Species Difference in the Composition of Milk with Special Reference to the Northern Fur Seal

Gross composition is given for five samples of milk from the northern fur seal (Callorh,inus ursinus). The major component was fat (43% of the whole milk). Fatty acid distribution by gas chromatography showed more long-chain fatty acids were unsaturated chains h~ the range of 20-22 carbons) than any other species studied: cow, water buffalo~ goat, and sow. Fur seals' milk fat had no fatty acid with chain length less than 10 C. Reducing sugars amounted to less than 0.1%. Casein accounted for about 50% of the total nitrogen. The major casein fraction appears to be fl-casein. The major ash constituents were the same as those found in cows' milk, but the total amounts were less.