Alicia, the simple reason that vegetable fats are used in "the other stuff"
is that they are cheaper. Animal fats, esp. dairy fat, can be sold as ice
cream and butter, which returns more on the investment than hiding this stuff
in baby food. Plant-based fats are cheaper to grow, harvest and extract, and
therefore sell. I believe they also have longer shelf-lives, but don't quote
me on that one.

I've tried unsuccessfully to find evidence that vegetable fats have been
thoroughly studied and shown to be both safe and effective replacements for
mother's milk fats (which are animal fats). The Infant Formula Act of 1980
regulates the gross minimum amount (no pun intended) of nutrients in ABM, but
does not specify the sources from which these nutrients derive. And only
"regular" formulas are regulated at all - the specialty ones are not
regulated by any law that I know of. (makes ya wonder, don't it???) The
scariest idea for me is that finding the "ideal" ABM is an essentially
uncontrolled experiment.

Fats are important in immune function and brain growth - 1/3 of the dry
weight of the human brain is fat. Babies' brains are only 25% complete at
birth; by age 4 they are up to 81% finished.  As humans, our #1 skill is
brain power. What do you want going in there to build the structure?  Ever
see a smart soybean?

Marsha Walker may have more on this, and so might Martha Brower (are you
reading this, MW and MGB?)

Linda Smith, getting more skeptical the more I read about manufacture of ABM.
private practice, Dayton OH