What was the joke Sutherland started telling?

Yes, I would like to know the punchline also! Casting is great and rapport outstanding between Sutherland & Allen.

Director Philip Kaufman explained the joke on the DVD commentary:

"The English Camel Corp are trapped in the Sahara Desert. They've been surrounded by Rommel for forty days and have run out of food. The Captain makes an announcement to the men: 'Men, I have some good news for you and some bad news for you. The bad news is, we have nothing left to eat but camel poop. The good news is, there's plenty of it.'