The phrase "to have a cow" is defined as "to be very worried, upset, or angry about something" in Free Dictionary Online.
Other sources also define it to mean to react very strongly and emotionally. While it almost always is a negative response to stressful news or events, I imagine it might be used under other more positive circumstances.
Many may have become recently acquainted with this expression from "The Simpsons" TV show, as "Don't have a cow" is a catchphrase of the character Bart Simpson.
This source says, without reference, that the phrase is said to have originated in the 1950s, and also may related to the British phase "to have kittens" (Phrase Finder).
My interest was piqued when I was acquainted with some of Gertrude Stein's writings from the movie "Paris Was a Woman". In particular, "A Book Concluding With As a Wife Has a Cow: A Love Story", published in Paris in 1926, (Google Books) caught my attention. The analyses that I heard say that there is little doubt from the context that "to have a cow" equated to having an orgasm. One summary of that analysis appears here.
My question comes down to whether Stein's metaphor is the origin of the phrase as it is currently used. It seems possible that the meaning of "an extreme, emotional reaction" might fall somewhere in the evolutionary path between Stein's usage and the current one. (It's also possible that she simply created a double entendre from an existing phrase.) What I've covered so far doesn't necessarily mean there is a relationship between Stein's metaphor and the more current expression, but it does look like a possibility.
I don't have a good understanding how to pursue this question any further. What I have seen about the origins (as cited above) is that they don't seem to be very certain, and only agree to a possibility about its provenance.
Is Stein's usage related to the current meaning? If so, how did it evolve? How did it come to be associated more with negative reactions. If it originated before Stein used it, what is the source?
Best Answer
The New Partridge Dictionary of Slang and Unconventional English (2008) says:
Speaking of Animals: A Dictionary of Animal Metaphors (1995) by Robert Allen Palmatier says:
WNNCD is Webster's Ninth New Collegiate Dictionary (1983) and O.E. means Old English, but the O.E. must apply to the plain word cow rather than the phrase. (The OED dates cow to Old English.)
This Yahoo Voices article - Idioms Unpacked: "Don't Have a Cow" - also claims it means to (not) give birth to a cow, which would be distressing for a human to do. It lists a number of references at the end, but I've not followed them.
A quick search of Google Books shows this snippet dated 1962 from Field and Stream, Volume 67:
(Care must be taken with Google Books' snippets as they're often mislabelled, but following the story text we find an advert for a "NEW 1963 book of homes", so it's likely from 1962 or 1963.)
Searching Subzin.com, the first film I found to use the phrase was Sixteen Candles (1984):
Edit: Good timing, as the OED have just released an update to the dictionary containing the phrase for the first time. The first quotation is from a 1959 newspaper: