There have been several attempts to animate Krazy Kat over the years. The earliest Krazy Kat silent shorts were produced by the Hearst Corporation in 1916. George Herriman was not involved in the project and the characters bear little resemblance to the originals.
In 1925, animation pioneer Bill Nolan (who animated Felix the Cat) and Charles B. Mintz took control of the Krazy Kat operation for Colombia and did a series of shorts that bear very little resemblance to the Herriman Krazy Kat. Krazy has a girlfriend and a pet dog and a magic flute.
King Features produced 50 "Krazy Kat" cartoons from 1962-1964, most of which were created at the great Gene Deitch's film studio in Prague. The Deitch shorts were made for television and have a truer connection to the comic strip. The backgrounds are drawn in a similar style, and Ignatz and Officer Pupp are both present.
Oddly, the earlier black and white animations of this series were much truer to the Herriman spirit than the later color versions.
Best of the bunch is this animated Krazy Kat is this 1996 3D tribute. It was directed by Derek Mogford and produced by Spitting Image Productions for King Features in 1996. It's all but perfect aside from the fact that Krazy Kat is male.
Of course what all of these are lacking are the Herrimanesque elements that make the comic strip so unique. The complexity of the plots and characters have been simplified to the point of being mundane, the visual creativity is lost and no one has even attempted to use the Herriman's unique verbal mix of Yiddish, English Spanish and Creole. All this of course just reinforces the greatness of the Comic Strip and underline how difficult it is to faithfully capture it in any other medium.