It takes 0.5 gallon of cream to make 1 pound of butter. How much butter could you make with 0.25 gallons of cream? How much cream would you need to make 2.5 pounds of butter?
To make 1 pound of butter, you need 0.5 gallons of cream.
Therefore, to make 0.25 gallons of butter, you would need 0.25 / 0.5 = <<0.25/0.5=0.5>>0.5 pounds of butter.
To make 1 pound of butter, you need 0.5 gallons of cream.
Therefore, to make 2.5 pounds of butter, you would need 2.5 * 0.5 = <<2.5*0.5=1.25>>1.25 gallons of cream. Answer: \boxed{1.25}.