires, However, milk from Jerseys with Danish sires contained mor e free cholesterol than milk from Jerseys with US sires, 17.5 versus 1 4.3 +/- .6 mg/dl. The proportion of polyunsaturated fatty acids was gr eater for milk from Jerseys with US sires than for milk from Jerseys w ith Danish sires (2.3 vs. 2.1%). Although lipid composition of milk fr om both groups was generally similar, the milk of Jersey cows with Dan ish sires had higher concentrations of free cholesterol and lower prop ortions of polyunsaturated fatty acids, both of which are possible neg ative factors for health of consumers.