I like the premise of this short: Captain Grogg has gotten fat, and he wants to find a way to shed some weight. The first part of it is just him thinking about ways to do just that, and it seems more like a way for Bergdahl to play around with animation than to entertain the audience.
The next part is Grogg trying to climb a big horse. Here Bergdahl misses the opportunity for more gags by having Grogg just standing around a bit too much, but the scene ends nicely. Or that is: there is another separate ending that might have been added for some redemption purposes? It's quite out of place, but I guess Bergdahl wanted to end it with Grogg doing something good, rather than being angry.