Unless your business is licensed by the University to use its marks, you should shy away from using any specific logos/marks of the University.
Examples of phrases which are permitted:
Congratulations Cowboys/Pokes on a Great Season!
Good luck Cowboys/Pokes!
Good luck Wyoming Football!
Wishing the Cowboys/Pokes a Great Game!
If these celebratory messages are done through printed advertisements, the retailer or business must not advertise its products and services in the same advertisement (i.e. Go Pokes, Buy Your Snow Chains Here...). Businesses should also avoid phrases such "ABC Company and the Cowboys, what a great season."