Greetings Barry,

We did some research on the issue of lactation before birth of offspring, but we did not find any particularly edifying information other than what you already probably are aware of. It has been shown that altered hormone levels can induce lactation before birth, and the Gemara could be referring to such a unique case. We have forwarded the question to a zoologist, and we will get back to you when we hear from her.

Y. Shaw