Toto the Cow?

From The Hanover Theatre web site:

The Wizard of Oz officially opened on Broadway at the Majestic Theatre on January 21, 1903 and became the longest running show of the decade, tallying over 290 performances. Following its Broadway engagement it toured the country until 1911. Toto, Dorothy’s dog, is actually replaced by a cow named Imogene in the 1903 adaptation. This was most likely done because it was easier to fit an actor inside a cow costume than a dog costume, much less attempt to train a dog for the stage.