Effects of protected cottonseed meal on reproductive performance of lactating dairy cows

Long-chain polyunsaturated fatty acid (LPUF) supplementation has improved reproductive performance of lactating dairy cows through increased size of ovulatory follicles, increased plasma concentration of progesterone and reduced secretion of prostaglandin metabolite. Among LPUF, linoleic acid was of most interest because of its cholesterol ester formations in low density lipoproteins (LDL) and high density lipoproteins which deliver cholesterol to follicles for steroidogenesis, and its precursor role of prostaglandin F-2 alpha (PGF(2 alpha)). However, the results are quite inconsistent as a substrate or inhibitor of PGF(2 alpha), which is probably the primary cause of mixed results from supplemented fat trials with lactating dairy cows. Further research on the amount of linoleic acid and ratio of linoleic to linolenic acid in fat supplementation would be value.