Efficiently add builds to all slides in Keynote 6.2
Solution 1:
Under the "format" menu, you should be able to copy the animation you want and paste it for any other object. Does that not work?
Solution 2:
In previous version of Keynote you could add animations to a section of the master, and those would apply to all slides with that master. It appears that Apple in its wisdom has disabled this feature. So the previous answer is correct: the only way to "automate" is to paste the animation into each slide.