DHA and grass fed cows

Confession -- I was trying to learn about self-tanning lotions.  A review website said the active ingredient is DHA (dihydroxyacetone).  So I googled DHA and read the entry on Docosahexaenoic acid on Wikipedia.  (Randy Pausch, author of The Last Lecture, says Wikipedia is OK, at least in comparison to Encyclopedia Britannica.) 

I don't think this is the same DHA - Docosahexaenoic acid is an Omega-3 fatty acid -- but the entry contained this interesting bit:

There is less DHA available in the average diet than formerly, due to cattle being taken off grass and fed grain before butchering; likewise, there is less in eggs due to intensive farming. DHA is widely believed to be helpful to people with a history of heart disease, for premature infants, and to support healthy brain development especially in young children. Some manufactured DHA is a vegetarian product extracted from algae. Both types are odorless and tasteless after processing.

The cited source for this paragraph is a New York Times article describing Martek Bioscience's vegetarian source DHA.

I still haven't learned anything about hte DHA in self-tanning lotions.