What is the origin of "woof!"?

The first line of an old question of mine reads: Scottish dogs used to waff

Further on, I quote:

The onomatopoeic waff (17th C) which means to bark or to yelp like a dog is, sad to say, virtually obsolete but its modern-day counterpart, woof (19th C), still thrives.

Chambers's Twentieth Century Dictionary

1. adj Waff waf (Scot.) weak, worthless, paltry
2. n Waff a worthless person
3. n Waff waf (Scot.) a slight hasty motion: a quick light blow: a sudden ailment: a faint but disagreeable odour: a ghost.
4. n Waff waf an obsolete form of wave.
5. v.i Waff waf (prov.) to bark

Source: The English Dialect Dictionary By Joseph Wright

There's nothing new under the sun, people have been bestializing man's behaviour and personality since antiquity, the Scots used the onomatopoeic waff to describe someone worthless, someone who would leave no mark or visible trace of their existence after death.

Hence (1) Waffinger, (2) Waffipoke, sb. a vagabond; a worthless, good-for-nothing person;
(3) Waffish, adj. disreputable; immoral;
(5) Waff-looking, ppl.adj. of a disreputable, suspicious appearance. [. . . ]
- Wauf-like painted women, _^STEVENSON Catriona (1893) xxiii

As can be seen, women were not exempt from being compared to canines. Perhaps wauff-like gave rise to the expression she's a real dog, a highly unattractive and unpleasant girl or woman.

Woof! as an interjection is originated in the American late-night talk show called The Arsenio Hall Show in 1989. Here is the definition and the origin of the expression from The Routledge Dictionary of Modern American Slang and Unconventional English (By Tom Dalzell):

used as a shout of approval, especially as a male declaration of appreciation for a sexually desirable female _{US, 1992}
Originated by television talk show host Arsenio Hall in 1989; the barking is accompanied by a pumped raised hand, fist clenched.

• The woof chorus went through the roof, everybody high-fiving, bopping in glee. — _{Richard Price, Clockers, p. 203, 1992}

The "Wuff, Wuff" sound was based on howlings used at Cleveland Browns (aka "The Dogs") football games:

In Cleveland, Hall's hometown, die-hard fans of the local NFL team, the Browns, are known as "the dogs." And when they root for the team, they "woof." - news.yahoo.com

There is another interesting theory for the origin of woof! and it is also associated with the gay slang term woof!. It is said that woof is first uttered by Madeline Kahn in Mel Brooks' movie Young Frankenstein in 1974.

Some bears say it stems from the actress Madeline Kahn—perhaps not a gay icon, but close enough—in her role as Elizabeth in Mel Brooks’ Young Frankenstein. When the monster wordlessly propositions her, and after an initial shock, she notes the impressive bulge in his pants and exclaims, “Woof!” The same humor and insinuation underlie the term today, which is an apt fit for a bear gathering: an atypical but exciting sexual situation that doesn’t take itself too seriously.

washingtoncitypaper.com