The earliest use of “growler” in print found so far (by etymologist Barry Popik, who has an entire page devoted to “growler” at barrypopik.com) comes from 1883, and there has been considerable debate as to the origin of the term. The explanation most frequently offered is that “growler” originally referred either to the sound the full pail made being shoved down the bar or, less plausibly, to the sound made by the escaping bubbles in a bucket full of beer. (Personally, I’d say that if your beer seems to be growling at you, it may be time to take a very long nap.) It’s also been suggested that “growler” refers to the cranky (or worse) temperament of someone who has consumed an entire pail of beer.
Researcher Gerald Cohen, on the other hand, has come up with what strikes me as a more likely origin. Noting that an alternate form of “rush the growler” back in the 1800s was “chase the duck,” Cohen suggests that the original metaphor behind such phrases was that of a hunting dog dispatched to find and retrieve a downed fowl. In “chase the duck,” the command to the “fetcher” is obvious. In “rush the growler,” the “growler” is the dog urged to fetch the prey quickly. Cohen’s theory seems entirely plausible, and I’d be willing to bet a bucket of beer that he’s right.
I found this on The Word-Detective.com.
Still no definite answer but I hope it helps.