Just to clarify: you can only have 0-2 "Broken Ribs" afflictions at once. The first and second have the same effect (-50% stamina, -25% carry capacity), but the first affliction lasts for 120 hours, and the second for 168 hours.

A third Moose attack still reduces Condition as the Moose is crunching you up, does not apply a third Broken Ribs.