(a) The board of trustees of a cooperative shall have full power and authority, without authorization by the members thereof, to authorize the execution and delivery of a mortgage or mortgages or a deed or deeds of trust of, or the pledging or encumbering of, any or all of the property, assets, rights, privileges, licenses, franchises and permits of the cooperative, whether acquired or to be acquired, and wherever situated, as well as the revenues and income therefrom, all upon such terms and conditions as the board of trustees determines, to secure any indebtedness of the cooperative to the United States of America or any agency or instrumentality thereof.

(b) A cooperative may not otherwise sell, mortgage, lease or otherwise dispose of or encumber all or a substantial portion of its property unless such sale, mortgage, lease or other disposition or encumbrance is authorized by the affirmative vote of not less than a majority of all the members of the cooperative.