Effect of Season and Stage of Lactation on Certain Polyunsaturated Fatty Acids of Milk Fat

Abstract
Milk samples from individual cows were analyzed monthly for a year by the alkali isomerization-spectrophotometric and lipoxidase procedures for their polyunsaturated fatty-acid content. Linoleate decreased during the first few months of lactation. Other polyunsaturated fatty-acids did not vary with the stage of lactation. Linoleate decreased when the cows were put on pasture. Nonconjugated trienoate and conjugated dienoate increased when the cows were on pasture.