Skin surface lipids of the cow.

1. Lipids extracted from the skin surface of cows (Bos taurus) with chloroform were analyzed by quantitative thin layer chromatography and found to contain at least 12 classes of lipids. 2. The major constituents were, in order of increasing polarity: cholesteryl esters, 3%; wax diesters Type I, 37.9%, wax dieters Type II, 7.9%; wax triesters, 29.9%; and triglycerides, 3.6%. 3. Each of the remaining constituents formed less than 5% of the lipid mixture and appeared to be derived from the above materials by loss of acyl groups. 4. With the exception of the triglycerides, all of the aliphatic constituents were composed of saturated, unbranched hydrocarbon chains having an even number of carbon atoms. 5. The triglycerides contained a high proportion of mono- and di-enoic C18 acids, suggesting that they are derived from the epidermis rather than from sebaceous glands.