This quote of M. Bateman (1975) starts the chapter on Biochemical
considerations in Jelliffe's book, Human Milk in the Modern World (out
of print):

"It's a bit late in the day to introduce the idea now, but almost any
mammal's milk would be easier to modify than cow's milk. Pig's milk is
actually nearest to human milk. Camel milk and mare's milk have a better
balance for humans. Sheep's milk is OK and so is goat's. Reindeer milk
would be a bit fat, dog's milk a bit thin. Now, otter's could be just
right. Perhaps we should look into it."

I once milked a rat while working in a research position in peds
gastroenterology. She was anesthetized and we got 5 ccs. I can't see
milking a pig - would that be like trying to make a pig sing (it makes
you look foolish and annoys the pig)? Anyone interested in otter
farming? It surely would be better for the ecology not having to devote
so many resources to maintaining dairy herds...Just wondering if it is
still not too late to look into this.

Katharine West, BSN, MPH
Sherman Oaks, CA