Final answer:
The main message highlights the value of cooperation and the efficient use of individual strengths in achieving common goals.
Step-by-step explanation:
The main message for the ox and the donkey is likely to illustrate the importance of cooperation and recognizing individual strengths to achieve a common goal.
This is similar to the example of Jethro and his friends, where the theory of comparative advantage suggests that everyone will benefit if they figure out their areas of comparative advantage.
Here, the principle applied is that working together, with each individual contributing in the area where their productivity disadvantage is smallest compared to others, leads to increased output and satisfaction for all involved.